Fixup rendering of empty paths (including inverted fills)
Add GM and Sample that draw empty paths with various styles and fills

Review URL: http://codereview.appspot.com/5185047/



git-svn-id: http://skia.googlecode.com/svn/trunk@2414 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/emptypath.cpp b/gm/emptypath.cpp
new file mode 100644
index 0000000..dd33f68
--- /dev/null
+++ b/gm/emptypath.cpp
@@ -0,0 +1,138 @@
+
+/*
+ * 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 "SkPaint.h"
+#include "SkRandom.h"
+
+namespace skiagm {
+
+class EmptyPathGM : public GM {
+public:
+    EmptyPathGM() {}
+
+protected:
+    SkString onShortName() {
+        return SkString("emptypath");
+    }
+        
+    SkISize onISize() { return make_isize(600, 280); }
+
+    void drawBG(SkCanvas* canvas) {
+        canvas->drawColor(SK_ColorWHITE);
+    }
+
+    void drawEmpty(SkCanvas* canvas,
+                    SkColor color,
+                    const SkRect& clip,
+                    SkPaint::Style style,
+                    SkPath::FillType fill) {
+        SkPath path;
+        path.setFillType(fill);
+        SkPaint paint;
+        paint.setColor(color);
+        paint.setStyle(style);
+        canvas->save();
+        canvas->clipRect(clip);
+        canvas->drawPath(path, paint);
+        canvas->restore();
+    }
+    
+    virtual void onDraw(SkCanvas* canvas) {
+        this->drawBG(canvas);
+        struct FillAndName {
+            SkPath::FillType fFill;
+            const char*      fName;
+        };
+        static const FillAndName gFills[] = {
+            {SkPath::kWinding_FillType, "Winding"},
+            {SkPath::kEvenOdd_FillType, "Even / Odd"},
+            {SkPath::kInverseWinding_FillType, "Inverse Winding"},
+            {SkPath::kInverseEvenOdd_FillType, "Inverse Even / Odd"},
+        };
+        struct StyleAndName {
+            SkPaint::Style fStyle;
+            const char*    fName;
+        };
+        static const StyleAndName gStyles[] = {
+            {SkPaint::kFill_Style, "Fill"},
+            {SkPaint::kStroke_Style, "Stroke"},
+            {SkPaint::kStrokeAndFill_Style, "Stroke And Fill"},
+        };
+
+        SkPaint titlePaint;
+        titlePaint.setColor(SK_ColorBLACK);
+        titlePaint.setAntiAlias(true);
+        titlePaint.setLCDRenderText(true);
+        titlePaint.setTextSize(15 * SK_Scalar1);
+        const char title[] = "Empty Paths Drawn Into Rectangle Clips With "
+                             "Indicated Style and Fill";
+        canvas->drawText(title, strlen(title),
+                            20 * SK_Scalar1,
+                            20 * SK_Scalar1,
+                            titlePaint);
+
+        SkRandom rand;
+        SkRect rect = SkRect::MakeWH(100*SK_Scalar1, 30*SK_Scalar1);
+        int i = 0;
+        canvas->save();
+        canvas->translate(10 * SK_Scalar1, 0);
+        canvas->save();
+        for (int style = 0; style < SK_ARRAY_COUNT(gStyles); ++style) {
+            for (int fill = 0; fill < SK_ARRAY_COUNT(gFills); ++fill) {
+                if (0 == i % 4) {
+                    canvas->restore();
+                    canvas->translate(0, rect.height() + 40 * SK_Scalar1);
+                    canvas->save();
+                } else {
+                    canvas->translate(rect.width() + 40 * SK_Scalar1, 0);
+                }
+                ++i;
+
+
+                SkColor color = rand.nextU();
+                color = 0xff000000| color; // force solid
+                this->drawEmpty(canvas, color, rect,
+                                gStyles[style].fStyle, gFills[fill].fFill);
+
+                SkPaint rectPaint;
+                rectPaint.setColor(SK_ColorBLACK);
+                rectPaint.setStyle(SkPaint::kStroke_Style);
+                rectPaint.setStrokeWidth(-1);
+                rectPaint.setAntiAlias(true);
+                canvas->drawRect(rect, rectPaint);
+
+                SkPaint labelPaint;
+                labelPaint.setColor(color);
+                labelPaint.setAntiAlias(true);
+                labelPaint.setLCDRenderText(true);
+                labelPaint.setTextSize(12 * SK_Scalar1);
+                canvas->drawText(gStyles[style].fName,
+                                 strlen(gStyles[style].fName),
+                                 0, rect.height() + 15 * SK_Scalar1,
+                                 labelPaint);
+                canvas->drawText(gFills[fill].fName,
+                                 strlen(gFills[fill].fName),
+                                 0, rect.height() + 28 * SK_Scalar1,
+                                 labelPaint);
+            }
+        }
+        canvas->restore();
+        canvas->restore();
+    }
+    
+private:
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new EmptyPathGM; }
+static GMRegistry reg(MyFactory);
+
+}