New gm to test anti-aliased clipping.

git-svn-id: http://skia.googlecode.com/svn/trunk@2914 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 115 insertions, 0 deletions

diff --git a/gm/aaclip.cpp b/gm/aaclip.cpp
new file mode 100644
index 0000000000..f130439bdb
--- /dev/null
+++ b/gm/aaclip.cpp
@@ -0,0 +1,115 @@
+/*
+ * Copyright 2011 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 "SkCanvas.h"
+#include "SkPath.h"
+
+namespace skiagm {
+
+/** Draw a 2px border around the target, then red behind the target;
+    set the clip to match the target, then draw >> the target in blue.
+*/
+
+void draw (SkCanvas* canvas, SkRect& target, int x, int y) {
+    SkPaint borderPaint;
+    borderPaint.setColor(SkColorSetRGB(0x0, 0xDD, 0x0));
+    borderPaint.setAntiAlias(true);
+    SkPaint backgroundPaint;
+    backgroundPaint.setColor(SkColorSetRGB(0xDD, 0x0, 0x0));
+    backgroundPaint.setAntiAlias(true);
+    SkPaint foregroundPaint;
+    foregroundPaint.setColor(SkColorSetRGB(0x0, 0x0, 0xDD));
+    foregroundPaint.setAntiAlias(true);
+
+    canvas->save();
+    canvas->translate(x, y);
+    target.inset(-2, -2);
+    canvas->drawRect(target, borderPaint);
+    target.inset(2, 2);
+    canvas->drawRect(target, backgroundPaint);
+    canvas->clipRect(target, SkRegion::kIntersect_Op, true);
+    target.inset(-4, -4);
+    canvas->drawRect(target, foregroundPaint);
+    canvas->restore();
+}
+
+void draw_square (SkCanvas* canvas, int x, int y) {
+    SkRect target (SkRect::MakeWH(10 * SK_Scalar1, 10 * SK_Scalar1));
+    draw(canvas, target, x, y);
+}
+
+void draw_column (SkCanvas* canvas, int x, int y) {
+    SkRect target (SkRect::MakeWH(1 * SK_Scalar1, 10 * SK_Scalar1));
+    draw(canvas, target, x, y);
+}
+
+void draw_bar (SkCanvas* canvas, int x, int y) {
+    SkRect target (SkRect::MakeWH(10 * SK_Scalar1, 1 * SK_Scalar1));
+    draw(canvas, target, x, y);
+}
+
+void draw_rect_tests (SkCanvas* canvas) {
+    draw_square(canvas, 10, 10);
+    draw_column(canvas, 30, 10);
+    draw_bar(canvas, 10, 30);
+}
+
+/**
+   Test a set of clipping problems discovered while writing blitAntiRect,
+   and test all the code paths through the clipping blitters.
+   Each region should show as a blue center surrounded by a 2px green
+   border, with no red.
+*/
+
+class AAClipGM : public GM {
+public:
+    AAClipGM() {
+
+    }
+
+protected:
+    virtual SkString onShortName() {
+        return SkString("aaclip");
+    }
+
+    virtual SkISize onISize() {
+        return make_isize(640, 480);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) {
+        // Initial pixel-boundary-aligned draw
+        draw_rect_tests(canvas);
+
+        // Repeat 4x with .2, .4, .6, .8 px offsets
+        canvas->translate(SK_Scalar1 / 5, SK_Scalar1 / 5);
+        canvas->translate(50, 0);
+        draw_rect_tests(canvas);
+
+        canvas->translate(SK_Scalar1 / 5, SK_Scalar1 / 5);
+        canvas->translate(50, 0);
+        draw_rect_tests(canvas);
+
+        canvas->translate(SK_Scalar1 / 5, SK_Scalar1 / 5);
+        canvas->translate(50, 0);
+        draw_rect_tests(canvas);
+
+        canvas->translate(SK_Scalar1 / 5, SK_Scalar1 / 5);
+        canvas->translate(50, 0);
+        draw_rect_tests(canvas);
+    }
+
+private:
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new AAClipGM; }
+static GMRegistry reg(MyFactory);
+
+}