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skia2/include/core/SkPaint.h
Ben Wagner e580649a38 Update doc and example for SkPaint::FontMetrics. 
The underline position is actually the top of the underline. Also
clarify that the strike through position is the bottom of the strike
through.

This adds documentation that the values are always y-down in a way that
will end up in the SkPaint header file for those who look for
information there.

Change-Id: I40281c0e47557d23291b6a91474e2d3e3b37f09f
Docs-Preview: https://skia.org/user/api/SkPaint_Reference?cl=69361#FontMetrics
Reviewed-on: https://skia-review.googlesource.com/69361
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
2017-11-09 18:20:14 +00:00

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/*
* Copyright 2006 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkPaint_DEFINED
#define SkPaint_DEFINED
#include "SkBlendMode.h"
#include "SkColor.h"
#include "SkFilterQuality.h"
#include "SkMatrix.h"
#include "SkRefCnt.h"
class SkAutoDescriptor;
class SkAutoGlyphCache;
class SkColorFilter;
class SkData;
class SkDescriptor;
class SkDrawLooper;
class SkReadBuffer;
class SkWriteBuffer;
class SkGlyph;
struct SkRect;
class SkGlyphCache;
class SkImageFilter;
class SkMaskFilter;
class SkPath;
class SkPathEffect;
struct SkPoint;
class SkRasterizer;
struct SkScalerContextEffects;
class SkShader;
class SkSurfaceProps;
class SkTextBlob;
class SkTypeface;
/** \class SkPaint
SkPaint controls options applied when drawing and measuring. SkPaint collects all
options outside of the SkCanvas clip and SkCanvas 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 SkCanvas
functionality; for instance, text size is identical to matrix scale.
SkPaint options are rarely exclusive; each option modifies a stage of the drawing
pipeline and multiple pipeline stages may be affected by a single SkPaint.
SkPaint collects effects and filters that describe single-pass and multiple-pass
algorithms that alter the drawing geometry, color, and transparency. For instance,
SkPaint does not directly implement dashing or blur, but contains the objects that do so.
The objects contained by SkPaint are opaque, and cannot be edited outside of the SkPaint
to affect it. The implementation is free to defer computations associated with the
SkPaint, or ignore them altogether. For instance, some GPU implementations draw all
SkPath geometries with anti-aliasing, regardless of how SkPaint::kAntiAlias_Flag
is set in SkPaint.
SkPaint 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
SkShader attached to SkPaint.
*/
class SK_API SkPaint {
public:
/** Constructs SkPaint with default values.
@return default initialized SkPaint
*/
SkPaint();
/** Makes a shallow copy of SkPaint. SkTypeface, SkPathEffect, SkShader,
SkMaskFilter, SkColorFilter, SkRasterizer, SkDrawLooper, and SkImageFilter are shared
between the original paint and the copy. Objects containing SkRefCnt increment
their references by one.
The referenced objects SkPathEffect, SkShader, SkMaskFilter, SkColorFilter, SkRasterizer,
SkDrawLooper, and SkImageFilter cannot be modified after they are created.
This prevents objects with SkRefCnt from being modified once SkPaint refers to them.
@param paint original to copy
@return shallow copy of paint
*/
SkPaint(const 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.
@param paint original to move
@return content of paint
*/
SkPaint(SkPaint&& paint);
/** Decreases SkPaint SkRefCnt of owned objects: SkTypeface, SkPathEffect, SkShader,
SkMaskFilter, SkColorFilter, SkRasterizer, SkDrawLooper, and SkImageFilter. If the
objects containing SkRefCnt go to zero, they are deleted.
*/
~SkPaint();
/** Makes a shallow copy of SkPaint. SkTypeface, SkPathEffect, SkShader,
SkMaskFilter, SkColorFilter, SkRasterizer, SkDrawLooper, and SkImageFilter are shared
between the original paint and the copy. Objects containing SkRefCnt in the
prior destination are decreased by one, and the referenced objects are deleted if the
resulting count is zero. Objects containing SkRefCnt in the parameter paint
are increased by one. paint is unmodified.
@param paint original to copy
@return content of paint
*/
SkPaint& operator=(const SkPaint& paint);
/** Moves the paint to avoid increasing the reference counts
of objects referenced by the paint parameter. Objects containing SkRefCnt 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.
@param paint original to move
@return content of paint
*/
SkPaint& operator=(SkPaint&& paint);
/** Compares a and b, and returns true if a and b are equivalent. May return false
if SkTypeface, SkPathEffect, SkShader, SkMaskFilter, SkColorFilter, SkRasterizer,
SkDrawLooper, or SkImageFilter have identical contents but different pointers.
@param a SkPaint to compare
@param b SkPaint to compare
@return true if SkPaint pair are equivalent
*/
SK_API friend 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 SkTypeface, SkPathEffect, SkShader, SkMaskFilter, SkColorFilter, SkRasterizer,
SkDrawLooper, or SkImageFilter have identical contents but different pointers.
@param a SkPaint to compare
@param b SkPaint to compare
@return true if SkPaint pair are not equivalent
*/
friend bool operator!=(const SkPaint& a, const SkPaint& b) {
return !(a == b);
}
/** Returns a hash generated from SkPaint 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 a shallow hash
*/
uint32_t getHash() const;
/** Serializes SkPaint into a buffer. A companion unflatten() call
can reconstitute the paint at a later time.
@param buffer SkWriteBuffer receiving the flattened SkPaint data
*/
void flatten(SkWriteBuffer& buffer) const;
/** Populates SkPaint, typically from a serialized stream, created by calling
flatten() at an earlier time.
SkReadBuffer class is not public, so unflatten() cannot be meaningfully called
by the client.
@param buffer serialized data describing SkPaint content
*/
void unflatten(SkReadBuffer& buffer);
/** Sets all SkPaint contents to their initial values. This is equivalent to replacing
SkPaint with the result of SkPaint().
*/
void reset();
/** \enum SkPaint::Hinting
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.
*/
enum Hinting {
/** 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.
*/
kNo_Hinting = 0,
/** 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.
*/
kSlight_Hinting = 1,
/** 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.
*/
kNormal_Hinting = 2,
/** Modifies glyph outlines for maxiumum 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.
*/
kFull_Hinting = 3,
};
/** Returns level of glyph outline adjustment.
@return one of: kNo_Hinting, kSlight_Hinting, kNormal_Hinting, kFull_Hinting
*/
Hinting getHinting() const {
return static_cast<Hinting>(fBitfields.fHinting);
}
/** Sets level of glyph outline adjustment.
Does not check for valid values of hintingLevel.
@param hintingLevel one of: kNo_Hinting, kSlight_Hinting, kNormal_Hinting, kFull_Hinting
*/
void setHinting(Hinting hintingLevel);
/** \enum SkPaint::Flags
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.
