Add unpremultiply support and GM

R=vandebo@chromium.org, edisonn@google.com

Author: richardlin@chromium.org

Review URL: https://chromiumcodereview.appspot.com/22831039

git-svn-id: http://skia.googlecode.com/svn/trunk@10901 2bbb7eff-a529-9590-31e7-b0007b416f81
This commit is contained in:
commit-bot@chromium.org 2013-08-23 21:43:03 +00:00
parent 884624764c
commit 52130e8a5e
3 changed files with 303 additions and 4 deletions

131
gm/bitmappremul.cpp Normal file
View File

@ -0,0 +1,131 @@
/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gm.h"
#include "SkBitmap.h"
#include "SkCanvas.h"
#include "SkColorPriv.h"
/**
* This GM checks that bitmap pixels are unpremultiplied before being exported
* to other formats. If unpremultiplication is implemented properly, this
* GM should come out completely white. If not, this GM looks like a row of two
* greyscale gradients above a row of grey lines.
* This tests both the ARGB4444 and ARGB8888 bitmap configurations.
*/
static const int SLIDE_SIZE = 256;
static const int PIXEL_SIZE_8888 = SLIDE_SIZE / 256;
static const int PIXEL_SIZE_4444 = SLIDE_SIZE / 16;
static SkBitmap init_bitmap(SkBitmap::Config config) {
SkBitmap bitmap;
bitmap.setConfig(config, SLIDE_SIZE, SLIDE_SIZE);
bitmap.allocPixels();
bitmap.eraseColor(SK_ColorWHITE);
return bitmap;
}
static SkBitmap make_argb8888_gradient() {
SkBitmap bitmap = init_bitmap(SkBitmap::kARGB_8888_Config);
uint8_t rowColor = 0;
for (int y = 0; y < SLIDE_SIZE; y++) {
uint32_t* dst = bitmap.getAddr32(0, y);
for (int x = 0; x < SLIDE_SIZE; x++) {
dst[x] = SkPackARGB32(rowColor, rowColor,
rowColor, rowColor);
}
if (y % PIXEL_SIZE_8888 == PIXEL_SIZE_8888 - 1) {
rowColor++;
}
}
return bitmap;
}
static SkBitmap make_argb4444_gradient() {
SkBitmap bitmap = init_bitmap(SkBitmap::kARGB_4444_Config);
uint8_t rowColor = 0;
for (int y = 0; y < SLIDE_SIZE; y++) {
uint16_t* dst = bitmap.getAddr16(0, y);
for (int x = 0; x < SLIDE_SIZE; x++) {
dst[x] = SkPackARGB4444(rowColor, rowColor,
rowColor, rowColor);
}
if (y % PIXEL_SIZE_4444 == PIXEL_SIZE_4444 - 1) {
rowColor++;
}
}
return bitmap;
}
static SkBitmap make_argb8888_stripes() {
SkBitmap bitmap = init_bitmap(SkBitmap::kARGB_8888_Config);
uint8_t rowColor = 0;
for (int y = 0; y < SLIDE_SIZE; y++) {
uint32_t* dst = bitmap.getAddr32(0, y);
for (int x = 0; x < SLIDE_SIZE; x++) {
dst[x] = SkPackARGB32(rowColor, rowColor,
rowColor, rowColor);
}
if (rowColor == 0) {
rowColor = 255;
} else {
rowColor = 0;
}
}
return bitmap;
}
static SkBitmap make_argb4444_stripes() {
SkBitmap bitmap = init_bitmap(SkBitmap::kARGB_4444_Config);
uint8_t rowColor = 0;;
for (int y = 0; y < SLIDE_SIZE; y++) {
uint16_t* dst = bitmap.getAddr16(0, y);
for (int x = 0; x < SLIDE_SIZE; x++) {
dst[x] = SkPackARGB4444(rowColor, rowColor,
rowColor, rowColor);
}
if (rowColor == 0) {
rowColor = 15;
} else {
rowColor = 0;
}
}
return bitmap;
}
namespace skiagm {
class BitmapPremulGM : public GM {
public:
BitmapPremulGM() {
this->setBGColor(SK_ColorWHITE);
}
protected:
SkString onShortName() SK_OVERRIDE {
return SkString("bitmap_premul");
}
virtual SkISize onISize() SK_OVERRIDE {
return SkISize::Make(SLIDE_SIZE * 2, SLIDE_SIZE * 2);
}
virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
SkScalar slideSize = SkIntToScalar(SLIDE_SIZE);
canvas->drawBitmap(make_argb8888_gradient(), 0, 0);
canvas->drawBitmap(make_argb4444_gradient(), slideSize, 0);
canvas->drawBitmap(make_argb8888_stripes(), 0, slideSize);
canvas->drawBitmap(make_argb4444_stripes(), slideSize, slideSize);
}
private:
typedef GM INHERITED;
};
DEF_GM( return new BitmapPremulGM; )
}

