SkPaint Reference
===
---
class SkPaint {
public:
SkPaint();
SkPaint(const SkPaint& paint);
SkPaint(SkPaint&& paint);
~SkPaint();
SkPaint& operator=(const SkPaint& paint);
SkPaint& operator=(SkPaint&& paint);
friend bool operator==(const SkPaint& a, const SkPaint& b);
friend bool operator!=(const SkPaint& a, const SkPaint& b);
uint32_t getHash() const;
void reset();
enum Hinting {
kNo_Hinting = 0,
kSlight_Hinting = 1,
kNormal_Hinting = 2,
kFull_Hinting = 3,
};
Hinting getHinting() const;
void setHinting(Hinting hintingLevel);
enum Flags {
kAntiAlias_Flag = 0x01,
kDither_Flag = 0x04,
kFakeBoldText_Flag = 0x20,
kLinearText_Flag = 0x40,
kSubpixelText_Flag = 0x80,
kLCDRenderText_Flag = 0x200,
kEmbeddedBitmapText_Flag = 0x400,
kAutoHinting_Flag = 0x800,
kAllFlags = 0xFFFF,
};
enum ReserveFlags {
kUnderlineText_ReserveFlag = 0x08,
kStrikeThruText_ReserveFlag = 0x10,
};
uint32_t getFlags() const;
void setFlags(uint32_t flags);
bool isAntiAlias() const;
void setAntiAlias(bool aa);
bool isDither() const;
void setDither(bool dither);
bool isLinearText() const;
void setLinearText(bool linearText);
bool isSubpixelText() const;
void setSubpixelText(bool subpixelText);
bool isLCDRenderText() const;
void setLCDRenderText(bool lcdText);
bool isEmbeddedBitmapText() const;
void setEmbeddedBitmapText(bool useEmbeddedBitmapText);
bool isAutohinted() const;
void setAutohinted(bool useAutohinter);
bool isFakeBoldText() const;
void setFakeBoldText(bool fakeBoldText);
bool isDevKernText() const;
void setDevKernText(bool);
SkFilterQuality getFilterQuality() const;
void setFilterQuality(SkFilterQuality quality);
enum Style {
kFill_Style,
kStroke_Style,
kStrokeAndFill_Style,
};
static constexpr int kStyleCount = kStrokeAndFill_Style + 1;
Style getStyle() const;
void setStyle(Style style);
SkColor getColor() const;
SkColor4f getColor4f() const;
void setColor(SkColor color);
void setColor4f(const SkColor4f& color, SkColorSpace* colorSpace);
uint8_t getAlpha() const;
void setAlpha(U8CPU a);
void setARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b);
SkScalar getStrokeWidth() const;
void setStrokeWidth(SkScalar width);
SkScalar getStrokeMiter() const;
void setStrokeMiter(SkScalar miter);
enum Cap {
kButt_Cap,
kRound_Cap,
kSquare_Cap,
kLast_Cap = kSquare_Cap,
kDefault_Cap = kButt_Cap,
};
static constexpr int kCapCount = kLast_Cap + 1;
enum Join {
kMiter_Join,
kRound_Join,
kBevel_Join,
kLast_Join = kBevel_Join,
kDefault_Join = kMiter_Join,
};
static constexpr int kJoinCount = kLast_Join + 1;
Cap getStrokeCap() const;
void setStrokeCap(Cap cap);
Join getStrokeJoin() const;
void setStrokeJoin(Join join);
bool getFillPath(const SkPath& src, SkPath* dst, const SkRect* cullRect,
SkScalar resScale = 1) const;
bool getFillPath(const SkPath& src, SkPath* dst) const;
SkShader* getShader() const;
sk_sp<SkShader> refShader() const;
void setShader(sk_sp<SkShader> shader);
SkColorFilter* getColorFilter() const;
sk_sp<SkColorFilter> refColorFilter() const;
void setColorFilter(sk_sp<SkColorFilter> colorFilter);
SkBlendMode getBlendMode() const;
bool isSrcOver() const;
void setBlendMode(SkBlendMode mode);
SkPathEffect* getPathEffect() const;
sk_sp<SkPathEffect> refPathEffect() const;
void setPathEffect(sk_sp<SkPathEffect> pathEffect);
SkMaskFilter* getMaskFilter() const;
sk_sp<SkMaskFilter> refMaskFilter() const;
void setMaskFilter(sk_sp<SkMaskFilter> maskFilter);
SkTypeface* getTypeface() const;
sk_sp<SkTypeface> refTypeface() const;
void setTypeface(sk_sp<SkTypeface> typeface);
SkImageFilter* getImageFilter() const;
sk_sp<SkImageFilter> refImageFilter() const;
void setImageFilter(sk_sp<SkImageFilter> imageFilter);
SkDrawLooper* getDrawLooper() const;
sk_sp<SkDrawLooper> refDrawLooper() const;
SkDrawLooper* getLooper() const;
void setDrawLooper(sk_sp<SkDrawLooper> drawLooper);
void setLooper(sk_sp<SkDrawLooper> drawLooper);
enum Align {
kLeft_Align,
kCenter_Align,
kRight_Align,
};
static constexpr int kAlignCount = 3;
Align getTextAlign() const;
void setTextAlign(Align align);
SkScalar getTextSize() const;
void setTextSize(SkScalar textSize);
SkScalar getTextScaleX() const;
void setTextScaleX(SkScalar scaleX);
SkScalar getTextSkewX() const;
void setTextSkewX(SkScalar skewX);
enum TextEncoding {
kUTF8_TextEncoding,
kUTF16_TextEncoding,
kUTF32_TextEncoding,
kGlyphID_TextEncoding,
};
TextEncoding getTextEncoding() const;
void setTextEncoding(TextEncoding encoding);
struct FontMetrics {
enum FontMetricsFlags {
kUnderlineThicknessIsValid_Flag = 1 << 0,
kUnderlinePositionIsValid_Flag = 1 << 1,
kStrikeoutThicknessIsValid_Flag = 1 << 2,
kStrikeoutPositionIsValid_Flag = 1 << 3,
};
uint32_t fFlags;
SkScalar fTop;
SkScalar fAscent;
SkScalar fDescent;
SkScalar fBottom;
SkScalar fLeading;
SkScalar fAvgCharWidth;
SkScalar fMaxCharWidth;
SkScalar fXMin;
SkScalar fXMax;
SkScalar fXHeight;
SkScalar fCapHeight;
SkScalar fUnderlineThickness;
SkScalar fUnderlinePosition;
SkScalar fStrikeoutThickness;
SkScalar fStrikeoutPosition;
bool hasUnderlineThickness(SkScalar* thickness) const;
bool hasUnderlinePosition(SkScalar* position) const;
bool hasStrikeoutThickness(SkScalar* thickness) const;
bool hasStrikeoutPosition(SkScalar* position) const;
};
SkScalar getFontMetrics(FontMetrics* metrics, SkScalar scale = 0) const;
SkScalar getFontSpacing() const;
int textToGlyphs(const void* text, size_t byteLength,
SkGlyphID glyphs[]) const;
bool containsText(const void* text, size_t byteLength) const;
void glyphsToUnichars(const SkGlyphID glyphs[], int count, SkUnichar text[]) const;
int countText(const void* text, size_t byteLength) const;
SkScalar measureText(const void* text, size_t length, SkRect* bounds) const;
SkScalar measureText(const void* text, size_t length) const;
size_t breakText(const void* text, size_t length, SkScalar maxWidth,
SkScalar* measuredWidth = nullptr) const;
int getTextWidths(const void* text, size_t byteLength, SkScalar widths[],
SkRect bounds[] = nullptr) const;
void getTextPath(const void* text, size_t length, SkScalar x, SkScalar y,
SkPath* path) const;
void getPosTextPath(const void* text, size_t length,
const SkPoint pos[], SkPath* path) const;
int getTextIntercepts(const void* text, size_t length, SkScalar x, SkScalar y,
const SkScalar bounds[2], SkScalar* intervals) const;
int getPosTextIntercepts(const void* text, size_t length, const SkPoint pos[],
const SkScalar bounds[2], SkScalar* intervals) const;
int getPosTextHIntercepts(const void* text, size_t length, const SkScalar xpos[],
SkScalar constY, const SkScalar bounds[2], SkScalar* intervals) const;
int getTextBlobIntercepts(const SkTextBlob* blob, const SkScalar bounds[2],
SkScalar* intervals) const;
SkRect getFontBounds() const;
bool nothingToDraw() const;
bool canComputeFastBounds() const;
const SkRect& computeFastBounds(const SkRect& orig, SkRect* storage) const;
const SkRect& computeFastStrokeBounds(const SkRect& orig,
SkRect* storage) const;
const SkRect& doComputeFastBounds(const SkRect& orig, SkRect* storage,
Style style) const;
};
Paint controls options applied when drawing and measuring. Paint collects all
options outside of the Canvas Clip and Canvas Matrix.
Various options apply to text, strokes and fills, and images.
Some options may not be implemented on all platforms; in these cases, setting
the option has no effect. Some options are conveniences that duplicate Canvas
functionality; for instance, text size is identical to matrix scale.
Paint options are rarely exclusive; each option modifies a stage of the drawing
pipeline and multiple pipeline stages may be affected by a single Paint.
Paint collects effects and filters that describe single-pass and multiple-pass
algorithms that alter the drawing geometry, color, and transparency. For instance,
Paint does not directly implement dashing or blur, but contains the objects that do so.
The objects contained by Paint are opaque, and cannot be edited outside of the Paint
to affect it. The implementation is free to defer computations associated with the
Paint, or ignore them altogether. For instance, some GPU implementations draw all
Path geometries with Anti Aliasing, regardless of how SkPaint::kAntiAlias Flag
is set in Paint.
Paint describes a single color, a single font, a single image quality, and so on.
Multiple colors are drawn either by using multiple paints or with objects like
Shader attached to Paint.