*/
enum Flags {
kAntiAlias_Flag = 0x01, //!< mask for setting anti-alias
kDither_Flag = 0x04, //!< mask for setting dither
kFakeBoldText_Flag = 0x20, //!< mask for setting fake bold
kLinearText_Flag = 0x40, //!< mask for setting linear text
kSubpixelText_Flag = 0x80, //!< mask for setting subpixel text
kDevKernText_Flag = 0x100, //!< mask for setting full hinting spacing
kLCDRenderText_Flag = 0x200, //!< mask for setting lcd text
kEmbeddedBitmapText_Flag = 0x400, //!< mask for setting font embedded bitmaps
kAutoHinting_Flag = 0x800, //!< mask for setting auto-hinting
kVerticalText_Flag = 0x1000, //!< mask for setting vertical text
/** Hack for GDI -- do not use if you can help it */
kGenA8FromLCD_Flag = 0x2000,
/** mask of all Flags, including private flags and flags reserved for future use */
kAllFlags = 0xFFFF,
};
#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
enum ReserveFlags {
kUnderlineText_ReserveFlag = 0x08, //!< mask for underline text
kStrikeThruText_ReserveFlag = 0x10, //!< mask for strike-thru text
};
#endif
/** Returns paint settings described by SkPaint::Flags. Each setting uses one
bit, and can be tested with SkPaint::Flags members.
@return zero, one, or more bits described by SkPaint::Flags
*/
uint32_t getFlags() const { return fBitfields.fFlags; }
/** Replaces SkPaint::Flags with flags, the union of the SkPaint::Flags members.
All SkPaint::Flags members may be cleared, or one or more may be set.
@param flags union of SkPaint::Flags for SkPaint
*/
void setFlags(uint32_t flags);
/** If true, pixels on the active edges of SkPath may be drawn with partial transparency.
Equivalent to getFlags() masked with kAntiAlias_Flag.
@return kAntiAlias_Flag state
*/
bool isAntiAlias() const {
return SkToBool(this->getFlags() & kAntiAlias_Flag);
}
/** Requests, but does not require, that SkPath edge pixels draw opaque or with
partial transparency.
Sets kAntiAlias_Flag if aa is true.
Clears kAntiAlias_Flag if aa is false.
@param aa setting for kAntiAlias_Flag
*/
void setAntiAlias(bool aa);
/** If true, color error may be distributed to smooth color transition.
Equivalent to getFlags() masked with kDither_Flag.
@return kDither_Flag state
*/
bool isDither() const {
return SkToBool(this->getFlags() & kDither_Flag);
}
/** Requests, but does not require, to distribute color error.
Sets kDither_Flag if dither is true.
Clears kDither_Flag if dither is false.
@param dither setting for kDither_Flag
*/
void setDither(bool dither);
/** If true, text is converted to SkPath before drawing and measuring.
Equivalent to getFlags() masked with kLinearText_Flag.
@return kLinearText_Flag state
*/
bool isLinearText() const {
return SkToBool(this->getFlags() & kLinearText_Flag);
}
/** If true, text is converted to SkPath before drawing and measuring.
By default, kLinearText_Flag is clear.
Sets kLinearText_Flag if linearText is true.
Clears kLinearText_Flag if linearText is false.
@param linearText setting for kLinearText_Flag
*/
void setLinearText(bool linearText);
/** If true, glyphs at different sub-pixel positions may differ on pixel edge coverage.
Equivalent to getFlags() masked with kSubpixelText_Flag.
@return kSubpixelText_Flag state
*/
bool isSubpixelText() const {
return SkToBool(this->getFlags() & kSubpixelText_Flag);
}
/** 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.
@param subpixelText setting for kSubpixelText_Flag
*/
void setSubpixelText(bool subpixelText);
/** If true, glyphs may use LCD striping to improve glyph edges.
Returns true if SkPaint::Flags kLCDRenderText_Flag is set.
@return kLCDRenderText_Flag state
*/
bool isLCDRenderText() const {
return SkToBool(this->getFlags() & kLCDRenderText_Flag);
}
/** 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.
@param lcdText setting for kLCDRenderText_Flag
*/
void setLCDRenderText(bool lcdText);
/** If true, font engine may return glyphs from font bitmaps instead of from outlines.
Equivalent to getFlags() masked with kEmbeddedBitmapText_Flag.
@return kEmbeddedBitmapText_Flag state
*/
bool isEmbeddedBitmapText() const {
return SkToBool(this->getFlags() & kEmbeddedBitmapText_Flag);
}
/** 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.
@param useEmbeddedBitmapText setting for kEmbeddedBitmapText_Flag
*/
void setEmbeddedBitmapText(bool useEmbeddedBitmapText);
/** If true, and if SkPaint::Hinting is set to kNormal_Hinting or kFull_Hinting, and if
platform uses FreeType as the font manager, instruct the font manager to always hint
glyphs.
Equivalent to getFlags() masked with kAutoHinting_Flag.
@return kAutoHinting_Flag state
*/
bool isAutohinted() const {
return SkToBool(this->getFlags() & kAutoHinting_Flag);
}
/** If SkPaint::Hinting is set to kNormal_Hinting or kFull_Hinting and useAutohinter is set,
instruct the font manager to always hint glyphs.
auto-hinting has no effect if SkPaint::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.
@param useAutohinter setting for kAutoHinting_Flag
*/
void setAutohinted(bool useAutohinter);
/** If true, glyphs are drawn top to bottom instead of left to right.
Equivalent to getFlags() masked with kVerticalText_Flag.
@return kVerticalText_Flag state
*/
bool isVerticalText() const {
return SkToBool(this->getFlags() & kVerticalText_Flag);
}
/** If true, text advance positions the next glyph below the previous glyph instead of to the
right of previous glyph.
Sets kVerticalText_Flag if vertical is true.
Clears kVerticalText_Flag if vertical is false.
@param verticalText setting for kVerticalText_Flag
*/
void setVerticalText(bool verticalText);
/** If true, approximate bold by increasing the stroke width when creating glyph bitmaps
from outlines.
Equivalent to getFlags() masked with kFakeBoldText_Flag.
@return kFakeBoldText_Flag state
*/
bool isFakeBoldText() const {
return SkToBool(this->getFlags() & kFakeBoldText_Flag);
}
/** Use increased 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.
@param fakeBoldText setting for kFakeBoldText_Flag
*/
void setFakeBoldText(bool fakeBoldText);
/** Returns if character spacing may be adjusted by the hinting difference.
Equivalent to getFlags() masked with kDevKernText_Flag.
