/* * Copyright 2013 Google Inc. * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ #include "gm.h" #include "SkBlurMask.h" #include "SkBlurMaskFilter.h" #include "SkCanvas.h" #include "SkColorFilter.h" #include "SkLayerDrawLooper.h" // This GM tests 3 different ways of drawing four shadows around a square: // just using 4 blurred rects // using 4 1-level draw loopers // using 1 4-level draw looper // They all produce exactly the same pixels class MegaLooperGM : public skiagm::GM { public: // The types define "<# of loopers> x <# of stages per looper>" enum Type { k0x0_Type, // draw without loopers at all k4x1_Type, // a looper for each shadow k1x4_Type, // all four shadows in one looper }; MegaLooperGM(Type type) : fType(type) {} protected: virtual SkString onShortName() { switch (fType) { case k0x0_Type: return SkString("megalooper_0x0"); break; case k4x1_Type: return SkString("megalooper_4x1"); break; case k1x4_Type: // fall through default: return SkString("megalooper_1x4"); break; } } virtual SkISize onISize() { return SkISize::Make(kWidth, kHeight); } virtual void onDraw(SkCanvas* canvas) { for (int y = 100; y < kHeight; y += 200) { for (int x = 100; x < kWidth; x += 200) { switch (fType) { case k0x0_Type: draw0x0(canvas, SkIntToScalar(x), SkIntToScalar(y)); break; case k4x1_Type: draw4x1(canvas, SkIntToScalar(x), SkIntToScalar(y)); break; case k1x4_Type: // fall through default: draw1x4(canvas, SkIntToScalar(x), SkIntToScalar(y)); break; } } } } private: static const int kWidth = 800; static const int kHeight = 800; static const int kHalfOuterClipSize = 100; static const int kHalfSquareSize = 50; static const int kOffsetToOutsideClip = kHalfSquareSize + kHalfOuterClipSize + 1; static const SkPoint gBlurOffsets[4]; static const SkColor gColors[4]; Type fType; // Just draw a blurred rect at each of the four corners of a square (centered at x,y). // Use two clips to define a rectori where we want pixels to appear. void draw0x0(SkCanvas* canvas, SkScalar x, SkScalar y) { SkRect innerClip = { -kHalfSquareSize, -kHalfSquareSize, kHalfSquareSize, kHalfSquareSize }; innerClip.offset(x, y); SkRect outerClip = { -kHalfOuterClipSize-kHalfSquareSize, -kHalfOuterClipSize-kHalfSquareSize, kHalfOuterClipSize+kHalfSquareSize, kHalfOuterClipSize+kHalfSquareSize }; outerClip.offset(x, y); canvas->save(); canvas->clipRect(outerClip, SkRegion::kIntersect_Op); canvas->clipRect(innerClip, SkRegion::kDifference_Op); SkPaint paint; paint.setAntiAlias(true); paint.setMaskFilter(createBlur())->unref(); for (int i = 0; i < 4; ++i) { paint.setColor(gColors[i]); SkRect rect = { -kHalfSquareSize, -kHalfSquareSize, kHalfSquareSize, kHalfSquareSize }; rect.offset(gBlurOffsets[i]); rect.offset(x, y); canvas->drawRect(rect, paint); } canvas->restore(); } SkMaskFilter* createBlur() { static const SkScalar kBlurSigma = SkBlurMask::ConvertRadiusToSigma(SkIntToScalar(25)); return SkBlurMaskFilter::Create(SkBlurMaskFilter::kNormal_BlurStyle, kBlurSigma, SkBlurMaskFilter::kHighQuality_BlurFlag); } // This draws 4 blurred shadows around a single square (centered at x, y). // Each blur is offset +/- half the square's side in x & y from the original // (so each blurred rect is centered at one of the corners of the original). // For each blur a large outer clip is centered around the blurred rect // while a difference clip stays at the location of the original rect. // Each blurred rect is drawn with a draw looper where the original (non- // blurred rect) is offset to reside outside of the large outer clip (so // it never appears) but the offset in the