SkMultiPictureDraw API

gm/multipicturedraw.cpp

Index: gm/multipicturedraw.cpp
diff --git a/gm/multipicturedraw.cpp b/gm/multipicturedraw.cpp
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+/*
+ * Copyright 2014 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 "SkColorFilter.h"
+#include "SkMultiPictureDraw.h"
+#include "SkPictureRecorder.h"
+#include "SkSurface.h"
+
+static const SkScalar kRoot3Over2 = 0.86602545f;  // sin(60)
+
+static const int kHexSide = 30;
+static const int kNumHexX = 6;
+static const int kNumHexY = 6;
+static const int kPicWidth = kNumHexX * kHexSide;
+static const int kPicHeight = SkScalarCeilToInt((kNumHexY - 0.5f) * 2 * kHexSide * kRoot3Over2);
+static const SkScalar kInset = 20.0f;
+
+// Create a hexagon centered at (originX, originY)
+static SkPath make_hex_path(SkScalar originX, SkScalar originY) {
+    SkPath hex;
+    hex.moveTo(originX-kHexSide, originY);
+    hex.rLineTo(SkScalarHalf(kHexSide), kRoot3Over2 * kHexSide);
+    hex.rLineTo(SkIntToScalar(kHexSide), 0);
+    hex.rLineTo(SkScalarHalf(kHexSide), -kHexSide * kRoot3Over2);
+    hex.rLineTo(-SkScalarHalf(kHexSide), -kHexSide * kRoot3Over2);
+    hex.rLineTo(-SkIntToScalar(kHexSide), 0);
+    hex.close();
+    return hex;
+}
+
+// Make a picture that is a tiling of the plane with stroked hexagons where
+// each hexagon is in its own layer. The layers are to exercise Ganesh's
+// layer hoisting.
+static const SkPicture* make_picture(SkColor fillColor) {
+
+    // Create a hexagon with its center at the origin
+    SkPath hex = make_hex_path(0, 0);
+
+    SkPaint fill;
+    fill.setStyle(SkPaint::kFill_Style);
+    fill.setColor(fillColor);
+
+    SkPaint stroke;
+    stroke.setStyle(SkPaint::kStroke_Style);
+    stroke.setStrokeWidth(3);
+
+    SkPictureRecorder recorder;
+
+    SkCanvas* canvas = recorder.beginRecording(kPicWidth, kPicHeight);
+
+    SkScalar xPos, yPos = 0;
+
+    for (int y = 0; y < kNumHexY; ++y) {
+        xPos = 0;
+
+        for (int x = 0; x < kNumHexX; ++x) {
+            canvas->saveLayer(NULL, NULL);
+            canvas->translate(xPos, yPos + ((x % 2) ? kRoot3Over2 * kHexSide : 0));
+            canvas->drawPath(hex, fill);
+            canvas->drawPath(hex, stroke);
+            canvas->restore();
+
+            xPos += 1.5f * kHexSide;
+        }
+
+        yPos += 2 * kHexSide * kRoot3Over2;
+    }
+
+    return recorder.endRecording();
+}
+
+static SkSurface* compat_surface(SkCanvas* canvas, int width, int height) {
+    SkImageInfo info = SkImageInfo::MakeN32Premul(width, height);
+
+    SkSurface* surface = canvas->newSurface(info);
+    if (NULL == surface) {
+        // picture canvas returns NULL so fall back to raster
+        surface = SkSurface::NewRaster(info);
+    }
+
+    return surface;
+}
+
+// This class stores the information required to compose all the result
+// fragments potentially generated by the MultiPictureDraw object
+class ComposeStep {
+public:
+    ComposeStep() : fSurf(NULL), fX(0.0f), fY(0.0f), fPaint(NULL) { }
+    ~ComposeStep() { SkSafeUnref(fSurf);  SkDELETE(fPaint); }
+
+    SkSurface* fSurf;
+    SkScalar   fX;
+    SkScalar   fY;
+    SkPaint*   fPaint;
+};
+
+typedef void (*PFContentMtd)(SkCanvas* canvas, const SkPicture* pictures[2]);
+
+// Just a single picture with no clip
