Граф связей класса Display transformation matrix functions:

Функции
double	av_display_rotation_get (const int32_t matrix[9])

void	av_display_rotation_set (int32_t matrix[9], double angle)

void	av_display_matrix_flip (int32_t matrix[9], int hflip, int vflip)

Подробное описание

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:

                               | a b u |
(a, b, u, c, d, v, x, y, w) -> | c d v |
                               | x y w |

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:

            | a b u |
(p, q, 1) . | c d v | = z * (p', q', 1)
            | x y w |

The transformation can also be more explicitly written in components as follows:

p' = (a * p + c * q + x) / z;
q' = (b * p + d * q + y) / z;
z  =  u * p + v * q + w

Функции

◆ av_display_rotation_get()

double av_display_rotation_get ( const int32_t matrix[9] )

#include <C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavutil/display.h>

Extract the rotation component of the transformation matrix.

Аргументы

matrix the transformation matrix

Возвращает: 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.

Заметки: floating point numbers are inherently inexact, so callers are recommended to round the return value to nearest integer before use.

◆ av_display_rotation_set()

void av_display_rotation_set	(	int32_t	matrix[9],
		double	angle
	)

#include <C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavutil/display.h>

Initialize a transformation matrix describing a pure counterclockwise rotation by the specified angle (in degrees).

Аргументы

matrix	an allocated transformation matrix (will be fully overwritten by this function)
angle	rotation angle in degrees.

◆ av_display_matrix_flip()

void av_display_matrix_flip	(	int32_t	matrix[9],
		int	hflip,
		int	vflip
	)

#include <C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavutil/display.h>

Flip the input matrix horizontally and/or vertically.

Аргументы

matrix	an allocated transformation matrix
hflip	whether the matrix should be flipped horizontally
vflip	whether the matrix should be flipped vertically