draw looper is used to translate // the blurred version back into the clip. void draw4x1(SkCanvas* canvas, SkScalar x, SkScalar y) { for (int i = 0; i < 4; ++i) { SkPaint loopPaint; loopPaint.setLooper(create1Looper(-kOffsetToOutsideClip, 0, gColors[i]))->unref(); loopPaint.setAntiAlias(true); SkRect outerClip = { -kHalfOuterClipSize, -kHalfOuterClipSize, kHalfOuterClipSize, kHalfOuterClipSize }; outerClip.offset(x, y); // center it on the blurred rect outerClip.offset(gBlurOffsets[i]); SkRect rect = { -kHalfSquareSize, -kHalfSquareSize, kHalfSquareSize, kHalfSquareSize }; rect.offset(x, y); canvas->save(); canvas->clipRect(outerClip, SkRegion::kIntersect_Op); canvas->clipRect(rect, SkRegion::kDifference_Op); // move the rect to where we want the blur to appear rect.offset(gBlurOffsets[i]); // then move it outside the clip (the blur stage of the draw // looper will undo this translation) rect.offset(SkIntToScalar(kOffsetToOutsideClip), 0); canvas->drawRect(rect, loopPaint); canvas->restore(); } } // Create a 1-tier drawlooper SkLayerDrawLooper* create1Looper(SkScalar xOff, SkScalar yOff, SkColor color) { SkLayerDrawLooper::Builder looperBuilder; SkLayerDrawLooper::LayerInfo info; info.fPaintBits = SkLayerDrawLooper::kColorFilter_Bit | SkLayerDrawLooper::kMaskFilter_Bit; info.fColorMode = SkXfermode::kSrc_Mode; info.fOffset.set(xOff, yOff); info.fPostTranslate = false; SkPaint* paint = looperBuilder.addLayer(info); paint->setMaskFilter(this->createBlur())->unref(); SkColorFilter* cf = SkColorFilter::CreateModeFilter(color, SkXfermode::kSrcIn_Mode); paint->setColorFilter(cf)->unref(); return looperBuilder.detachLooper(); } void draw1x4(SkCanvas* canvas, SkScalar x, SkScalar y) { SkRect rect = { -kHalfSquareSize, -kHalfSquareSize, kHalfSquareSize, kHalfSquareSize }; rect.offset(x, y); SkRect outerClip = { -kHalfOuterClipSize-kHalfSquareSize, -kHalfOuterClipSize-kHalfSquareSize, kHalfOuterClipSize+kHalfSquareSize, kHalfOuterClipSize+kHalfSquareSize }; outerClip.offset(x, y); SkPaint paint; paint.setAntiAlias(true); paint.setLooper(create4Looper(-kOffsetToOutsideClip-kHalfSquareSize, 0))->unref(); canvas->save(); canvas->clipRect(outerClip, SkRegion::kIntersect_Op); canvas->clipRect(rect, SkRegion::kDifference_Op); rect.offset(SkIntToScalar(kOffsetToOutsideClip+kHalfSquareSize), 0); canvas->drawRect(rect, paint); canvas->restore(); } // Create a 4-tier draw looper SkLayerDrawLooper* create4Looper(SkScalar xOff, SkScalar yOff) { SkLayerDrawLooper::Builder looperBuilder; SkLayerDrawLooper::LayerInfo info; info.fPaintBits = SkLayerDrawLooper::kColorFilter_Bit | SkLayerDrawLooper::kMaskFilter_Bit; info.fColorMode = SkXfermode::kSrc_Mode; info.fPostTranslate = false; SkPaint* paint; for (int i = 3; i >= 0; --i) { info.fOffset.set(xOff+gBlurOffsets[i].fX, yOff+gBlurOffsets[i].fY); paint = looperBuilder.addLayer(info); paint->setMaskFilter(this->createBlur())->unref(); SkColorFilter* cf = SkColorFilter::CreateModeFilter(gColors[i], SkXfermode::kSrcIn_Mode); paint->setColorFilter(cf)->unref(); } return looperBuilder.detachLooper(); } typedef GM INHERITED; }; const SkPoint MegaLooperGM::gBlurOffsets[4] = { { kHalfSquareSize, kHalfSquareSize }, { -kHalfSquareSize, kHalfSquareSize }, { kHalfSquareSize, -kHalfSquareSize }, { -kHalfSquareSize, -kHalfSquareSize } }; const SkColor MegaLooperGM::gColors[4] = { SK_ColorGREEN, SK_ColorYELLOW, SK_ColorBLUE, SK_ColorRED }; DEF_GM( return new MegaLooperGM(MegaLooperGM::k0x0_Type); ) DEF_GM( return new MegaLooperGM(MegaLooperGM::k4x1_Type); ) DEF_GM( return new MegaLooperGM(MegaLooperGM::k1x4_Type); )