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expand SkShader's flag kConstInY to 16 and 32 variants, allowing a shader

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(like gradients) to support predithering. If they do, then they would suppress
kConstInY16, since they no longer are const.

The blitters now check for each flag separately, so we don't have to give up
const-in-Y in the 32bit case, since in that mode we don't care about dithering.



git-svn-id: http://skia.googlecode.com/svn/trunk@339 2bbb7eff-a529-9590-31e7-b0007b416f81
This commit is contained in:
reed@android.com 2009-08-27 19:28:37 +00:00
parent 2a4d1ff189
commit 3c9b2a4a0e
6 changed files with 82 additions and 118 deletions
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21
include/core/SkShader.h
View File

@ -76,9 +76,17 @@ public:
/** set (after setContext) if the spans only vary in X (const in Y).
e.g. an Nx1 bitmap that is being tiled in Y, or a linear-gradient
that varies from left-to-right
that varies from left-to-right. This flag specifies this for
shadeSpan().
*/
kConstInY_Flag = 0x08
kConstInY32_Flag = 0x08,
/** same as kConstInY32_Flag, but is set if this is true for shadeSpan16
which may not always be the case, since shadeSpan16 may be
predithered, which would mean it was not const in Y, even though
the 32bit shadeSpan() would be const.
*/
kConstInY16_Flag = 0x10
};
/** Called sometimes before drawing with this shader.
@ -99,8 +107,7 @@ public:
parameters, or false if not. If false is returned, nothing
will be drawn.
*/
virtual bool setContext( const SkBitmap& device,
const SkPaint& paint,
virtual bool setContext(const SkBitmap& device, const SkPaint& paint,
const SkMatrix& matrix);
/** Called for each span of the object being drawn. Your subclass
@ -108,7 +115,8 @@ public:
correspond to the specified device coordinates.
*/
virtual void shadeSpan(int x, int y, SkPMColor[], int count) = 0;
/** Called only for 16bit devices when getFlags() returns kOpaqueAlphaFlag | kHasSpan16_Flag
/** Called only for 16bit devices when getFlags() returns
kOpaqueAlphaFlag | kHasSpan16_Flag
*/
virtual void shadeSpan16(int x, int y, uint16_t[], int count);
/** Similar to shadeSpan, but only returns the alpha-channel for a span.
@ -120,8 +128,7 @@ public:
/** Helper function that returns true if this shader's shadeSpan16() method can
be called.
*/
bool canCallShadeSpan16()
{
bool canCallShadeSpan16() {
return SkShader::CanCallShadeSpan16(this->getFlags());
}

29
samplecode/SampleDitherBitmap.cpp
View File

@ -1,9 +1,35 @@
#include "SampleCode.h"
#include "SkColorPriv.h"
#include "SkGradientShader.h"
#include "SkView.h"
#include "SkCanvas.h"
#include "SkUtils.h"
static void draw_rect(SkCanvas* canvas, const SkRect& r, const SkPaint& p) {
canvas->drawRect(r, p);
SkPaint frame(p);
frame.setShader(NULL);
frame.setStyle(SkPaint::kStroke_Style);
canvas->drawRect(r, frame);
}
static void draw_gradient(SkCanvas* canvas) {
SkRect r = { 0, 0, SkIntToScalar(256), SkIntToScalar(32) };
SkPoint pts[] = { r.fLeft, r.fTop, r.fRight, r.fTop };
SkColor colors[] = { 0xFF000000, 0xFFFF0000 };
SkShader* s = SkGradientShader::CreateLinear(pts, colors, NULL, 2,
SkShader::kClamp_TileMode);
SkPaint p;
p.setShader(s)->unref();
draw_rect(canvas, r, p);
canvas->translate(0, SkIntToScalar(40));
p.setDither(true);
draw_rect(canvas, r, p);
}
static void test_pathregion() {
SkPath path;
SkRegion region;
@ -103,6 +129,9 @@ protected:
draw2(canvas, fBM8);
canvas->translate(0, SkIntToScalar(fBM8.height() *3));
draw2(canvas, fBM32);
canvas->translate(0, SkIntToScalar(fBM8.height() *3));
draw_gradient(canvas);
}
private:

5
src/core/SkBitmapProcShader.cpp
View File

@ -132,7 +132,10 @@ bool SkBitmapProcShader::setContext(const SkBitmap& device,
// if we're only 1-pixel heigh, and we don't rotate, then we can claim this
if (1 == fState.fBitmap->height() &&
only_scale_and_translate(this->getTotalInverse())) {
flags |= kConstInY_Flag;
flags |= kConstInY32_Flag;
if (flags & kHasSpan16_Flag) {
flags |= kConstInY16_Flag;
}
}
fFlags = flags;