@return kDevKernText_Flag state
*/
bool isDevKernText() const {
return SkToBool(this->getFlags() & kDevKernText_Flag);
}
/** Requests, but does not require, to use hinting to adjust glyph spacing.
Sets kDevKernText_Flag if devKernText is true.
Clears kDevKernText_Flag if devKernText is false.
@param devKernText setting for devKernText
*/
void setDevKernText(bool devKernText);
/** Returns SkFilterQuality, the image filtering level. A lower setting
draws faster; a higher setting looks better when the image is scaled.
@return one of: kNone_SkFilterQuality, kLow_SkFilterQuality,
kMedium_SkFilterQuality, kHigh_SkFilterQuality
*/
SkFilterQuality getFilterQuality() const {
return (SkFilterQuality)fBitfields.fFilterQuality;
}
/** Sets SkFilterQuality, 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.
@param quality one of: kNone_SkFilterQuality, kLow_SkFilterQuality,
kMedium_SkFilterQuality, kHigh_SkFilterQuality
*/
void setFilterQuality(SkFilterQuality quality);
/** \enum SkPaint::Style
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.
*/
enum Style {
/** Set to fill geometry.
Applies to SkRect, SkRegion, SkRRect, circles, ovals, SkPath, and text.
SkBitmap, SkImage, patches, SkRegion, sprites, and vertices are painted as if
kFill_Style is set, and ignore the set Style.
The FillType 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.
*/
kFill_Style,
/** Set to stroke geometry.
Applies to SkRect, SkRegion, SkRRect, arcs, circles, ovals, SkPath, and text.
Arcs, lines, and SkPoint, are always drawn as if kStroke_Style is set,
and ignore the set Style.
The stroke construction is unaffected by the FillType.
*/
kStroke_Style,
/** Set to stroke and fill geometry.
Applies to SkRect, SkRegion, SkRRect, circles, ovals, SkPath, and text.
SkPath is treated as if it is set to SkPath::kWinding_FillType,
and the set FillType is ignored.
*/
kStrokeAndFill_Style,
};
enum {
/** The number of different Style values defined.
May be used to verify that Style is a legal value.
*/
kStyleCount = kStrokeAndFill_Style + 1,
};
/** Whether the geometry is filled, stroked, or filled and stroked.
@return one of:kFill_Style, kStroke_Style, kStrokeAndFill_Style
*/
Style getStyle() const { return (Style)fBitfields.fStyle; }
/** Sets whether the geometry is filled, stroked, or filled and stroked.
Has no effect if style is not a legal SkPaint::Style value.
@param style one of: kFill_Style, kStroke_Style, kStrokeAndFill_Style
*/
void setStyle(Style style);
/** Retrieves alpha and RGB, unpremultiplied, packed into 32 bits.
Use helpers SkColorGetA(), SkColorGetR(), SkColorGetG(), and SkColorGetB() to extract
a color component.
@return unpremultiplied ARGB
*/
SkColor getColor() const { return fColor; }
/** 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.
@param color unpremultiplied ARGB
*/
void setColor(SkColor color);
/** Retrieves alpha from the color used when stroking and filling.
@return alpha ranging from zero, fully transparent, to 255, fully opaque
*/
uint8_t getAlpha() const { return SkToU8(SkColorGetA(fColor)); }
/** 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.
@param a alpha component of color
*/
void setAlpha(U8CPU a);
/** 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.
@param a amount of color alpha, from fully transparent (0) to fully opaque (255)
@param r amount of color rgb red, from no red (0) to full red (255)
@param g amount of color rgb green, from no green (0) to full green (255)
@param b amount of color rgb blue, from no blue (0) to full blue (255)
*/
void setARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b);
/** Returns the thickness of the pen used by SkPaint to
outline the shape.
@return zero for hairline, greater than zero for pen thickness
*/
SkScalar getStrokeWidth() const { return fWidth; }
/** Sets the thickness of the pen used by the paint to
outline the shape.
Has no effect if width is less than zero.
@param width zero thickness for hairline; greater than zero for pen thickness
*/
void setStrokeWidth(SkScalar width);
/** The limit at which a sharp corner is drawn beveled.
@return zero and greater miter limit
*/
SkScalar getStrokeMiter() const { return fMiterLimit; }
/** 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.
@param miter zero and greater miter limit
*/
void setStrokeMiter(SkScalar miter);
/** \enum SkPaint::Cap
Cap draws at the beginning and end of an open path contour.
*/
enum Cap {
kButt_Cap, //!< Does not extend the stroke past the beginning or the end.
/** Adds a circle with a diameter equal to stroke width at the beginning
and end.
*/
kRound_Cap,
/** Adds a square with sides equal to stroke width at the beginning
and end. The square sides are parallel to the initial and final direction
of the stroke.
*/
kSquare_Cap,
kLast_Cap = kSquare_Cap, //!< Equivalent to the largest value for Cap.
/** Equivalent to kButt_Cap.
Cap is set to kButt_Cap by default.
*/
kDefault_Cap = kButt_Cap,
};
static constexpr int kCapCount = kLast_Cap + 1;
/** \enum SkPaint::Join
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.
*/
enum Join {
/** Extends the outside corner to the extent allowed by miter limit.
If the extension exceeds miter limit, kBevel_Join is used instead.
*/
kMiter_Join,
/** Adds a circle with a diameter of stroke width at the sharp corner. */
kRound_Join,
kBevel_Join, //!< Connects the outside edges of the sharp corner.
kLast_Join = kBevel_Join, //!< Equivalent to the largest value for Join.
/** Equivalent to kMiter_Join.
Join is set to kMiter_Join by default.
*/
kDefault_Join = kMiter_Join,
};
static constexpr int kJoinCount = kLast_Join + 1;
/** The geometry drawn at the beginning and end of strokes.
@return one of: kButt_Cap, kRound_Cap, kSquare_Cap
*/
Cap getStrokeCap() const { return (Cap)fBitfields.fCapType; }
/** The geometry drawn at the beginning and end of strokes.
@param cap one of: kButt_Cap, kRound_Cap, kSquare_Cap;
has no effect if cap is not valid
*/
void setStrokeCap(Cap cap);
/** The geometry drawn at the corners of strokes.
@return one of: kMiter_Join, kRound_Join, kBevel_Join
*/
Join getStrokeJoin() const { return (Join)fBitfields.fJoinType; }
/** The geometry drawn at the corners of strokes.
@param join one of: kMiter_Join, kRound_Join, kBevel_Join;
otherwise, has no effect
*/
void setStrokeJoin(Join join);
/** The filled equivalent of the stroked path.
