1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/core/SkMatrixUtils.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,54 @@
1.4 +/*
1.5 + * Copyright 2013 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#ifndef SkMatrixUtils_DEFINED
1.12 +#define SkMatrixUtils_DEFINED
1.13 +
1.14 +#include "SkMatrix.h"
1.15 +
1.16 +/**
1.17 + * Number of subpixel bits used in skia's bilerp.
1.18 + * See SkBitmapProcState_procs.h and SkBitmapProcState_filter.h
1.19 + */
1.20 +#define kSkSubPixelBitsForBilerp 4
1.21 +
1.22 +/**
1.23 + * Given a matrix and width/height, return true if the computed dst-rect would
1.24 + * align such that there is a 1-to-1 coorspondence between src and dst pixels.
1.25 + * This can be called by drawing code to see if drawBitmap can be turned into
1.26 + * drawSprite (which is faster).
1.27 + *
1.28 + * The src-rect is defined to be { 0, 0, width, height }
1.29 + *
1.30 + * The "closeness" test is based on the subpixelBits parameter. Pass 0 for
1.31 + * round-to-nearest behavior (e.g. nearest neighbor sampling). Pass the number
1.32 + * of subpixel-bits to simulate filtering.
1.33 + */
1.34 +bool SkTreatAsSprite(const SkMatrix&, int width, int height,
1.35 + unsigned subpixelBits);
1.36 +
1.37 +/**
1.38 + * Calls SkTreatAsSprite() with default subpixelBits value to match Skia's
1.39 + * filter-bitmap implementation (i.e. kSkSubPixelBitsForBilerp).
1.40 + */
1.41 +static inline bool SkTreatAsSpriteFilter(const SkMatrix& matrix,
1.42 + int width, int height) {
1.43 + return SkTreatAsSprite(matrix, width, height, kSkSubPixelBitsForBilerp);
1.44 +}
1.45 +
1.46 +/** Decomposes the upper-left 2x2 of the matrix into a rotation (represented by
1.47 + the cosine and sine of the rotation angle), followed by a non-uniform scale,
1.48 + followed by another rotation. If there is a reflection, one of the scale
1.49 + factors will be negative.
1.50 + Returns true if successful. Returns false if the matrix is degenerate.
1.51 + */
1.52 +bool SkDecomposeUpper2x2(const SkMatrix& matrix,
1.53 + SkPoint* rotation1,
1.54 + SkPoint* scale,
1.55 + SkPoint* rotation2);
1.56 +
1.57 +#endif
