1a6382f5e7
R=bsalomon@google.com Review URL: https://codereview.chromium.org/37593002 git-svn-id: http://skia.googlecode.com/svn/trunk@11926 2bbb7eff-a529-9590-31e7-b0007b416f81
286 lines
10 KiB
C++
286 lines
10 KiB
C++
|
|
/*
|
|
* 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 SkXfermode_DEFINED
|
|
#define SkXfermode_DEFINED
|
|
|
|
#include "SkFlattenable.h"
|
|
#include "SkColor.h"
|
|
|
|
class GrEffectRef;
|
|
class GrTexture;
|
|
class SkString;
|
|
|
|
/** \class SkXfermode
|
|
*
|
|
* SkXfermode is the base class for objects that are called to implement custom
|
|
* "transfer-modes" in the drawing pipeline. The static function Create(Modes)
|
|
* can be called to return an instance of any of the predefined subclasses as
|
|
* specified in the Modes enum. When an SkXfermode is assigned to an SkPaint,
|
|
* then objects drawn with that paint have the xfermode applied.
|
|
*
|
|
* All subclasses are required to be reentrant-safe : it must be legal to share
|
|
* the same instance between several threads.
|
|
*/
|
|
class SK_API SkXfermode : public SkFlattenable {
|
|
public:
|
|
SK_DECLARE_INST_COUNT(SkXfermode)
|
|
|
|
SkXfermode() {}
|
|
|
|
virtual void xfer32(SkPMColor dst[], const SkPMColor src[], int count,
|
|
const SkAlpha aa[]) const;
|
|
virtual void xfer16(uint16_t dst[], const SkPMColor src[], int count,
|
|
const SkAlpha aa[]) const;
|
|
virtual void xferA8(SkAlpha dst[], const SkPMColor src[], int count,
|
|
const SkAlpha aa[]) const;
|
|
|
|
/** Enum of possible coefficients to describe some xfermodes
|
|
*/
|
|
enum Coeff {
|
|
kZero_Coeff, /** 0 */
|
|
kOne_Coeff, /** 1 */
|
|
kSC_Coeff, /** src color */
|
|
kISC_Coeff, /** inverse src color (i.e. 1 - sc) */
|
|
kDC_Coeff, /** dst color */
|
|
kIDC_Coeff, /** inverse dst color (i.e. 1 - dc) */
|
|
kSA_Coeff, /** src alpha */
|
|
kISA_Coeff, /** inverse src alpha (i.e. 1 - sa) */
|
|
kDA_Coeff, /** dst alpha */
|
|
kIDA_Coeff, /** inverse dst alpha (i.e. 1 - da) */
|
|
|
|
kCoeffCount
|
|
};
|
|
|
|
/** If the xfermode can be expressed as an equation using the coefficients
|
|
in Coeff, then asCoeff() returns true, and sets (if not null) src and
|
|
dst accordingly.
|
|
|
|
result = src_coeff * src_color + dst_coeff * dst_color;
|
|
|
|
As examples, here are some of the porterduff coefficients
|
|
|
|
MODE SRC_COEFF DST_COEFF
|
|
clear zero zero
|
|
src one zero
|
|
dst zero one
|
|
srcover one isa
|
|
dstover ida one
|
|
*/
|
|
virtual bool asCoeff(Coeff* src, Coeff* dst) const;
|
|
|
|
/**
|
|
* The same as calling xfermode->asCoeff(..), except that this also checks
|
|
* if the xfermode is NULL, and if so, treats it as kSrcOver_Mode.
|
|
*/
|
|
static bool AsCoeff(const SkXfermode*, Coeff* src, Coeff* dst);
|
|
|
|
/** List of predefined xfermodes.
|
|
The algebra for the modes uses the following symbols:
|
|
Sa, Sc - source alpha and color
|
|
Da, Dc - destination alpha and color (before compositing)
|
|
[a, c] - Resulting (alpha, color) values
|
|
For these equations, the colors are in premultiplied state.
|
|
If no xfermode is specified, kSrcOver is assumed.
|
|
The modes are ordered by those that can be expressed as a pair of Coeffs, followed by those
|
|
that aren't Coeffs but have separable r,g,b computations, and finally
|
|
those that are not separable.
