New GM: image_scale_aligned

gm/imagescalealigned.cpp

+/*
+ * Copyright 2015 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 "SkImage.h"
+#include "SkSurface.h"
+#include "SkTArray.h"
+
+class ImageScaleAlignedGM : public skiagm::GM {
+protected:
+    void onOnceBeforeDraw() override {
+        const SkVector vectors[] = { { 1, 0 }, { 0, 1 } };
+
+        for (size_t i = 0; i < SK_ARRAY_COUNT(vectors); ++i) {
+           auto& set = fSets.push_back();
+
+           set.fVector = vectors[i];
+           set.fImages.push_back().reset(MakeImage(vectors[i], SK_ColorGREEN));
+           set.fScales.push_back() = 1;
+           set.fImages.push_back().reset(MakeImage(vectors[i], SK_ColorRED));
+           set.fScales.push_back() = kStretchFactor;
+           set.fImages.push_back().reset(MakeImage(vectors[i], SK_ColorGREEN));
+           set.fScales.push_back() = 1;
+        }
+    }
+
+    SkString onShortName() override {
+        return SkString("image_scale_aligned");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(550, 300);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        struct {
+            SkPoint offset;
+            SkScalar scale;
+        } cfgs[] = {
+            { {  10,    10    }, 1 },
+            { { 140.5f, 10    }, 1 },
+            { {  10,    80.5f }, 1 },
+            { { 140.5f, 80.5f }, 1 },
+
+            { { 280.49f, 10.49f }, 1 },
+            { { 410.51f, 10.49f }, 1 },
+            { { 280.49f, 80.51f }, 1 },
+            { { 410.51f, 80.51f }, 1 },
+
+            { {  10,    170    }, 1.1f },
+            { { 140.5f, 170    }, 1.1f },
+            { {  10,    240.5f }, 1.1f },
+            { { 140.5f, 240.5f }, 1.1f },
+
+            { { 280.49f, 170.49f }, 1.1f },
+            { { 410.51f, 170.49f }, 1.1f },
+            { { 280.49f, 240.51f }, 1.1f },
+            { { 410.51f, 240.51f }, 1.1f },
+        };
+
+        for (size_t i = 0; i < SK_ARRAY_COUNT(cfgs); ++i) {
+            SkAutoCanvasRestore acr(canvas, true);
+            canvas->translate(cfgs[i].offset.x(), cfgs[i].offset.y());
+            canvas->scale(cfgs[i].scale, cfgs[i].scale);
+            drawSets(canvas);
+        }
+    }
+
+private:
+    struct ImageSet {
+        SkSTArray<3, SkAutoTUnref<SkImage>, true> fImages;
+        SkSTArray<3, SkScalar>                    fScales;
+        SkVector                                  fVector;
+    };
+
+    static SkImage* MakeImage(const SkVector& vec, SkColor color) {
+        const SkPoint start = SkPoint::Make(vec.y() * kSegLen / 2, vec.x() * kSegLen / 2);
+        const SkPoint end   = SkPoint::Make(start.x() + vec.x() * (kSegLen - 1),
+                                            start.y() + vec.y() * (kSegLen - 1));
+
+        SkAutoTUnref<SkSurface> surface(SkSurface::NewRasterN32Premul(kSegLen, kSegLen));
+        surface->getCanvas()->clear(SK_ColorTRANSPARENT);
+
+        SkPaint paint;
+        paint.setAntiAlias(true);
+        paint.setColor(SK_ColorBLACK);
+        surface->getCanvas()->drawLine(start.x(), start.y(), end.x(), end.y(), paint);
+        surface->getCanvas()->drawPoint(start.x(), start.y(), color);
+        surface->getCanvas()->drawPoint(end.x(), end.y(), color);
+
+        return surface->newImageSnapshot();
+    }
+
+    void drawSets(SkCanvas* canvas) const {
+        SkAutoCanvasRestore acr(canvas, true);
+
+        const SkFilterQuality filters[] = {
+            kNone_SkFilterQuality,
+            kLow_SkFilterQuality,
+            kMedium_SkFilterQuality,
+            kHigh_SkFilterQuality
+        };
+        const bool AAs[] = { false, true };
+
+        SkPaint paint;
+        for (int i = 0; i < fSets.count(); ++i) {
+            auto& set = fSets[i];
+            SkPoint lastPt;
+            for (size_t j = 0; j < SK_ARRAY_COUNT(AAs); ++j) {
+                paint.setAntiAlias(AAs[j]);
+                for (size_t k = 0; k < SK_ARRAY_COUNT(filters); ++k) {
+                    paint.setFilterQuality(filters[k]);
+                    lastPt = drawSet(canvas, set, paint);
+                    canvas->translate((kSegLen / 2) * set.fVector.y(),
+                                      (kSegLen / 2) * set.fVector.x());
+                }
+            }
+            canvas->translate(lastPt.x() + kSegLen,
+                - SkIntToScalar(kSegLen) / 2 * SK_ARRAY_COUNT(filters) * SK_ARRAY_COUNT(AAs));
+        }
+    }
+
+    SkPoint drawSet(SkCanvas* canvas, const ImageSet& set, const SkPaint& paint) const {
+        SkASSERT(set.fImages.count() == set.fScales.count());
+
+        SkPoint pt = SkPoint::Make(0, 0);
+        for (int i = 0; i < set.fImages.count(); ++i) {
+            auto& img = set.fImages[i];
+            const SkRect dst =
+                SkRect::MakeXYWH(pt.x(), pt.y(),
+                    img->width() * (1 + (set.fScales[i] - 1) * set.fVector.x()),
+                    img->height() * (1 + (set.fScales[i] - 1) * set.fVector.y()));
+
+            canvas->drawImageRect(img, dst, &paint);
+            pt.offset(dst.width() * set.fVector.x(), dst.height() * set.fVector.y());
+        }
+
+        return pt;
+    }
+
+    static const unsigned  kSegLen = 9;
+    static const unsigned  kStretchFactor = 2;
+    SkSTArray<2, ImageSet> fSets;
+
+    typedef GM INHERITED;
+};
+
+DEF_GM(return new ImageScaleAlignedGM();)