Add new GM/bench for line-only convex paths

gm/convex_all_line_paths.cpp

+/*
+ * Copyright 2015 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"
+
+static void create_ngon(int n, SkPoint* pts, SkScalar width, SkScalar height) {
+    float angleStep = 360.0f / n, angle = 0.0f, sin, cos;
+    if ((n % 2) == 1) {
+        angle = angleStep/2.0f;
+    }
+
+    for (int i = 0; i < n; ++i) {
+        sin = SkScalarSinCos(SkDegreesToRadians(angle), &cos);
+        pts[i].fX = -sin * width;
+        pts[i].fY = cos * height;
+        angle += angleStep;
+    }
+}
+
+namespace skiagm {
+
+// This GM is intended to exercise Ganesh's handling of convex line-only
+// paths
+class ConvexLineOnlyPathsGM : public GM {
+public:
+    ConvexLineOnlyPathsGM() { 
+        fOffset.set(0, SkScalarHalf(kMaxPathHeight));
+        this->setBGColor(0xFFFFFFFF);
+    }
+
+protected:
+    SkString onShortName() override { return SkString("convex-lineonly-paths"); }
+    SkISize onISize() override { return SkISize::Make(kGMWidth, kGMHeight); }
+    bool runAsBench() const override { return true; }
+
+    static SkPath GetPath(int index, int offset, SkPath::Direction dir) {
+        // narrow rect
+        const SkPoint gPoints0[] = {
+            { -1.5f, -50.0f },
+            {  1.5f, -50.0f },
+            {  1.5f,  50.0f },
+            { -1.5f,  50.0f }
+        };
+        // narrow rect on an angle
+        const SkPoint gPoints1[] = {
+            { -50.0f, -49.0f },
+            { -49.0f, -50.0f },
+            {  50.0f,  49.0f },
+            {  49.0f,  50.0f }
+        };
+        // trap - narrow on top - wide on bottom
+        const SkPoint gPoints2[] = {
+            { -10.0f, -50.0f },
+            {  10.0f, -50.0f },
+            {  50.0f,  50.0f },
+            { -50.0f,  50.0f }
+        };
+        // wide skewed rect
+        const SkPoint gPoints3[] = {
+            { -50.0f, -50.0f },
+            {   0.0f, -50.0f },
+            {  50.0f,  50.0f },
+            {   0.0f,  50.0f }
+        };
+        // thin rect with colinear-ish lines
+        const SkPoint gPoints4[] = {
+            { -6.0f, -50.0f },
+            {  4.0f, -50.0f },
+            {  5.0f, -25.0f },
+            {  6.0f,   0.0f },
+            {  5.0f,  25.0f },
+            {  4.0f,  50.0f },
+            { -4.0f,  50.0f }
+        };
+        // degenerate
+        const SkPoint gPoints5[] = {
+            { -0.025f, -0.025f  },
+            {  0.025f, -0.025f  },
+            {  0.025f,  0.025f },
+            { -0.025f,  0.025f }
+        };
+        // Triangle in which the first point should fuse with last
+        const SkPoint gPoints6[] = {
+            { -20.0f, -13.0f },
+            { -20.0f, -13.05f },
+            {  20.0f, -13.0f },
+            {  20.0f,  27.0f }
+        };
+        // thin rect with colinear lines
+        const SkPoint gPoints7[] = {
+            { -10.0f, -50.0f },
+            {  10.0f, -50.0f },
+            {  10.0f, -25.0f },
+            {  10.0f,   0.0f },
+            {  10.0f,  25.0f },
+            {  10.0f,  50.0f },
+            { -10.0f,  50.0f }
+        };
+        // capped teardrop
+        const SkPoint gPoints8[] = {
+            {  50.00f,  50.00f },
+            {   0.00f,  50.00f },
+            { -15.45f,  47.55f },
+            { -29.39f,  40.45f },
+            { -40.45f,  29.39f },
+            { -47.55f,  15.45f },
+            { -50.00f,   0.00f },
+            { -47.55f, -15.45f },
+            { -40.45f, -29.39f },
+            { -29.39f, -40.45f },
+            { -15.45f, -47.55f },
+            {   0.00f, -50.00f },
+            {  50.00f, -50.00f }
+        };
+        // teardrop
+        const SkPoint gPoints9[] = {
+            {   4.39f,  40.45f },
+            {  -9.55f,  47.55f },
+            { -25.00f,  50.00f },
+            { -40.45f,  47.55f },
+            { -54.39f,  40.45f },
+            { -65.45f,  29.39f },
+            { -72.55f,  15.45f },
+            { -75.00f,   0.00f },
+            { -72.55f, -15.45f },
+            { -65.45f, -29.39f },
+            { -54.39f, -40.45f },
+            { -40.45f, -47.55f },
+            { -25.0f,  -50.0f },
+            {  -9.55f, -47.55f },
+            {   4.39f, -40.45f },
+            {  75.00f,   0.00f }
+        };
+        // clipped triangle
+        const SkPoint gPoints10[] = {
+            { -10.0f, -50.0f },
+            {  10.0f, -50.0f },
+            {  50.0f,  31.0f },
+            {  40.0f,  50.0f },
+            { -40.0f,  50.0f },
+            { -50.0f,  31.0f },
+        };
+
+        const SkPoint* gPoints[] = {
+            gPoints0, gPoints1, gPoints2, gPoints3, gPoints4, gPoints5, gPoints6,
+            gPoints7, gPoints8, gPoints9, gPoints10,
+        };
+
+        const size_t gSizes[] = {
+            SK_ARRAY_COUNT(gPoints0),
+            SK_ARRAY_COUNT(gPoints1),
+            SK_ARRAY_COUNT(gPoints2),
+            SK_ARRAY_COUNT(gPoints3),
+            SK_ARRAY_COUNT(gPoints4),
+            SK_ARRAY_COUNT(gPoints5),
+            SK_ARRAY_COUNT(gPoints6),
+            SK_ARRAY_COUNT(gPoints7),
+            SK_ARRAY_COUNT(gPoints8),