@param src SkPath read to create a filled version
@param dst resulting SkPath; may be the same as src, but may not be nullptr
@param cullRect optional limit passed to SkPathEffect
@param resScale if > 1, increase precision, else if (0 < res < 1) reduce precision
to favor speed and size
@return true if the path represents style fill, or false if it represents hairline
*/
bool getFillPath(const SkPath& src, SkPath* dst, const SkRect* cullRect,
SkScalar resScale = 1) const;
/** The filled equivalent of the stroked path.
Replaces dst with the src path modified by SkPathEffect and style stroke.
SkPathEffect, if any, is not culled. stroke width is created with default precision.
@param src SkPath read to create a filled version
@param dst resulting SkPath dst may be the same as src, but may not be nullptr
@return true if the path represents style fill, or false if it represents hairline
*/
bool getFillPath(const SkPath& src, SkPath* dst) const {
return this->getFillPath(src, dst, nullptr, 1);
}
/** Optional colors used when filling a path, such as a gradient.
Does not alter SkShader SkRefCnt.
@return SkShader if previously set, nullptr otherwise
*/
SkShader* getShader() const { return fShader.get(); }
/** Optional colors used when filling a path, such as a gradient.
Increases SkShader SkRefCnt by one.
@return SkShader if previously set, nullptr otherwise
*/
sk_sp<SkShader> refShader() const;
/** Optional colors used when filling a path, such as a gradient.
Sets SkShader to shader, decreasing SkRefCnt of the previous SkShader.
Increments shader SkRefCnt by one.
@param shader how geometry is filled with color; if nullptr, color is used instead
*/
void setShader(sk_sp<SkShader> shader);
/** Returns SkColorFilter if set, or nullptr.
Does not alter SkColorFilter SkRefCnt.
@return SkColorFilter if previously set, nullptr otherwise
*/
SkColorFilter* getColorFilter() const { return fColorFilter.get(); }
/** Returns SkColorFilter if set, or nullptr.
Increases SkColorFilter SkRefCnt by one.
@return SkColorFilter if set, or nullptr
*/
sk_sp<SkColorFilter> refColorFilter() const;
/** Sets SkColorFilter to filter, decreasing SkRefCnt of the previous
SkColorFilter. Pass nullptr to clear SkColorFilter.
Increments filter SkRefCnt by one.
@param colorFilter SkColorFilter to apply to subsequent draw
*/
void setColorFilter(sk_sp<SkColorFilter> colorFilter);
/** Returns SkBlendMode.
By default, returns SkBlendMode::kSrcOver.
@return mode used to combine source color with destination color
*/
SkBlendMode getBlendMode() const { return (SkBlendMode)fBlendMode; }
/** Returns true if SkBlendMode is SkBlendMode::kSrcOver, the default.
@return true if SkBlendMode is SkBlendMode::kSrcOver
*/
bool isSrcOver() const { return (SkBlendMode)fBlendMode == SkBlendMode::kSrcOver; }
/** Sets SkBlendMode to mode.
Does not check for valid input.
@param mode SkBlendMode used to combine source color and destination
*/
void setBlendMode(SkBlendMode mode) { fBlendMode = (unsigned)mode; }
/** Returns SkPathEffect if set, or nullptr.
Does not alter SkPathEffect SkRefCnt.
@return SkPathEffect if previously set, nullptr otherwise
*/
SkPathEffect* getPathEffect() const { return fPathEffect.get(); }
/** Returns SkPathEffect if set, or nullptr.
Increases SkPathEffect SkRefCnt by one.
@return SkPathEffect if previously set, nullptr otherwise
*/
sk_sp<SkPathEffect> refPathEffect() const;
/** Sets SkPathEffect to pathEffect, decreasing SkRefCnt of the previous
SkPathEffect. Pass nullptr to leave the path geometry unaltered.
Increments pathEffect SkRefCnt by one.
@param pathEffect replace SkPath with a modification when drawn
*/
void setPathEffect(sk_sp<SkPathEffect> pathEffect);
/** Returns SkMaskFilter if set, or nullptr.
Does not alter SkMaskFilter SkRefCnt.
@return SkMaskFilter if previously set, nullptr otherwise
*/
SkMaskFilter* getMaskFilter() const { return fMaskFilter.get(); }
/** Returns SkMaskFilter if set, or nullptr.
Increases SkMaskFilter SkRefCnt by one.
@return SkMaskFilter if previously set, nullptr otherwise
*/
sk_sp<SkMaskFilter> refMaskFilter() const;
/** Sets SkMaskFilter to maskFilter, decreasing SkRefCnt of the previous
SkMaskFilter. Pass nullptr to clear SkMaskFilter and leave SkMaskFilter effect on
mask alpha unaltered.
Does not affect SkRasterizer.
Increments maskFilter SkRefCnt by one.
@param maskFilter modifies clipping mask generated from drawn geometry
*/
void setMaskFilter(sk_sp<SkMaskFilter> maskFilter);
/** Returns SkTypeface if set, or nullptr.
Increments SkTypeface SkRefCnt by one.
@return SkTypeface if previously set, nullptr otherwise
*/
SkTypeface* getTypeface() const { return fTypeface.get(); }
/** Increases SkTypeface SkRefCnt by one.
@return SkTypeface if previously set, nullptr otherwise
*/
sk_sp<SkTypeface> refTypeface() const;
/** Sets SkTypeface to typeface, decreasing SkRefCnt of the previous SkTypeface.
Pass nullptr to clear SkTypeface and use the default typeface. Increments
typeface SkRefCnt by one.
@param typeface font and style used to draw text
*/
void setTypeface(sk_sp<SkTypeface> typeface);
/** Returns SkRasterizer if set, or nullptr.
Does not alter SkRasterizer SkRefCnt.
@return SkRasterizer if previously set, nullptr otherwise
*/
SkRasterizer* getRasterizer() const { return fRasterizer.get(); }
/** Returns SkRasterizer if set, or nullptr.
Increases SkRasterizer SkRefCnt by one.
@return SkRasterizer if previously set, nullptr otherwise
*/
sk_sp<SkRasterizer> refRasterizer() const;
/** Sets SkRasterizer to rasterizer, decreasing SkRefCnt of the previous
SkRasterizer. Pass nullptr to clear SkRasterizer and leave SkRasterizer effect on
mask alpha unaltered.
Does not affect SkMaskFilter.
Increments rasterizer SkRefCnt by one.
@param rasterizer how geometry is converted to mask alpha
*/
void setRasterizer(sk_sp<SkRasterizer> rasterizer);
/** Returns SkImageFilter if set, or nullptr.
Does not alter SkImageFilter SkRefCnt.
@return SkImageFilter if previously set, nullptr otherwise
*/
SkImageFilter* getImageFilter() const { return fImageFilter.get(); }
/** Returns SkImageFilter if set, or nullptr.
Increases SkImageFilter SkRefCnt by one.
