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
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gm/bitmappremul.cpp
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131
gm/bitmappremul.cpp
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/*
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* Copyright 2013 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "gm.h"
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#include "SkBitmap.h"
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#include "SkCanvas.h"
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#include "SkColorPriv.h"
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/**
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* This GM checks that bitmap pixels are unpremultiplied before being exported
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* to other formats. If unpremultiplication is implemented properly, this
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* GM should come out completely white. If not, this GM looks like a row of two
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* greyscale gradients above a row of grey lines.
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* This tests both the ARGB4444 and ARGB8888 bitmap configurations.
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*/
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static const int SLIDE_SIZE = 256;
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static const int PIXEL_SIZE_8888 = SLIDE_SIZE / 256;
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static const int PIXEL_SIZE_4444 = SLIDE_SIZE / 16;
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static SkBitmap init_bitmap(SkBitmap::Config config) {
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SkBitmap bitmap;
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bitmap.setConfig(config, SLIDE_SIZE, SLIDE_SIZE);
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bitmap.allocPixels();
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bitmap.eraseColor(SK_ColorWHITE);
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return bitmap;
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}
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static SkBitmap make_argb8888_gradient() {
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SkBitmap bitmap = init_bitmap(SkBitmap::kARGB_8888_Config);
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uint8_t rowColor = 0;
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for (int y = 0; y < SLIDE_SIZE; y++) {
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uint32_t* dst = bitmap.getAddr32(0, y);
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for (int x = 0; x < SLIDE_SIZE; x++) {
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dst[x] = SkPackARGB32(rowColor, rowColor,
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rowColor, rowColor);
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}
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if (y % PIXEL_SIZE_8888 == PIXEL_SIZE_8888 - 1) {
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rowColor++;
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}
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}
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return bitmap;
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}
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static SkBitmap make_argb4444_gradient() {
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SkBitmap bitmap = init_bitmap(SkBitmap::kARGB_4444_Config);
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uint8_t rowColor = 0;
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for (int y = 0; y < SLIDE_SIZE; y++) {
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uint16_t* dst = bitmap.getAddr16(0, y);
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for (int x = 0; x < SLIDE_SIZE; x++) {
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dst[x] = SkPackARGB4444(rowColor, rowColor,
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rowColor, rowColor);
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}
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if (y % PIXEL_SIZE_4444 == PIXEL_SIZE_4444 - 1) {
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rowColor++;
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}
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}
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return bitmap;
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}
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static SkBitmap make_argb8888_stripes() {
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SkBitmap bitmap = init_bitmap(SkBitmap::kARGB_8888_Config);
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uint8_t rowColor = 0;
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for (int y = 0; y < SLIDE_SIZE; y++) {
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uint32_t* dst = bitmap.getAddr32(0, y);
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for (int x = 0; x < SLIDE_SIZE; x++) {
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dst[x] = SkPackARGB32(rowColor, rowColor,
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rowColor, rowColor);
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}
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if (rowColor == 0) {
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rowColor = 255;
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} else {
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rowColor = 0;
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}
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}
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return bitmap;
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}
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static SkBitmap make_argb4444_stripes() {
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SkBitmap bitmap = init_bitmap(SkBitmap::kARGB_4444_Config);
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uint8_t rowColor = 0;;
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for (int y = 0; y < SLIDE_SIZE; y++) {
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uint16_t* dst = bitmap.getAddr16(0, y);
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for (int x = 0; x < SLIDE_SIZE; x++) {
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dst[x] = SkPackARGB4444(rowColor, rowColor,
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rowColor, rowColor);
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}
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if (rowColor == 0) {
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rowColor = 15;
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} else {
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rowColor = 0;
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}
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}
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return bitmap;
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}
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namespace skiagm {
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class BitmapPremulGM : public GM {
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public:
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BitmapPremulGM() {
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this->setBGColor(SK_ColorWHITE);
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}
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protected:
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SkString onShortName() SK_OVERRIDE {
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return SkString("bitmap_premul");
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}
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virtual SkISize onISize() SK_OVERRIDE {
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return SkISize::Make(SLIDE_SIZE * 2, SLIDE_SIZE * 2);
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}
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virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
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SkScalar slideSize = SkIntToScalar(SLIDE_SIZE);
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canvas->drawBitmap(make_argb8888_gradient(), 0, 0);
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canvas->drawBitmap(make_argb4444_gradient(), slideSize, 0);
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canvas->drawBitmap(make_argb8888_stripes(), 0, slideSize);
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canvas->drawBitmap(make_argb4444_stripes(), slideSize, slideSize);
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}
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private:
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typedef GM INHERITED;
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};
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DEF_GM( return new BitmapPremulGM; )
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}
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@ -13,6 +13,7 @@
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'../gm/bitmapcopy.cpp',
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'../gm/bitmapmatrix.cpp',
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'../gm/bitmapfilters.cpp',
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'../gm/bitmappremul.cpp',
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'../gm/bitmaprect.cpp',
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'../gm/bitmaprecttest.cpp',
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'../gm/bitmapscroll.cpp',
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@ -336,6 +336,157 @@ static SkPDFArray* make_indexed_color_space(SkColorTable* table) {
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return result;
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}
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/**
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* Removes the alpha component of an ARGB color (including unpremultiply) while
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* keeping the output in the same format as the input.