View File

@ -13,6 +13,7 @@
'../gm/bitmapcopy.cpp',
'../gm/bitmapmatrix.cpp',
'../gm/bitmapfilters.cpp',
'../gm/bitmappremul.cpp',
'../gm/bitmaprect.cpp',
'../gm/bitmaprecttest.cpp',
'../gm/bitmapscroll.cpp',

View File

@ -336,6 +336,157 @@ static SkPDFArray* make_indexed_color_space(SkColorTable* table) {
return result;
}
/**
* Removes the alpha component of an ARGB color (including unpremultiply) while
* keeping the output in the same format as the input.
*/
static uint32_t remove_alpha_argb8888(uint32_t pmColor) {
SkColor color = SkUnPreMultiply::PMColorToColor(pmColor);
return SkPackARGB32NoCheck(SK_AlphaOPAQUE,
SkColorGetR(color),
SkColorGetG(color),
SkColorGetB(color));
}
static uint16_t remove_alpha_argb4444(uint16_t pmColor) {
return SkPixel32ToPixel4444(
remove_alpha_argb8888(SkPixel4444ToPixel32(pmColor)));
}
static uint32_t get_argb8888_neighbor_avg_color(const SkBitmap& bitmap,
int xOrig, int yOrig) {
uint8_t count = 0;
uint16_t r = 0;
uint16_t g = 0;
uint16_t b = 0;
for (int y = yOrig - 1; y <= yOrig + 1; y++) {
if (y < 0 || y >= bitmap.height()) {
continue;
}
uint32_t* src = bitmap.getAddr32(0, y);
for (int x = xOrig - 1; x <= xOrig + 1; x++) {
if (x < 0 || x >= bitmap.width()) {
continue;
}
if (SkGetPackedA32(src[x]) != SK_AlphaTRANSPARENT) {
uint32_t color = remove_alpha_argb8888(src[x]);
r += SkGetPackedR32(color);
g += SkGetPackedG32(color);
b += SkGetPackedB32(color);
count++;
}
}
}
if (count == 0) {
return SkPackARGB32NoCheck(SK_AlphaOPAQUE, 0, 0, 0);
} else {
return SkPackARGB32NoCheck(SK_AlphaOPAQUE,
r / count, g / count, b / count);
}
}
static uint16_t get_argb4444_neighbor_avg_color(const SkBitmap& bitmap,
int xOrig, int yOrig) {
uint8_t count = 0;
uint8_t r = 0;
uint8_t g = 0;
uint8_t b = 0;
for (int y = yOrig - 1; y <= yOrig + 1; y++) {
if (y < 0 || y >= bitmap.height()) {
continue;
}
uint16_t* src = bitmap.getAddr16(0, y);
for (int x = xOrig - 1; x <= xOrig + 1; x++) {
if (x < 0 || x >= bitmap.width()) {
continue;
}
if ((SkGetPackedA4444(src[x]) & 0x0F) != SK_AlphaTRANSPARENT) {
uint16_t color = remove_alpha_argb4444(src[x]);
r += SkGetPackedR4444(color);
g += SkGetPackedG4444(color);
b += SkGetPackedB4444(color);
count++;
}
}
}
if (count == 0) {
return SkPackARGB4444(SK_AlphaOPAQUE & 0x0F, 0, 0, 0);
} else {
return SkPackARGB4444(SK_AlphaOPAQUE & 0x0F,
r / count, g / count, b / count);
}
}
static SkBitmap unpremultiply_bitmap(const SkBitmap& bitmap,
const SkIRect& srcRect) {
SkBitmap outBitmap;
outBitmap.setConfig(bitmap.config(), srcRect.width(), srcRect.height());
SkASSERT(outBitmap.allocPixels());
size_t dstRow = 0;
outBitmap.lockPixels();
bitmap.lockPixels();
switch (bitmap.config()) {
case SkBitmap::kARGB_4444_Config: {
for (int y = srcRect.fTop; y < srcRect.fBottom; y++) {
