SkMatrixUtils.h

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/*
 * Copyright 2013 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
#ifndef SkMatrixUtils_DEFINED
#define SkMatrixUtils_DEFINED
 
#include "include/core/SkPoint.h"
#include "include/core/SkSize.h"
 
class SkMatrix;
struct SkSamplingOptions;
 
/**
 *  Given a matrix, size and an antialias setting, return true if the computed dst-rect
 *  would align such that there is a 1-to-1 coorspondence between src and dst pixels.
 *  This can be called by drawing code to see if drawBitmap can be turned into
 *  drawSprite (which is faster).
 *
 *  The src-rect is defined to be { 0, 0, size.width(), size.height() }
 */
bool SkTreatAsSprite(const SkMatrix&, const SkISize& size, const SkSamplingOptions&,
                     bool isAntiAlias);
 
/** Decomposes the upper-left 2x2 of the matrix into a rotation (represented by
    the cosine and sine of the rotation angle), followed by a non-uniform scale,
    followed by another rotation. If there is a reflection, one of the scale
    factors will be negative.
    Returns true if successful. Returns false if the matrix is degenerate.
    */
bool SkDecomposeUpper2x2(const SkMatrix& matrix,
                         SkPoint* rotation1,
                         SkPoint* scale,
                         SkPoint* rotation2);
 
#endif