implement A8 destination fast-path for SkPixelInfo::CopyPixels

tests/ReadPixelsTest.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCanvas.h"
 #include "SkColorPriv.h"
 #include "SkMathPriv.h"
@@ skipping 117 matching lines @@
 }
 #endif
 
 static void fill_dst_bmp_with_init_data(SkBitmap* bitmap) {
     SkAutoLockPixels alp(*bitmap);
     int w = bitmap->width();
     int h = bitmap->height();
     intptr_t pixels = reinterpret_cast<intptr_t>(bitmap->getPixels());
     for (int y = 0; y < h; ++y) {
         for (int x = 0; x < w; ++x) {
-            SkPMColor* pixel = reinterpret_cast<SkPMColor*>(pixels + y * bitmap->rowBytes() + x * bitmap->bytesPerPixel());
-            *pixel = get_dst_bmp_init_color(x, y, w);
+            SkPMColor initColor = get_dst_bmp_init_color(x, y, w);
+            if (kAlpha_8_SkColorType == bitmap->colorType()) {
+                uint8_t* alpha = reinterpret_cast<uint8_t*>(pixels + y * bitmap->rowBytes() + x);
+                *alpha = SkGetPackedA32(initColor);
+            } else {
+                SkPMColor* pixel = reinterpret_cast<SkPMColor*>(pixels + y * bitmap->rowBytes() + x * bitmap->bytesPerPixel());
+                *pixel = initColor;
+            }
         }
     }
 }
 
 static bool check_read_pixel(SkPMColor a, SkPMColor b, bool didPremulConversion) {
     if (!didPremulConversion) {
         return a == b;
     }
     int32_t aA = static_cast<int32_t>(SkGetPackedA32(a));
     int32_t aR = static_cast<int32_t>(SkGetPackedR32(a));
@@ skipping 11 matching lines @@
            SkAbs32(aB - bB) <= 1;
 }
 
 // checks the bitmap contains correct pixels after the readPixels
 // if the bitmap was prefilled with pixels it checks that these weren't
 // overwritten in the area outside the readPixels.
 static bool check_read(skiatest::Reporter* reporter,
                        const SkBitmap& bitmap,
                        int x, int y,
                        bool checkCanvasPixels,
-                       bool checkBitmapPixels) {
-    SkASSERT(4 == bitmap.bytesPerPixel());
+                       bool checkBitmapPixels,
+                       SkColorType ct,
+                       SkAlphaType at) {
+    SkASSERT(ct == bitmap.colorType() && at == bitmap.alphaType());
     SkASSERT(!bitmap.isNull());
     SkASSERT(checkCanvasPixels || checkBitmapPixels);
 
-    const SkColorType ct = bitmap.colorType();
-    const SkAlphaType at = bitmap.alphaType();
-
     int bw = bitmap.width();
     int bh = bitmap.height();
 
     SkIRect srcRect = SkIRect::MakeXYWH(x, y, bw, bh);
     SkIRect clippedSrcRect = DEV_RECT;
     if (!clippedSrcRect.intersect(srcRect)) {
         clippedSrcRect.setEmpty();
     }
     SkAutoLockPixels alp(bitmap);
+    if (kAlpha_8_SkColorType == ct) {
+        for (int by = 0; by < bh; ++by) {
+            for (int bx = 0; bx < bw; ++bx) {
+                int devx = bx + srcRect.fLeft;
+                int devy = by + srcRect.fTop;
+                const uint8_t* alpha = bitmap.getAddr8(bx, by);
+
+                if (clippedSrcRect.contains(devx, devy)) {
+                    if (checkCanvasPixels) {
+                        uint8_t canvasAlpha = SkGetPackedA32(get_src_color(devx, devy));
+                        if (canvasAlpha != *alpha) {
+                            ERRORF(reporter, "Expected readback alpha (%d, %d) value 0x%02x, got 0x%02x. ",
+                                   bx, by, canvasAlpha, *alpha);
+                            return false;
+                        }
+                    }
+                } else if (checkBitmapPixels) {
+                    uint32_t origDstAlpha = SkGetPackedA32(get_dst_bmp_init_color(bx, by, bw));
+                    if (origDstAlpha != *alpha) {
+                        ERRORF(reporter, "Expected clipped out area of readback to be unchanged. "
+                            "Expected 0x%02x, got 0x%02x", origDstAlpha, *alpha);
+                        return false;
+                    }
+                }
+            }
+        }
+        return true;
+    }
     for (int by = 0; by < bh; ++by) {
         for (int bx = 0; bx < bw; ++bx) {
             int devx = bx + srcRect.fLeft;
             int devy = by + srcRect.fTop;
 
             const uint32_t* pixel = bitmap.getAddr32(bx, by);
 
             if (clippedSrcRect.contains(devx, devy)) {
                 if (checkCanvasPixels) {
                     SkPMColor canvasPixel = get_src_color(devx, devy);
@@ skipping 44 matching lines @@
                         SkAlphaType at) {
     SkImageInfo info = SkImageInfo::Make(rect.width(), rect.height(), ct, at);
     size_t rowBytes = 0;
     bool alloc = true;
     switch (init) {
         case kNoPixels_BitmapInit:
             alloc = false;
         case kTight_BitmapInit:
             break;
         case kRowBytes_BitmapInit:
-            rowBytes = (info.width() + 16) * sizeof(SkPMColor);
+            rowBytes = SkAlign4((info.width() + 16) * info.bytesPerPixel());
             break;
         case kRowBytesOdd_BitmapInit:
-            rowBytes = (info.width() * sizeof(SkPMColor)) + 3;
+            rowBytes = SkAlign4(info.width() * info.bytesPerPixel()) + 3;
             break;
         default:
             SkASSERT(0);
             break;
     }
 