+static void no_clip(SkCanvas* canvas, const SkPicture* pictures[2]) {
+    canvas->drawPicture(pictures[0]);
+}
+
+// Two pictures with a rect clip on the second one
+static void rect_clip(SkCanvas* canvas, const SkPicture* pictures[2]) {
+    canvas->drawPicture(pictures[0]);
+
+    SkRect rect = SkRect::MakeWH(SkIntToScalar(kPicWidth), SkIntToScalar(kPicHeight));
+    rect.inset(kInset, kInset);
+
+    canvas->clipRect(rect);
+
+    canvas->drawPicture(pictures[1]);
+}
+
+// Two pictures with a round rect clip on the second one
+static void rrect_clip(SkCanvas* canvas, const SkPicture* pictures[2]) {
+    canvas->drawPicture(pictures[0]);
+
+    SkRect rect = SkRect::MakeWH(SkIntToScalar(kPicWidth), SkIntToScalar(kPicHeight));
+    rect.inset(kInset, kInset);
+        
+    SkRRect rrect;
+    rrect.setRectXY(rect, kInset, kInset);
+
+    canvas->clipRRect(rrect);
+
+    canvas->drawPicture(pictures[1]);
+}
+
+// Two pictures with a clip path on the second one
+static void path_clip(SkCanvas* canvas, const SkPicture* pictures[2]) {
+    canvas->drawPicture(pictures[0]);
+
+    // Create a hexagon centered on the middle of the hex grid
+    SkPath hex = make_hex_path((kNumHexX / 2.0f) * kHexSide, kNumHexY * kHexSide * kRoot3Over2);
+
+    canvas->clipPath(hex);
+
+    canvas->drawPicture(pictures[1]);
+}
+
+// Two pictures with an inverse clip path on the second one
+static void invpath_clip(SkCanvas* canvas, const SkPicture* pictures[2]) {
+    canvas->drawPicture(pictures[0]);
+
+    // Create a hexagon centered on the middle of the hex grid
+    SkPath hex = make_hex_path((kNumHexX / 2.0f) * kHexSide, kNumHexY * kHexSide * kRoot3Over2);
+    hex.setFillType(SkPath::kInverseEvenOdd_FillType);
+
+    canvas->clipPath(hex);
+
+    canvas->drawPicture(pictures[1]);
+}
+
+static const PFContentMtd gContentMthds[] = {
+    no_clip,
+    rect_clip,
+    rrect_clip,
+    path_clip,
+    invpath_clip
+};
+
+static void create_content(SkMultiPictureDraw* mpd, PFContentMtd pfGen,
+                           const SkPicture* pictures[2],
+                           SkCanvas* dest, const SkMatrix& xform) {
+    SkAutoTUnref<SkPicture> composite;
+
+    {
+        SkPictureRecorder recorder;
+
+        SkCanvas* pictureCanvas = recorder.beginRecording(kPicWidth, kPicHeight);
+
+        (*pfGen)(pictureCanvas, pictures);
+
+        composite.reset(recorder.endRecording());
+    }
+
+    mpd->add(dest, composite, &xform);
+}
+
+typedef void(*PFLayoutMtd)(SkCanvas* finalCanvas, SkMultiPictureDraw* mpd, 
+                           PFContentMtd pfGen, const SkPicture* pictures[2],
+                           SkTArray<ComposeStep>* composeSteps);
+
+// Draw the content into a single canvas
+static void simple(SkCanvas* finalCanvas, SkMultiPictureDraw* mpd, 
+                   PFContentMtd pfGen, 
+                   const SkPicture* pictures[2],
+                   SkTArray<ComposeStep> *composeSteps) {
+
+    ComposeStep& step = composeSteps->push_back();
+
+    step.fSurf = SkSafeRef(compat_surface(finalCanvas, kPicWidth, kPicHeight));
+
+    SkCanvas* subCanvas = step.fSurf->getCanvas();
+
+    create_content(mpd, pfGen, pictures, subCanvas, SkMatrix::I());
+}
+
+// Draw the content into multiple canvases/tiles
+static void tiled(SkCanvas* finalCanvas, SkMultiPictureDraw* mpd,
+                  PFContentMtd pfGen, 