|
|
*/
|
|
enum Mode {
|
|
kClear_Mode, //!< [0, 0]
|
|
kSrc_Mode, //!< [Sa, Sc]
|
|
kDst_Mode, //!< [Da, Dc]
|
|
kSrcOver_Mode, //!< [Sa + Da - Sa*Da, Rc = Sc + (1 - Sa)*Dc]
|
|
kDstOver_Mode, //!< [Sa + Da - Sa*Da, Rc = Dc + (1 - Da)*Sc]
|
|
kSrcIn_Mode, //!< [Sa * Da, Sc * Da]
|
|
kDstIn_Mode, //!< [Sa * Da, Sa * Dc]
|
|
kSrcOut_Mode, //!< [Sa * (1 - Da), Sc * (1 - Da)]
|
|
kDstOut_Mode, //!< [Da * (1 - Sa), Dc * (1 - Sa)]
|
|
kSrcATop_Mode, //!< [Da, Sc * Da + (1 - Sa) * Dc]
|
|
kDstATop_Mode, //!< [Sa, Sa * Dc + Sc * (1 - Da)]
|
|
kXor_Mode, //!< [Sa + Da - 2 * Sa * Da, Sc * (1 - Da) + (1 - Sa) * Dc]
|
|
kPlus_Mode, //!< [Sa + Da, Sc + Dc]
|
|
kModulate_Mode, // multiplies all components (= alpha and color)
|
|
|
|
// Following blend modes are defined in the CSS Compositing standard:
|
|
// https://dvcs.w3.org/hg/FXTF/rawfile/tip/compositing/index.html#blending
|
|
kScreen_Mode,
|
|
kLastCoeffMode = kScreen_Mode,
|
|
|
|
kOverlay_Mode,
|
|
kDarken_Mode,
|
|
kLighten_Mode,
|
|
kColorDodge_Mode,
|
|
kColorBurn_Mode,
|
|
kHardLight_Mode,
|
|
kSoftLight_Mode,
|
|
kDifference_Mode,
|
|
kExclusion_Mode,
|
|
kMultiply_Mode,
|
|
kLastSeparableMode = kMultiply_Mode,
|
|
|
|
kHue_Mode,
|
|
kSaturation_Mode,
|
|
kColor_Mode,
|
|
kLuminosity_Mode,
|
|
kLastMode = kLuminosity_Mode
|
|
};
|
|
|
|
/**
|
|
* Gets the name of the Mode as a string.
|
|
*/
|
|
static const char* ModeName(Mode);
|
|
|
|
/**
|
|
* If the xfermode is one of the modes in the Mode enum, then asMode()
|
|
* returns true and sets (if not null) mode accordingly. Otherwise it
|
|
* returns false and ignores the mode parameter.
|
|
*/
|
|
virtual bool asMode(Mode* mode) const;
|
|
|
|
/**
|
|
* The same as calling xfermode->asMode(mode), except that this also checks
|
|
* if the xfermode is NULL, and if so, treats it as kSrcOver_Mode.
|
|
*/
|
|
static bool AsMode(const SkXfermode*, Mode* mode);
|
|
|
|
/**
|
|
* Returns true if the xfermode claims to be the specified Mode. This works
|
|
* correctly even if the xfermode is NULL (which equates to kSrcOver.) Thus
|
|
* you can say this without checking for a null...
|
|
*
|
|
* If (SkXfermode::IsMode(paint.getXfermode(),
|
|
* SkXfermode::kDstOver_Mode)) {
|
|
* ...
|
|
* }
|
|
*/
|
|
static bool IsMode(const SkXfermode* xfer, Mode mode);
|
|
|
|
/** Return an SkXfermode object for the specified mode.
|
|
*/
|
|
static SkXfermode* Create(Mode mode);
|
|
|
|
/** Return a function pointer to a routine that applies the specified
|
|
porter-duff transfer mode.
|
|
*/
|
|
static SkXfermodeProc GetProc(Mode mode);
|
|
|
|
/** Return a function pointer to a routine that applies the specified
|
|
porter-duff transfer mode and srcColor to a 16bit device color. Note,
|
|
if the mode+srcColor might return a non-opaque color, then there is not
|
|
16bit proc, and this will return NULL.
|
|
*/
|
|
static SkXfermodeProc16 GetProc16(Mode mode, SkColor srcColor);
|
|
|
|
/**
|
|
* If the specified mode can be represented by a pair of Coeff, then return
|
|
* true and set (if not NULL) the corresponding coeffs. If the mode is
|
|
* not representable as a pair of Coeffs, return false and ignore the
|
|
* src and dst parameters.
|
|
*/
|
|
static bool ModeAsCoeff(Mode mode, Coeff* src, Coeff* dst);
|
|
|
|
// DEPRECATED: call AsMode(...)
