1 files changed, 65 insertions, 0 deletions
diff --git a/test/SkSetPoly3To3_D.cpp b/test/SkSetPoly3To3_D.cpp
new file mode 100644
index 0000000..72ee9b1
--- /dev/null
+++ b/test/SkSetPoly3To3_D.cpp
@@ -0,0 +1,65 @@
+#include "SkMatrix.h"
+
+typedef int64_t SkDScalar;
+
+static SkScalar SkDScalar_toScalar(SkDScalar value) {
+    SkDScalar result = (value + (1 << 15)) >> 16;
+    int top = result >> 31;
+    SkASSERT(top == 0 || top == -1);
+    return (SkScalar)result;
+}
+
+static SkDScalar SkDScalar_setMul(SkScalar a, SkScalar b) {
+    return (SkDScalar)a * b;
+}
+
+static void computeOuterProduct(SkMatrix* matrix,
+                                const SkPoint pts0[3], const SkPoint& ave0,
+                                const SkPoint pts1[3], const SkPoint& ave1) {
+    SkDScalar tmp[4];
+    bzero(tmp, sizeof(tmp));
+    
+    for (int i = 0; i < 3; i++) {
+        SkScalar x0 = pts0[i].fX - ave0.fX;
+        SkScalar y0 = pts0[i].fY - ave0.fY;
+        SkScalar x1 = pts1[i].fX - ave1.fX;
+        SkScalar y1 = pts1[i].fY - ave1.fY;
+        tmp[0] += SkDScalar_setMul(x0, x1);
+        tmp[1] += SkDScalar_setMul(x0, y1);
+        tmp[2] += SkDScalar_setMul(y0, x1);
+        tmp[3] += SkDScalar_setMul(y0, y1);
+    }
+    matrix->reset();
+    matrix->setScaleX(SkDScalar_toScalar(tmp[0]));
+    matrix->setSkewY( SkDScalar_toScalar(tmp[1]));
+    matrix->setSkewX( SkDScalar_toScalar(tmp[2]));
+    matrix->setScaleY(SkDScalar_toScalar(tmp[3]));
+}
+
+static SkScalar dot(SkScalar ax, SkScalar ay, SkScalar bx, SkScalar by) {
+    return SkDScalar_toScalar(SkDScalar_setMul(ax, bx) +
+                              SkDScalar_setMul(ay, by));
+}
+
+bool SkSetPoly3To3(SkMatrix* matrix, const SkPoint src[3], const SkPoint dst[3]) {
+    const SkPoint& srcAve = src[0];
+    const SkPoint& dstAve = dst[0];
+    
+    SkMatrix srcOP, dstOP;
+    
+    computeOuterProduct(&srcOP, src, srcAve, src, srcAve);
+
+    if (!srcOP.invert(&srcOP)) {
+        return false;
+    }
+
+    computeOuterProduct(&dstOP, src, srcAve, dst, dstAve);
+
+    matrix->setConcat(dstOP, srcOP);
+    matrix->setTranslateX(dstAve.fX - dot(srcAve.fX, srcAve.fY,
+                                    matrix->getScaleX(), matrix->getSkewX()));
+    matrix->setTranslateY(dstAve.fY - dot(srcAve.fX, srcAve.fY,
+                                    matrix->getSkewY(), matrix->getScaleY()));
+    return true;
+}
+