1/*
2 * Copyright 2017 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkEncodedOrigin_DEFINED
9#define SkEncodedOrigin_DEFINED
10
11#include "include/core/SkMatrix.h"
12
13// These values match the orientation www.exif.org/Exif2-2.PDF.
14enum SkEncodedOrigin {
15    kTopLeft_SkEncodedOrigin     = 1, // Default
16    kTopRight_SkEncodedOrigin    = 2, // Reflected across y-axis
17    kBottomRight_SkEncodedOrigin = 3, // Rotated 180
18    kBottomLeft_SkEncodedOrigin  = 4, // Reflected across x-axis
19    kLeftTop_SkEncodedOrigin     = 5, // Reflected across x-axis, Rotated 90 CCW
20    kRightTop_SkEncodedOrigin    = 6, // Rotated 90 CW
21    kRightBottom_SkEncodedOrigin = 7, // Reflected across x-axis, Rotated 90 CW
22    kLeftBottom_SkEncodedOrigin  = 8, // Rotated 90 CCW
23    kDefault_SkEncodedOrigin     = kTopLeft_SkEncodedOrigin,
24    kLast_SkEncodedOrigin        = kLeftBottom_SkEncodedOrigin,
25};
26
27/**
28 * Given an encoded origin and the width and height of the source data, returns a matrix
29 * that transforms the source rectangle with upper left corner at [0, 0] and origin to a correctly
30 * oriented destination rectangle of [0, 0, w, h].
31 */
32static inline SkMatrix SkEncodedOriginToMatrix(SkEncodedOrigin origin, int w, int h) {
33    switch (origin) {
34        case     kTopLeft_SkEncodedOrigin: return SkMatrix::I();
35        case    kTopRight_SkEncodedOrigin: return SkMatrix::MakeAll(-1,  0, w,  0,  1, 0, 0, 0, 1);
36        case kBottomRight_SkEncodedOrigin: return SkMatrix::MakeAll(-1,  0, w,  0, -1, h, 0, 0, 1);
37        case  kBottomLeft_SkEncodedOrigin: return SkMatrix::MakeAll( 1,  0, 0,  0, -1, h, 0, 0, 1);
38        case     kLeftTop_SkEncodedOrigin: return SkMatrix::MakeAll( 0,  1, 0,  1,  0, 0, 0, 0, 1);
39        case    kRightTop_SkEncodedOrigin: return SkMatrix::MakeAll( 0, -1, w,  1,  0, 0, 0, 0, 1);
40        case kRightBottom_SkEncodedOrigin: return SkMatrix::MakeAll( 0, -1, w, -1,  0, h, 0, 0, 1);
41        case  kLeftBottom_SkEncodedOrigin: return SkMatrix::MakeAll( 0,  1, 0, -1,  0, h, 0, 0, 1);
42    }
43    SK_ABORT("Unexpected origin");
44}
45
46/**
47 * Return true if the encoded origin includes a 90 degree rotation, in which case the width
48 * and height of the source data are swapped relative to a correctly oriented destination.
49 */
50static inline bool SkEncodedOriginSwapsWidthHeight(SkEncodedOrigin origin) {
51    return origin >= kLeftTop_SkEncodedOrigin;
52}
53
54#endif // SkEncodedOrigin_DEFINED
55