1 files changed, 176 insertions, 0 deletions
diff --git a/experimental/Intersection/EdgeDemo.cpp b/experimental/Intersection/EdgeDemo.cpp
new file mode 100644
index 0000000000..b71b8186b2
--- /dev/null
+++ b/experimental/Intersection/EdgeDemo.cpp
@@ -0,0 +1,176 @@
+#include "EdgeDemo.h"
+#include "EdgeWalker_Test.h"
+#include "ShapeOps.h"
+#import "SkCanvas.h"
+#import "SkPaint.h"
+
+// Three circles bounce inside a rectangle. The circles describe three, four
+// or five points which in turn describe a polygon. The polygon points
+// bounce inside the circles. The circles rotate and scale over time. The
+// polygons are combined into a single path, simplified, and stroked.
+static bool drawCircles(SkCanvas* canvas, int step)
+{
+    const int circles = 3;
+    int scales[circles];
+    int angles[circles];
+    int locs[circles * 2];
+    int pts[circles * 2 * 4];
+    int c, p;
+    for (c = 0; c < circles; ++c) {
+        scales[c] = abs(10 - (step + c * 4) % 21);
+        angles[c] = (step + c * 6) % 600;
+        locs[c * 2] = abs(130 - (step + c * 9) % 261);
+        locs[c * 2 + 1] = abs(170 - (step + c * 11) % 341);
+        for (p = 0; p < 4; ++p) {
+            pts[c * 8 + p * 2] = abs(90 - ((step + c * 121 + p * 13) % 190));
+            pts[c * 8 + p * 2 + 1] = abs(110 - ((step + c * 223 + p * 17) % 230));
+        }
+    }
+    SkPath path, out;
+    for (c = 0; c < circles; ++c) {
+        for (p = 0; p < 4; ++p) {
+            SkScalar x = pts[c * 8 + p * 2];
+            SkScalar y = pts[c * 8 + p * 2 + 1];
+            x *= 3 + scales[c] / 10.0f;
+            y *= 3 + scales[c] / 10.0f;
+            SkScalar angle = angles[c] * 3.1415f * 2 / 600;
+            SkScalar temp = x * cos(angle) - y * sin(angle);
+            y = x * sin(angle) + y * cos(angle);
+            x = temp;
+            x += locs[c * 2] * 200 / 130.0f;
+            y += locs[c * 2 + 1] * 200 / 170.0f;
+            x += 50;
+    //        y += 200;
+            if (p == 0) {
+                path.moveTo(x, y);
+            } else {
+                path.lineTo(x, y);
+            }
+        }
+        path.close();
+    }
+    showPath(path, "original:");
+    simplify(path, true, out);
+    showPath(out, "simplified:");
+    SkPaint paint;
+    paint.setAntiAlias(true);
+    paint.setStyle(SkPaint::kStroke_Style);
+    paint.setStrokeWidth(3);
+    paint.setColor(0x3F007fbF);
+    canvas->drawPath(path, paint);
+    paint.setColor(0xFF60FF00);
+    paint.setStrokeWidth(1);
+    canvas->drawPath(out, paint);
+    return true;
+}
+
+static void createStar(SkPath& path, SkScalar innerRadius, SkScalar outerRadius, 
+        SkScalar startAngle, int points, SkPoint center) {
+    SkScalar angle = startAngle;
+    for (int index = 0; index < points * 2; ++index) {
+        SkScalar radius = index & 1 ? outerRadius : innerRadius;
+        SkScalar x = radius * cos(angle);
+        SkScalar y = radius * sin(angle);
+        x += center.fX;
+        y += center.fY;
+        if (index == 0) {
+            path.moveTo(x, y);
+        } else {
+            path.lineTo(x, y);
+        }
+        angle += 3.1415f / points;
+    }
+    path.close();
+}
+
+static bool drawStars(SkCanvas* canvas, int step)
+{
+    SkPath path, out;
+    const int stars = 25;
+    int pts[stars];
+    static bool initialize = true;
+    int s;
+    for (s = 0; s < stars; ++s) {
+        pts[s] = 4 + (s % 7);
+    }
+    SkPoint locs[stars];
+    SkScalar angles[stars];
+    SkScalar innerRadius[stars];
+    SkScalar outerRadius[stars];
+    const int width = 640;
+    const int height = 480;
+    const int margin = 30;
+    const int minRadius = 120;
+    const int maxInner = 800;
+    const int maxOuter = 1153;
+    for (s = 0; s < stars; ++s) {
+        int starW = width - margin * 2 + (SkScalar) s * (stars - s) / stars;
+        locs[s].fX = (int) (step * (1.3f * (s + 1) / stars) + s * 121) % (starW * 2);
+        if (locs[s].fX > starW) {
+            locs[s].fX = starW * 2 - locs[s].fX;
+        }
+        locs[s].fX += margin;
+        int starH = height - margin * 2 + (SkScalar) s * s / stars;
+        locs[s].fY = (int) (step * (1.7f * (s + 1) / stars) + s * 183) % (starH * 2);
+        if (locs[s].fY > starH) {
+            locs[s].fY = starH * 2 - locs[s].fY;
+        }
+        locs[s].fY += margin;
+        angles[s] = ((step + s * 47) % (360 * 4)) * 3.1415f / 180 / 4;
+        innerRadius[s] = (step + s * 30) % (maxInner * 2);
+        if (innerRadius[s] > maxInner) {
+            innerRadius[s] = (maxInner * 2) - innerRadius[s];
+        }
+        innerRadius[s] = innerRadius[s] / 4 + minRadius;
+        outerRadius[s] = (step + s * 70) % (maxOuter * 2);
+        if (outerRadius[s] > maxOuter) {
+            outerRadius[s] = (maxOuter * 2) - outerRadius[s];
+        }
+        outerRadius[s] = outerRadius[s] / 4 + minRadius;
+        createStar(path, innerRadius[s] / 4.0f, outerRadius[s] / 4.0f,
+                angles[s], pts[s], locs[s]);
+    }
+#define SHOW_PATH 0
+#if SHOW_PATH
+    showPath(path, "original:");
+#endif
+#define TEST_SIMPLIFY 01
+#if TEST_SIMPLIFY
+    simplify(path, true, out);
+#if SHOW_PATH
+    showPath(out, "simplified:");
+#endif
+#endif
+    SkPaint paint;
+    paint.setAntiAlias(true);
+    paint.setStyle(SkPaint::kStroke_Style);
+    paint.setStrokeWidth(6);
+    paint.setColor(0x1F003f7f);
+    canvas->drawPath(path, paint);
+    paint.setColor(0xFF305F00);
+    paint.setStrokeWidth(1);
+#if TEST_SIMPLIFY
+    canvas->drawPath(out, paint);
+#endif
+    return true;
+}
+
+static bool (*drawDemos[])(SkCanvas* , int) = {
+    drawStars,
+    drawCircles
+};
+
+static size_t drawDemosCount = sizeof(drawDemos) / sizeof(drawDemos[0]);
+
+static bool (*firstTest)(SkCanvas* , int) = 0;
+
+
+bool DrawEdgeDemo(SkCanvas* canvas, int step) {
+    size_t index = 0;
+    if (firstTest) {
+        while (index < drawDemosCount && drawDemos[index] != firstTest) {
+            ++index;
+        }
+    }
+    return (*drawDemos[index])(canvas, step);
+}