| /* | |
| * Copyright (c) 2014 Vittorio Giovara <[email protected]> | |
| * | |
| * This file is part of FFmpeg. | |
| * | |
| * FFmpeg is free software; you can redistribute it and/or | |
| * modify it under the terms of the GNU Lesser General Public | |
| * License as published by the Free Software Foundation; either | |
| * version 2.1 of the License, or (at your option) any later version. | |
| * | |
| * FFmpeg is distributed in the hope that it will be useful, | |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| * Lesser General Public License for more details. | |
| * | |
| * You should have received a copy of the GNU Lesser General Public | |
| * License along with FFmpeg; if not, write to the Free Software | |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
| */ | |
| /** | |
| * @file | |
| * @ingroup lavu_video_display | |
| * Display matrix | |
| */ | |
| /** | |
| * @defgroup lavu_video_display Display transformation matrix functions | |
| * @ingroup lavu_video | |
| * | |
| * The display transformation matrix specifies an affine transformation that | |
| * should be applied to video frames for correct presentation. It is compatible | |
| * with the matrices stored in the ISO/IEC 14496-12 container format. | |
| * | |
| * The data is a 3x3 matrix represented as a 9-element array: | |
| * | |
| * @code{.unparsed} | |
| * | a b u | | |
| * (a, b, u, c, d, v, x, y, w) -> | c d v | | |
| * | x y w | | |
| * @endcode | |
| * | |
| * All numbers are stored in native endianness, as 16.16 fixed-point values, | |
| * except for u, v and w, which are stored as 2.30 fixed-point values. | |
| * | |
| * The transformation maps a point (p, q) in the source (pre-transformation) | |
| * frame to the point (p', q') in the destination (post-transformation) frame as | |
| * follows: | |
| * | |
| * @code{.unparsed} | |
| * | a b u | | |
| * (p, q, 1) . | c d v | = z * (p', q', 1) | |
| * | x y w | | |
| * @endcode | |
| * | |
| * The transformation can also be more explicitly written in components as | |
| * follows: | |
| * | |
| * @code{.unparsed} | |
| * p' = (a * p + c * q + x) / z; | |
| * q' = (b * p + d * q + y) / z; | |
| * z = u * p + v * q + w | |
| * @endcode | |
| * | |
| * @{ | |
| */ | |
| /** | |
| * Extract the rotation component of the transformation matrix. | |
| * | |
| * @param matrix the transformation matrix | |
| * @return the angle (in degrees) by which the transformation rotates the frame | |
| * counterclockwise. The angle will be in range [-180.0, 180.0], | |
| * or NaN if the matrix is singular. | |
| * | |
| * @note floating point numbers are inherently inexact, so callers are | |
| * recommended to round the return value to nearest integer before use. | |
| */ | |
| double av_display_rotation_get(const int32_t matrix[9]); | |
| /** | |
| * Initialize a transformation matrix describing a pure clockwise | |
| * rotation by the specified angle (in degrees). | |
| * | |
| * @param[out] matrix a transformation matrix (will be fully overwritten | |
| * by this function) | |
| * @param angle rotation angle in degrees. | |
| */ | |
| void av_display_rotation_set(int32_t matrix[9], double angle); | |
| /** | |
| * Flip the input matrix horizontally and/or vertically. | |
| * | |
| * @param[in,out] matrix a transformation matrix | |
| * @param hflip whether the matrix should be flipped horizontally | |
| * @param vflip whether the matrix should be flipped vertically | |
| */ | |
| void av_display_matrix_flip(int32_t matrix[9], int hflip, int vflip); | |
| /** | |
| * @} | |
| */ | |