Move alpha-ramp AA to GrContext, detect cases when AA is applied via other methods (smooth lines, MSAA) or rect falls on integer coords and skip the alpha ramp path. Use pre-fab index buffer for alpha-ramped fill rects and stroke rects.

Review URL: http://codereview.appspot.com/4449047/

git-svn-id: http://skia.googlecode.com/svn/trunk@1169 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 197 insertions, 0 deletions

diff --git a/samplecode/SampleAARects.cpp b/samplecode/SampleAARects.cpp
new file mode 100644
index 0000000000..94f8ce98a5
--- /dev/null
+++ b/samplecode/SampleAARects.cpp
@@ -0,0 +1,197 @@
+#include "SampleCode.h"
+#include "SkView.h"
+#include "SkCanvas.h"
+#include "SkDevice.h"
+#include "SkPaint.h"
+#include "SkShader.h"
+
+static SkBitmap createBitmap(int n) {
+    SkBitmap bitmap;
+    bitmap.setConfig(SkBitmap::kARGB_8888_Config, n, n);
+    bitmap.allocPixels();
+    bitmap.eraseColor(SK_ColorGREEN);
+    
+    SkCanvas canvas(bitmap);
+    SkRect r;
+    r.set(0, 0, SkIntToScalar(n), SkIntToScalar(n));
+    SkPaint paint;
+    paint.setAntiAlias(true);
+    
+    paint.setColor(SK_ColorRED);
+    canvas.drawOval(r, paint);
+    paint.setColor(SK_ColorBLUE);
+    paint.setStrokeWidth(SkIntToScalar(n)/15);
+    paint.setStyle(SkPaint::kStroke_Style);
+    canvas.drawLine(0, 0, r.fRight, r.fBottom, paint);
+    canvas.drawLine(0, r.fBottom, r.fRight, 0, paint);
+    
+    return bitmap;
+}
+
+class AARectView : public SkView {
+    SkBitmap fBitmap;
+    enum {
+        N = 64
+    };
+public:
+    AARectView() {
+        fBitmap = createBitmap(N);
+        
+        fWidth = N;
+    }
+    
+protected:
+    // overrides from SkEventSink
+    virtual bool onQuery(SkEvent* evt) {
+        if (SampleCode::TitleQ(*evt)) {
+            SampleCode::TitleR(evt, "AA Rects");
+            return true;
+        }
+        return this->INHERITED::onQuery(evt);
+    }
+
+    void drawBG(SkCanvas* canvas) {
+        canvas->drawColor(SK_ColorWHITE);
+    }
+    
+    virtual void onDraw(SkCanvas* canvas) {
+        this->drawBG(canvas);
+
+        canvas->translate(SkIntToScalar(10), SkIntToScalar(10));
+
+        SkPaint bluePaint;
+        bluePaint.setARGB(0xff, 0x0, 0x0, 0xff);
+        SkPaint bmpPaint;
+        SkShader* bmpShader = SkShader::CreateBitmapShader(fBitmap, SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode);
+        bmpPaint.setShader(bmpShader);
+        bmpShader->unref();
+
+        bluePaint.setStrokeWidth(3);
+        bmpPaint.setStrokeWidth(3);
+
+        SkPaint paints[] = { bluePaint, bmpPaint };
+
+        SkRect rect;
+
+        SkScalar dx = SkIntToScalar(80);
+        SkScalar dy = SkIntToScalar(100);
+        SkMatrix matrix;
+        for (int p = 0; p < SK_ARRAY_COUNT(paints); ++p) {
+            for (int stroke = 0; stroke < 2; ++stroke) {
+                paints[p].setStyle(stroke ? SkPaint::kStroke_Style : SkPaint::kFill_Style);
+                for (int a = 0; a < 3; ++ a) {
+                    paints[p].setAntiAlias(a > 0);
+                    paints[p].setAlpha(a > 1 ? 0x80 : 0xff);
+
+                    canvas->save();
+                        rect = SkRect::MakeLTRB(SkFloatToScalar(0.f),
+                                                SkFloatToScalar(0.f),
+                                                SkFloatToScalar(40.f),
+                                                SkFloatToScalar(40.f));
+                        canvas->drawRect(rect, paints[p]);
+                        canvas->translate(dx, 0);
+
+                        rect = SkRect::MakeLTRB(SkFloatToScalar(0.5f),
+                                                SkFloatToScalar(0.5f),
+                                                SkFloatToScalar(40.5f),
+                                                SkFloatToScalar(40.5f));
+                        canvas->drawRect(rect, paints[p]);
+                        canvas->translate(dx, 0);
+
+                        rect = SkRect::MakeLTRB(SkFloatToScalar(0.5f),
+                                                SkFloatToScalar(0.5f),
+                                                SkFloatToScalar(40.f),
+                                                SkFloatToScalar(40.f));
+                        canvas->drawRect(rect, paints[p]);
+                        canvas->translate(dx, 0);
+
+                        rect = SkRect::MakeLTRB(SkFloatToScalar(0.75f),
+                                                SkFloatToScalar(0.75f),
