Remove SkImageShader -> SkColorShader optimization.

It's turned out to be surprisingly subtle to make the optimization colorspace
correct (it's not today, but with this CL the affected images become colorspace
correct).

Before implementing a colorspace correct color shader, let's check we really need this.

Update: I should say, it's hard to do this optimization and make the resulting color shader be both colorspace correct and "legacy correct".  SkColorShader and SkColor4fShader are both colorspace correct.  It's just challenging to create one shader that's correct for both modes from an image.

Change-Id: I6593b6348175a10d7cbaaf3b531d7a7e2bf2f578
Reviewed-on: https://skia-review.googlesource.com/6548
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>

diff --git a/src/image/SkImageShader.cpp b/src/image/SkImageShader.cpp
index e009b4a..1417ac8 100644 (file)
--- a/src/image/SkImageShader.cpp
+++ b/src/image/SkImageShader.cpp
@@ -8,7 +8,6 @@
 #include "SkBitmapController.h"
 #include "SkBitmapProcShader.h"
 #include "SkBitmapProvider.h"
-#include "SkColorShader.h"
 #include "SkColorTable.h"
 #include "SkEmptyShader.h"
 #include "SkFixedAlloc.h"
@@ -101,58 +100,16 @@ static bool bitmap_is_too_big(int w, int h) {
     return w > kMaxSize || h > kMaxSize;
 }
 
-// returns true and set color if the bitmap can be drawn as a single color
-// (for efficiency)
-static bool can_use_color_shader(const SkImage* image, SkColor* color) {
-#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
-    // HWUI does not support color shaders (see b/22390304)
-    return false;
-#endif
-
-    if (1 != image->width() || 1 != image->height()) {
-        return false;
-    }
-
-    SkPixmap pmap;
-    if (!image->peekPixels(&pmap)) {
-        return false;
-    }
-
-    switch (pmap.colorType()) {
-        case kN32_SkColorType:
-            *color = SkUnPreMultiply::PMColorToColor(*pmap.addr32(0, 0));
-            return true;
-        case kRGB_565_SkColorType:
-            *color = SkPixel16ToColor(*pmap.addr16(0, 0));
-            return true;
-        case kIndex_8_SkColorType: {
-            const SkColorTable& ctable = *pmap.ctable();
-            *color = SkUnPreMultiply::PMColorToColor(ctable[*pmap.addr8(0, 0)]);
-            return true;
-        }
-        default: // just skip the other configs for now
-            break;
-    }
-    return false;
-}
-
 sk_sp<SkShader> SkImageShader::Make(sk_sp<SkImage> image, TileMode tx, TileMode ty,
                                     const SkMatrix* localMatrix,
                                     SkTBlitterAllocator* allocator) {
     SkShader* shader;
-    SkColor color;
     if (!image || bitmap_is_too_big(image->width(), image->height())) {
         if (nullptr == allocator) {
             shader = new SkEmptyShader;
         } else {
             shader = allocator->createT<SkEmptyShader>();
         }
-    } else if (can_use_color_shader(image.get(), &color)) {
-        if (nullptr == allocator) {
-            shader = new SkColorShader(color);
-        } else {
-            shader = allocator->createT<SkColorShader>(color);
-        }
     } else {
         if (nullptr == allocator) {
             shader = new SkImageShader(image, tx, ty, localMatrix);