6
src/core/SkBlitter_RGB16.cpp
View File

@ -528,7 +528,7 @@ void SkRGB16_Shader16_Blitter::blitRect(int x, int y, int width, int height) {
int alpha = shader->getSpan16Alpha();
if (0xFF == alpha) {
if (fShaderFlags & SkShader::kConstInY_Flag) {
if (fShaderFlags & SkShader::kConstInY16_Flag) {
// have the shader blit directly into the device the first time
shader->shadeSpan16(x, y, dst, width);
// and now just memcpy that line on the subsequent lines
@ -549,7 +549,7 @@ void SkRGB16_Shader16_Blitter::blitRect(int x, int y, int width, int height) {
} else {
int scale = SkAlpha255To256(alpha);
uint16_t* span16 = (uint16_t*)fBuffer;
if (fShaderFlags & SkShader::kConstInY_Flag) {
if (fShaderFlags & SkShader::kConstInY16_Flag) {
shader->shadeSpan16(x, y, span16, width);
do {
SkBlendRGB16(span16, dst, scale, width);
@ -668,7 +668,7 @@ void SkRGB16_Shader_Blitter::blitRect(int x, int y, int width, int height) {
uint16_t* dst = fDevice.getAddr16(x, y);
size_t dstRB = fDevice.rowBytes();
if (fShaderFlags & SkShader::kConstInY_Flag) {
if (fShaderFlags & SkShader::kConstInY32_Flag) {
shader->shadeSpan(x, y, buffer, width);
do {
proc(dst, buffer, width, 0xFF, x, y);

2
src/core/SkShader.cpp
View File

@ -263,7 +263,7 @@ bool SkColorShader::setContext(const SkBitmap& device, const SkPaint& paint,
}
fPMColor = SkPackARGB32(a, r, g, b);
fFlags = kHasSpan16_Flag | kConstInY_Flag;
fFlags = kHasSpan16_Flag | kConstInY32_Flag;
if (SkGetPackedA32(fPMColor) == 255) {
fFlags |= kOpaqueAlpha_Flag;
}