+            SK_ARRAY_COUNT(gPoints9),
+            SK_ARRAY_COUNT(gPoints10),
+        };
+        SK_COMPILE_ASSERT(SK_ARRAY_COUNT(gSizes) == SK_ARRAY_COUNT(gPoints), array_mismatch);
+
+        SkAutoTDelete<SkPoint> data;
+        const SkPoint* points;
+        int numPts;
+        if (index < (int) SK_ARRAY_COUNT(gPoints)) {
+            // manually specified
+            points = gPoints[index];
+            numPts = (int) gSizes[index];
+        } else {
+            // procedurally generated
+            SkScalar width = kMaxPathHeight/2;
+            SkScalar height = kMaxPathHeight/2;
+            switch (index-SK_ARRAY_COUNT(gPoints)) {
+            case 0:
+                numPts = 3;
+                break;
+            case 1:
+                numPts = 4;
+                break;
+            case 2:
+                numPts = 5;
+                break;
+            case 3:             // squashed pentagon
+                numPts = 5;
+                width = kMaxPathHeight/5;
+                break;
+            case 4:
+                numPts = 6;
+                break;
+            case 5:
+                numPts = 8;
+                break;
+            case 6:              // squashed octogon
+                numPts = 8;
+                width = kMaxPathHeight/5;
+                break;
+            case 7:
+                numPts = 20;
+                break;
+            case 8:
+                numPts = 100;
+                break;
+            default:
+                numPts = 3;
+                break;
+            }
+
+            data.reset(SkNEW_ARRAY(SkPoint, numPts));
+
+            create_ngon(numPts, data.get(), width, height);
+            points = data.get();
+        }
+
+        SkPath path;
+
+        if (SkPath::kCW_Direction == dir) {
+            path.moveTo(points[0]);
+            for (int i = 1; i < numPts; ++i) {
+                path.lineTo(points[i]);
+            }
+        } else {
+            path.moveTo(points[numPts-1]);
+            for (int i = numPts-2; i >= 0; --i) {
+                path.lineTo(points[i]);
+            }
+        }
+
+        path.close();
+#ifdef SK_DEBUG
+        // Each path this method returns should be convex, only composed of
+        // lines, wound the right direction, and short enough to fit in one
+        // of the GMs rows.
+        SkASSERT(path.isConvex());
+        SkASSERT(SkPath::kLine_SegmentMask == path.getSegmentMasks());
+        SkPath::Direction actualDir;
+        SkASSERT(path.cheapComputeDirection(&actualDir));
+        SkASSERT(dir == actualDir);
+        SkRect bounds = path.getBounds();
+        SkASSERT(SkScalarNearlyEqual(bounds.centerX(), 0.0f));
+        SkASSERT(bounds.height() <= kMaxPathHeight);
+#endif
+        return path;
+    }
+
+    // Draw a single path several times, shrinking it, flipping its direction
+    // and changing its start vertex each time.
+    void drawPath(SkCanvas* canvas, int index) {
+
+        SkPoint center;
+        {
+            SkPath path = GetPath(index, 0, SkPath::kCW_Direction);
+            if (fOffset.fX+path.getBounds().width() > kGMWidth) {
+                fOffset.fX = 0;
+                fOffset.fY += kMaxPathHeight;
+            }
+            center = { fOffset.fX + SkScalarHalf(path.getBounds().width()), fOffset.fY};
+            fOffset.fX += path.getBounds().width();
+        }
+
+        const SkColor colors[2] = { SK_ColorBLACK, SK_ColorWHITE };
+        const SkPath::Direction dirs[2] = { SkPath::kCW_Direction, SkPath::kCCW_Direction };
+        const float scales[] = { 1.0f, 0.75f, 0.5f, 0.25f, 0.1f, 0.01f, 0.001f };
+
+        SkPaint paint;
+        paint.setAntiAlias(true);
+
+        for (size_t i = 0; i < SK_ARRAY_COUNT(scales); ++i) {
+            SkPath path = GetPath(index, (int) i, dirs[i%2]);
+
+            canvas->save();
+                canvas->translate(center.fX, center.fY);
+                canvas->scale(scales[i], scales[i]);
+                paint.setColor(colors[i%2]);
+                canvas->drawPath(path, paint);
+            canvas->restore();
+        }
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        for (int i = 0; i < kNumPaths; ++i) {
+            this->drawPath(canvas, i);
+        }
+
+        // Repro for crbug.com/472723 (Missing AA on portions of graphic with GPU rasterization)
+        {
+            canvas->translate(356.0f, 50.0f);
+
+            SkPaint p;
+            p.setAntiAlias(true);
+
+            SkPath p1;
+            p1.moveTo(60.8522949f, 364.671021f);
+            p1.lineTo(59.4380493f, 364.671021f);
+            p1.lineTo(385.414276f, 690.647217f);
+            p1.lineTo(386.121399f, 689.940125f);
+            canvas->drawPath(p1, p);
+        }
+    }
+
+private:
+    static const int kNumPaths      = 20;
+    static const int kMaxPathHeight = 100;
+    static const int kGMWidth       = 512;
+    static const int kGMHeight      = 512;
+
+    SkPoint fOffset;        // the right edge of the last drawn path
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return SkNEW(ConvexLineOnlyPathsGM); )
+
+}