---
SkPaint()
Constructs Paint with default values.
| attribute | default value |
| --- | --- |
| Anti Alias | false |
| Blend Mode | SkBlendMode::kSrcOver |
| Color | SK ColorBLACK |
| Color Alpha | 255 |
| Color Filter | nullptr |
| Dither | false |
| Draw Looper | nullptr |
| Fake Bold | false |
| Filter Quality | kNone_SkFilterQuality |
| Font Embedded Bitmaps | false |
| Automatic Hinting | false |
| Full Hinting Spacing | false |
| Hinting | kNormal Hinting |
| Image Filter | nullptr |
| LCD Text | false |
| Linear Text | false |
| Miter Limit | 4 |
| Mask Filter | nullptr |
| Path Effect | nullptr |
| Shader | nullptr |
| Style | kFill Style |
| Text Encoding | kUTF8 TextEncoding |
| Text Scale X | 1 |
| Text Size | 12 |
| Text Skew X | 0 |
| Typeface | nullptr |
| Stroke Cap | kButt Cap |
| Stroke Join | kMiter Join |
| Stroke Width | 0 |
| Subpixel Text | false |
The flags, text size, hinting, and miter limit may be overridden at compile time by defining
paint default values. The overrides may be included in "SkUserConfig.h" or predefined by the
build system.
### Return Value
default initialized Paint
### Example
---
SkPaint(const SkPaint& paint)
Makes a shallow copy of Paint. Typeface, Path Effect, Shader,
Mask Filter, Color Filter, Draw Looper, and Image Filter are shared
between the original paint and the copy. Objects containing Reference Count increment
their references by one.
The referenced objects Path Effect, Shader, Mask Filter, Color Filter,
Draw Looper, and Image Filter cannot be modified after they are created.
This prevents objects with Reference Count from being modified once Paint refers to them.
### Parameters
### Return Value
shallow copy of paint
### Example
#### Example Output
~~~~
SK_ColorRED == paint1.getColor()
SK_ColorBLUE == paint2.getColor()
~~~~
---
SkPaint(SkPaint&& paint)
Implements a move constructor to avoid increasing the reference counts
of objects referenced by the paint.
After the call, paint is undefined, and can be safely destructed.
### Parameters
### Return Value
content of paint
### Example
#### Example Output
~~~~
path effect unique: true
~~~~
---
void reset()
Sets all Paint contents to their initial values. This is equivalent to replacing
Paint with the result of SkPaint().
### Example
#### Example Output
~~~~
paint1 == paint2
~~~~
---
~SkPaint()
Decreases Paint Reference Count of owned objects: Typeface, Path Effect, Shader,
Mask Filter, Color Filter, Draw Looper, and Image Filter. If the
objects containing Reference Count go to zero, they are deleted.
---
SkPaint& operator=(const SkPaint& paint)
Makes a shallow copy of Paint. Typeface, Path Effect, Shader,
Mask Filter, Color Filter, Draw Looper, and Image Filter are shared
between the original paint and the copy. Objects containing Reference Count in the
prior destination are decreased by one, and the referenced objects are deleted if the
resulting count is zero. Objects containing Reference Count in the parameter paint
are increased by one. paint is unmodified.
### Parameters
### Return Value
content of paint
### Example
#### Example Output
~~~~
SK_ColorRED == paint1.getColor()
SK_ColorRED == paint2.getColor()
~~~~
---
SkPaint& operator=(SkPaint&& paint)
Moves the paint to avoid increasing the reference counts
of objects referenced by the paint parameter. Objects containing Reference Count in the
prior destination are decreased by one; those objects are deleted if the resulting count
is zero.
After the call, paint is undefined, and can be safely destructed.
### Parameters
### Return Value
content of paint
### Example
#### Example Output
~~~~
SK_ColorRED == paint2.getColor()
~~~~
---
bool operator==(const SkPaint& a, const SkPaint& b)
Compares a and b, and returns true if a and b are equivalent. May return false
if Typeface, Path Effect, Shader, Mask Filter, Color Filter,
Draw Looper, or Image Filter have identical contents but different pointers.
### Parameters
### Return Value
true if Paint pair are equivalent
### Example
#### Example Output
~~~~
paint1 == paint2
paint1 != paint2
~~~~
### See Also
operator!=(const SkPaint& a, const SkPaint& b)
---
bool operator!=(const SkPaint& a, const SkPaint& b)
Compares a and b, and returns true if a and b are not equivalent. May return true
if Typeface, Path Effect, Shader, Mask Filter, Color Filter,
Draw Looper, or Image Filter have identical contents but different pointers.
### Parameters
### Return Value
true if Paint pair are not equivalent
### Example
#### Example Output
~~~~
paint1 == paint2
paint1 == paint2
~~~~
### See Also
operator==(const SkPaint& a, const SkPaint& b)
---
uint32_t getHash() const
Returns a hash generated from Paint values and pointers.
Identical hashes guarantee that the paints are
equivalent, but differing hashes do not guarantee that the paints have differing
contents.
If operator==(const SkPaint& a, const SkPaint& b) returns true for two paints,
their hashes are also equal.
The hash returned is platform and implementation specific.
### Return Value
a shallow hash
### Example
#### Example Output
~~~~
paint1 == paint2
paint1.getHash() == paint2.getHash()
~~~~
---
enum Hinting {
kNo_Hinting = 0,
kSlight_Hinting = 1,
kNormal_Hinting = 2,
kFull_Hinting = 3,
};
Hinting adjusts the glyph outlines so that the shape provides a uniform
look at a given point size on font engines that support it. Hinting may have a
muted effect or no effect at all depending on the platform.
The four levels roughly control corresponding features on platforms that use FreeType
as the Font Engine.
### Constants
| Const |
Value |
Description |
|---|
SkPaint::kNo_Hinting |
0 |
Leaves glyph outlines unchanged from their native representation.
With FreeType, this is equivalent to the FT_LOAD_NO_HINTING
bit-field constant supplied to FT_Load_Glyph, which indicates that the vector
outline being loaded should not be fitted to the pixel grid but simply scaled
to 26.6 fractional pixels.
|
SkPaint::kSlight_Hinting |
1 |
Modifies glyph outlines minimally to improve constrast.
With FreeType, this is equivalent in spirit to the
FT_LOAD_TARGET_LIGHT value supplied to FT_Load_Glyph. It chooses a
lighter hinting algorithm for non-monochrome modes.
Generated Glyphs may be fuzzy but better resemble their original shape.
|
SkPaint::kNormal_Hinting |
2 |
Modifies glyph outlines to improve constrast. This is the default.
With FreeType, this supplies FT_LOAD_TARGET_NORMAL to FT_Load_Glyph,
choosing the default hinting algorithm, which is optimized for standard
gray-level rendering.
|
SkPaint::kFull_Hinting |
3 |
Modifies glyph outlines for maximum constrast. With FreeType, this selects
FT_LOAD_TARGET_LCD or FT_LOAD_TARGET_LCD_V if kLCDRenderText Flag is set.
FT_LOAD_TARGET_LCD is a variant of FT_LOAD_TARGET_NORMAL optimized for
horizontally decimated LCD displays; FT_LOAD_TARGET_LCD_V is a
variant of FT_LOAD_TARGET_NORMAL optimized for vertically decimated LCD displays.
|
On OS X and iOS, hinting controls whether Core Graphics dilates the font outlines
to account for LCD text. No hinting uses Core Text Grayscale output.
Normal hinting uses Core Text LCD output. If kLCDRenderText Flag is clear,
the LCD output is reduced to a single Grayscale channel.
On Windows with DirectWrite, Hinting has no effect.
Hinting defaults to kNormal Hinting.
Set SkPaintDefaults Hinting at compile time to change the default setting.
---
Hinting getHinting() const
Returns level of glyph outline adjustment.
### Return Value
one of: kNo Hinting, kSlight Hinting, kNormal Hinting, kFull Hinting
### Example
#### Example Output
~~~~
SkPaint::kNormal_Hinting == paint.getHinting()
~~~~
---
void setHinting(Hinting hintingLevel)
Sets level of glyph outline adjustment.
Does not check for valid values of hintingLevel.
| Hinting | value | effect on generated glyph outlines |
| --- | --- | --- |
| kNo Hinting | 0 | leaves glyph outlines unchanged from their native representation |
| kSlight Hinting | 1 | modifies glyph outlines minimally to improve contrast |
| kNormal Hinting | 2 | modifies glyph outlines to improve contrast |
| kFull Hinting | 3 | modifies glyph outlines for maximum contrast |
### Parameters
### Example
#### Example Output
~~~~
paint1 == paint2
~~~~
---
enum Flags {
kAntiAlias_Flag = 0x01,
kDither_Flag = 0x04,
kFakeBoldText_Flag = 0x20,
kLinearText_Flag = 0x40,
kSubpixelText_Flag = 0x80,
kLCDRenderText_Flag = 0x200,
kEmbeddedBitmapText_Flag = 0x400,
kAutoHinting_Flag = 0x800,
kAllFlags = 0xFFFF,
};
The bit values stored in Flags.
The default value for Flags, normally zero, can be changed at compile time
with a custom definition of SkPaintDefaults Flags.
All flags can be read and written explicitly; Flags allows manipulating
multiple settings at once.
### Constants
---
To be deprecated soon.
Only valid for Android framework.
enum ReserveFlags {
kUnderlineText_ReserveFlag = 0x08,
kStrikeThruText_ReserveFlag = 0x10,
};
### Constants
---
uint32_t getFlags() const
Returns paint settings described by Flags. Each setting uses one
bit, and can be tested with Flags members.
### Return Value
zero, one, or more bits described by Flags
### Example
#### Example Output
~~~~
(SkPaint::kAntiAlias_Flag & paint.getFlags()) != 0
~~~~
---
void setFlags(uint32_t flags)
Replaces Flags with flags, the union of the Flags members.
All Flags members may be cleared, or one or more may be set.
### Parameters
### Example
#### Example Output
~~~~
paint.isAntiAlias()
paint.isDither()
~~~~
---
Anti Alias drawing approximates partial pixel coverage with transparency.
If kAntiAlias Flag is clear, pixel centers contained by the shape edge are drawn opaque.
