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1 /*
2  * Copyright (C) 2010 Georg Martius <georg.martius@web.de>
3  * Copyright (C) 2010 Daniel G. Taylor <dan@programmer-art.org>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #ifndef AVFILTER_TRANSFORM_H
23 #define AVFILTER_TRANSFORM_H
24 
25 #include <stdint.h>
26 
27 /**
28  * @file
29  * transform input video
30  *
31  * All matrices are defined as a single 9-item block of contiguous memory. For
32  * example, the identity matrix would be:
33  *
34  *     float *matrix = {1, 0, 0,
35  *                      0, 1, 0,
36  *                      0, 0, 1};
37  */
38 
39 enum InterpolateMethod {
40     INTERPOLATE_NEAREST,        //< Nearest-neighbor (fast)
41     INTERPOLATE_BILINEAR,       //< Bilinear
42     INTERPOLATE_BIQUADRATIC,    //< Biquadratic (best)
43     INTERPOLATE_COUNT,          //< Number of interpolation methods
44 };
45 
46 // Shortcuts for the fastest and best interpolation methods
47 #define INTERPOLATE_DEFAULT INTERPOLATE_BILINEAR
48 #define INTERPOLATE_FAST    INTERPOLATE_NEAREST
49 #define INTERPOLATE_BEST    INTERPOLATE_BIQUADRATIC
50 
51 enum FillMethod {
52     FILL_BLANK,         //< Fill zeroes at blank locations
53     FILL_ORIGINAL,      //< Original image at blank locations
54     FILL_CLAMP,         //< Extruded edge value at blank locations
55     FILL_MIRROR,        //< Mirrored edge at blank locations
56     FILL_COUNT,         //< Number of edge fill methods
57 };
58 
59 // Shortcuts for fill methods
60 #define FILL_DEFAULT FILL_ORIGINAL
61 
62 /**
63  * Get an affine transformation matrix from given translation, rotation, and
64  * zoom factors. The matrix will look like:
65  *
66  * [ scale_x * cos(angle),           -sin(angle),     x_shift,
67  *             sin(angle),  scale_y * cos(angle),     y_shift,
68  *                      0,                     0,           1 ]
69  *
70  * @param x_shift   horizontal translation
71  * @param y_shift   vertical translation
72  * @param angle     rotation in radians
73  * @param scale_x   x scale percent (1.0 = 100%)
74  * @param scale_y   y scale percent (1.0 = 100%)
75  * @param matrix    9-item affine transformation matrix
76  */
77 void ff_get_matrix(
78     float x_shift,
79     float y_shift,
80     float angle,
81     float scale_x,
82     float scale_y,
83     float *matrix
84 );
85 
86 /**
87  * Add two matrices together. result = m1 + m2.
88  *
89  * @param m1     9-item transformation matrix
90  * @param m2     9-item transformation matrix
91  * @param result 9-item transformation matrix
92  */
93 void avfilter_add_matrix(const float *m1, const float *m2, float *result);
94 
95 /**
96  * Subtract one matrix from another. result = m1 - m2.
97  *
98  * @param m1     9-item transformation matrix
99  * @param m2     9-item transformation matrix
100  * @param result 9-item transformation matrix
101  */
102 void avfilter_sub_matrix(const float *m1, const float *m2, float *result);
103 
104 /**
105  * Multiply a matrix by a scalar value. result = m1 * scalar.
106  *
107  * @param m1     9-item transformation matrix
108  * @param scalar a number
109  * @param result 9-item transformation matrix
110  */
111 void avfilter_mul_matrix(const float *m1, float scalar, float *result);
112 
113 /**
114  * Do an affine transformation with the given interpolation method. This
115  * multiplies each vector [x,y,1] by the matrix and then interpolates to
116  * get the final value.
117  *
118  * @param src         source image
119  * @param dst         destination image
120  * @param src_stride  source image line size in bytes
121  * @param dst_stride  destination image line size in bytes
122  * @param width       image width in pixels
123  * @param height      image height in pixels
124  * @param matrix      9-item affine transformation matrix
125  * @param interpolate pixel interpolation method
126  * @param fill        edge fill method
127  * @return negative on error
128  */
129 int avfilter_transform(const uint8_t *src, uint8_t *dst,
130                         int src_stride, int dst_stride,
131                         int width, int height, const float *matrix,
132                         enum InterpolateMethod interpolate,
133                         enum FillMethod fill);
134 
135 #endif /* AVFILTER_TRANSFORM_H */
136