diff options
Diffstat (limited to 'experimental/SkSetPoly3To3_D.cpp')
-rw-r--r-- | experimental/SkSetPoly3To3_D.cpp | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/experimental/SkSetPoly3To3_D.cpp b/experimental/SkSetPoly3To3_D.cpp new file mode 100644 index 0000000..72ee9b1 --- /dev/null +++ b/experimental/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; +} + |