If kAntiAlias Flag is set, pixels are drawn with Color Alpha equal to their coverage.
The rule for Aliased pixels is inconsistent across platforms. A shape edge
passing through the pixel center may, but is not required to, draw the pixel.
Raster Engine draws Aliased pixels whose centers are on or to the right of the start of an
active Path edge, and whose center is to the left of the end of the active Path edge.
A platform may only support Anti Aliased drawing. Some GPU-backed platforms use
Supersampling to Anti Alias all drawing, and have no mechanism to selectively
Alias.
The amount of coverage computed for Anti Aliased pixels also varies across platforms.
Anti Alias is disabled by default.
Anti Alias can be enabled by default by setting SkPaintDefaults Flags to kAntiAlias Flag
at compile time.
### Example
A red line is drawn with transparency on the edges to make it look smoother.
A blue line draws only where the pixel centers are contained.
The lines are drawn into
Bitmap, then drawn magnified to make the
Aliasing easier to see.
bool isAntiAlias() const
Returns true if pixels on the active edges of Path may be drawn with partial transparency.
Equivalent to getFlags masked with kAntiAlias Flag.
### Return Value
kAntiAlias Flag state
### Example
#### Example Output
~~~~
paint.isAntiAlias() == !!(paint.getFlags() & SkPaint::kAntiAlias_Flag)
paint.isAntiAlias() == !!(paint.getFlags() & SkPaint::kAntiAlias_Flag)
~~~~
---
void setAntiAlias(bool aa)
Requests, but does not require, that Path edge pixels draw opaque or with
partial transparency.
Sets kAntiAlias Flag if aa is true.
Clears kAntiAlias Flag if aa is false.
### Parameters
### Example
#### Example Output
~~~~
paint1 == paint2
~~~~
---
Dither increases fidelity by adjusting the color of adjacent pixels.
This can help to smooth color transitions and reducing banding in gradients.
Dithering lessens visible banding from kRGB_565_SkColorType
and kRGBA_8888_SkColorType gradients,
and improves rendering into a kRGB_565_SkColorType Surface.
Dithering is always enabled for linear gradients drawing into
kRGB_565_SkColorType Surface and kRGBA_8888_SkColorType Surface.
Dither cannot be enabled for kAlpha_8_SkColorType Surface and
kRGBA_F16_SkColorType Surface.
Dither is disabled by default.
Dither can be enabled by default by setting SkPaintDefaults Flags to kDither Flag
at compile time.
Some platform implementations may ignore dithering. Set SK_IGNORE_GPU_DITHERto ignore Dither on GPU Surface.
### Example
Dithering in the bottom half more closely approximates the requested color by
alternating nearby colors from pixel to pixel.
Dithering introduces subtle adjustments to color to smooth gradients.
Drawing the gradient repeatedly with
SkBlendMode::kPlus exaggerates the
dither, making it easier to see.
bool isDither() const
Returns true if color error may be distributed to smooth color transition.
Equivalent to getFlags masked with kDither Flag.
### Return Value
kDither Flag state
### Example
#### Example Output
~~~~
paint.isDither() == !!(paint.getFlags() & SkPaint::kDither_Flag)
paint.isDither() == !!(paint.getFlags() & SkPaint::kDither_Flag)
~~~~
---
void setDither(bool dither)
Requests, but does not require, to distribute color error.
Sets kDither Flag if dither is true.
Clears kDither Flag if dither is false.
### Parameters
### Example
#### Example Output
~~~~
paint1 == paint2
~~~~
### See Also
kRGB_565_SkColorType
---
LCD Text and Subpixel Text increase the precision of glyph position.
When set, Flags kLCDRenderText Flag takes advantage of the organization of RGB stripes that
create a color, and relies
on the small size of the stripe and visual perception to make the color fringing imperceptible.
LCD Text can be enabled on devices that orient stripes horizontally or vertically, and that order
the color components as RGB or BGR.
Flags kSubpixelText Flag uses the pixel transparency to represent a fractional offset.
As the opaqueness
of the color increases, the edge of the glyph appears to move towards the outside of the pixel.
Either or both techniques can be enabled.
kLCDRenderText Flag and kSubpixelText Flag are clear by default.
LCD Text or Subpixel Text can be enabled by default by setting SkPaintDefaults Flags to
kLCDRenderText Flag or kSubpixelText Flag (or both) at compile time.
### Example
Linear Text selects whether text is rendered as a Glyph or as a Path.
If kLinearText Flag is set, it has the same effect as setting Hinting to kNormal Hinting.
If kLinearText Flag is clear, it is the same as setting Hinting to kNo Hinting.
---
bool isLinearText() const
Returns true if text is converted to Path before drawing and measuring.
Equivalent to getFlags masked with kLinearText Flag.
### Return Value
kLinearText Flag state
### Example
### See Also
setLinearText Hinting
---
void setLinearText(bool linearText)
Returns true if text is converted to Path before drawing and measuring.
By default, kLinearText Flag is clear.
Sets kLinearText Flag if linearText is true.
Clears kLinearText Flag if linearText is false.
### Parameters
### Example
### See Also
isLinearText Hinting
Flags kSubpixelText Flag uses the pixel transparency to represent a fractional offset.
As the opaqueness
of the color increases, the edge of the glyph appears to move towards the outside of the pixel.
---
bool isSubpixelText() const
Returns true if Glyphs at different sub-pixel positions may differ on pixel edge coverage.
Equivalent to getFlags masked with kSubpixelText Flag.
### Return Value
kSubpixelText Flag state
### Example
#### Example Output
~~~~
paint.isSubpixelText() == !!(paint.getFlags() & SkPaint::kSubpixelText_Flag)
paint.isSubpixelText() == !!(paint.getFlags() & SkPaint::kSubpixelText_Flag)
~~~~
---
void setSubpixelText(bool subpixelText)
Requests, but does not require, that Glyphs respect sub-pixel positioning.
Sets kSubpixelText Flag if subpixelText is true.
Clears kSubpixelText Flag if subpixelText is false.
### Parameters
### Example
#### Example Output
~~~~
paint1 == paint2
~~~~
When set, Flags kLCDRenderText Flag takes advantage of the organization of RGB stripes that
create a color, and relies
on the small size of the stripe and visual perception to make the color fringing imperceptible.
LCD Text can be enabled on devices that orient stripes horizontally or vertically, and that order
the color components as RGB or BGR.
---
bool isLCDRenderText() const
Returns true if Glyphs may use LCD striping to improve glyph edges.
Returns true if Flags kLCDRenderText Flag is set.
### Return Value
kLCDRenderText Flag state
### Example
#### Example Output
~~~~
paint.isLCDRenderText() == !!(paint.getFlags() & SkPaint::kLCDRenderText_Flag)
paint.isLCDRenderText() == !!(paint.getFlags() & SkPaint::kLCDRenderText_Flag)
~~~~
---
void setLCDRenderText(bool lcdText)
Requests, but does not require, that Glyphs use LCD striping for glyph edges.
Sets kLCDRenderText Flag if lcdText is true.
Clears kLCDRenderText Flag if lcdText is false.
### Parameters
### Example
#### Example Output
~~~~
paint1 == paint2
~~~~
---
Font Embedded Bitmaps allows selecting custom sized bitmap Glyphs.
Flags kEmbeddedBitmapText Flag when set chooses an embedded bitmap glyph over an outline contained
in a font if the platform supports this option.
FreeType selects the bitmap glyph if available when kEmbeddedBitmapText Flag is set, and selects
the outline glyph if kEmbeddedBitmapText Flag is clear.
Windows may select the bitmap glyph but is not required to do so.
OS X and iOS do not support this option.
Font Embedded Bitmaps is disabled by default.
Font Embedded Bitmaps can be enabled by default by setting SkPaintDefaults Flags to
kEmbeddedBitmapText Flag at compile time.
### Example
The "hintgasp" TrueType font in the Skia resources/fonts directory
includes an embedded bitmap Glyph at odd font sizes. This example works
on platforms that use FreeType as their Font_Engine.
Windows may, but is not required to, return a bitmap glyph if
kEmbeddedBitmapText_Flag is set.
SkBitmap bitmap;
bitmap.allocN32Pixels(30, 15);
bitmap.eraseColor(0);
SkCanvas offscreen(bitmap);
SkPaint paint;
paint.setAntiAlias(true);
paint.setTextSize(13);
paint.setTypeface(MakeResourceAsTypeface("fonts/hintgasp.ttf"));
for (bool embedded : { false, true}) {
paint.setEmbeddedBitmapText(embedded);
offscreen.drawString("A", embedded ? 5 : 15, 15, paint);
}
canvas->drawBitmap(bitmap, 0, 0);
canvas->scale(10, 10);
canvas->drawBitmap(bitmap, -2, 1);
---
bool isEmbeddedBitmapText() const
Returns true if Font Engine may return Glyphs from font bitmaps instead of from outlines.
Equivalent to getFlags masked with kEmbeddedBitmapText Flag.
### Return Value
kEmbeddedBitmapText Flag state
### Example
#### Example Output
~~~~
paint.isEmbeddedBitmapText() == !!(paint.getFlags() & SkPaint::kEmbeddedBitmapText_Flag)
paint.isEmbeddedBitmapText() == !!(paint.getFlags() & SkPaint::kEmbeddedBitmapText_Flag)
~~~~
---
void setEmbeddedBitmapText(bool useEmbeddedBitmapText)
Requests, but does not require, to use bitmaps in fonts instead of outlines.
Sets kEmbeddedBitmapText Flag if useEmbeddedBitmapText is true.
Clears kEmbeddedBitmapText Flag if useEmbeddedBitmapText is false.
### Parameters
### Example
#### Example Output
~~~~
paint1 == paint2
~~~~
If Hinting is set to kNormal Hinting or kFull Hinting, Automatic Hinting
instructs the Font Manager to always hint Glyphs.
Automatic Hinting has no effect if Hinting is set to kNo Hinting or
kSlight Hinting.
Automatic Hinting only affects platforms that use FreeType as the Font Manager.
