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75 lines
2.4 KiB
75 lines
2.4 KiB
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/* |
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* Copyright 2011 Google Inc. |
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* |
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* Use of this source code is governed by a BSD-style license that can be |
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* found in the LICENSE file. |
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*/ |
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#include "SkMatrix.h" |
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#include "SkMalloc.h" |
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// FIXME: needs to be in a header |
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bool SkSetPoly3To3_D(SkMatrix* matrix, const SkPoint src[3], const SkPoint dst[3]); |
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typedef int64_t SkDScalar; |
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static SkScalar SkDScalar_toScalar(SkDScalar value) { |
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SkDScalar result = (value + (1 << 15)) >> 16; |
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SkDEBUGCODE(int top = static_cast<int>(result >> 31);) |
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SkASSERT(top == 0 || top == -1); |
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return (SkScalar)result; |
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} |
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static SkDScalar SkDScalar_setMul(SkScalar a, SkScalar b) { |
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return (SkDScalar) ((SkDScalar) a * (SkDScalar) b); |
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} |
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static void computeOuterProduct(SkMatrix* matrix, |
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const SkPoint pts0[3], const SkPoint& ave0, |
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const SkPoint pts1[3], const SkPoint& ave1) { |
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SkDScalar tmp[4]; |
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sk_bzero(tmp, sizeof(tmp)); |
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for (int i = 0; i < 3; i++) { |
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SkScalar x0 = pts0[i].fX - ave0.fX; |
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SkScalar y0 = pts0[i].fY - ave0.fY; |
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SkScalar x1 = pts1[i].fX - ave1.fX; |
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SkScalar y1 = pts1[i].fY - ave1.fY; |
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tmp[0] += SkDScalar_setMul(x0, x1); |
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tmp[1] += SkDScalar_setMul(x0, y1); |
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tmp[2] += SkDScalar_setMul(y0, x1); |
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tmp[3] += SkDScalar_setMul(y0, y1); |
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} |
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matrix->reset(); |
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matrix->setScaleX(SkDScalar_toScalar(tmp[0])); |
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matrix->setSkewY( SkDScalar_toScalar(tmp[1])); |
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matrix->setSkewX( SkDScalar_toScalar(tmp[2])); |
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matrix->setScaleY(SkDScalar_toScalar(tmp[3])); |
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} |
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static SkScalar dot(SkScalar ax, SkScalar ay, SkScalar bx, SkScalar by) { |
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return SkDScalar_toScalar(SkDScalar_setMul(ax, bx) + |
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SkDScalar_setMul(ay, by)); |
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} |
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bool SkSetPoly3To3_D(SkMatrix* matrix, const SkPoint src[3], const SkPoint dst[3]) { |
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const SkPoint& srcAve = src[0]; |
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const SkPoint& dstAve = dst[0]; |
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SkMatrix srcOP, dstOP; |
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computeOuterProduct(&srcOP, src, srcAve, src, srcAve); |
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if (!srcOP.invert(&srcOP)) { |
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return false; |
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} |
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computeOuterProduct(&dstOP, src, srcAve, dst, dstAve); |
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matrix->setConcat(dstOP, srcOP); |
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matrix->setTranslateX(dstAve.fX - dot(srcAve.fX, srcAve.fY, |
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matrix->getScaleX(), matrix->getSkewX())); |
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matrix->setTranslateY(dstAve.fY - dot(srcAve.fX, srcAve.fY, |
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matrix->getSkewY(), matrix->getScaleY())); |
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return true; |
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}
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