     if (alloc) {
         bitmap->allocPixels(info, rowBytes);
     } else {
         bitmap->setInfo(info, rowBytes);
     }
 }
 
 static const struct {
     SkColorType fColorType;
     SkAlphaType fAlphaType;
 } gReadPixelsConfigs[] = {
     { kRGBA_8888_SkColorType,   kPremul_SkAlphaType },
     { kRGBA_8888_SkColorType,   kUnpremul_SkAlphaType },
     { kBGRA_8888_SkColorType,   kPremul_SkAlphaType },
     { kBGRA_8888_SkColorType,   kUnpremul_SkAlphaType },
+    { kAlpha_8_SkColorType,     kPremul_SkAlphaType },
 };
 const SkIRect gReadPixelsTestRects[] = {
     // entire thing
     DEV_RECT,
     // larger on all sides
     SkIRect::MakeLTRB(-10, -10, DEV_W + 10, DEV_H + 10),
     // fully contained
     SkIRect::MakeLTRB(DEV_W / 4, DEV_H / 4, 3 * DEV_W / 4, 3 * DEV_H / 4),
     // outside top left
     SkIRect::MakeLTRB(-10, -10, -1, -1),
@@ skipping 60 matching lines @@
                 // we expect to succeed when the read isn't fully clipped
                 // out.
                 bool expectSuccess = SkIRect::Intersects(srcRect, DEV_RECT);
                 // determine whether we expected the read to succeed.
                 REPORTER_ASSERT(reporter, success == expectSuccess);
                 // read pixels should never change the gen id
                 REPORTER_ASSERT(reporter, idBefore == idAfter);
 
                 if (success || startsWithPixels) {
                     check_read(reporter, bmp, srcRect.fLeft, srcRect.fTop,
-                               success, startsWithPixels);
+                               success, startsWithPixels,
+                               gReadPixelsConfigs[c].fColorType, gReadPixelsConfigs[c].fAlphaType);
                 } else {
                     // if we had no pixels beforehand and the readPixels
                     // failed then our bitmap should still not have pixels
                     REPORTER_ASSERT(reporter, bmp.isNull());
                 }
             }
             // check the old webkit version of readPixels that clips the
             // bitmap size
             SkBitmap wkbmp;
             bool success = canvas->readPixels(srcRect, &wkbmp);
             SkIRect clippedRect = DEV_RECT;
             if (clippedRect.intersect(srcRect)) {
                 REPORTER_ASSERT(reporter, success);
                 REPORTER_ASSERT(reporter, kN32_SkColorType == wkbmp.colorType());
                 REPORTER_ASSERT(reporter, kPremul_SkAlphaType == wkbmp.alphaType());
                 check_read(reporter, wkbmp, clippedRect.fLeft,
-                           clippedRect.fTop, true, false);
+                           clippedRect.fTop, true, false,
+                           kN32_SkColorType, kPremul_SkAlphaType);
             } else {
                 REPORTER_ASSERT(reporter, !success);
             }
         }
     }
 }
 DEF_TEST(ReadPixels, reporter) {
     const SkImageInfo info = SkImageInfo::MakeN32Premul(DEV_W, DEV_H);
     auto surface(SkSurface::MakeRaster(info));
     // SW readback fails a premul check when reading back to an unaligned rowbytes.
@@ skipping 35 matching lines @@
                     uint32_t flags = 0;
                     if (gReadPixelsConfigs[c].fAlphaType == kUnpremul_SkAlphaType) {
                         flags = GrContext::kUnpremul_PixelOpsFlag;
                     }
                     bmp.lockPixels();
                     bool success = texture->readPixels(srcRect.fLeft, srcRect.fTop, bmp.width(),
                                                        bmp.height(), dstConfig, bmp.getPixels(),
                                                        bmp.rowBytes(), flags);
                     bmp.unlockPixels();
                     check_read(reporter, bmp, srcRect.fLeft, srcRect.fTop,
-                               success, true);
+                               success, true,
+                               gReadPixelsConfigs[c].fColorType, gReadPixelsConfigs[c].fAlphaType);
                 }
             }
         }
     }
 }
 DEF_GPUTEST_FOR_RENDERING_CONTEXTS(ReadPixels_Texture, reporter, ctxInfo) {
     // On the GPU we will also try reading back from a non-renderable texture.
     for (auto& origin : {kBottomLeft_GrSurfaceOrigin, kTopLeft_GrSurfaceOrigin}) {
         SkAutoTUnref<GrTexture> texture;
         GrSurfaceDesc desc;
         desc.fFlags = kRenderTarget_GrSurfaceFlag;
         desc.fWidth = DEV_W;
         desc.fHeight = DEV_H;
         desc.fConfig = kSkia8888_GrPixelConfig;
         desc.fOrigin = origin;
         desc.fFlags = kNone_GrSurfaceFlags;
         texture.reset(ctxInfo.grContext()->textureProvider()->createTexture(desc,
                                                                             SkBudgeted::kNo));
         test_readpixels_texture(reporter, texture);
     }
 }
 #endif