respect dither setting in index8->565 sprite case

git-svn-id: http://skia.googlecode.com/svn/trunk@328 2bbb7eff-a529-9590-31e7-b0007b416f81

samplecode/SampleDitherBitmap.cpp

@@ -0,0 +1,80 @@
+#include "SampleCode.h"
+#include "SkColorPriv.h"
+#include "SkView.h"
+#include "SkCanvas.h"
+#include "SkUtils.h"
+
+static SkBitmap make_bitmap() {
+    SkBitmap bm;
+    SkColorTable* ctable = new SkColorTable(256);
+
+    SkPMColor* c = ctable->lockColors();
+    for (int i = 0; i < 256; i++) {
+        c[i] = SkPackARGB32(0xFF, 0, 0, i);
+    }
+    ctable->unlockColors(true);
+    bm.setConfig(SkBitmap::kIndex8_Config, 256, 32);
+    bm.allocPixels(ctable);
+    ctable->unref();
+
+    bm.lockPixels();
+    for (int y = 0; y < bm.height(); y++) {
+        uint8_t* p = bm.getAddr8(0, y);
+        for (int x = 0; x < 256; x++) {
+            p[x] = x;
+        }
+    }
+    bm.unlockPixels();
+    return bm;
+}
+
+class DitherBitmapView : public SkView {
+    SkBitmap    fBM8;
+    SkBitmap    fBM32;
+public:
+	DitherBitmapView() {
+        fBM8 = make_bitmap();
+        fBM8.copyTo(&fBM32, SkBitmap::kARGB_8888_Config);
+    }
+    
+protected:
+    // overrides from SkEventSink
+    virtual bool onQuery(SkEvent* evt) {
+        if (SampleCode::TitleQ(*evt)) {
+            SampleCode::TitleR(evt, "DitherBitmap");
+            return true;
+        }
+        return this->INHERITED::onQuery(evt);
+    }
+    
+    void drawBG(SkCanvas* canvas) {
+        canvas->drawColor(0xFFDDDDDD);
+    }
+    
+    static void draw2(SkCanvas* canvas, const SkBitmap& bm) {
+        SkPaint paint;
+        
+        canvas->drawBitmap(bm, 0, 0, &paint);
+        paint.setDither(true);
+        canvas->drawBitmap(bm, 0, SkIntToScalar(bm.height() + 10), &paint);
+    }
+    
+    virtual void onDraw(SkCanvas* canvas) {
+        drawBG(canvas);
+        
+        canvas->translate(SkIntToScalar(20), SkIntToScalar(20));
+
+        draw2(canvas, fBM8);
+        canvas->translate(0, SkIntToScalar(fBM8.height() *3));
+        draw2(canvas, fBM32);
+    }
+    
+private:
+    typedef SkView INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static SkView* MyFactory() { return new DitherBitmapView; }
+static SkViewRegister reg(MyFactory);
+

src/core/SkSpriteBlitter_RGB16.cpp

@@ -356,6 +356,10 @@ SkSpriteBlitter* SkSpriteBlitter::ChooseD16(const SkBitmap& source,
             }
             break;
         case SkBitmap::kIndex8_Config:
+            if (paint.isDither()) {
+                // we don't support dither yet in these special cases
+                break;
+            }
             if (source.isOpaque()) {
                 if (255 == alpha) {
                     SK_PLACEMENT_NEW_ARGS(blitter, Sprite_D16_SIndex8_Opaque,