Add new GM to demonstrates SkGaussianEdgeShader
This would've caught the incorrect distances in the center bug
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=3111
Change-Id: I9461a8865b561cc139a18a5e779e933d7979ee0d
Reviewed-on: https://skia-review.googlesource.com/3111
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
diff --git a/gm/gaussianedge.cpp b/gm/gaussianedge.cpp
new file mode 100644
index 0000000..bed42af
--- /dev/null
+++ b/gm/gaussianedge.cpp
@@ -0,0 +1,218 @@
+/*
+ * Copyright 2016 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 "SkRRect.h"
+#include "SkGaussianEdgeShader.h"
+
+//#define VIZ 1
+
+#ifdef VIZ
+#include "SkStroke.h"
+
+static void draw_stroke(SkCanvas* canvas, const SkRRect& rr, const SkPaint& p, SkColor color) {
+ SkPath output;
+
+ if (SkPaint::kFill_Style == p.getStyle()) {
+ output.addRRect(rr);
+ } else {
+ SkPath input;
+ input.addRRect(rr);
+
+ SkStroke stroke(p);
+ stroke.strokePath(input, &output);
+ }
+
+ SkPaint paint;
+ paint.setStyle(SkPaint::kStroke_Style);
+ paint.setColor(color);
+
+ canvas->drawPath(output, paint);
+}
+
+static void extract_pts(const SkBitmap& bm, SkTDArray<SkPoint>* pts,
+ int xOff, int width) {
+ pts->rewind();
+
+ for (int x = 0; x < width; ++x) {
+ SkColor color = bm.getColor(xOff+x, 0);
+
+ pts->append()->set(SkIntToScalar(x), 255.0f-SkColorGetB(color));
+ if (x > 0 && x < width-1) {
+ pts->append()->set(SkIntToScalar(x), 255.0f-SkColorGetB(color));
+ }
+ }
+}
+
+static void draw_row(SkCanvas* canvas, int row, int width) {
+ SkPaint paint;
+ paint.setAntiAlias(true);
+
+ SkBitmap readback;
+
+ if (!canvas->readPixels(SkIRect::MakeXYWH(0, row, width, 1), &readback)) {
+ return;
+ }
+
+ SkTDArray<SkPoint> pts;
+ pts.setReserve(width/3);
+
+ extract_pts(readback, &pts, 0, width/3);
+ paint.setColor(SK_ColorRED);
+ canvas->drawPoints(SkCanvas::kLines_PointMode, pts.count(), pts.begin(), paint);
+
+ extract_pts(readback, &pts, width/3, width/3);
+ paint.setColor(SK_ColorGREEN);
+ canvas->drawPoints(SkCanvas::kLines_PointMode, pts.count(), pts.begin(), paint);
+
+ extract_pts(readback, &pts, 2*width/3, width/3);
+ paint.setColor(SK_ColorBLUE);
+ canvas->drawPoints(SkCanvas::kLines_PointMode, pts.count(), pts.begin(), paint);
+}
+#endif
+
+namespace skiagm {
+
+// This GM exercises the SkGaussianEdgeShader.
+// It draws three columns showing filled, stroked, and stroke and filled rendering.
+// It draws three rows showing a blur radius smaller than, equal to
+// and, finally, double the RRect's corner radius
+// In VIZ mode an extra column is drawn showing the blur ramps (they should all line up).