@return SkImageFilter if previously set, nullptr otherwise
*/
sk_sp<SkImageFilter> refImageFilter() const;
/** Sets SkImageFilter to imageFilter, decreasing SkRefCnt of the previous
SkImageFilter. Pass nullptr to clear SkImageFilter, and remove SkImageFilter effect
on drawing.
Does not affect SkRasterizer or SkMaskFilter.
Increments imageFilter SkRefCnt by one.
@param imageFilter how SkImage is sampled when transformed
*/
void setImageFilter(sk_sp<SkImageFilter> imageFilter);
/** Returns SkDrawLooper if set, or nullptr.
Does not alter SkDrawLooper SkRefCnt.
@return SkDrawLooper if previously set, nullptr otherwise
*/
SkDrawLooper* getDrawLooper() const { return fDrawLooper.get(); }
/** Returns SkDrawLooper if set, or nullptr.
Increases SkDrawLooper SkRefCnt by one.
@return SkDrawLooper if previously set, nullptr otherwise
*/
sk_sp<SkDrawLooper> refDrawLooper() const;
/** Deprecated.
(see bug.skia.org/6259)
@return SkDrawLooper if previously set, nullptr otherwise
*/
SkDrawLooper* getLooper() const { return fDrawLooper.get(); }
/** Sets SkDrawLooper to drawLooper, decreasing SkRefCnt of the previous
drawLooper. Pass nullptr to clear SkDrawLooper and leave SkDrawLooper effect on
drawing unaltered.
Increments drawLooper SkRefCnt by one.
@param drawLooper iterates through drawing one or more time, altering SkPaint
*/
void setDrawLooper(sk_sp<SkDrawLooper> drawLooper);
/** Deprecated.
(see bug.skia.org/6259)
@param drawLooper sets SkDrawLooper to drawLooper
*/
void setLooper(sk_sp<SkDrawLooper> drawLooper);
/** \enum SkPaint::Align
Align adjusts the text relative to the text position.
Align affects glyphs drawn with: SkCanvas::drawText, SkCanvas::drawPosText,
SkCanvas::drawPosTextH, SkCanvas::drawTextOnPath,
SkCanvas::drawTextOnPathHV, SkCanvas::drawTextRSXform, SkCanvas::drawTextBlob,
and SkCanvas::drawString;
as well as calls that place text glyphs like getTextWidths() and getTextPath().
The text position is set by the font for both horizontal and vertical text.
Typically, for horizontal text, the position is to the left side of the glyph on the
base line; and for vertical text, the position is the horizontal center of the glyph
at the caps height.
Align adjusts the glyph position to center it or move it to abut the position
using the metrics returned by the font.
Align defaults to kLeft_Align.
*/
enum Align {
/** Leaves the glyph at the position computed by the font offset by the text position. */
kLeft_Align,
/** Moves the glyph half its width if Flags has kVerticalText_Flag clear, and
half its height if Flags has kVerticalText_Flag set.
*/
kCenter_Align,
/** Moves the glyph by its width if Flags has kVerticalText_Flag clear,
and by its height if Flags has kVerticalText_Flag set.
*/
kRight_Align,
};
enum {
kAlignCount = 3, //!< The number of different Align values defined.
};
/** Returns SkPaint::Align.
Returns kLeft_Align if SkPaint::Align has not been set.
@return text placement relative to position
*/
Align getTextAlign() const { return (Align)fBitfields.fTextAlign; }
/** Sets SkPaint::Align to align.
Has no effect if align is an invalid value.
@param align text placement relative to position
*/
void setTextAlign(Align align);
/** Returns text size in points.
@return typographic height of text
*/
SkScalar getTextSize() const { return fTextSize; }
/** Sets text size in points.
Has no effect if textSize is not greater than or equal to zero.
@param textSize typographic height of text
*/
void setTextSize(SkScalar textSize);
/** Returns text scale x.
Default value is 1.
@return text horizontal scale
*/
SkScalar getTextScaleX() const { return fTextScaleX; }
/** Sets text scale x.
Default value is 1.
@param scaleX text horizontal scale
*/
void setTextScaleX(SkScalar scaleX);
/** Returns text skew x.
Default value is zero.
@return additional shear in x-axis relative to y-axis
*/
SkScalar getTextSkewX() const { return fTextSkewX; }
/** Sets text skew x.
Default value is zero.
@param skewX additional shear in x-axis relative to y-axis
*/
void setTextSkewX(SkScalar skewX);
/** \enum SkPaint::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.
*/
enum TextEncoding {
kUTF8_TextEncoding, //!< Uses bytes to represent UTF-8 or ASCII.
kUTF16_TextEncoding, //!< Uses two byte words to represent most of Unicode.
kUTF32_TextEncoding, //!< Uses four byte words to represent all of Unicode.
kGlyphID_TextEncoding, //!< Uses two byte words to represent glyph indices.
};
/** Returns SkPaint::TextEncoding.
SkPaint::TextEncoding determines how character code points are mapped to font glyph indices.
@return one of: kUTF8_TextEncoding, kUTF16_TextEncoding, kUTF32_TextEncoding, or
kGlyphID_TextEncoding
*/
TextEncoding getTextEncoding() const {
return (TextEncoding)fBitfields.fTextEncoding;
}
/** Sets SkPaint::TextEncoding to encoding.
SkPaint::TextEncoding determines how character code points are mapped to font glyph indices.
Invalid values for encoding are ignored.
@param encoding one of: kUTF8_TextEncoding, kUTF16_TextEncoding, kUTF32_TextEncoding, or
kGlyphID_TextEncoding
*/
void setTextEncoding(TextEncoding encoding);
/** \struct SkPaint::FontMetrics
FontMetrics is filled out by getFontMetrics(). FontMetrics contents reflect the values
computed by font manager using SkTypeface. Values are set to zero if they are
not available.
All vertical values relative to the baseline are given y-down. As such, 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.
*/
struct FontMetrics {
/** \enum SkPaint::FontMetrics::FontMetricsFlags
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.
*/
enum FontMetricsFlags {
kUnderlineThicknessIsValid_Flag = 1 << 0, //!< Set if fUnderlineThickness is valid.
kUnderlinePositionIsValid_Flag = 1 << 1, //!< Set if fUnderlinePosition is valid.
kStrikeoutThicknessIsValid_Flag = 1 << 2, //!< Set if fStrikeoutThickness is valid.
kStrikeoutPositionIsValid_Flag = 1 << 3, //!< Set if fStrikeoutPosition is valid.
};
uint32_t fFlags; //!< fFlags is set when underline metrics are valid.
/** Greatest extent above the baseline for any glyph.
Typically less than zero.
*/
SkScalar fTop;
/** Recommended distance above the baseline to reserve for a line of text.