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*/
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static uint32_t remove_alpha_argb8888(uint32_t pmColor) {
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SkColor color = SkUnPreMultiply::PMColorToColor(pmColor);
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return SkPackARGB32NoCheck(SK_AlphaOPAQUE,
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SkColorGetR(color),
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SkColorGetG(color),
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SkColorGetB(color));
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}
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static uint16_t remove_alpha_argb4444(uint16_t pmColor) {
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return SkPixel32ToPixel4444(
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remove_alpha_argb8888(SkPixel4444ToPixel32(pmColor)));
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}
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static uint32_t get_argb8888_neighbor_avg_color(const SkBitmap& bitmap,
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int xOrig, int yOrig) {
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uint8_t count = 0;
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uint16_t r = 0;
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uint16_t g = 0;
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uint16_t b = 0;
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for (int y = yOrig - 1; y <= yOrig + 1; y++) {
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if (y < 0 || y >= bitmap.height()) {
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continue;
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}
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uint32_t* src = bitmap.getAddr32(0, y);
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for (int x = xOrig - 1; x <= xOrig + 1; x++) {
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if (x < 0 || x >= bitmap.width()) {
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continue;
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}
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if (SkGetPackedA32(src[x]) != SK_AlphaTRANSPARENT) {
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uint32_t color = remove_alpha_argb8888(src[x]);
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r += SkGetPackedR32(color);
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g += SkGetPackedG32(color);
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b += SkGetPackedB32(color);
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count++;
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}
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}
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}
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if (count == 0) {
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return SkPackARGB32NoCheck(SK_AlphaOPAQUE, 0, 0, 0);
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} else {
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return SkPackARGB32NoCheck(SK_AlphaOPAQUE,
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r / count, g / count, b / count);
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}
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}
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static uint16_t get_argb4444_neighbor_avg_color(const SkBitmap& bitmap,
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int xOrig, int yOrig) {
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uint8_t count = 0;
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uint8_t r = 0;
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uint8_t g = 0;
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uint8_t b = 0;
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for (int y = yOrig - 1; y <= yOrig + 1; y++) {
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if (y < 0 || y >= bitmap.height()) {
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continue;
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}
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uint16_t* src = bitmap.getAddr16(0, y);
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for (int x = xOrig - 1; x <= xOrig + 1; x++) {
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if (x < 0 || x >= bitmap.width()) {
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continue;
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}
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if ((SkGetPackedA4444(src[x]) & 0x0F) != SK_AlphaTRANSPARENT) {
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uint16_t color = remove_alpha_argb4444(src[x]);
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r += SkGetPackedR4444(color);
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g += SkGetPackedG4444(color);
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b += SkGetPackedB4444(color);
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count++;
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}
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}
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}
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if (count == 0) {
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return SkPackARGB4444(SK_AlphaOPAQUE & 0x0F, 0, 0, 0);
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} else {
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return SkPackARGB4444(SK_AlphaOPAQUE & 0x0F,
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r / count, g / count, b / count);
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}
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}
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static SkBitmap unpremultiply_bitmap(const SkBitmap& bitmap,
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const SkIRect& srcRect) {
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SkBitmap outBitmap;
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outBitmap.setConfig(bitmap.config(), srcRect.width(), srcRect.height());
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SkASSERT(outBitmap.allocPixels());
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size_t dstRow = 0;
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outBitmap.lockPixels();
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bitmap.lockPixels();
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switch (bitmap.config()) {
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case SkBitmap::kARGB_4444_Config: {
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for (int y = srcRect.fTop; y < srcRect.fBottom; y++) {
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uint16_t* dst = outBitmap.getAddr16(0, dstRow);
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uint16_t* src = bitmap.getAddr16(0, y);
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for (int x = srcRect.fLeft; x < srcRect.fRight; x++) {
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uint8_t a = SkGetPackedA4444(src[x]);
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// It is necessary to average the color component of
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// transparent pixels with their surrounding neighbors
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// since the PDF renderer may separately re-sample the
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// alpha and color channels when the image is not
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// displayed at its native resolution. Since an alpha of
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// zero gives no information about the color component,
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// the pathological case is a white image with sharp
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// transparency bounds - the color channel goes to black,
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// and the should-be-transparent pixels are rendered
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// as grey because of the separate soft mask and color
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// resizing.
