Image filters: implement SkImage::makeWithFilter().

gm/imagemakewithfilter.cpp

+/*
+ * Copyright 2016 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 "SkBlurImageFilter.h"
+#include "SkCanvas.h"
+#include "SkColorFilter.h"
+#include "SkColorFilterImageFilter.h"
+#include "SkDropShadowImageFilter.h"
+#include "SkSurface.h"
+
+///////////////////////////////////////////////////////////////////////////////
+
+class ImageMakeWithFilterGM : public skiagm::GM {
+public:
+    ImageMakeWithFilterGM () {}
+
+protected:
+    SkString onShortName() override {
+        return SkString("imagemakewithfilter");
+    }
+
+    SkISize onISize() override { return SkISize::Make(320, 100); }
+
+    void onDraw(SkCanvas* canvas) override {
+        auto cf = SkColorFilter::MakeModeFilter(SK_ColorGREEN, SkXfermode::kSrc_Mode);
+        sk_sp<SkImageFilter> filters[] = {
+            SkColorFilterImageFilter::Make(std::move(cf), nullptr),
+            SkBlurImageFilter::Make(2.0f, 2.0f, nullptr),
+            SkDropShadowImageFilter::Make(
+                10.0f, 5.0f, 3.0f, 3.0f, SK_ColorBLUE,
+                SkDropShadowImageFilter::kDrawShadowAndForeground_ShadowMode,
+                nullptr),
+        };
+
+        const SkImageInfo info = SkImageInfo::MakeN32(100, 100, kPremul_SkAlphaType);
+        SkScalar MARGIN = SkIntToScalar(10);
+        SkScalar DX = info.width() + MARGIN;
+
+        canvas->translate(MARGIN, MARGIN);
+
+        sk_sp<SkSurface> surface = canvas->makeSurface(info);
+        if (!surface) {
+            surface = SkSurface::MakeRaster(info);
+        }
+        sk_tool_utils::draw_checkerboard(surface->getCanvas());
+        sk_sp<SkImage> source = surface->makeImageSnapshot();
+        SkIRect clipBounds = SkIRect::MakeXYWH(0, 0, 75, 75);
+        for (size_t i = 0; i < SK_ARRAY_COUNT(filters); ++i) {
+            SkIRect subset = SkIRect::MakeXYWH(25, 25, 50, 50);
+            SkIRect outSubset;
+            SkIPoint offset;
+            sk_sp<SkImage> result = source->makeWithFilter(filters[i].get(), subset, clipBounds,
+                                                           &outSubset, &offset);
+            SkASSERT(result);
+            SkASSERT(source->isTextureBacked() == result->isTextureBacked());
+            result = result->makeSubset(outSubset);
+            canvas->drawImage(result.get(), SkIntToScalar(offset.fX), SkIntToScalar(offset.fY));
+            canvas->translate(DX, 0);
+        }
+    }
+
+private:
+    typedef GM INHERITED;
+};
+DEF_GM( return new ImageMakeWithFilterGM; )