---
bool isAutohinted() const
Returns true if Hinting is set to kNormal Hinting or kFull Hinting, and if
platform uses FreeType as the Font Manager. If true, instructs
the Font Manager to always hint Glyphs.
Equivalent to getFlags masked with kAutoHinting Flag.
### Return Value
kAutoHinting Flag state
### Example
#### Example Output
~~~~
paint.isAutohinted() == !!(paint.getFlags() & SkPaint::kAutoHinting_Flag)
paint.isAutohinted() == !!(paint.getFlags() & SkPaint::kAutoHinting_Flag)
~~~~
### See Also
setAutohinted Hinting
---
void setAutohinted(bool useAutohinter)
Sets whether to always hint Glyphs.
If Hinting is set to kNormal Hinting or kFull Hinting and useAutohinter is set,
instructs the Font Manager to always hint Glyphs.
Automatic Hinting has no effect if Hinting is set to kNo Hinting or
kSlight Hinting.
Only affects platforms that use FreeType as the Font Manager.
Sets kAutoHinting Flag if useAutohinter is true.
Clears kAutoHinting Flag if useAutohinter is false.
### Parameters
### Example
### See Also
isAutohinted Hinting
---
Fake Bold approximates the bold font style accompanying a normal font when a bold font face
is not available. Skia does not provide font substitution; it is up to the client to find the
bold font face using the platform Font Manager.
Use Text Skew X to approximate an italic font style when the italic font face
is not available.
A FreeType based port may define SK_USE_FREETYPE_EMBOLDEN at compile time to direct
the font engine to create the bold Glyphs. Otherwise, the extra bold is computed
by increasing the stroke width and setting the Style to kStrokeAndFill Style as needed.
Fake Bold is disabled by default.
### Example
---
bool isFakeBoldText() const
Returns true if approximate bold by increasing the stroke width when creating glyph bitmaps
from outlines.
Equivalent to getFlags masked with kFakeBoldText Flag.
### Return Value
kFakeBoldText Flag state
### Example
#### Example Output
~~~~
paint.isFakeBoldText() == !!(paint.getFlags() & SkPaint::kFakeBoldText_Flag)
paint.isFakeBoldText() == !!(paint.getFlags() & SkPaint::kFakeBoldText_Flag)
~~~~
---
void setFakeBoldText(bool fakeBoldText)
Increases stroke width when creating glyph bitmaps to approximate a bold typeface.
Sets kFakeBoldText Flag if fakeBoldText is true.
Clears kFakeBoldText Flag if fakeBoldText is false.
### Parameters
### Example
#### Example Output
~~~~
paint1 == paint2
~~~~
if Hinting is set to kFull Hinting, Full Hinting Spacing adjusts the character
spacing by the difference of the hinted and Unhinted Left Side Bearing and
Right Side Bearing. Full Hinting Spacing only applies to platforms that use
FreeType as their Font Engine.
Full Hinting Spacing is not related to text Kerning, where the space between
a specific pair of characters is adjusted using data in the font Kerning tables.
---
bool isDevKernText() const
Deprecated.
---
void setDevKernText(bool)
Deprecated.
---
Filter Quality trades speed for image filtering when the image is scaled.
A lower Filter Quality draws faster, but has less fidelity.
A higher Filter Quality draws slower, but looks better.
If the image is drawn without scaling, the Filter Quality choice will not result
in a noticeable difference.
Filter Quality is used in Paint passed as a parameter to
and when Paint has a Shader specialization that uses Image or Bitmap.
Filter Quality is kNone_SkFilterQuality by default.
### Example
---
SkFilterQuality getFilterQuality() const
Returns Filter Quality, the image filtering level. A lower setting
draws faster; a higher setting looks better when the image is scaled.
### Return Value
one of: kNone_SkFilterQuality, kLow_SkFilterQuality,
kMedium_SkFilterQuality, kHigh_SkFilterQuality
### Example
#### Example Output
~~~~
kNone_SkFilterQuality == paint.getFilterQuality()
~~~~
---
void setFilterQuality(SkFilterQuality quality)
Sets Filter Quality, the image filtering level. A lower setting
draws faster; a higher setting looks better when the image is scaled.
Does not check to see if quality is valid.
### Parameters
### Example
#### Example Output
~~~~
kHigh_SkFilterQuality == paint.getFilterQuality()
~~~~
### See Also
SkFilterQuality Image Scaling
---
| name | description |
| --- | --- |
| getColor | returns Color Alpha and RGB, one drawing color |
| setColor | sets Color Alpha and RGB, one drawing color |
Color specifies the red, blue, green, and Color Alpha
values used to draw a filled or stroked shape in a 32-bit value. Each component
occupies 8-bits, ranging from zero: no contribution; to 255: full intensity.
All values in any combination are valid.
Color is not Premultiplied; Color Alpha sets the transparency independent of
RGB: red, blue, and green.
The bit positions of Color Alpha and RGB are independent of the bit
positions on the output device, which may have more or fewer bits, and may have
a different arrangement.
| bit positions | Color Alpha | red | blue | green |
| --- | --- | --- | --- | --- |
| | 31 - 24 | 23 - 16 | 15 - 8 | 7 - 0 |
### Example
---
SkColor getColor() const
Retrieves Alpha and RGB, Unpremultiplied, packed into 32 bits.
Use helpers SkColorGetA, SkColorGetR, SkColorGetG, and SkColorGetB to extract
a color component.
### Return Value
Unpremultiplied ARGB
### Example
#### Example Output
~~~~
Yellow is 100% red, 100% green, and 0% blue.
~~~~
### See Also
getColor4f SkColor
---
SkColor4f getColor4f() const
Retrieves alpha and RGB, unpmreultiplied, as four floating point values. RGB are
are extended sRGB values (sRGB gamut, and encoded with the sRGB transfer function).
### Return Value
Unpremultiplied RGBA
### Example
#### Example Output
~~~~
Yellow is 100% red, 100% green, and 0% blue.
~~~~
### See Also
getColor SkColor
---
void setColor(SkColor color)
Sets Alpha and RGB used when stroking and filling. The color is a 32-bit value,
Unpremultiplied, packing 8-bit components for Alpha, red, blue, and green.
### Parameters
### Example
#### Example Output
~~~~
green1 == green2
~~~~
### See Also
SkColor setColor4f setARGB SkColorSetARGB
---
void setColor4f(const SkColor4f& color, SkColorSpace* colorSpace)
Sets alpha and RGB used when stroking and filling. The color is four floating
point values, unpremultiplied. The color values are interpreted as being in
the colorSpace. If colorSpace is nullptr, then color is assumed to be in the
sRGB color space.
### Parameters
### Example
#### Example Output
~~~~
green1 == green2
~~~~
### See Also
SkColor setColor setARGB SkColorSetARGB
Color Alpha sets the transparency independent of RGB: red, blue, and green.
---
uint8_t getAlpha() const
Retrieves Alpha from the Color used when stroking and filling.
### Return Value
Alpha ranging from zero, fully transparent, to 255, fully opaque
### Example
#### Example Output
~~~~
255 == paint.getAlpha()
~~~~
---
void setAlpha(U8CPU a)
Replaces Alpha, leaving RGB
unchanged. An out of range value triggers an assert in the debug
build. a is a value from zero to 255.
a set to zero makes Color fully transparent; a set to 255 makes Color
fully opaque.
### Parameters
### Example
#### Example Output
~~~~
0x44112233 == paint.getColor()
~~~~
---
void setARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b)
Sets Color used when drawing solid fills. The color components range from 0 to 255.
The color is Unpremultiplied; Alpha sets the transparency independent of RGB.
### Parameters
a |
amount of Color Alpha, from fully transparent (0) to fully opaque (255) |
r |
amount of red, from no red (0) to full red (255) |
g |
amount of green, from no green (0) to full green (255) |
b |
amount of blue, from no blue (0) to full blue (255) |
### Example
#### Example Output
~~~~
transRed1 == transRed2
~~~~
### See Also
setColor SkColorSetARGB
---
Style specifies if the geometry is filled, stroked, or both filled and stroked.
Some shapes ignore Style and are always drawn filled or stroked.
Set Style to kFill Style to fill the shape.
The fill covers the area inside the geometry for most shapes.
Set Style to kStroke Style to stroke the shape.
The stroke covers the area described by following the shape edge with a pen or brush of
Stroke Width. The area covered where the shape starts and stops is described by Stroke Cap.
The area covered where the shape turns a corner is described by Stroke Join.
The stroke is centered on the shape; it extends equally on either side of the shape edge.As Stroke Width gets smaller, the drawn path frame is thinner. Stroke Width less than one
may have gaps, and if kAntiAlias Flag is set, Color Alpha will increase to visually decrease coverage.
### See Also
Path Fill Type Path Effect Style Fill Style Stroke
---
Stroke Width of zero has a special meaning and switches drawing to use Hairline.
Hairline draws the thinnest continuous frame. If kAntiAlias Flag is clear, adjacent pixels
flow horizontally, vertically,or diagonally.
Path drawing with Hairline may hit the same pixel more than once. For instance, Path containing
two lines in one Path Contour will draw the corner point once, but may both lines may draw the adjacent
pixel. If kAntiAlias Flag is set, transparency is applied twice, resulting in a darker pixel. Some
GPU-backed implementations apply transparency at a later drawing stage, avoiding double hit pixels
while stroking.
### See Also
Path Fill Type Path Effect Style Fill Style Stroke
---
enum Style {
kFill_Style,
kStroke_Style,
kStrokeAndFill_Style,
};
static constexpr int kStyleCount = kStrokeAndFill_Style + 1;
Set Style to fill, stroke, or both fill and stroke geometry.
The stroke and fill
share all paint attributes; for instance, they are drawn with the same color.
Use kStrokeAndFill Style to avoid hitting the same pixels twice with a stroke draw and
a fill draw.
### Constants
| Const |
Value |
Description |
|---|
SkPaint::kFill_Style |
0 |
Applies to Rect, Region, Round Rect, Circles, Ovals, Path, and Text.
