Create a semi-stable API for capturing the state of an SkCanvas and reconstructing that state acros…

tests/CanvasStateTest.cpp

Index: tests/CanvasStateTest.cpp
diff --git a/tests/CanvasStateTest.cpp b/tests/CanvasStateTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..d18e3280ed7b300229a33bd32897ea4cd4753855
--- /dev/null
+++ b/tests/CanvasStateTest.cpp
@@ -0,0 +1,140 @@
+
+/*
+ * 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 "Test.h"
+#include "SkCanvas.h"
+#include "SkCanvasStateUtils.h"
+#include "SkDevice.h"
+#include "SkDrawFilter.h"
+#include "SkPaint.h"
+#include "SkRect.h"
+#include "SkRRect.h"
+
+static void test_complex_layers(skiatest::Reporter* reporter) {
+
+    const int WIDTH = 400;
+    const int HEIGHT = 400;
+    const int SPACER = 10;
+
+    SkRect rect = SkRect::MakeXYWH(SPACER, SPACER, WIDTH-(2*SPACER), (HEIGHT-(2*SPACER)) / 7);
+
+    const SkBitmap::Config configs[] = { SkBitmap::kRGB_565_Config,
+                                         SkBitmap::kARGB_8888_Config
+    };
+    const int configCount = sizeof(configs) / sizeof(SkBitmap::Config);

[scroggo, 2013/08/29 17:24:07]

Won't this cause a warning somewhere (size_t to int)?

+
+    const int layerAlpha[] = { 255, 255, 0 };
+    const SkCanvas::SaveFlags flags[] = { SkCanvas::kARGB_NoClipLayer_SaveFlag,
+                                          SkCanvas::kARGB_ClipLayer_SaveFlag,
+                                          SkCanvas::kARGB_NoClipLayer_SaveFlag
+    };
+    REPORTER_ASSERT(reporter, sizeof(layerAlpha) == sizeof(flags));
+    const int layerCombinations = sizeof(layerAlpha) / sizeof(int);

[scroggo, 2013/08/29 17:24:07]

Warning?

+
+    for (int i = 0; i < configCount; ++i) {
+        SkBitmap bitmaps[2];
+        for (int j = 0; j < 2; ++j) {
+            bitmaps[j].setConfig(configs[i], WIDTH, HEIGHT);
+            bitmaps[j].allocPixels();
+
+            SkCanvas canvas(bitmaps[j]);
+
+            canvas.drawColor(SK_ColorRED);
+
+            for (int k = 0; k < layerCombinations; ++k) {
+                // draw a rect within the layer's bounds and again outside the layer's bounds
+                canvas.saveLayerAlpha(&rect, layerAlpha[k], flags[k]);
+
+                SkCanvasState* state = NULL;
+                SkCanvas* tmpCanvas = NULL;
+                if (j) {
+                    state = SkCanvasStateUtils::CaptureCanvasState(&canvas);
+                    REPORTER_ASSERT(reporter, state);
+                    tmpCanvas = SkCanvasStateUtils::CreateFromCanvasState(state);
+                    REPORTER_ASSERT(reporter, tmpCanvas);
+                } else {
+                    tmpCanvas = SkRef(&canvas);
+                }
+
+                SkPaint bluePaint;
+                bluePaint.setColor(SK_ColorBLUE);
+                bluePaint.setStyle(SkPaint::kFill_Style);
+
+                tmpCanvas->drawRect(rect, bluePaint);
+                tmpCanvas->translate(0, rect.height() + SPACER);
+                tmpCanvas->drawRect(rect, bluePaint);
+
+                tmpCanvas->unref();
+                SkCanvasStateUtils::ReleaseCanvasState(state);
+
+                canvas.restore();
+
+                // translate the canvas for the next iteration
+                canvas.translate(0, 2*(rect.height() + SPACER));
+            }
+        }
+
+        // now we memcmp the two bitmaps
+        REPORTER_ASSERT(reporter, bitmaps[0].getSize() == bitmaps[1].getSize());
+        REPORTER_ASSERT(reporter, !memcmp(bitmaps[0].getPixels(),
+                                          bitmaps[1].getPixels(),
+                                          bitmaps[0].getSize()));
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+class TestDrawFilter : public SkDrawFilter {
+public:
+    virtual bool filter(SkPaint*, Type) SK_OVERRIDE { return true; }
+};
+
+static void test_draw_filters(skiatest::Reporter* reporter) {
+    TestDrawFilter drawFilter;
+    SkDevice device(SkBitmap::kARGB_8888_Config, 10, 10);
+    SkCanvas canvas(&device);
+
+    canvas.setDrawFilter(&drawFilter);
+
+    SkCanvasState* state = SkCanvasStateUtils::CaptureCanvasState(&canvas);
+    REPORTER_ASSERT(reporter, state);
+    SkCanvas* tmpCanvas = SkCanvasStateUtils::CreateFromCanvasState(state);
+    REPORTER_ASSERT(reporter, tmpCanvas);
+
+    REPORTER_ASSERT(reporter, NULL != canvas.getDrawFilter());
+    REPORTER_ASSERT(reporter, NULL == tmpCanvas->getDrawFilter());
+
+    tmpCanvas->unref();
+    SkCanvasStateUtils::ReleaseCanvasState(state);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+static void test_soft_clips(skiatest::Reporter* reporter) {
+    SkDevice device(SkBitmap::kARGB_8888_Config, 10, 10);
+    SkCanvas canvas(&device);
+
+    SkRRect roundRect;
+    roundRect.setOval(SkRect::MakeWH(5, 5));
+
+    canvas.clipRRect(roundRect, SkRegion::kIntersect_Op, true);
+
+    SkCanvasState* state = SkCanvasStateUtils::CaptureCanvasState(&canvas);
+    REPORTER_ASSERT(reporter, !state);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+static void test_canvas_state_utils(skiatest::Reporter* reporter) {
+    test_complex_layers(reporter);
+    test_draw_filters(reporter);
+    test_soft_clips(reporter);
+}
+
+#include "TestClassDef.h"
+DEFINE_TESTCLASS("CanvasState", TestCanvasStateClass, test_canvas_state_utils)