125
src/effects/SkGradientShader.cpp
View File

@ -20,18 +20,6 @@
#include "SkUnitMapper.h"
#include "SkUtils.h"
/*
ToDo
- not sure we still need the full Rec struct, now that we're using a cache
- detect const-alpha (but not opaque) in getFlags()
*/
/* dither seems to look better, but not stuningly yet, and it slows us down a little
so its not on by default yet.
*/
#define TEST_GRADIENT_DITHER
///////////////////////////////////////////////////////////////////////////
typedef SkFixed (*TileProc)(SkFixed);
@ -503,12 +491,9 @@ static inline U16CPU dot6to16(unsigned x) {
const uint16_t* Gradient_Shader::getCache16() {
if (fCache16 == NULL) {
if (fCache16Storage == NULL) // set the storage and our working ptr
#ifdef TEST_GRADIENT_DITHER
if (fCache16Storage == NULL) { // set the storage and our working ptr
fCache16Storage = (uint16_t*)sk_malloc_throw(sizeof(uint16_t) * kCache16Count * 2);
#else
fCache16Storage = (uint16_t*)sk_malloc_throw(sizeof(uint16_t) * kCache16Count);
#endif
}
fCache16 = fCache16Storage;
if (fColorCount == 2) {
build_16bit_cache(fCache16, fOrigColors[0], fOrigColors[1], kCache16Count);
@ -527,20 +512,14 @@ const uint16_t* Gradient_Shader::getCache16() {
}
if (fMapper) {
#ifdef TEST_GRADIENT_DITHER
fCache16Storage = (uint16_t*)sk_malloc_throw(sizeof(uint16_t) * kCache16Count * 2);
#else
fCache16Storage = (uint16_t*)sk_malloc_throw(sizeof(uint16_t) * kCache16Count);
#endif
uint16_t* linear = fCache16; // just computed linear data
uint16_t* mapped = fCache16Storage; // storage for mapped data
SkUnitMapper* map = fMapper;
for (int i = 0; i < 64; i++) {
int index = map->mapUnit16(dot6to16(i)) >> 10;
mapped[i] = linear[index];
#ifdef TEST_GRADIENT_DITHER
mapped[i + 64] = linear[index + 64];
#endif
}
sk_free(fCache16);
fCache16 = fCache16Storage;
@ -655,7 +634,13 @@ bool Linear_Gradient::setContext(const SkBitmap& device, const SkPaint& paint,
unsigned mask = SkMatrix::kTranslate_Mask | SkMatrix::kScale_Mask;
if ((fDstToIndex.getType() & ~mask) == 0) {
fFlags |= SkShader::kConstInY_Flag;
fFlags |= SkShader::kConstInY32_Flag;
if ((fFlags & SkShader::kHasSpan16_Flag) && !paint.isDither()) {
// only claim this if we do have a 16bit mode (i.e. none of our
// colors have alpha), and if we are not dithering (which obviously
// is not const in Y).
fFlags |= SkShader::kConstInY16_Flag;
}
}
return true;
}
@ -779,11 +764,9 @@ bool Linear_Gradient::asABitmap(SkBitmap* bitmap, SkMatrix* matrix,
return true;
}
#ifdef TEST_GRADIENT_DITHER
static void dither_memset16(uint16_t dst[], uint16_t value, uint16_t other, int count)
{
if (reinterpret_cast<uintptr_t>(dst) & 2)
{
static void dither_memset16(uint16_t dst[], uint16_t value, uint16_t other,
int count) {
if (reinterpret_cast<uintptr_t>(dst) & 2) {
*dst++ = value;
count -= 1;
SkTSwap(value, other);
@ -791,10 +774,10 @@ static void dither_memset16(uint16_t dst[], uint16_t value, uint16_t other, int
sk_memset32((uint32_t*)dst, (value << 16) | other, count >> 1);
if (count & 1)
if (count & 1) {
dst[count - 1] = value;
}
}
#endif
void Linear_Gradient::shadeSpan16(int x, int y, uint16_t dstC[], int count)
{
@ -804,9 +787,7 @@ void Linear_Gradient::shadeSpan16(int x, int y, uint16_t dstC[], int count)
SkMatrix::MapXYProc dstProc = fDstToIndexProc;
TileProc proc = fTileProc;
const uint16_t* cache = this->getCache16();
#ifdef TEST_GRADIENT_DITHER
int toggle = ((x ^ y) & 1) << kCache16Bits;
#endif
if (fDstToIndexClass != kPerspective_MatrixClass) {
dstProc(fDstToIndex, SkIntToScalar(x), SkIntToScalar(y), &srcPt);
@ -827,34 +808,22 @@ void Linear_Gradient::shadeSpan16(int x, int y, uint16_t dstC[], int count)
// we're a vertical gradient, so no change in a span
unsigned fi = proc(fx) >> 10;
SkASSERT(fi <= 63);
#ifdef TEST_GRADIENT_DITHER
dither_memset16(dstC, cache[toggle + fi], cache[(toggle ^ (1 << kCache16Bits)) + fi], count);
#else
sk_memset16(dstC, cache[fi], count);
#endif
} else if (proc == clamp_tileproc) {
do {
unsigned fi = SkClampMax(fx >> 10, 63);
SkASSERT(fi <= 63);
fx += dx;
#ifdef TEST_GRADIENT_DITHER
*dstC++ = cache[toggle + fi];
toggle ^= (1 << kCache16Bits);
#else
*dstC++ = cache[fi];
#endif
} while (--count != 0);
} else if (proc == mirror_tileproc) {
do {
unsigned fi = mirror_6bits(fx >> 10);
SkASSERT(fi <= 0x3F);
fx += dx;
#ifdef TEST_GRADIENT_DITHER
*dstC++ = cache[toggle + fi];
toggle ^= (1 << kCache16Bits);
#else
*dstC++ = cache[fi];
#endif