Bitmap, Image, Patches, Region, Sprites, and Vertices are painted as if
kFill Style is set, and ignore the set Style.
The Path Fill Type specifies additional rules to fill the area outside the path edge,
and to create an unfilled hole inside the shape.
Style is set to kFill Style by default.
|
SkPaint::kStroke_Style |
1 |
Applies to Rect, Region, Round Rect, Arcs, Circles, Ovals, Path, and Text.
Arcs, Lines, and points, are always drawn as if kStroke Style is set,
and ignore the set Style.
The stroke construction is unaffected by the Path Fill Type.
|
SkPaint::kStrokeAndFill_Style |
2 |
Applies to Rect, Region, Round Rect, Circles, Ovals, Path, and Text.
Path is treated as if it is set to SkPath::kWinding FillType,
and the set Path Fill Type is ignored.
|
SkPaint::kStyleCount |
3 |
May be used to verify that Style is a legal value.
|
---
Style getStyle() const
Returns whether the geometry is filled, stroked, or filled and stroked.
### Return Value
one of:kFill Style, kStroke Style, kStrokeAndFill Style
### Example
#### Example Output
~~~~
SkPaint::kFill_Style == paint.getStyle()
~~~~
### See Also
Style setStyle
---
void setStyle(Style style)
Sets whether the geometry is filled, stroked, or filled and stroked.
Has no effect if style is not a legal Style value.
### Parameters
### Example
### See Also
Style getStyle
---
Stroke Width sets the width for stroking. The width is the thickness
of the stroke perpendicular to the path direction when the paint style is
set to kStroke Style or kStrokeAndFill Style.
When width is greater than zero, the stroke encompasses as many pixels partially
or fully as needed. When the width equals zero, the paint enables hairlines;
the stroke is always one pixel wide.
The stroke dimensions are scaled by the canvas matrix, but Hairline stroke
remains one pixel wide regardless of scaling.
The default width for the paint is zero.
### Example
The pixels hit to represent thin lines vary with the angle of the
line and the platform implementation.
SkScalar getStrokeWidth() const
Returns the thickness of the pen used by Paint to
outline the shape.
### Return Value
zero for Hairline, greater than zero for pen thickness
### Example
#### Example Output
~~~~
0 == paint.getStrokeWidth()
~~~~
---
void setStrokeWidth(SkScalar width)
Sets the thickness of the pen used by the paint to
outline the shape.
Has no effect if width is less than zero.
### Parameters
width |
zero thickness for Hairline; greater than zero for pen thickness |
### Example
#### Example Output
~~~~
5 == paint.getStrokeWidth()
~~~~
---
Miter Limit specifies the maximum miter length,
relative to the stroke width.
Miter Limit is used when the Stroke Join
is set to kMiter Join, and the Style is either kStroke Style
or kStrokeAndFill Style.
If the miter at a corner exceeds this limit, kMiter Join
is replaced with kBevel Join.
Miter Limit can be computed from the corner angle using:
miter limit = 1 / sin \( angle / 2 \).
Miter Limit default value is 4.
The default may be changed at compile time by setting SkPaintDefaults MiterLimit
in "SkUserConfig.h" or as a define supplied by the build environment.
Here are some miter limits and the angles that triggers them.
| miter limit | angle in degrees |
| --- | --- |
| 10 | 11.48 |
| 9 | 12.76 |
| 8 | 14.36 |
| 7 | 16.43 |
| 6 | 19.19 |
| 5 | 23.07 |
| 4 | 28.96 |
| 3 | 38.94 |
| 2 | 60 |
| 1 | 180 |
### Example
This example draws a stroked corner and the miter length beneath.
When the miter limit is decreased slightly, the miter join is replaced
by a bevel join.
SkScalar getStrokeMiter() const
Returns the limit at which a sharp corner is drawn beveled.
### Return Value
zero and greater Miter Limit
### Example
#### Example Output
~~~~
default miter limit == 4
~~~~
### See Also
Miter Limit setStrokeMiter Join
---
void setStrokeMiter(SkScalar miter)
Sets the limit at which a sharp corner is drawn beveled.
Valid values are zero and greater.
Has no effect if miter is less than zero.
### Parameters
### Example
#### Example Output
~~~~
default miter limit == 8
~~~~
### See Also
Miter Limit getStrokeMiter Join
---
enum Cap {
kButt_Cap,
kRound_Cap,
kSquare_Cap,
kLast_Cap = kSquare_Cap,
kDefault_Cap = kButt_Cap,
};
static constexpr int kCapCount = kLast_Cap + 1;
Stroke Cap draws at the beginning and end of an open Path Contour.
### Constants
Stroke describes the area covered by a pen of Stroke Width as it
follows the Path Contour, moving parallel to the contour direction.
If the Path Contour is not terminated by SkPath::kClose Verb, the contour has a
visible beginning and end.
Path Contour may start and end at the same point; defining Zero Length Contour.
kButt Cap and Zero Length Contour is not drawn.
kRound Cap and Zero Length Contour draws a circle of diameter Stroke Width
at the contour point.
kSquare Cap and Zero Length Contour draws an upright square with a side of
Stroke Width at the contour point.
Stroke Cap is kButt Cap by default.
### Example
---
Cap getStrokeCap() const
Returns the geometry drawn at the beginning and end of strokes.
### Return Value
one of: kButt Cap, kRound Cap, kSquare Cap
### Example
#### Example Output
~~~~
kButt_Cap == default stroke cap
~~~~
### See Also
Stroke Cap setStrokeCap
---
void setStrokeCap(Cap cap)
Sets the geometry drawn at the beginning and end of strokes.
### Parameters
### Example
#### Example Output
~~~~
kRound_Cap == paint.getStrokeCap()
~~~~
### See Also
Stroke Cap getStrokeCap
Stroke Join draws at the sharp corners of an open or closed Path Contour.
Stroke describes the area covered by a pen of Stroke Width as it
follows the Path Contour, moving parallel to the contour direction.
If the contour direction changes abruptly, because the tangent direction leading
to the end of a curve within the contour does not match the tangent direction of
the following curve, the pair of curves meet at Stroke Join.
### Example
---
enum Join {
kMiter_Join,
kRound_Join,
kBevel_Join,
kLast_Join = kBevel_Join,
kDefault_Join = kMiter_Join,
};
static constexpr int kJoinCount = kLast_Join + 1;
Join specifies how corners are drawn when a shape is stroked. Join
affects the four corners of a stroked rectangle, and the connected segments in a
stroked path.
Choose miter join to draw sharp corners. Choose round join to draw a circle with a
radius equal to the stroke width on top of the corner. Choose bevel join to minimally
connect the thick strokes.
The fill path constructed to describe the stroked path respects the join setting but may
not contain the actual join. For instance, a fill path constructed with round joins does
not necessarily include circles at each connected segment.
### Constants
### Example
### See Also
setStrokeJoin getStrokeJoin setStrokeMiter getStrokeMiter
---
Join getStrokeJoin() const
Returns the geometry drawn at the corners of strokes.
### Return Value
one of: kMiter Join, kRound Join, kBevel Join
### Example
#### Example Output
~~~~
kMiter_Join == default stroke join
~~~~
### See Also
Stroke Join setStrokeJoin
---
void setStrokeJoin(Join join)
Sets the geometry drawn at the corners of strokes.
### Parameters
### Example
#### Example Output
~~~~
kMiter_Join == paint.getStrokeJoin()
~~~~
### See Also
Stroke Join getStrokeJoin
### See Also
Miter Limit
---
Fill Path creates a Path by applying the Path Effect, followed by the Style Stroke.
If Paint contains Path Effect, Path Effect operates on the source Path; the result
replaces the destination Path. Otherwise, the source Path is replaces the
destination Path.
Fill Path can request the Path Effect to restrict to a culling rectangle, but
the Path Effect is not required to do so.
If Style is kStroke Style or kStrokeAndFill Style,
and Stroke Width is greater than zero, the Stroke Width, Stroke Cap, Stroke Join,
and Miter Limit operate on the destination Path, replacing it.
Fill Path can specify the precision used by Stroke Width to approximate the stroke geometry.
If the Style is kStroke Style and the Stroke Width is zero, getFillPath
returns false since Hairline has no filled equivalent.
### See Also
Style Stroke Stroke Width Path Effect
---
bool getFillPath(const SkPath& src, SkPath* dst, const SkRect* cullRect, SkScalar resScale = 1) const
Returns the filled equivalent of the stroked path.
### Parameters
src |
Path read to create a filled version |
dst |
resulting Path; may be the same as src, but may not be nullptr |
cullRect |
optional limit passed to Path Effect |
resScale |
if > 1, increase precision, else if (0 < res < 1) reduce precision
to favor speed and size |
### Return Value
true if the path represents Style Fill, or false if it represents Hairline
### Example
A very small
Quad stroke is turned into a filled path with increasing levels of precision.
At the lowest precision, the
Quad stroke is approximated by a rectangle.
At the highest precision, the filled path has high fidelity compared to the original stroke.
bool getFillPath(const SkPath& src, SkPath* dst) const
Returns the filled equivalent of the stroked path.
Replaces dst with the src path modified by Path Effect and Style Stroke.
Path Effect, if any, is not culled. Stroke Width is created with default precision.
### Parameters
src |
Path read to create a filled version |
dst |
resulting Path dst may be the same as src, but may not be nullptr |
### Return Value
true if the path represents Style Fill, or false if it represents Hairline
### Example
---
Shader defines the colors used when drawing a shape.
Shader may be an image, a gradient, or a computed fill.
If Paint has no Shader, then Color fills the shape.
Shader is modulated by Color Alpha component of Color.
If Shader object defines only Color Alpha, then Color modulated by Color Alpha describes
the fill.
The drawn transparency can be modified without altering Shader, by changing Color Alpha.
### Example
If Shader generates only Color Alpha then all components of Color modulate the output.
### Example
---
SkShader* getShader() const
Returns optional colors used when filling a path, such as a gradient.
Does not alter Shader Reference Count.
