| /* |
| * Copyright (c) 2014 Vittorio Giovara <vittorio.giovara@gmail.com> |
| * |
| * 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 |
| * Display matrix |
| */ |
| |
| #ifndef AVUTIL_DISPLAY_H |
| #define AVUTIL_DISPLAY_H |
| |
| #include <stdint.h> |
| #include "common.h" |
| |
| /** |
| * @addtogroup lavu_video |
| * @{ |
| * |
| * @defgroup lavu_video_display Display transformation matrix functions |
| * @{ |
| */ |
| |
| /** |
| * @addtogroup lavu_video_display |
| * 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 counterclockwise |
| * rotation by the specified angle (in degrees). |
| * |
| * @param matrix an allocated 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 matrix an allocated 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); |
| |
| /** |
| * @} |
| * @} |
| */ |
| |
| #endif /* AVUTIL_DISPLAY_H */ |