uint16_t* dst = outBitmap.getAddr16(0, dstRow);
uint16_t* src = bitmap.getAddr16(0, y);
for (int x = srcRect.fLeft; x < srcRect.fRight; x++) {
uint8_t a = SkGetPackedA4444(src[x]);
// It is necessary to average the color component of
// transparent pixels with their surrounding neighbors
// since the PDF renderer may separately re-sample the
// alpha and color channels when the image is not
// displayed at its native resolution. Since an alpha of
// zero gives no information about the color component,
// the pathological case is a white image with sharp
// transparency bounds - the color channel goes to black,
// and the should-be-transparent pixels are rendered
// as grey because of the separate soft mask and color
// resizing.
if (a == (SK_AlphaTRANSPARENT & 0x0F)) {
*dst = get_argb4444_neighbor_avg_color(bitmap, x, y);
} else {
*dst = remove_alpha_argb4444(src[x]);
}
dst++;
}
dstRow++;
}
break;
}
case SkBitmap::kARGB_8888_Config: {
for (int y = srcRect.fTop; y < srcRect.fBottom; y++) {
uint32_t* dst = outBitmap.getAddr32(0, dstRow);
uint32_t* src = bitmap.getAddr32(0, y);
for (int x = srcRect.fLeft; x < srcRect.fRight; x++) {
uint8_t a = SkGetPackedA32(src[x]);
if (a == SK_AlphaTRANSPARENT) {
*dst = get_argb8888_neighbor_avg_color(bitmap, x, y);
} else {
*dst = remove_alpha_argb8888(src[x]);
}
dst++;
}
dstRow++;
}
break;
}
default:
SkASSERT(false);
}
bitmap.unlockPixels();
outBitmap.unlockPixels();
outBitmap.setImmutable();
return outBitmap;
}
// static
SkPDFImage* SkPDFImage::CreateImage(const SkBitmap& bitmap,
const SkIRect& srcRect,
@ -358,8 +509,18 @@ SkPDFImage* SkPDFImage::CreateImage(const SkBitmap& bitmap,
return NULL;
}
SkPDFImage* image = SkNEW_ARGS(SkPDFImage, (NULL, bitmap,
false, srcRect, encoder));
SkPDFImage* image;
SkBitmap::Config config = bitmap.config();
if (alphaData.get() != NULL && (config == SkBitmap::kARGB_8888_Config ||
config == SkBitmap::kARGB_4444_Config)) {
SkBitmap unpremulBitmap = unpremultiply_bitmap(bitmap, srcRect);
SkIRect newSrcRect = srcRect;
newSrcRect.offset(-srcRect.left(), -srcRect.top());
image = SkNEW_ARGS(SkPDFImage, (NULL, unpremulBitmap,
false, newSrcRect, encoder));
} else {
image = SkNEW_ARGS(SkPDFImage, (NULL, bitmap, false, srcRect, encoder));
}
if (alphaData.get() != NULL) {
SkAutoTUnref<SkPDFImage> mask(
SkNEW_ARGS(SkPDFImage, (alphaData.get(), bitmap,
@ -391,11 +552,17 @@ SkPDFImage::SkPDFImage(SkStream* stream,
bool isAlpha,
const SkIRect& srcRect,
EncodeToDCTStream encoder)
: fBitmap(bitmap),
fIsAlpha(isAlpha),
: fIsAlpha(isAlpha),
fSrcRect(srcRect),
fEncoder(encoder) {
if (bitmap.isImmutable()) {
fBitmap = bitmap;
} else {
bitmap.deepCopyTo(&fBitmap, bitmap.config());
fBitmap.setImmutable();
}
if (stream != NULL) {
setData(stream);
fStreamValid = true;