SkBlitter_A8.cpp File Reference

#include "src/core/SkBlitter_A8.h"
#include "include/core/SkBlendMode.h"
#include "include/core/SkColorType.h"
#include "include/core/SkPaint.h"
#include "include/core/SkRect.h"
#include "include/core/SkShader.h"
#include "include/core/SkTypes.h"
#include "include/private/base/SkDebug.h"
#include "src/base/SkArenaAlloc.h"
#include "src/core/SkMask.h"
#include <cstring>
#include <optional>

Go to the source code of this file.

Classes
struct	A8_RowBlitBWPair
class	SkA8_Blitter

Macros
#define	WRAP_BLIT(proc, canFoldAA)

Typedefs
using	AlphaProc = uint8_t(*)(uint8_t src, uint8_t dst)
using	A8_RowBlitBW = void(*)(uint8_t[], uint8_t, int)
using	A8_RowBlitAA = void(*)(uint8_t[], uint8_t, int, uint8_t aa)

Functions
static uint8_t	div255 (unsigned prod)
static unsigned	u8_lerp (uint8_t a, uint8_t b, uint8_t t)
static uint8_t	srcover_p (uint8_t src, uint8_t dst)
static uint8_t	src_p (uint8_t src, uint8_t dst)
template<typename Mode >
void	A8_row_bw (uint8_t dst[], uint8_t src, int N, Mode proc)
template<typename Mode >
void	A8_row_aa (uint8_t dst[], uint8_t src, int N, uint8_t aa, Mode proc, const bool canFoldAA)
static const A8_RowBlitBWPair *	find_a8_rowproc_pair (SkBlendMode bm)
SkBlitter *	SkA8Blitter_Choose (const SkPixmap &dst, const SkMatrix &ctm, const SkPaint &paint, SkArenaAlloc *alloc, bool drawCoverage, sk_sp< SkShader > clipShader, const SkSurfaceProps &)

Variables
constexpr A8_RowBlitBWPair	gA8_RowBlitPairs []

Macro Definition Documentation

WRAP_BLIT

#define WRAP_BLIT	(		proc,
			canFoldAA
	)

Value:

    proc,                                               \
    [](uint8_t dst[], uint8_t src, int N)               \
      { A8_row_bw(dst, src, N, proc); },                \
    [](uint8_t dst[], uint8_t src, int N, uint8_t aa)   \
      { A8_row_aa(dst, src, N, aa, proc, canFoldAA); }

Definition at line 140 of file SkBlitter_A8.cpp.

      { A8_row_bw(dst, src, N, proc); },                \
    [](uint8_t dst[], uint8_t src, int N, uint8_t aa)   \
      { A8_row_aa(dst, src, N, aa, proc, canFoldAA); }

Typedef Documentation

A8_RowBlitAA

using A8_RowBlitAA = void(*)(uint8_t[], uint8_t, int, uint8_t aa)

Definition at line 138 of file SkBlitter_A8.cpp.

A8_RowBlitBW

using A8_RowBlitBW = void(*)(uint8_t[], uint8_t, int)

Definition at line 123 of file SkBlitter_A8.cpp.

AlphaProc

using AlphaProc = uint8_t(*)(uint8_t src, uint8_t dst)

Definition at line 113 of file SkBlitter_A8.cpp.

Function Documentation

A8_row_aa()

template<typename Mode >

void A8_row_aa	(	uint8_t	dst[],
		uint8_t	src,
		int	N,
		uint8_t	aa,
		Mode	proc,
		const bool	canFoldAA
	)

Definition at line 126 of file SkBlitter_A8.cpp.

                                                                                               {
    if (canFoldAA) {
        src = div255(src * aa);
        for (int i = 0; i < N; ++i) {
            dst[i] = proc(src, dst[i]);
        }
    } else {
        for (int i = 0; i < N; ++i) {
            dst[i] = u8_lerp(dst[i], proc(src, dst[i]), aa);
        }
    }
}

A8_row_bw()

template<typename Mode >

void A8_row_bw	(	uint8_t	dst[],
		uint8_t	src,
		int	N,
		Mode	proc
	)

Definition at line 118 of file SkBlitter_A8.cpp.

                                                                                      {
    for (int i = 0; i < N; ++i) {
        dst[i] = proc(src, dst[i]);
    }
}

div255()

static uint8_t div255 ( unsigned  prod )

inlinestatic

Definition at line 104 of file SkBlitter_A8.cpp.

                                            {
    SkASSERT(prod <= 255*255);
    return (prod + 128) * 257 >> 16;
}

find_a8_rowproc_pair()

static const A8_RowBlitBWPair * find_a8_rowproc_pair ( SkBlendMode  bm )

static

Definition at line 159 of file SkBlitter_A8.cpp.

                                                                    {
    for (auto& pair : gA8_RowBlitPairs) {
        if (pair.mode == bm) {
            return &pair;
        }
    }
    return nullptr;
}

SkA8Blitter_Choose()

SkBlitter * SkA8Blitter_Choose	(	const SkPixmap &	dst,
		const SkMatrix &	ctm,
		const SkPaint &	paint,
		SkArenaAlloc *	alloc,
		bool	drawCoverage,
		sk_sp< SkShader >	clipShader,
		const SkSurfaceProps &
	)

Definition at line 286 of file SkBlitter_A8.cpp.

                                                     {
    if (dst.colorType() != SkColorType::kAlpha_8_SkColorType) {
        return nullptr;
    }
    if (paint.getShader() || paint.getColorFilter()) {
        return nullptr;
    }
    if (clipShader) {
        return nullptr; // would not be hard to support ...?
    }
 
    if (drawCoverage) {
        return alloc->make<SkA8_Coverage_Blitter>(dst, paint);
    } else {
        // we only support certain blendmodes...
        auto mode = paint.asBlendMode();
        if (mode && find_a8_rowproc_pair(*mode)) {
            return alloc->make<SkA8_Blitter>(dst, paint);
        }
    }
    return nullptr;
}

src_p()

static uint8_t src_p ( uint8_t  src, uint8_t  dst  )

static

Definition at line 116 of file SkBlitter_A8.cpp.

{ return src; }

srcover_p()

static uint8_t srcover_p ( uint8_t  src, uint8_t  dst  )

static

Definition at line 115 of file SkBlitter_A8.cpp.

{ return src + div255((255 - src) * dst); }

u8_lerp()

static unsigned u8_lerp ( uint8_t  a, uint8_t  b, uint8_t  t  )

inlinestatic

Definition at line 109 of file SkBlitter_A8.cpp.

                                                                {
    return div255((255 - t) * a + t * b);
}

Variable Documentation

gA8_RowBlitPairs

constexpr A8_RowBlitBWPair gA8_RowBlitPairs[]

constexpr

Initial value:

= {
    {SkBlendMode::kSrcOver,  WRAP_BLIT(srcover_p,  true)},
    {SkBlendMode::kSrc,      WRAP_BLIT(src_p,      false)},
}

Definition at line 153 of file SkBlitter_A8.cpp.

                                                {
    {SkBlendMode::kSrcOver,  WRAP_BLIT(srcover_p,  true)},
    {SkBlendMode::kSrc,      WRAP_BLIT(src_p,      false)},
};