+                  const SkPicture* pictures[2],
+                  SkTArray<ComposeStep> *composeSteps) {
+    static const int kNumTilesX = 2;
+    static const int kNumTilesY = 2;
+    static const int kTileWidth = kPicWidth / kNumTilesX;
+    static const int kTileHeight = kPicHeight / kNumTilesY;
+
+    SkASSERT(kPicWidth == kNumTilesX * kTileWidth);
+    SkASSERT(kPicHeight == kNumTilesY * kTileHeight);
+
+    static const SkColor colors[kNumTilesX][kNumTilesY] = {
+        { SK_ColorCYAN,   SK_ColorMAGENTA }, 
+        { SK_ColorYELLOW, SK_ColorGREEN   }
+    };
+
+    for (int y = 0; y < kNumTilesY; ++y) {
+        for (int x = 0; x < kNumTilesX; ++x) {
+            ComposeStep& step = composeSteps->push_back();
+
+            step.fX = SkIntToScalar(x*kTileWidth);
+            step.fY = SkIntToScalar(y*kTileHeight);
+            step.fPaint = SkNEW(SkPaint);
+            step.fPaint->setColorFilter(
+                SkColorFilter::CreateModeFilter(colors[x][y], SkXfermode::kModulate_Mode))->unref();
+
+            step.fSurf = SkSafeRef(compat_surface(finalCanvas, kTileWidth, kTileHeight));
+
+            SkCanvas* subCanvas = step.fSurf->getCanvas();
+
+            SkMatrix trans;
+            trans.setTranslate(-SkIntToScalar(x*kTileWidth), -SkIntToScalar(y*kTileHeight));
+
+            create_content(mpd, pfGen, pictures, subCanvas, trans);
+        }
+    }
+}
+
+static const PFLayoutMtd gLayoutMthds[] = { simple, tiled };
+
+namespace skiagm {
+    /**
+     * This GM exercises the SkMultiPictureDraw object. It tests the
+     * cross product of:
+     *      tiled vs. all-at-once rendering (e.g., into many or just 1 canvas)
+     *      different clips (e.g., none, rect, rrect)
+     *      single vs. multiple pictures (e.g., normal vs. picture-pile-style content)
+     */
+    class MultiPictureDraw : public GM {
+    public:
+        enum Content {
+            kNoClipSingle_Content,
+            kRectClipMulti_Content,
+            kRRectClipMulti_Content,
+            kPathClipMulti_Content,
+            kInvPathClipMulti_Content,
+
+            kLast_Content = kInvPathClipMulti_Content
+        };
+
+        static const int kContentCnt = kLast_Content + 1;
+
+        enum Layout {
+            kSimple_Layout,
+            kTiled_Layout,
+
+            kLast_Layout = kTiled_Layout
+        };
+
+        static const int kLayoutCnt = kLast_Layout + 1;
+
+        MultiPictureDraw(Content content, Layout layout) : fContent(content), fLayout(layout) {
+            SkASSERT(SK_ARRAY_COUNT(gLayoutMthds) == kLayoutCnt);
+            SkASSERT(SK_ARRAY_COUNT(gContentMthds) == kContentCnt);
+
+            fPictures[0] = fPictures[1] = NULL;
+        }
+
+        virtual ~MultiPictureDraw() {
+            SkSafeUnref(fPictures[0]);
+            SkSafeUnref(fPictures[1]);
+        }
+
+    protected:
+        Content          fContent;
+        Layout           fLayout;
+        const SkPicture* fPictures[2];
+
+        virtual void onOnceBeforeDraw() SK_OVERRIDE {
+            fPictures[0] = SkRef(make_picture(SK_ColorWHITE));
+            fPictures[1] = SkRef(make_picture(SK_ColorGRAY));
+        }
+
+        virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE{
+            SkMultiPictureDraw mpd;
+            SkTArray<ComposeStep> composeSteps;
