зеркало из https://github.com/mozilla/moz-skia.git
98 строки
3.1 KiB
C++
98 строки
3.1 KiB
C++
|
|
/*
|
|
* Copyright 2011 Google Inc.
|
|
*
|
|
* Use of this source code is governed by a BSD-style license that can be
|
|
* found in the LICENSE file.
|
|
*/
|
|
#include "SkMatrix.h"
|
|
|
|
#ifdef SK_SCALAR_IS_FIXED
|
|
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 SkScalar divide(SkDScalar numer, SkDScalar denom) {
|
|
denom >>= 16;
|
|
return numer / denom;
|
|
}
|
|
#else
|
|
typedef double SkDScalar;
|
|
|
|
static SkScalar SkDScalar_toScalar(SkDScalar value) {
|
|
return static_cast<float>(value);
|
|
}
|
|
static SkScalar divide(SkDScalar numer, SkDScalar denom) {
|
|
return static_cast<float>(numer / denom);
|
|
}
|
|
#endif
|
|
|
|
static SkDScalar SkDScalar_setMul(SkScalar a, SkScalar b) {
|
|
return (SkDScalar)a * b;
|
|
}
|
|
|
|
static void computeOuterProduct(SkScalar op[4],
|
|
const SkPoint pts0[3], const SkPoint& ave0,
|
|
const SkPoint pts1[3], const SkPoint& ave1) {
|
|
sk_bzero(op, 4 * sizeof(op[0]));
|
|
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;
|
|
op[0] += SkScalarMul(x0, x1);
|
|
op[1] += SkScalarMul(x0, y1);
|
|
op[2] += SkScalarMul(y0, x1);
|
|
op[3] += SkScalarMul(y0, y1);
|
|
}
|
|
}
|
|
|
|
static SkDScalar ddot(SkScalar ax, SkScalar ay, SkScalar bx, SkScalar by) {
|
|
return SkDScalar_setMul(ax, bx) + SkDScalar_setMul(ay, by);
|
|
}
|
|
|
|
static SkScalar dot(SkScalar ax, SkScalar ay, SkScalar bx, SkScalar by) {
|
|
return SkDScalar_toScalar(ddot(ax, ay, bx, by));
|
|
}
|
|
|
|
bool SkSetPoly3To3(SkMatrix* matrix, const SkPoint src[3], const SkPoint dst[3]) {
|
|
const SkPoint& srcAve = src[0];
|
|
const SkPoint& dstAve = dst[0];
|
|
|
|
SkScalar srcOP[4], dstOP[4];
|
|
|
|
computeOuterProduct(srcOP, src, srcAve, src, srcAve);
|
|
computeOuterProduct(dstOP, src, srcAve, dst, dstAve);
|
|
|
|
SkDScalar det = SkDScalar_setMul(srcOP[0], srcOP[3]) -
|
|
SkDScalar_setMul(srcOP[1], srcOP[2]);
|
|
|
|
SkDScalar M[4];
|
|
|
|
const SkScalar srcOP0 = srcOP[3];
|
|
const SkScalar srcOP1 = -srcOP[1];
|
|
const SkScalar srcOP2 = -srcOP[2];
|
|
const SkScalar srcOP3 = srcOP[0];
|
|
|
|
M[0] = ddot(srcOP0, srcOP1, dstOP[0], dstOP[2]);
|
|
M[1] = ddot(srcOP2, srcOP3, dstOP[0], dstOP[2]);
|
|
M[2] = ddot(srcOP0, srcOP1, dstOP[1], dstOP[3]);
|
|
M[3] = ddot(srcOP2, srcOP3, dstOP[1], dstOP[3]);
|
|
|
|
matrix->reset();
|
|
matrix->setScaleX(divide(M[0], det));
|
|
matrix->setSkewX( divide(M[1], det));
|
|
matrix->setSkewY (divide(M[2], det));
|
|
matrix->setScaleY(divide(M[3], det));
|
|
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;
|
|
}
|
|
|