add check/hack to avoid drawing outside of the clip for hairlines
git-svn-id: http://skia.googlecode.com/svn/trunk@134 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/samplecode/SampleHairline.cpp b/samplecode/SampleHairline.cpp
new file mode 100644
index 0000000..9763d0f
--- /dev/null
+++ b/samplecode/SampleHairline.cpp
@@ -0,0 +1,157 @@
+#include "SampleCode.h"
+#include "SkView.h"
+#include "SkCanvas.h"
+#include "Sk64.h"
+#include "SkCornerPathEffect.h"
+#include "SkGradientShader.h"
+#include "SkGraphics.h"
+#include "SkImageDecoder.h"
+#include "SkKernel33MaskFilter.h"
+#include "SkPath.h"
+#include "SkRandom.h"
+#include "SkRegion.h"
+#include "SkShader.h"
+#include "SkUtils.h"
+#include "SkColorPriv.h"
+#include "SkColorFilter.h"
+#include "SkTime.h"
+#include "SkTypeface.h"
+#include "SkXfermode.h"
+
+#include "SkStream.h"
+#include "SkXMLParser.h"
+#include "SkColorPriv.h"
+#include "SkImageDecoder.h"
+
+static SkRandom gRand;
+
+static void test_chromium_9005() {
+ SkBitmap bm;
+ bm.setConfig(SkBitmap::kARGB_8888_Config, 800, 600);
+ bm.allocPixels();
+
+ SkCanvas canvas(bm);
+
+ SkPoint pt0 = { SkFloatToScalar(799.33374f), SkFloatToScalar(1.2360189f) };
+ SkPoint pt1 = { SkFloatToScalar(808.49969f), SkFloatToScalar(-7.4338055f) };
+
+ SkPaint paint;
+ paint.setAntiAlias(true);
+ canvas.drawLine(pt0.fX, pt0.fY, pt1.fX, pt1.fY, paint);
+}
+
+static void generate_pts(SkPoint pts[], int count, int w, int h) {
+ for (int i = 0; i < count; i++) {
+ pts[i].set(gRand.nextUScalar1() * 3 * w - SkIntToScalar(w),
+ gRand.nextUScalar1() * 3 * h - SkIntToScalar(h));
+ }
+}
+
+static bool check_zeros(const SkPMColor pixels[], int count, int skip) {
+ for (int i = 0; i < count; i++) {
+ if (*pixels) {
+ return false;
+ }
+ pixels += skip;
+ }
+ return true;
+}
+
+static bool check_bitmap_margin(const SkBitmap& bm, int margin) {
+ size_t rb = bm.rowBytes();
+ for (int i = 0; i < margin; i++) {
+ if (!check_zeros(bm.getAddr32(0, i), bm.width(), 1)) {
+ return false;
+ }
+ int bottom = bm.height() - i - 1;
+ if (!check_zeros(bm.getAddr32(0, bottom), bm.width(), 1)) {
+ return false;
+ }
+ // left column
+ if (!check_zeros(bm.getAddr32(i, 0), bm.height(), rb >> 2)) {
+ return false;
+ }
+ int right = bm.width() - margin + i;
+ if (!check_zeros(bm.getAddr32(right, 0), bm.height(), rb >> 2)) {
+ return false;
+ }
+ }
+ return true;
+}
+
+#define WIDTH 80
+#define HEIGHT 60
+#define MARGIN 4
+
+class HairlineView : public SkView {
+public:
+ HairlineView() {}
+
+protected:
+ // overrides from SkEventSink
+ virtual bool onQuery(SkEvent* evt) {
+ if (SampleCode::TitleQ(*evt)) {
+ SampleCode::TitleR(evt, "Hairines");
+ return true;
+ }
+ return this->INHERITED::onQuery(evt);
+ }
+
+ void show_bitmaps(SkCanvas* canvas, const SkBitmap& b0, const SkBitmap& b1,
+ const SkIRect& inset) {
+ canvas->drawBitmap(b0, 0, 0, NULL);
+ canvas->drawBitmap(b1, SkIntToScalar(b0.width()), 0, NULL);
+ }
+
+ void drawBG(SkCanvas* canvas) {
+// canvas->drawColor(0xFFDDDDDD);
+ canvas->drawColor(SK_ColorWHITE);
+ // canvas->drawColor(SK_ColorBLACK);
+ }
+
+ virtual void onDraw(SkCanvas* canvas) {
+ this->drawBG(canvas);
+
+ if (true) {
+ test_chromium_9005();
+ }
+
+ SkBitmap bm, bm2;
+ bm.setConfig(SkBitmap::kARGB_8888_Config,
+ WIDTH + MARGIN*2,
+ HEIGHT + MARGIN*2);
+ bm.allocPixels();
+ // this will erase our margin, which we want to always stay 0
+ bm.eraseColor(0);
+
+ bm2.setConfig(SkBitmap::kARGB_8888_Config, WIDTH, HEIGHT,
+ bm.rowBytes());
+ bm2.setPixels(bm.getAddr32(MARGIN, MARGIN));
+
+ SkCanvas c2(bm2);
+ SkPaint paint;
+ paint.setAntiAlias(true);
+ for (int i = 0; i < 10000; i++) {
+ SkPoint pts[2];
+ generate_pts(pts, 2, WIDTH, HEIGHT);
+ bm2.eraseColor(0);
+ c2.drawLine(pts[0].fX, pts[0].fY, pts[1].fX, pts[1].fY, paint);
+ if (!check_bitmap_margin(bm, MARGIN)) {
+ SkDebugf("---- hairline failure (%g %g) (%g %g)\n",
+ pts[0].fX, pts[0].fY, pts[1].fX, pts[1].fY);
+ break;
+ }
+ }
+
+ this->inval(NULL);
+ }
+
+private:
+ typedef SkView INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static SkView* MyFactory() { return new HairlineView; }
+static SkViewRegister reg(MyFactory);
+