Typically less than zero.
*/
SkScalar fAscent;
/** Recommended distance below the baseline to reserve for a line of text.
Typically greater than zero.
*/
SkScalar fDescent;
/** Greatest extent below the baseline for any glyph.
Typically greater than zero.
*/
SkScalar fBottom;
/** Recommended distance to add between lines of text.
Typically greater than or equal to zero.
*/
SkScalar fLeading;
/** Average character width, if it is available.
Zero if no average width is stored in the font.
*/
SkScalar fAvgCharWidth;
SkScalar fMaxCharWidth; //!< Maximum character width.
/** Minimum bounding box x value for all glyphs.
Typically less than zero.
*/
SkScalar fXMin;
/** Maximum bounding box x value for all glyphs.
Typically greater than zero.
*/
SkScalar fXMax;
/** Height of a lower-case 'x'.
May be zero if no lower-case height is stored in the font.
*/
SkScalar fXHeight;
/** Height of an upper-case letter.
May be zero if no upper-case height is stored in the font.
*/
SkScalar fCapHeight;
/** Underline thickness.
If the metric is valid, the kUnderlineThicknessIsValid_Flag is set in fFlags.
If kUnderlineThicknessIsValid_Flag is clear, fUnderlineThickness is zero.
*/
SkScalar fUnderlineThickness;
/** Position of the top of the underline stroke relative to the baseline.
Typically positive when valid.
If the metric is valid, the kUnderlinePositionIsValid_Flag is set in fFlags.
If kUnderlinePositionIsValid_Flag is clear, fUnderlinePosition is zero.
*/
SkScalar fUnderlinePosition;
/** Strikeout thickness.
If the metric is valid, the kStrikeoutThicknessIsValid_Flag is set in fFlags.
If kStrikeoutThicknessIsValid_Flag is clear, fStrikeoutThickness is zero.
*/
SkScalar fStrikeoutThickness;
/** Position of the bottom of the strikeout stroke relative to the baseline.
Typically negative when valid.
If the metric is valid, the kStrikeoutPositionIsValid_Flag is set in fFlags.
If kStrikeoutPositionIsValid_Flag is clear, fStrikeoutPosition is zero.
*/
SkScalar fStrikeoutPosition;
/** If SkPaint::FontMetrics has a valid underline thickness, return true, and set
thickness to that value. If the underline thickness is not valid,
return false, and ignore thickness.
@param thickness storage for underline width
@return true if font specifies underline width
*/
bool hasUnderlineThickness(SkScalar* thickness) const {
if (SkToBool(fFlags & kUnderlineThicknessIsValid_Flag)) {
*thickness = fUnderlineThickness;
return true;
}
return false;
}
/** If SkPaint::FontMetrics has a valid underline position, return true, and set
position to that value. If the underline position is not valid,
return false, and ignore position.
@param position storage for underline position
@return true if font specifies underline position
*/
bool hasUnderlinePosition(SkScalar* position) const {
if (SkToBool(fFlags & kUnderlinePositionIsValid_Flag)) {
*position = fUnderlinePosition;
return true;
}
return false;
}
/** If SkPaint::FontMetrics has a valid strikeout thickness, return true, and set
thickness to that value. If the underline thickness is not valid,
return false, and ignore thickness.
@param thickness storage for strikeout width
@return true if font specifies strikeout width
*/
bool hasStrikeoutThickness(SkScalar* thickness) const {
if (SkToBool(fFlags & kStrikeoutThicknessIsValid_Flag)) {
*thickness = fStrikeoutThickness;
return true;
}
return false;
}
/** If SkPaint::FontMetrics has a valid strikeout position, return true, and set
position to that value. If the underline position is not valid,
return false, and ignore position.
@param position storage for strikeout position
@return true if font specifies strikeout position
*/
bool hasStrikeoutPosition(SkScalar* position) const {
if (SkToBool(fFlags & kStrikeoutPositionIsValid_Flag)) {
*position = fStrikeoutPosition;
return true;
}
return false;
}
};
/** Returns SkPaint::FontMetrics associated with SkTypeface.
The return value is the recommended spacing between lines: the sum of metrics
descent, ascent, and leading.
If metrics is not nullptr, SkPaint::FontMetrics 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 SkPathEffect.
Results can be additionally scaled by scale; a scale of zero
is ignored.
@param metrics storage for SkPaint::FontMetrics from SkTypeface; may be nullptr
@param scale additional multiplier for returned values
@return recommended spacing between lines
*/
SkScalar getFontMetrics(FontMetrics* metrics, SkScalar scale = 0) 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 SkPathEffect.
Returns the same result as getFontMetrics().
@return recommended spacing between lines
*/
SkScalar getFontSpacing() const { return this->getFontMetrics(nullptr, 0); }
/** Converts text into glyph indices.
Returns the number of glyph indices represented by text.
SkPaint::TextEncoding 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 SkPaint::TextEncoding is kUTF8_TextEncoding and
text contains an invalid UTF-8 sequence, zero is returned.
@param text character storage encoded with SkPaint::TextEncoding
@param byteLength length of character storage in bytes
@param glyphs storage for glyph indices; may be nullptr
@return number of glyphs represented by text of length byteLength
*/
int textToGlyphs(const void* text, size_t byteLength,
SkGlyphID glyphs[]) const;
/** Returns true if all text corresponds to a non-zero glyph index.
Returns false if any characters in text are not supported in
SkTypeface.
If SkPaint::TextEncoding 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 SkTypeface.
Returns true if byteLength is zero.
@param text array of characters or glyphs
@param byteLength number of bytes in text array
@return true if all text corresponds to a non-zero glyph index
*/
bool containsText(const void* text, size_t byteLength) const;
/** Converts glyphs into text if possible.
Glyph values without direct Unicode equivalents are mapped to zero.
Uses the SkTypeface, but is unaffected
by SkPaint::TextEncoding; the text values returned are equivalent to kUTF32_TextEncoding.
Only supported on platforms that use FreeType as the font engine.
@param glyphs array of indices into font
@param count length of glyph array
@param text storage for character codes, one per glyph
*/
void glyphsToUnichars(const SkGlyphID glyphs[], int count, SkUnichar text[]) const;
/** Returns the number of glyphs in text.
Uses SkPaint::TextEncoding to count the glyphs.
Returns the same result as textToGlyphs().
@param text character storage encoded with SkPaint::TextEncoding
@param byteLength length of character storage in bytes
@return number of glyphs represented by text of length byteLength
*/
int countText(const void* text, size_t byteLength) const {
return this->textToGlyphs(text, byteLength, nullptr);
}
/** Returns the advance width of text if kVerticalText_Flag is clear,
and the height of text if kVerticalText_Flag is set.