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if (a == (SK_AlphaTRANSPARENT & 0x0F)) {
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*dst = get_argb4444_neighbor_avg_color(bitmap, x, y);
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} else {
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*dst = remove_alpha_argb4444(src[x]);
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}
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dst++;
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}
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dstRow++;
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}
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break;
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}
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case SkBitmap::kARGB_8888_Config: {
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for (int y = srcRect.fTop; y < srcRect.fBottom; y++) {
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uint32_t* dst = outBitmap.getAddr32(0, dstRow);
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uint32_t* src = bitmap.getAddr32(0, y);
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for (int x = srcRect.fLeft; x < srcRect.fRight; x++) {
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uint8_t a = SkGetPackedA32(src[x]);
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if (a == SK_AlphaTRANSPARENT) {
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*dst = get_argb8888_neighbor_avg_color(bitmap, x, y);
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} else {
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*dst = remove_alpha_argb8888(src[x]);
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}
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dst++;
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}
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dstRow++;
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}
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break;
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}
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default:
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SkASSERT(false);
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}
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bitmap.unlockPixels();
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outBitmap.unlockPixels();
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outBitmap.setImmutable();
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return outBitmap;
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}
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// static
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SkPDFImage* SkPDFImage::CreateImage(const SkBitmap& bitmap,
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const SkIRect& srcRect,
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@ -358,8 +509,18 @@ SkPDFImage* SkPDFImage::CreateImage(const SkBitmap& bitmap,
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return NULL;
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}
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SkPDFImage* image = SkNEW_ARGS(SkPDFImage, (NULL, bitmap,
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false, srcRect, encoder));
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SkPDFImage* image;
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SkBitmap::Config config = bitmap.config();
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if (alphaData.get() != NULL && (config == SkBitmap::kARGB_8888_Config ||
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config == SkBitmap::kARGB_4444_Config)) {
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SkBitmap unpremulBitmap = unpremultiply_bitmap(bitmap, srcRect);
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SkIRect newSrcRect = srcRect;
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newSrcRect.offset(-srcRect.left(), -srcRect.top());
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image = SkNEW_ARGS(SkPDFImage, (NULL, unpremulBitmap,
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false, newSrcRect, encoder));
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} else {
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image = SkNEW_ARGS(SkPDFImage, (NULL, bitmap, false, srcRect, encoder));
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}
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if (alphaData.get() != NULL) {
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SkAutoTUnref<SkPDFImage> mask(
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SkNEW_ARGS(SkPDFImage, (alphaData.get(), bitmap,
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@ -391,11 +552,17 @@ SkPDFImage::SkPDFImage(SkStream* stream,
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bool isAlpha,
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const SkIRect& srcRect,
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EncodeToDCTStream encoder)
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: fBitmap(bitmap),
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fIsAlpha(isAlpha),
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: fIsAlpha(isAlpha),
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fSrcRect(srcRect),
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fEncoder(encoder) {
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if (bitmap.isImmutable()) {
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fBitmap = bitmap;
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} else {
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bitmap.deepCopyTo(&fBitmap, bitmap.config());
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fBitmap.setImmutable();
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}
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if (stream != NULL) {
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setData(stream);
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fStreamValid = true;
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