### Return Value
Shader if previously set, nullptr otherwise
### Example
#### Example Output
~~~~
nullptr == shader
nullptr != shader
~~~~
---
sk sp<SkShader> refShader() const
Returns optional colors used when filling a path, such as a gradient.
Increases Shader Reference Count by one.
### Return Value
Shader if previously set, nullptr otherwise
### Example
#### Example Output
~~~~
shader unique: true
shader unique: false
~~~~
---
void setShader(sk sp<SkShader> shader)
Sets optional colors used when filling a path, such as a gradient.
Sets Shader to shader, decreasing Reference Count of the previous Shader.
Increments shader Reference Count by one.
### Parameters
shader |
how geometry is filled with color; if nullptr, Color is used instead |
### Example
---
Color Filter alters the color used when drawing a shape.
Color Filter may apply Blend Mode, transform the color through a matrix, or composite multiple filters.
If Paint has no Color Filter, the color is unaltered.
The drawn transparency can be modified without altering Color Filter, by changing Color Alpha.
### Example
---
SkColorFilter* getColorFilter() const
Returns Color Filter if set, or nullptr.
Does not alter Color Filter Reference Count.
### Return Value
Color Filter if previously set, nullptr otherwise
### Example
#### Example Output
~~~~
nullptr == color filter
nullptr != color filter
~~~~
---
sk sp<SkColorFilter> refColorFilter() const
Returns Color Filter if set, or nullptr.
Increases Color Filter Reference Count by one.
### Return Value
Color Filter if set, or nullptr
### Example
#### Example Output
~~~~
color filter unique: true
color filter unique: false
~~~~
---
void setColorFilter(sk sp<SkColorFilter> colorFilter)
Sets Color Filter to filter, decreasing Reference Count of the previous
Color Filter. Pass nullptr to clear Color Filter.
Increments filter Reference Count by one.
### Parameters
### Example
---
Blend Mode describes how Color combines with the destination color.
The default setting, SkBlendMode::kSrcOver, draws the source color
over the destination color.
### Example
### See Also
Blend Mode
---
SkBlendMode getBlendMode() const
Returns Blend Mode.
By default, returns SkBlendMode::kSrcOver.
### Return Value
mode used to combine source color with destination color
### Example
#### Example Output
~~~~
kSrcOver == getBlendMode
kSrcOver != getBlendMode
~~~~
---
bool isSrcOver() const
Returns true if Blend Mode is SkBlendMode::kSrcOver, the default.
### Return Value
true if Blend Mode is SkBlendMode::kSrcOver
### Example
#### Example Output
~~~~
isSrcOver == true
isSrcOver != true
~~~~
---
void setBlendMode(SkBlendMode mode)
Sets Blend Mode to mode.
Does not check for valid input.
### Parameters
### Example
#### Example Output
~~~~
isSrcOver == true
isSrcOver != true
~~~~
---
Path Effect modifies the path geometry before drawing it.
Path Effect may implement dashing, custom fill effects and custom stroke effects.
If Paint has no Path Effect, the path geometry is unaltered when filled or stroked.
### Example
### See Also
Path Effect
---
SkPathEffect* getPathEffect() const
Returns Path Effect if set, or nullptr.
Does not alter Path Effect Reference Count.
### Return Value
Path Effect if previously set, nullptr otherwise
### Example
#### Example Output
~~~~
nullptr == path effect
nullptr != path effect
~~~~
---
sk sp<SkPathEffect> refPathEffect() const
Returns Path Effect if set, or nullptr.
Increases Path Effect Reference Count by one.
### Return Value
Path Effect if previously set, nullptr otherwise
### Example
#### Example Output
~~~~
path effect unique: true
path effect unique: false
~~~~
---
void setPathEffect(sk sp<SkPathEffect> pathEffect)
Sets Path Effect to pathEffect, decreasing Reference Count of the previous
Path Effect. Pass nullptr to leave the path geometry unaltered.
Increments pathEffect Reference Count by one.
### Parameters
### Example
---
Mask Filter uses coverage of the shape drawn to create Mask Alpha.
Mask Filter takes a Mask, and returns a Mask.
Mask Filter may change the geometry and transparency of the shape, such as
creating a blur effect. Set Mask Filter to nullptr to prevent Mask Filter from
modifying the draw.
### Example
---
SkMaskFilter* getMaskFilter() const
Returns Mask Filter if set, or nullptr.
Does not alter Mask Filter Reference Count.
### Return Value
Mask Filter if previously set, nullptr otherwise
### Example
#### Example Output
~~~~
nullptr == mask filter
nullptr != mask filter
~~~~
---
sk sp<SkMaskFilter> refMaskFilter() const
Returns Mask Filter if set, or nullptr.
Increases Mask Filter Reference Count by one.
### Return Value
Mask Filter if previously set, nullptr otherwise
### Example
#### Example Output
~~~~
mask filter unique: true
mask filter unique: false
~~~~
---
void setMaskFilter(sk sp<SkMaskFilter> maskFilter)
Sets Mask Filter to maskFilter, decreasing Reference Count of the previous
Mask Filter. Pass nullptr to clear Mask Filter and leave Mask Filter effect on
Mask Alpha unaltered.
Increments maskFilter Reference Count by one.
### Parameters
maskFilter |
modifies clipping mask generated from drawn geometry |
### Example
---
Typeface identifies the font used when drawing and measuring text.
Typeface may be specified by name, from a file, or from a data stream.
The default Typeface defers to the platform-specific default font
implementation.
### Example
---
SkTypeface* getTypeface() const
Returns Typeface if set, or nullptr.
Does not alter Typeface Reference Count.
### Return Value
Typeface if previously set, nullptr otherwise
### Example
#### Example Output
~~~~
nullptr == typeface
nullptr != typeface
~~~~
---
sk sp<SkTypeface> refTypeface() const
Increases Typeface Reference Count by one.
### Return Value
Typeface if previously set, nullptr otherwise
### Example
#### Example Output
~~~~
typeface1 != typeface2
typeface1 == typeface2
~~~~
---
void setTypeface(sk sp<SkTypeface> typeface)
Sets Typeface to typeface, decreasing Reference Count of the previous Typeface.
Pass nullptr to clear Typeface and use the default typeface. Increments
typeface Reference Count by one.
### Parameters
typeface |
font and style used to draw text |
### Example
---
Image Filter operates on the pixel representation of the shape, as modified by Paint
with Blend Mode set to SkBlendMode::kSrcOver. Image Filter creates a new bitmap,
which is drawn to the device using the set Blend Mode.
Image Filter is higher level than Mask Filter; for instance, an Image Filter
can operate on all channels of Color, while Mask Filter generates Alpha only.
Image Filter operates independently of and can be used in combination with
Mask Filter.
### Example
---
SkImageFilter* getImageFilter() const
Returns Image Filter if set, or nullptr.
Does not alter Image Filter Reference Count.
### Return Value
Image Filter if previously set, nullptr otherwise
### Example
#### Example Output
~~~~
nullptr == image filter
nullptr != image filter
~~~~
---
sk sp<SkImageFilter> refImageFilter() const
Returns Image Filter if set, or nullptr.
Increases Image Filter Reference Count by one.
### Return Value
Image Filter if previously set, nullptr otherwise
### Example
#### Example Output
~~~~
image filter unique: true
image filter unique: false
~~~~
---
void setImageFilter(sk sp<SkImageFilter> imageFilter)
Sets Image Filter to imageFilter, decreasing Reference Count of the previous
Image Filter. Pass nullptr to clear Image Filter, and remove Image Filter effect
on drawing.
Increments imageFilter Reference Count by one.
### Parameters
### Example
---
Draw Looper sets a modifier that communicates state from one Draw Layer
to another to construct the draw.
Draw Looper draws one or more times, modifying the canvas and paint each time.
Draw Looper may be used to draw multiple colors or create a colored shadow.
Set Draw Looper to nullptr to prevent Draw Looper from modifying the draw.
### Example
---
SkDrawLooper* getDrawLooper() const
Returns Draw Looper if set, or nullptr.
Does not alter Draw Looper Reference Count.
### Return Value
Draw Looper if previously set, nullptr otherwise
### Example
#### Example Output
~~~~
nullptr == draw looper
nullptr != draw looper
~~~~
---
sk sp<SkDrawLooper> refDrawLooper() const
Returns Draw Looper if set, or nullptr.
Increases Draw Looper Reference Count by one.
### Return Value
Draw Looper if previously set, nullptr otherwise
### Example
#### Example Output
~~~~
draw looper unique: true
draw looper unique: false
~~~~
---
SkDrawLooper* getLooper() const
Deprecated.
---
void setDrawLooper(sk sp<SkDrawLooper> drawLooper)
Sets Draw Looper to drawLooper, decreasing Reference Count of the previous
drawLooper. Pass nullptr to clear Draw Looper and leave Draw Looper effect on
drawing unaltered.
Increments drawLooper Reference Count by one.
### Parameters
### Example
---
void setLooper(sk sp<SkDrawLooper> drawLooper)
Deprecated.
---
enum Align {
kLeft_Align,
kCenter_Align,
kRight_Align,
};
### Constants
Deprecated.
### Constants
---
Align getTextAlign() const
Deprecated.
---
void setTextAlign(Align align)
Deprecated.
---
Text Size adjusts the overall text size in points.
Text Size can be set to any positive value or zero.
Text Size defaults to 12.
Set SkPaintDefaults TextSize at compile time to change the default setting.
### Example
---
SkScalar getTextSize() const
Returns Text Size in points.
### Return Value
typographic height of text
### Example
---
void setTextSize(SkScalar textSize)
Sets Text Size in points.
Has no effect if textSize is not greater than or equal to zero.
### Parameters
### Example
---
Text Scale X adjusts the text horizontal scale.
Text scaling approximates condensed and expanded type faces when the actual face
is not available.
Text Scale X can be set to any value.
Text Scale X defaults to 1.
### Example
---
SkScalar getTextScaleX() const
Returns Text Scale X.
Default value is 1.
### Return Value
text horizontal scale
### Example
---
void setTextScaleX(SkScalar scaleX)
Sets Text Scale X.