+                                                SkFloatToScalar(40.75f),
+                                                SkFloatToScalar(40.75f));
+                        canvas->drawRect(rect, paints[p]);
+                        canvas->translate(dx, 0);
+
+                        canvas->save();
+                            canvas->translate(SkFloatToScalar(.33f), SkFloatToScalar(.67f));
+                            rect = SkRect::MakeLTRB(SkFloatToScalar(0.0f),
+                                                    SkFloatToScalar(0.0f),
+                                                    SkFloatToScalar(40.0f),
+                                                    SkFloatToScalar(40.0f));
+                            canvas->drawRect(rect, paints[p]);
+                        canvas->restore();
+                        canvas->translate(dx, 0);
+
+                        canvas->save();
+                            matrix.setRotate(SkFloatToScalar(45.f));
+                            canvas->concat(matrix);
+                            canvas->translate(SkFloatToScalar(20.0f / sqrtf(2.f)),
+                                                SkFloatToScalar(20.0f / sqrtf(2.f)));
+                            rect = SkRect::MakeLTRB(SkFloatToScalar(-20.0f),
+                                                    SkFloatToScalar(-20.0f),
+                                                    SkFloatToScalar(20.0f),
+                                                    SkFloatToScalar(20.0f));
+                            canvas->drawRect(rect, paints[p]);
+                        canvas->restore();
+                        canvas->translate(dx, 0);
+
+                        canvas->save();
+                            canvas->rotate(SkFloatToScalar(90.f));
+                            rect = SkRect::MakeLTRB(SkFloatToScalar(0.0f),
+                                                    SkFloatToScalar(0.0f),
+                                                    SkFloatToScalar(40.0f),
+                                                    SkFloatToScalar(-40.0f));
+                            canvas->drawRect(rect, paints[p]);
+                        canvas->restore();
+                        canvas->translate(dx, 0);
+
+                        canvas->save();
+                            canvas->rotate(SkFloatToScalar(90.f));
+                            rect = SkRect::MakeLTRB(SkFloatToScalar(0.5f),
+                                                    SkFloatToScalar(0.5f),
+                                                    SkFloatToScalar(40.5f),
+                                                    SkFloatToScalar(-40.5f));
+                            canvas->drawRect(rect, paints[p]);
+                        canvas->restore();
+                        canvas->translate(dx, 0);
+
+                        canvas->save();
+                            matrix.setScale(SkFloatToScalar(-1.f), SkFloatToScalar(-1.f));
+                            canvas->concat(matrix);
+                            rect = SkRect::MakeLTRB(SkFloatToScalar(0.5f),
+                                                    SkFloatToScalar(0.5f),
+                                                    SkFloatToScalar(-40.5f),
+                                                    SkFloatToScalar(-40.5f));
+                            canvas->drawRect(rect, paints[p]);
+                        canvas->restore();
+                        canvas->translate(dx, 0);
+
+                        canvas->save();
+                            matrix.setScale(SkFloatToScalar(2.1f), SkFloatToScalar(4.1f));
+                            canvas->concat(matrix);
+                            rect = SkRect::MakeLTRB(SkFloatToScalar(0.1f),
+                                                    SkFloatToScalar(0.1f),
+                                                    SkFloatToScalar(19.1f),
+                                                    SkFloatToScalar(9.1f));
+                            canvas->drawRect(rect, paints[p]);
+                        canvas->restore();
+                        canvas->translate(dx, 0);
+
+                    canvas->restore();
+                    canvas->translate(0, dy);
+                }
+            }
+        }
+    }
+    
+private:
+    int fWidth;
+
+    typedef SkView INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static SkView* MyFactory() { return new AARectView; }
+static SkViewRegister reg(MyFactory);
+