The advance is the normal distance to move before drawing additional text.
Uses SkPaint::TextEncoding to decode text, SkTypeface to get the font metrics,
and text size, text scale x, text skew x, stroke width, and
SkPathEffect 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.
@param text character codes or glyph indices to be measured
@param length number of bytes of text to measure
@param bounds returns bounding box relative to (0, 0) if not nullptr
@return advance width or height
*/
SkScalar measureText(const void* text, size_t length, SkRect* bounds) const;
/** Returns the advance width of text if kVerticalText_Flag is clear,
and the height of text if kVerticalText_Flag is set.
The advance is the normal distance to move before drawing additional text.
Uses SkPaint::TextEncoding to decode text, SkTypeface to get the font metrics,
and text size to scale the metrics.
Does not scale the advance or bounds by fake bold or SkPathEffect.
@param text character codes or glyph indices to be measured
@param length number of bytes of text to measure
@return advance width or height
*/
SkScalar measureText(const void* text, size_t length) const {
return this->measureText(text, length, nullptr);
}
/** Returns the bytes of text that fit within maxWidth.
If kVerticalText_Flag is clear, the text fragment fits if its advance width is less than or
equal to maxWidth.
If kVerticalText_Flag is set, the text fragment fits if its advance height 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 SkPaint::TextEncoding to decode text, SkTypeface to get the font metrics,
and text size to scale the metrics.
Does not scale the advance or bounds by fake bold or SkPathEffect.
@param text character codes or glyph indices to be measured
@param length number of bytes of text to measure
@param maxWidth advance limit; text is measured while advance is less than maxWidth
@param measuredWidth returns the width of the text less than or equal to maxWidth
@return bytes of text that fit, always less than or equal to length
*/
size_t breakText(const void* text, size_t length, SkScalar maxWidth,
SkScalar* measuredWidth = 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.
If kVerticalText_Flag is clear, widths returns the horizontal advance.
If kVerticalText_Flag is set, widths returns the vertical advance.
Uses SkPaint::TextEncoding to decode text, SkTypeface to get the font metrics,
and text size to scale the widths and bounds.
Does not scale the advance by fake bold or SkPathEffect.
Does include fake bold and SkPathEffect in the bounds.
@param text character codes or glyph indices to be measured
@param byteLength number of bytes of text to measure
@param widths returns text advances for each glyph; may be nullptr
@param bounds returns bounds for each glyph relative to (0, 0); may be nullptr
@return glyph count in text
*/
int getTextWidths(const void* text, size_t byteLength, SkScalar widths[],
SkRect bounds[] = nullptr) const;
/** Returns the geometry as SkPath equivalent to the drawn text.
Uses SkPaint::TextEncoding to decode text, SkTypeface to get the glyph paths,
and text size, fake bold, and SkPathEffect to scale and modify the glyph paths.
All of the glyph paths are stored in path.
Uses x, y, and SkPaint::Align to position path.
@param text character codes or glyph indices
@param length number of bytes of text
@param x x-coordinate of the origin of the text
@param y y-coordinate of the origin of the text
@param path geometry of the glyphs
*/
void getTextPath(const void* text, size_t length, SkScalar x, SkScalar y,
SkPath* path) const;
/** Returns the geometry as SkPath equivalent to the drawn text.
Uses SkPaint::TextEncoding to decode text, SkTypeface to get the glyph paths,
and text size, fake bold, and SkPathEffect to scale and modify the glyph paths.
All of the glyph paths are stored in path.
Uses pos array and SkPaint::Align to position path.
pos contains a position for each glyph.
@param text character codes or glyph indices
@param length number of bytes of text
@param pos positions of each glyph
@param path geometry of the glyphs
*/
void getPosTextPath(const void* text, size_t length,
const SkPoint pos[], SkPath* path) 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 SkPaint::TextEncoding to decode text, SkTypeface to get the glyph paths,
and text size, fake bold, and SkPathEffect to scale and modify the glyph paths.
Uses x, y, and SkPaint::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.
@param text character codes or glyph indices
@param length number of bytes of text
@param x x-coordinate of the origin of the text
@param y y-coordinate of the origin of the text
@param bounds lower and upper line parallel to the advance
@param intervals returned intersections; may be nullptr
@return number of intersections; may be zero
*/
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 SkPaint::TextEncoding to decode text, SkTypeface to get the glyph paths,
and text size, fake bold, and SkPathEffect to scale and modify the glyph paths.
Uses pos array and SkPaint::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.
@param text character codes or glyph indices
@param length number of bytes of text
@param pos positions of each glyph
@param bounds lower and upper line parallel to the advance
@param intervals returned intersections; may be nullptr
@return number of intersections; may be zero
*/
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 SkPaint::TextEncoding to decode text, SkTypeface to get the glyph paths,
and text size, fake bold, and SkPathEffect to scale and modify the glyph paths.
Uses xpos array, constY, and SkPaint::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.
@param text character codes or glyph indices
@param length number of bytes of text
@param xpos positions of each glyph in x
@param constY position of each glyph in y
@param bounds lower and upper line parallel to the advance
@param intervals returned intersections; may be nullptr
@return number of intersections; may be zero
*/
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 SkPaint::TextEncoding to decode text, SkTypeface to get the glyph paths,
and text size, fake bold, and SkPathEffect to scale and modify the glyph paths.
Uses run array and SkPaint::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.
@param blob glyphs, positions, and text paint attributes
@param bounds lower and upper line parallel to the advance
@param intervals returned intersections; may be nullptr
@return number of intersections; may be zero
*/
int getTextBlobIntercepts(const SkTextBlob* blob, const SkScalar bounds[2],
SkScalar* intervals) const;
/** Returns the union of bounds of all glyphs.
Returned dimensions are computed by font manager from font data,
ignoring SkPaint::Hinting. Includes text size, text scale x,
and text skew x, but not fake bold or SkPathEffect.
If text size is large, text scale x is one, and text skew x is zero,
returns the same bounds as SkPaint::FontMetrics { FontMetrics::fXMin,
FontMetrics::fTop, FontMetrics::fXMax, FontMetrics::fBottom }.
@return union of bounds of all glyphs
*/
SkRect getFontBounds() const;
/** Returns true if SkPaint prevents all drawing;
otherwise, the SkPaint may or may not allow drawing.
Returns true if, for example, SkBlendMode combined with color alpha computes a
new alpha of zero.
@return true if SkPaint prevents all drawing
*/
bool nothingToDraw() const;
/** (to be made private)
Returns true if SkPaint does not include elements requiring extensive computation
to compute SkBaseDevice bounds of drawn geometry. For instance, SkPaint with SkPathEffect
always returns false.