Default value is 1.
### Parameters
### Example
---
Text Skew X adjusts the text horizontal slant.
Text skewing approximates italic and oblique type faces when the actual face
is not available.
Text Skew X can be set to any value.
Text Skew X defaults to 0.
### Example
---
SkScalar getTextSkewX() const
Returns Text Skew X.
Default value is zero.
### Return Value
additional shear in x-axis relative to y-axis
### Example
---
void setTextSkewX(SkScalar skewX)
Sets Text Skew X.
Default value is zero.
### Parameters
skewX |
additional shear in x-axis relative to y-axis |
### Example
---
---
enum TextEncoding {
kUTF8_TextEncoding,
kUTF16_TextEncoding,
kUTF32_TextEncoding,
kGlyphID_TextEncoding,
};
TextEncoding determines whether text specifies character codes and their encoded
size, or glyph indices. Characters are encoded as specified by the Unicode standard .
Character codes encoded size are specified by UTF-8, UTF-16, or UTF-32.
All character code formats are able to represent all of Unicode, differing only
in the total storage required.
UTF-8 (RFC 3629) encodes each character as one or more 8-bit bytes.
UTF-16 (RFC 2781) encodes each character as one or two 16-bit words.
UTF-32 encodes each character as one 32-bit word.
Font Manager uses font data to convert character code points into glyph indices.
A glyph index is a 16-bit word.
TextEncoding is set to kUTF8 TextEncoding by default.
### Constants
### Example
First line is encoded in UTF-8.
Second line is encoded in UTF-16.
Third line is encoded in UTF-32.
Fourth line has 16-bit glyph indices.
TextEncoding getTextEncoding() const
Returns Text Encoding.
Text Encoding determines how character code points are mapped to font glyph indices.
### Return Value
one of: kUTF8 TextEncoding, kUTF16 TextEncoding, kUTF32 TextEncoding, or
kGlyphID TextEncoding
### Example
#### Example Output
~~~~
kUTF8_TextEncoding == text encoding
kGlyphID_TextEncoding == text encoding
~~~~
---
void setTextEncoding(TextEncoding encoding)
Sets Text Encoding to encoding.
Text Encoding determines how character code points are mapped to font glyph indices.
Invalid values for encoding are ignored.
### Parameters
### Example
#### Example Output
~~~~
4 != text encoding
~~~~
---
Font Metrics describe dimensions common to the Glyphs in Typeface.
The dimensions are computed by Font Manager from font data and do not take
Paint settings other than Text Size into account.
Font dimensions specify the anchor to the left of the glyph at baseline as the origin.
X-axis values to the left of the glyph are negative, and to the right of the left glyph edge
are positive.
Y-axis values above the baseline are negative, and below the baseline are positive.
### Example
---
struct FontMetrics {
enum FontMetricsFlags {
kUnderlineThicknessIsValid_Flag = 1 << 0,
kUnderlinePositionIsValid_Flag = 1 << 1,
kStrikeoutThicknessIsValid_Flag = 1 << 2,
kStrikeoutPositionIsValid_Flag = 1 << 3,
};
uint32_t fFlags;
SkScalar fTop;
SkScalar fAscent;
SkScalar fDescent;
SkScalar fBottom;
SkScalar fLeading;
SkScalar fAvgCharWidth;
SkScalar fMaxCharWidth;
SkScalar fXMin;
SkScalar fXMax;
SkScalar fXHeight;
SkScalar fCapHeight;
SkScalar fUnderlineThickness;
SkScalar fUnderlinePosition;
SkScalar fStrikeoutThickness;
SkScalar fStrikeoutPosition;
bool hasUnderlineThickness(SkScalar* thickness) const;
bool hasUnderlinePosition(SkScalar* position) const;
bool hasStrikeoutThickness(SkScalar* thickness) const;
bool hasStrikeoutPosition(SkScalar* position) const;
};
FontMetrics is filled out by getFontMetrics. FontMetrics contents reflect the values
computed by Font Manager using Typeface. Values are set to zero if they are
not available.
All vertical values are relative to the baseline, on a y-axis pointing down.
Zero is on the baseline, negative values are above the baseline, and positive
values are below the baseline.
fUnderlineThickness and fUnderlinePosition have a bit set in fFlags if their values
are valid, since their value may be zero.
fStrikeoutThickness and fStrikeoutPosition have a bit set in fFlags if their values
are valid, since their value may be zero.
---
enum FontMetricsFlags {
kUnderlineThicknessIsValid_Flag = 1 << 0,
kUnderlinePositionIsValid_Flag = 1 << 1,
kStrikeoutThicknessIsValid_Flag = 1 << 2,
kStrikeoutPositionIsValid_Flag = 1 << 3,
};
FontMetricsFlags are set in fFlags when underline and strikeout metrics are valid;
the underline or strikeout metric may be valid and zero.
Fonts with embedded bitmaps may not have valid underline or strikeout metrics.
### Constants
---
bool hasUnderlineThickness(SkScalar* thickness) const
Returns true if Font Metrics has a valid underline thickness, and sets
thickness to that value. If the underline thickness is not valid,
return false, and ignore thickness.
### Parameters
### Return Value
true if font specifies underline width
---
bool hasUnderlinePosition(SkScalar* position) const
Returns true if Font Metrics has a valid underline position, and sets
position to that value. If the underline position is not valid,
return false, and ignore position.
### Parameters
### Return Value
true if font specifies underline position
---
bool hasStrikeoutThickness(SkScalar* thickness) const
Returns true if Font Metrics has a valid strikeout thickness, and sets
thickness to that value. If the underline thickness is not valid,
return false, and ignore thickness.
### Parameters
### Return Value
true if font specifies strikeout width
---
bool hasStrikeoutPosition(SkScalar* position) const
Returns true if Font Metrics has a valid strikeout position, and sets
position to that value. If the underline position is not valid,
return false, and ignore position.
### Parameters
### Return Value
true if font specifies strikeout position
---
SkScalar getFontMetrics(FontMetrics* metrics, SkScalar scale = 0) const
Returns Font Metrics associated with Typeface.
The return value is the recommended spacing between lines: the sum of metrics
descent, ascent, and leading.
If metrics is not nullptr, Font Metrics is copied to metrics.
Results are scaled by Text Size but does not take into account
dimensions required by Text Scale X, Text Skew X, Fake Bold,
Style Stroke, and Path Effect.
Results can be additionally scaled by scale; a scale of zero
is ignored.
### Parameters
### Return Value
recommended spacing between lines
### Example
### See Also
Text Size Typeface Typeface Methods
---
SkScalar getFontSpacing() const
Returns the recommended spacing between lines: the sum of metrics
descent, ascent, and leading.
Result is scaled by Text Size but does not take into account
dimensions required by stroking and Path Effect.
Returns the same result as getFontMetrics.
### Return Value
recommended spacing between lines
### Example
#### Example Output
~~~~
textSize: 12 fontSpacing: 13.9688
textSize: 18 fontSpacing: 20.9531
textSize: 24 fontSpacing: 27.9375
textSize: 32 fontSpacing: 37.25
~~~~
---
SkRect getFontBounds() const
Returns the union of bounds of all Glyphs.
Returned dimensions are computed by Font Manager from font data,
ignoring Hinting. Includes Text Size, Text Scale X,
and Text Skew X, but not Fake Bold or Path Effect.
If Text Size is large, Text Scale X is one, and Text Skew X is zero,
returns the same bounds as Font Metrics { FontMetrics::fXMin,
FontMetrics::fTop, FontMetrics::fXMax, FontMetrics::fBottom }.
### Return Value
union of bounds of all Glyphs
### Example
#### Example Output
~~~~
metrics bounds = { -12.2461, -14.7891, 21.5215, 5.55469 }
font bounds = { -12.2461, -14.7891, 21.5215, 5.55469 }
~~~~
---
int textToGlyphs(const void* text, size_t byteLength, SkGlyphID glyphs[]) const
Converts text into glyph indices.
Returns the number of glyph indices represented by text.
Text Encoding specifies how text represents characters or glyphs.
glyphs may be nullptr, to compute the glyph count.
Does not check text for valid character codes or valid glyph indices.
If byteLength equals zero, returns zero.
If byteLength includes a partial character, the partial character is ignored.
If Text Encoding is kUTF8 TextEncoding and
text contains an invalid UTF-8 sequence, zero is returned.
### Parameters
### Return Value
number of glyphs represented by text of length byteLength
### Example
---
int countText(const void* text, size_t byteLength) const
Returns the number of Glyphs in text.
Uses Text Encoding to count the Glyphs.
Returns the same result as textToGlyphs.
### Parameters
### Return Value
number of Glyphs represented by text of length byteLength
### Example
#### Example Output
~~~~
count = 5
~~~~
---
bool containsText(const void* text, size_t byteLength) const
Returns true if all text corresponds to a non-zero glyph index.
Returns false if any characters in text are not supported in
Typeface.
If Text Encoding is kGlyphID TextEncoding,
returns true if all glyph indices in text are non-zero;
does not check to see if text contains valid glyph indices for Typeface.
Returns true if byteLength is zero.
### Parameters
### Return Value
true if all text corresponds to a non-zero glyph index
containsText succeeds for degree symbol, but cannot find a glyph index
corresponding to the Unicode surrogate code point.
#### Example Output
~~~~
0x00b0 == has char
0xd800 != has char
~~~~
### Example
containsText returns true that glyph index is greater than zero, not
that it corresponds to an entry in
Typeface.
#### Example Output
~~~~
0x01ff == has glyph
0x0000 != has glyph
0xffff == has glyph
~~~~
void glyphsToUnichars(const SkGlyphID glyphs[], int count, SkUnichar text[]) const
Converts glyphs into text if possible.
Glyph values without direct Unicode equivalents are mapped to zero.
Uses the Typeface, but is unaffected
by Text Encoding; the text values returned are equivalent to kUTF32 TextEncoding.
Only supported on platforms that use FreeType as the Font Engine.
