path ops : make it real

Add an option to SkCanvas to turn on path
ops when combining clips. 

Allow Op() to use one of the input paths
as an output path.

Fix a bug in Op() when the minuend is empty
and the subtrahend is not (for difference).

Change the build to allow core to depend on pathops.
Review URL: https://codereview.chromium.org/14474002

git-svn-id: http://skia.googlecode.com/svn/trunk@8855 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 73 insertions, 0 deletions

diff --git a/gm/pathopsskpclip.cpp b/gm/pathopsskpclip.cpp
new file mode 100644
index 0000000000..b85b294fef
--- /dev/null
+++ b/gm/pathopsskpclip.cpp
@@ -0,0 +1,73 @@
+/*
+ * 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 "gm.h"
+#include "SkBitmap.h"
+#include "SkCanvas.h"
+#include "SkClipStack.h"
+#include "SkDevice.h"
+#include "SkPath.h"
+#include "SkPathOps.h"
+#include "SkPicture.h"
+#include "SkRect.h"
+
+namespace skiagm {
+
+class PathOpsSkpClipGM : public GM {
+public:
+    PathOpsSkpClipGM() {
+    }
+
+protected:
+    virtual SkString onShortName() SK_OVERRIDE {
+        return SkString("pathopsskpclip");
+    }
+
+    virtual SkISize onISize() SK_OVERRIDE {
+        return make_isize(1200, 900);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        SkPicture* pict = SkNEW(SkPicture);
+        SkCanvas* rec = pict->beginRecording(1200, 900);
+        SkPath p;
+        SkRect r = {
+            SkIntToScalar(100),
+            SkIntToScalar(200),
+            SkIntToScalar(400),
+            SkIntToScalar(700)
+        };
+        p.addRoundRect(r, SkIntToScalar(50), SkIntToScalar(50));
+        rec->clipPath(p, SkRegion::kIntersect_Op, true);
+        rec->translate(SkIntToScalar(250), SkIntToScalar(250));
+        rec->clipPath(p, SkRegion::kIntersect_Op, true);
+        rec->drawColor(0xffff0000);
+        pict->endRecording();
+
+        canvas->setAllowSimplifyClip(true);
+        canvas->save();
+        canvas->drawPicture(*pict);
+        canvas->restore();
+
+        canvas->setAllowSimplifyClip(false);
+        canvas->save();
+        canvas->translate(SkIntToScalar(1200 / 2), 0);
+        canvas->drawPicture(*pict);
+        canvas->restore();
+        SkSafeUnref(pict);
+    }
+
+private:
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new PathOpsSkpClipGM; }
+static GMRegistry reg(MyFactory);
+
+}