+class GaussianEdgeGM : public GM {
+public:
+ GaussianEdgeGM() {
+ this->setBGColor(SK_ColorWHITE);
+ }
+
+protected:
+
+ SkString onShortName() override {
+ return SkString("gaussianedge");
+ }
+
+ SkISize onISize() override {
+ int numCols = kNumBaseCols;
+#ifdef VIZ
+ numCols++;
+#endif
+
+ return SkISize::Make(kPad + numCols*(kCellWidth+kPad),
+ kPad + kNumRows*(kCellWidth+kPad));
+ }
+
+ static void DrawRow(SkCanvas* canvas, int blurRad, int midLine) {
+ SkAutoCanvasRestore acr(canvas, true);
+
+ SkRRect rrects[kNumBaseCols];
+ SkPaint paints[kNumBaseCols];
+
+ {
+ const SkRect r = SkRect::MakeIWH(kRRSize, kRRSize);
+ const SkRRect baseRR = SkRRect::MakeRectXY(r,
+ SkIntToScalar(kRRRad),
+ SkIntToScalar(kRRRad));
+
+ SkPaint basePaint;
+ basePaint.setAntiAlias(true);
+ basePaint.setShader(SkGaussianEdgeShader::Make());
+ basePaint.setColor(SkColorSetARGB(255, (4 * blurRad) >> 8, (4 * blurRad) & 0xff, 0));
+
+ //----
+ paints[0] = basePaint;
+ rrects[0] = baseRR;
+
+ //----
+ paints[1] = basePaint;
+ paints[1].setStyle(SkPaint::kStroke_Style);
+
+ rrects[1] = baseRR;
+ if (blurRad/2.0f < kRRRad) {
+ rrects[1].inset(blurRad/2.0f, blurRad/2.0f);
+ paints[1].setStrokeWidth(SkIntToScalar(blurRad));
+ } else {
+ SkScalar inset = kRRRad - 0.5f;
+ rrects[1].inset(inset, inset);
+ SkScalar pad = blurRad/2.0f - inset;
+ paints[1].setStrokeWidth(blurRad + 2.0f * pad);
+ paints[1].setColor(SkColorSetARGB(255, (4 * blurRad) >> 8, (4 * blurRad) & 0xff,
+ (int)(4.0f*pad)));
+ }
+
+ //----
+ paints[2] = basePaint;
+ paints[2].setStyle(SkPaint::kStrokeAndFill_Style);
+
+ rrects[2] = baseRR;
+ if (blurRad/2.0f < kRRRad) {
+ rrects[2].inset(blurRad/2.0f, blurRad/2.0f);
+ paints[2].setStrokeWidth(SkIntToScalar(blurRad));
+ } else {
+ SkScalar inset = kRRRad - 0.5f;
+ rrects[2].inset(inset, inset);
+ SkScalar pad = blurRad/2.0f - inset;
+ paints[2].setStrokeWidth(blurRad + 2.0f * pad);
+ paints[2].setColor(SkColorSetARGB(255, (4 * blurRad) >> 8, (4 * blurRad) & 0xff,
+ (int)(4.0f*pad)));
+ }
+ }
+
+ //----
+ canvas->save();
+ // draw the shadows
+ for (int i = 0; i < kNumBaseCols; ++i) {
+ canvas->drawRRect(rrects[i], paints[i]);
+ canvas->translate(SkIntToScalar(kCellWidth+kPad), 0.0f);
+ }
+
+#ifdef VIZ
+ // draw the visualization of the shadow ramps
+ draw_row(canvas, midLine, 3*(kRRSize+kPad));
+#endif
+ canvas->restore();
+
+#ifdef VIZ
+ const SkColor colors[kNumBaseCols] = { SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE };
+
+ // circle back and draw the stroked geometry (they would mess up the viz otherwise)
+ for (int i = 0; i < kNumBaseCols; ++i) {
+ draw_stroke(canvas, rrects[i], paints[i], colors[i]);
+ canvas->translate(SkIntToScalar(kCellWidth+kPad), 0.0f);
+ }
+#endif
+ }
+
+ void onDraw(SkCanvas* canvas) override {
+ GrDrawContext* drawContext = canvas->internal_private_accessTopLayerDrawContext();
+ if (!drawContext) {
+ skiagm::GM::DrawGpuOnlyMessage(canvas);
+ return;
+ }
+
+ const int blurRadii[kNumRows] = { kRRRad/2, kRRRad, 2*kRRRad };
+
+ canvas->translate(SkIntToScalar(kPad), SkIntToScalar(kPad));
+ for (int i = 0; i < kNumRows; ++i) {
+ DrawRow(canvas, blurRadii[i], kPad+(i*kRRSize)+kRRSize/2);
+ canvas->translate(0.0f, SkIntToScalar(kCellWidth+kPad));
+ }
+ }
+
+private:
+ static const int kNumRows = 3;
+ static const int kNumBaseCols = 3;
+ static const int kPad = 5;
+ static const int kRRSize = 256;
+ static const int kRRRad = 64;
+ static const int kCellWidth = kRRSize;
+
+ typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM(return new GaussianEdgeGM;)
+}