@return true if SkPaint allows for fast computation of bounds
*/
bool canComputeFastBounds() const;
/** (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 SkRect 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
SkRect.
e.g.
if (paint.canComputeFastBounds()) {
SkRect r, storage;
path.computeBounds(&r, SkPath::kFast_BoundsType);
const SkRect& fastR = paint.computeFastBounds(r, &storage);
if (canvas->quickReject(fastR, ...)) {
// don't draw the path
}
}
@param orig geometry modified by SkPaint when drawn
@param storage computed bounds of geometry; may not be nullptr
@return fast computed bounds
*/
const SkRect& computeFastBounds(const SkRect& orig, SkRect* storage) const {
// Things like stroking, etc... will do math on the bounds rect, assuming that it's sorted.
SkASSERT(orig.isSorted());
SkPaint::Style style = this->getStyle();
// ultra fast-case: filling with no effects that affect geometry
if (kFill_Style == style) {
uintptr_t effects = reinterpret_cast<uintptr_t>(this->getLooper());
effects |= reinterpret_cast<uintptr_t>(this->getMaskFilter());
effects |= reinterpret_cast<uintptr_t>(this->getPathEffect());
effects |= reinterpret_cast<uintptr_t>(this->getImageFilter());
if (!effects) {
return orig;
}
}
return this->doComputeFastBounds(orig, storage, style);
}
/** (to be made private)
@param orig geometry modified by SkPaint when drawn
@param storage computed bounds of geometry
@return fast computed bounds
*/
const SkRect& computeFastStrokeBounds(const SkRect& orig,
SkRect* storage) const {
return this->doComputeFastBounds(orig, storage, kStroke_Style);
}
/** (to be made private)
Computes the bounds, overriding the SkPaint SkPaint::Style. This can be used to
account for additional width required by stroking orig, without
altering SkPaint::Style set to fill.
@param orig geometry modified by SkPaint when drawn
@param storage computed bounds of geometry
@param style overrides SkPaint::Style
@return fast computed bounds
*/
const SkRect& doComputeFastBounds(const SkRect& orig, SkRect* storage,
Style style) const;
/** macro expands to: void toString(SkString* str) const;
Creates string representation of SkPaint. The representation is read by
internal debugging tools. The interface and implementation may be
suppressed by defining SK_IGNORE_TO_STRING.
@param str storage for string representation of SkPaint
*/
SK_TO_STRING_NONVIRT()
private:
typedef const SkGlyph& (*GlyphCacheProc)(SkGlyphCache*, const char**);
sk_sp<SkTypeface> fTypeface;
sk_sp<SkPathEffect> fPathEffect;
sk_sp<SkShader> fShader;
sk_sp<SkMaskFilter> fMaskFilter;
sk_sp<SkColorFilter> fColorFilter;
sk_sp<SkRasterizer> fRasterizer;
sk_sp<SkDrawLooper> fDrawLooper;
sk_sp<SkImageFilter> fImageFilter;
SkScalar fTextSize;
SkScalar fTextScaleX;
SkScalar fTextSkewX;
SkColor fColor;
SkScalar fWidth;
SkScalar fMiterLimit;
uint32_t fBlendMode; // just need 5-6 bits
union {
struct {
// all of these bitfields should add up to 32
unsigned fFlags : 16;
unsigned fTextAlign : 2;
unsigned fCapType : 2;
unsigned fJoinType : 2;
unsigned fStyle : 2;
unsigned fTextEncoding : 2; // 3 values
unsigned fHinting : 2;
unsigned fFilterQuality : 2;
//unsigned fFreeBits : 2;
} fBitfields;
uint32_t fBitfieldsUInt;
};
static GlyphCacheProc GetGlyphCacheProc(TextEncoding encoding,
bool isDevKern,
bool needFullMetrics);
SkScalar measure_text(SkGlyphCache*, const char* text, size_t length,
int* count, SkRect* bounds) const;
enum ScalerContextFlags : uint32_t {
kNone_ScalerContextFlags = 0,
kFakeGamma_ScalerContextFlag = 1 << 0,
kBoostContrast_ScalerContextFlag = 1 << 1,
kFakeGammaAndBoostContrast_ScalerContextFlags =
kFakeGamma_ScalerContextFlag | kBoostContrast_ScalerContextFlag,
};
/*
* Allocs an SkDescriptor on the heap and return it to the caller as a refcnted
* SkData. Caller is responsible for managing the lifetime of this object.
*/
void getScalerContextDescriptor(SkScalerContextEffects*, SkAutoDescriptor*,
const SkSurfaceProps& surfaceProps,
uint32_t scalerContextFlags, const SkMatrix*) const;
SkGlyphCache* detachCache(const SkSurfaceProps* surfaceProps, uint32_t scalerContextFlags,
const SkMatrix*) const;
void descriptorProc(const SkSurfaceProps* surfaceProps, uint32_t scalerContextFlags,
const SkMatrix* deviceMatrix,
void (*proc)(SkTypeface*, const SkScalerContextEffects&,
const SkDescriptor*, void*),
void* context) const;
/*
* The luminance color is used to determine which Gamma Canonical color to map to. This is
* really only used by backends which want to cache glyph masks, and need some way to know if
* they need to generate new masks based off a given color.
*/
SkColor computeLuminanceColor() const;
enum {
/* This is the size we use when we ask for a glyph's path. We then
* post-transform it as we draw to match the request.
* This is done to try to re-use cache entries for the path.
*
* This value is somewhat arbitrary. In theory, it could be 1, since
* we store paths as floats. However, we get the path from the font
* scaler, and it may represent its paths as fixed-point (or 26.6),
* so we shouldn't ask for something too big (might overflow 16.16)
* or too small (underflow 26.6).
*
* This value could track kMaxSizeForGlyphCache, assuming the above
* constraints, but since we ask for unhinted paths, the two values
* need not match per-se.
*/
kCanonicalTextSizeForPaths = 64,
};
static bool TooBigToUseCache(const SkMatrix& ctm, const SkMatrix& textM);
// Set flags/hinting/textSize up to use for drawing text as paths.
// Returns scale factor to restore the original textSize, since will will
// have change it to kCanonicalTextSizeForPaths.
SkScalar setupForAsPaths();
static SkScalar MaxCacheSize2();
friend class SkAutoGlyphCache;
friend class SkAutoGlyphCacheNoGamma;
friend class SkCanvas;
friend class SkDraw;
friend class SkPDFDevice;
friend class GrAtlasTextBlob;
friend class GrAtlasTextContext;
friend class GrStencilAndCoverTextContext;
friend class GrPathRendering;
friend class GrTextUtils;
friend class GrGLPathRendering;
friend class SkScalerContext;
friend class SkTextBaseIter;
friend class SkCanonicalizePaint;
};
#endif
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