} while (--count != 0);
} else {
SkASSERT(proc == repeat_tileproc);
@ -862,12 +831,8 @@ void Linear_Gradient::shadeSpan16(int x, int y, uint16_t dstC[], int count)
unsigned fi = repeat_6bits(fx >> 10);
SkASSERT(fi <= 0x3F);
fx += dx;
#ifdef TEST_GRADIENT_DITHER
*dstC++ = cache[toggle + fi];
toggle ^= (1 << kCache16Bits);
#else
*dstC++ = cache[fi];
#endif
} while (--count != 0);
}
} else {
@ -879,12 +844,8 @@ void Linear_Gradient::shadeSpan16(int x, int y, uint16_t dstC[], int count)
SkASSERT(fi <= 0xFFFF);
int index = fi >> (16 - kCache16Bits);
#ifdef TEST_GRADIENT_DITHER
*dstC++ = cache[toggle + index];
toggle ^= (1 << kCache16Bits);
#else
*dstC++ = cache[index];
#endif
dstX += SK_Scalar1;
} while (--count != 0);
@ -1033,40 +994,33 @@ public:
} while (--count != 0);
}
}
virtual void shadeSpan16(int x, int y, uint16_t dstC[], int count)
{
virtual void shadeSpan16(int x, int y, uint16_t dstC[], int count) {
SkASSERT(count > 0);
SkPoint srcPt;
SkMatrix::MapXYProc dstProc = fDstToIndexProc;
TileProc proc = fTileProc;
const uint16_t* cache = this->getCache16();
#ifdef TEST_GRADIENT_DITHER
int toggle = ((x ^ y) & 1) << kCache16Bits;
#endif
if (fDstToIndexClass != kPerspective_MatrixClass)
{
if (fDstToIndexClass != kPerspective_MatrixClass) {
dstProc(fDstToIndex, SkIntToScalar(x), SkIntToScalar(y), &srcPt);
SkFixed dx, fx = SkScalarToFixed(srcPt.fX);
SkFixed dy, fy = SkScalarToFixed(srcPt.fY);
if (fDstToIndexClass == kFixedStepInX_MatrixClass)
{
if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
SkFixed storage[2];
(void)fDstToIndex.fixedStepInX(SkIntToScalar(y), &storage[0], &storage[1]);
dx = storage[0];
dy = storage[1];
}
else
{
} else {
SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
dx = SkScalarToFixed(fDstToIndex.getScaleX());
dy = SkScalarToFixed(fDstToIndex.getSkewY());
}
if (proc == clamp_tileproc)
{
if (proc == clamp_tileproc) {
const uint8_t* sqrt_table = gSqrt8Table;
/* knock these down so we can pin against +- 0x7FFF, which is an immediate load,
@ -1079,8 +1033,7 @@ public:
dx >>= 1;
fy >>= 1;
dy >>= 1;
if (dy == 0) // might perform this check for the other modes, but the win will be a smaller % of the total
{
if (dy == 0) { // might perform this check for the other modes, but the win will be a smaller % of the total
fy = SkPin32(fy, -0xFFFF >> 1, 0xFFFF >> 1);
fy *= fy;
do {
@ -1088,16 +1041,10 @@ public:
unsigned fi = (xx * xx + fy) >> (14 + 16 - kSQRT_TABLE_BITS);
fi = SkFastMin32(fi, 0xFFFF >> (16 - kSQRT_TABLE_BITS));
fx += dx;
#ifdef TEST_GRADIENT_DITHER
*dstC++ = cache[toggle + (sqrt_table[fi] >> (8 - kCache16Bits))];
toggle ^= (1 << kCache16Bits);
#else
*dstC++ = cache[sqrt_table[fi] >> (8 - kCache16Bits)];
#endif
} while (--count != 0);
}
else
{
} else {
do {
unsigned xx = SkPin32(fx, -0xFFFF >> 1, 0xFFFF >> 1);
unsigned fi = SkPin32(fy, -0xFFFF >> 1, 0xFFFF >> 1);
@ -1105,33 +1052,21 @@ public:
fi = SkFastMin32(fi, 0xFFFF >> (16 - kSQRT_TABLE_BITS));
fx += dx;
fy += dy;
#ifdef TEST_GRADIENT_DITHER
*dstC++ = cache[toggle + (sqrt_table[fi] >> (8 - kCache16Bits))];
toggle ^= (1 << kCache16Bits);
#else
*dstC++ = cache[sqrt_table[fi] >> (8 - kCache16Bits)];
#endif
} while (--count != 0);
}
}
else if (proc == mirror_tileproc)
{
} else if (proc == mirror_tileproc) {
do {
SkFixed dist = SkFixedSqrt(SkFixedSquare(fx) + SkFixedSquare(fy));
unsigned fi = mirror_tileproc(dist);
SkASSERT(fi <= 0xFFFF);
fx += dx;
fy += dy;
#ifdef TEST_GRADIENT_DITHER
*dstC++ = cache[toggle + (fi >> (16 - kCache16Bits))];
toggle ^= (1 << kCache16Bits);
#else
*dstC++ = cache[fi >> (16 - kCache16Bits)];
#endif
} while (--count != 0);
}
else
{
} else {
SkASSERT(proc == repeat_tileproc);
do {
SkFixed dist = SkFixedSqrt(SkFixedSquare(fx) + SkFixedSquare(fy));
@ -1139,17 +1074,11 @@ public:
SkASSERT(fi <= 0xFFFF);
fx += dx;
fy += dy;
#ifdef TEST_GRADIENT_DITHER
*dstC++ = cache[toggle + (fi >> (16 - kCache16Bits))];
toggle ^= (1 << kCache16Bits);
#else
*dstC++ = cache[fi >> (16 - kCache16Bits)];
#endif
} while (--count != 0);
}
}
else // perspective case
{
} else { // perspective case
SkScalar dstX = SkIntToScalar(x);
SkScalar dstY = SkIntToScalar(y);
do {
@ -1158,12 +1087,8 @@ public:
SkASSERT(fi <= 0xFFFF);
int index = fi >> (16 - kCache16Bits);
#ifdef TEST_GRADIENT_DITHER
*dstC++ = cache[toggle + index];
toggle ^= (1 << kCache16Bits);
#else
*dstC++ = cache[index];
#endif
dstX += SK_Scalar1;
} while (--count != 0);