skia2/experimental/SkSetPoly3To3.cpp
caryclark@google.com 9da0cea3a3 fix warnings on Mac in experimental
Fix these class of warnings:
- unused functions
- unused locals
- sign mismatch
- missing function prototypes
- missing newline at end of file
- 64 to 32 bit truncation

The changes prefer to link in dead code in the debug build
with 'if (false)' than to comment it out, but trivial cases
are commented out or sometimes deleted if it appears to be
a copy/paste error.
Review URL: https://codereview.appspot.com/6307044

git-svn-id: http://skia.googlecode.com/svn/trunk@4187 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-06-06 12:11:33 +00:00

71 lines
2.5 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"
// FIXME: needs to be in a header
bool SkSetPoly3To3(SkMatrix* matrix, const SkPoint src[3], const SkPoint dst[3]);
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 SkScalar dot(SkScalar ax, SkScalar ay, SkScalar bx, SkScalar by) {
return SkScalarMul(ax, bx) + SkScalarMul(ay, 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);
SkScalar det = SkScalarMul(srcOP[0], srcOP[3]) - SkScalarMul(srcOP[1], srcOP[2]);
// need SkScalarNearlyZeroSquared for this (to match Chrome's fix)
if (SkScalarNearlyZero(det)) {
return false;
}
SkScalar invDet = SkScalarInvert(det);
// now compute invDet * [srcOP]T * [dstOP]
// scale and transpose
const SkScalar srcOP0 = SkScalarMul( srcOP[3], invDet);
const SkScalar srcOP1 = SkScalarMul(-srcOP[1], invDet);
const SkScalar srcOP2 = SkScalarMul(-srcOP[2], invDet);
const SkScalar srcOP3 = SkScalarMul( srcOP[0], invDet);
matrix->reset();
matrix->setScaleX(dot(srcOP0, srcOP1, dstOP[0], dstOP[2]));
matrix->setSkewX( dot(srcOP2, srcOP3, dstOP[0], dstOP[2]));
matrix->setSkewY (dot(srcOP0, srcOP1, dstOP[1], dstOP[3]));
matrix->setScaleY(dot(srcOP2, srcOP3, dstOP[1], dstOP[3]));
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;
}