+
+            // Fill up the MultiPictureDraw
+            (*gLayoutMthds[fLayout])(canvas, &mpd, 
+                                     gContentMthds[fContent], 
+                                     fPictures, &composeSteps);
+
+            mpd.draw();
+
+            // Compose all the drawn canvases into the final canvas
+            for (int i = 0; i < composeSteps.count(); ++i) {
+                const ComposeStep& step = composeSteps[i];
+
+                SkAutoTUnref<SkImage> image(step.fSurf->newImageSnapshot());
+
+                image->draw(canvas, step.fX, step.fY, step.fPaint);
+            }
+        }
+
+        virtual SkISize onISize() SK_OVERRIDE{ return SkISize::Make(kPicWidth, kPicHeight); }
+
+        virtual SkString onShortName() SK_OVERRIDE{
+            static const char* gContentNames[] = { 
+                "noclip", "rectclip", "rrectclip", "pathclip", "invpathclip" 
+            };
+            static const char* gLayoutNames[] = { "simple", "tiled" };
+
+            SkASSERT(SK_ARRAY_COUNT(gLayoutNames) == kLayoutCnt);
+            SkASSERT(SK_ARRAY_COUNT(gContentNames) == kContentCnt);
+
+            SkString name("multipicturedraw_");
+
+            name.append(gContentNames[fContent]);
+            name.append("_");
+            name.append(gLayoutNames[fLayout]);
+            return name;
+        }
+
+        virtual uint32_t onGetFlags() const SK_OVERRIDE { return kAsBench_Flag | kSkipTiled_Flag; }
+
+    private:
+        typedef GM INHERITED;
+    };
+
+    DEF_GM(return SkNEW_ARGS(MultiPictureDraw, (MultiPictureDraw::kNoClipSingle_Content,     
+                                                MultiPictureDraw::kSimple_Layout));)
+    DEF_GM(return SkNEW_ARGS(MultiPictureDraw, (MultiPictureDraw::kRectClipMulti_Content,    
+                                                MultiPictureDraw::kSimple_Layout));)
+    DEF_GM(return SkNEW_ARGS(MultiPictureDraw, (MultiPictureDraw::kRRectClipMulti_Content,   
+                                                MultiPictureDraw::kSimple_Layout));)
+    DEF_GM(return SkNEW_ARGS(MultiPictureDraw, (MultiPictureDraw::kPathClipMulti_Content,    
+                                                MultiPictureDraw::kSimple_Layout));)
+    DEF_GM(return SkNEW_ARGS(MultiPictureDraw, (MultiPictureDraw::kInvPathClipMulti_Content, 
+                                                MultiPictureDraw::kSimple_Layout));)
+
+    DEF_GM(return SkNEW_ARGS(MultiPictureDraw, (MultiPictureDraw::kNoClipSingle_Content,     
+                                                MultiPictureDraw::kTiled_Layout));)
+    DEF_GM(return SkNEW_ARGS(MultiPictureDraw, (MultiPictureDraw::kRectClipMulti_Content,    
+                                                MultiPictureDraw::kTiled_Layout));)
+    DEF_GM(return SkNEW_ARGS(MultiPictureDraw, (MultiPictureDraw::kRRectClipMulti_Content,   
+                                                MultiPictureDraw::kTiled_Layout));)
+    DEF_GM(return SkNEW_ARGS(MultiPictureDraw, (MultiPictureDraw::kPathClipMulti_Content,    
+                                                MultiPictureDraw::kTiled_Layout));)
+    DEF_GM(return SkNEW_ARGS(MultiPictureDraw, (MultiPictureDraw::kInvPathClipMulti_Content, 
+                                                MultiPictureDraw::kTiled_Layout));)
+}