### Parameters
glyphs |
array of indices into font |
count |
length of glyph array |
text |
storage for character codes, one per glyph |
### Example
---
SkScalar measureText(const void* text, size_t length, SkRect* bounds) const
Returns the advance width of text.
The advance is the normal distance to move before drawing additional text.
Uses Text Encoding to decode text, Typeface to get the font metrics,
and Text Size, Text Scale X, Text Skew X, Stroke Width, and
Path Effect to scale the metrics and bounds.
Returns the bounding box of text if bounds is not nullptr.
The bounding box is computed as if the text was drawn at the origin.
### Parameters
text |
character codes or glyph indices to be measured |
length |
number of bytes of text to measure |
bounds |
returns bounding box relative to (0, 0) if not nullptr |
### Return Value
advance width or height
### Example
---
SkScalar measureText(const void* text, size_t length) const
Returns the advance width of text.
The advance is the normal distance to move before drawing additional text.
Uses Text Encoding to decode text, Typeface to get the font metrics,
and Text Size to scale the metrics.
Does not scale the advance or bounds by Fake Bold or Path Effect.
### Parameters
text |
character codes or glyph indices to be measured |
length |
number of bytes of text to measure |
### Return Value
advance width or height
### Example
#### Example Output
~~~~
default width = 5
double width = 10
~~~~
---
size_t breakText(const void* text, size_t length, SkScalar maxWidth,
SkScalar* measuredWidth = nullptr) const
Returns the bytes of text that fit within maxWidth.
The text fragment fits if its advance width is less than or equal to maxWidth.
Measures only while the advance is less than or equal to maxWidth.
Returns the advance or the text fragment in measuredWidth if it not nullptr.
Uses Text Encoding to decode text, Typeface to get the font metrics,
and Text Size to scale the metrics.
Does not scale the advance or bounds by Fake Bold or Path Effect.
### Parameters
### Return Value
bytes of text that fit, always less than or equal to length
### Example
Line under "" shows desired width, shorter than available characters.
Line under "" shows measured width after breaking
text.
int getTextWidths(const void* text, size_t byteLength, SkScalar widths[], SkRect bounds[] = nullptr) const
Retrieves the advance and bounds for each glyph in text, and returns
the glyph count in text.
Both widths and bounds may be nullptr.
If widths is not nullptr, widths must be an array of glyph count entries.
if bounds is not nullptr, bounds must be an array of glyph count entries.
Widths returns the horizontal advance.
Uses Text Encoding to decode text, Typeface to get the font metrics,
and Text Size to scale the widths and bounds.
Does not scale the advance by Fake Bold or Path Effect.
Does include Fake Bold and Path Effect in the bounds.
### Parameters
text |
character codes or glyph indices to be measured |
byteLength |
number of bytes of text to measure |
widths |
returns text advances for each glyph; may be nullptr |
bounds |
returns bounds for each glyph relative to (0, 0); may be nullptr |
### Return Value
glyph count in text
### Example
Bounds of
Glyphs increase for stroked
text, but
text advance remains the same.
The underlines show the
text advance, spaced to keep them distinct.
void getTextPath(const void* text, size_t length, SkScalar x, SkScalar y, SkPath* path) const
Returns the geometry as Path equivalent to the drawn text.
Uses Text Encoding to decode text, Typeface to get the glyph paths,
and Text Size, Fake Bold, and Path Effect to scale and modify the glyph paths.
All of the glyph paths are stored in path.
Uses x, y, and Text Align to position path.
### Parameters
### Example
Text is added to
Path, offset, and subtracted from
Path, then added at
the offset location. The result is rendered with one draw call.
void getPosTextPath(const void* text, size_t length, const SkPoint pos[], SkPath* path) const
Returns the geometry as Path equivalent to the drawn text.
Uses Text Encoding to decode text, Typeface to get the glyph paths,
and Text Size, Fake Bold, and Path Effect to scale and modify the glyph paths.
All of the glyph paths are stored in path.
Uses pos array and Text Align to position path.
pos contains a position for each glyph.
### Parameters
### Example
Simplifies three
Glyphs to eliminate overlaps, and strokes the result.
int getTextIntercepts(const void* text, size_t length, SkScalar x, SkScalar y,
const SkScalar bounds[2], SkScalar* intervals) const
Returns the number of intervals that intersect bounds.
bounds describes a pair of lines parallel to the text advance.
The return count is zero or a multiple of two, and is at most twice the number of Glyphs in
the string.
Uses Text Encoding to decode text, Typeface to get the glyph paths,
and Text Size, Fake Bold, and Path Effect to scale and modify the glyph paths.
Uses x, y, and Text Align to position intervals.
Pass nullptr for intervals to determine the size of the interval array.
intervals are cached to improve performance for multiple calls.
### Parameters
text |
character codes or glyph indices |
length |
number of bytes of text |
x |
x-axis value of the origin of the text |
y |
y-axis value of the origin of the text |
bounds |
lower and upper line parallel to the advance |
intervals |
returned intersections; may be nullptr |
### Return Value
number of intersections; may be zero
### Example
Underline uses intercepts to draw on either side of the glyph Descender.
int getPosTextIntercepts(const void* text, size_t length, const SkPoint pos[],
const SkScalar bounds[2], SkScalar* intervals) const
Returns the number of intervals that intersect bounds.
bounds describes a pair of lines parallel to the text advance.
The return count is zero or a multiple of two, and is at most twice the number of Glyphs in
the string.
Uses Text Encoding to decode text, Typeface to get the glyph paths,
and Text Size, Fake Bold, and Path Effect to scale and modify the glyph paths.
Uses pos array and Text Align to position intervals.
Pass nullptr for intervals to determine the size of the interval array.
intervals are cached to improve performance for multiple calls.
### Parameters
text |
character codes or glyph indices |
length |
number of bytes of text |
pos |
positions of each glyph |
bounds |
lower and upper line parallel to the advance |
intervals |
returned intersections; may be nullptr |
### Return Value
number of intersections; may be zero
### Example
Text intercepts draw on either side of, but not inside,
Glyphs in a run.
int getPosTextHIntercepts(const void* text, size_t length, const SkScalar xpos[], SkScalar constY,
const SkScalar bounds[2], SkScalar* intervals) const
Returns the number of intervals that intersect bounds.
bounds describes a pair of lines parallel to the text advance.
The return count is zero or a multiple of two, and is at most twice the number of Glyphs in
the string.
Uses Text Encoding to decode text, Typeface to get the glyph paths,
and Text Size, Fake Bold, and Path Effect to scale and modify the glyph paths.
Uses xpos array, constY, and Text Align to position intervals.
Pass nullptr for intervals to determine the size of the interval array.
intervals are cached to improve performance for multiple calls.
### Parameters
text |
character codes or glyph indices |
length |
number of bytes of text |
xpos |
positions of each glyph in x |
constY |
position of each glyph in y |
bounds |
lower and upper line parallel to the advance |
intervals |
returned intersections; may be nullptr |
### Return Value
number of intersections; may be zero
### Example
Text intercepts do not take stroke thickness into consideration.
int getTextBlobIntercepts(const SkTextBlob* blob, const SkScalar bounds[2], SkScalar* intervals) const
Returns the number of intervals that intersect bounds.
bounds describes a pair of lines parallel to the text advance.
The return count is zero or a multiple of two, and is at most twice the number of Glyphs in
the string.
Uses Typeface to get the glyph paths,
and Text Size, Fake Bold, and Path Effect to scale and modify the glyph paths.
Uses run array and Text Align to position intervals.
Text Encoding must be set to SkPaint::kGlyphID TextEncoding.
Pass nullptr for intervals to determine the size of the interval array.
intervals are cached to improve performance for multiple calls.
### Parameters
blob |
Glyphs, positions, and text paint attributes |
bounds |
lower and upper line parallel to the advance |
intervals |
returned intersections; may be nullptr |
### Return Value
number of intersections; may be zero
### Example
---
bool nothingToDraw() const
Returns true if Paint prevents all drawing;
otherwise, the Paint may or may not allow drawing.
Returns true if, for example, Blend Mode combined with Color Alpha computes a
new Alpha of zero.
### Return Value
true if Paint prevents all drawing
### Example
#### Example Output
~~~~
initial nothing to draw: false
blend dst nothing to draw: true
blend src over nothing to draw: false
alpha 0 nothing to draw: true
~~~~
Private: To be made private.
Fast Bounds functions conservatively outset a drawing bounds by additional area
Paint may draw to.
---
bool canComputeFastBounds() const
Private: (to be made private)
Returns true if Paint does not include elements requiring extensive computation
to compute Device bounds of drawn geometry. For instance, Paint with Path Effect
always returns false.
### Return Value
true if Paint allows for fast computation of bounds
---
const SkRect& computeFastBounds(const SkRect& orig, SkRect* storage) const
Private: (to be made private)
Only call this if canComputeFastBounds returned true. This takes a
raw rectangle (the raw bounds of a shape), and adjusts it for stylistic
effects in the paint (e.g. stroking). If needed, it uses the storage
parameter. It returns the adjusted bounds that can then be used
for SkCanvas::quickReject tests.
The returned Rect will either be orig or storage, thus the caller
should not rely on storage being set to the result, but should always
use the returned value. It is legal for orig and storage to be the same
Rect.
Private: For example:
if (!path.isInverseFillType() && paint.canComputeFastBounds()) {
SkRect storage;
if (canvas->quickReject(paint.computeFastBounds(path.getBounds(), &storage))) {
return; // do not draw the path
}
}
// draw the path
### Parameters
orig |
geometry modified by Paint when drawn |
storage |
computed bounds of geometry; may not be nullptr |
### Return Value
fast computed bounds
---
const SkRect& computeFastStrokeBounds(const SkRect& orig, SkRect* storage) const
Private: (to be made private)
### Parameters
### Return Value
fast computed bounds
---
const SkRect& doComputeFastBounds(const SkRect& orig, SkRect* storage, Style style) const
Private: (to be made private)
Computes the bounds, overriding the Paint Style. This can be used to
account for additional width required by stroking orig, without
altering Style set to fill.
### Parameters
### Return Value
fast computed bounds