|
|
static bool IsMode(const SkXfermode* xfer, Mode* mode) {
|
|
return AsMode(xfer, mode);
|
|
}
|
|
|
|
/** A subclass may implement this factory function to work with the GPU backend. It is legal
|
|
to call this with all params NULL to simply test the return value. If effect is non-NULL
|
|
then the xfermode may optionally allocate an effect to return and the caller as *effect.
|
|
The caller will install it and own a ref to it. Since the xfermode may or may not assign
|
|
*effect, the caller should set *effect to NULL beforehand. background specifies the
|
|
texture to use as the background for compositing, and should be accessed in the effect's
|
|
fragment shader. If NULL, the effect should request access to destination color
|
|
(setWillReadDstColor()), and use that in the fragment shader (builder->dstColor()).
|
|
*/
|
|
virtual bool asNewEffect(GrEffectRef** effect, GrTexture* background = NULL) const;
|
|
|
|
/** Returns true if the xfermode can be expressed as coeffs (src, dst), or as an effect
|
|
(effect). This helper calls the asCoeff() and asNewEffect() virtuals. If the xfermode is
|
|
NULL, it is treated as kSrcOver_Mode. It is legal to call this with all params NULL to
|
|
simply test the return value. effect, src, and dst must all be NULL or all non-NULL.
|
|
*/
|
|
static bool AsNewEffectOrCoeff(SkXfermode*,
|
|
GrEffectRef** effect,
|
|
Coeff* src,
|
|
Coeff* dst,
|
|
GrTexture* background = NULL);
|
|
|
|
SkDEVCODE(virtual void toString(SkString* str) const = 0;)
|
|
SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP()
|
|
SK_DEFINE_FLATTENABLE_TYPE(SkXfermode)
|
|
|
|
protected:
|
|
SkXfermode(SkFlattenableReadBuffer& rb) : SkFlattenable(rb) {}
|
|
|
|
/** The default implementation of xfer32/xfer16/xferA8 in turn call this
|
|
method, 1 color at a time (upscaled to a SkPMColor). The default
|
|
implmentation of this method just returns dst. If performance is
|
|
important, your subclass should override xfer32/xfer16/xferA8 directly.
|
|
|
|
This method will not be called directly by the client, so it need not
|
|
be implemented if your subclass has overridden xfer32/xfer16/xferA8
|
|
*/
|
|
virtual SkPMColor xferColor(SkPMColor src, SkPMColor dst) const;
|
|
|
|
private:
|
|
enum {
|
|
kModeCount = kLastMode + 1
|
|
};
|
|
|
|
friend class SkGraphics;
|
|
static void Term();
|
|
|
|
typedef SkFlattenable INHERITED;
|
|
};
|
|
|
|
///////////////////////////////////////////////////////////////////////////////
|
|
|
|
/** \class SkProcXfermode
|
|
|
|
SkProcXfermode is a xfermode that applies the specified proc to its colors.
|
|
This class is not exported to java.
|
|
*/
|
|
class SkProcXfermode : public SkXfermode {
|
|
public:
|
|
SkProcXfermode(SkXfermodeProc proc) : fProc(proc) {}
|
|
|
|
// overrides from SkXfermode
|
|
virtual void xfer32(SkPMColor dst[], const SkPMColor src[], int count,
|
|
const SkAlpha aa[]) const SK_OVERRIDE;
|
|
virtual void xfer16(uint16_t dst[], const SkPMColor src[], int count,
|
|
const SkAlpha aa[]) const SK_OVERRIDE;
|
|
virtual void xferA8(SkAlpha dst[], const SkPMColor src[], int count,
|
|
const SkAlpha aa[]) const SK_OVERRIDE;
|
|
|
|
SK_DEVELOPER_TO_STRING()
|
|
SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkProcXfermode)
|
|
|
|
protected:
|
|
SkProcXfermode(SkFlattenableReadBuffer&);
|
|
virtual void flatten(SkFlattenableWriteBuffer&) const SK_OVERRIDE;
|
|
|
|
// allow subclasses to update this after we unflatten
|
|
void setProc(SkXfermodeProc proc) {
|
|
fProc = proc;
|
|
}
|
|
|
|
SkXfermodeProc getProc() const {
|
|
return fProc;
|
|
}
|
|
|
|
private:
|
|
SkXfermodeProc fProc;
|
|
|
|
typedef SkXfermode INHERITED;
|
|
};
|
|
|
|
#endif
|