NAME

       caca_transform - libcaca canvas transformation

   Functions
       __extern int caca_invert (caca_canvas_t *)
           Invert a canvas' colours.
       __extern int caca_flip (caca_canvas_t *)
           Flip a canvas horizontally.
       __extern int caca_flop (caca_canvas_t *)
           Flip a canvas vertically.
       __extern int caca_rotate_180 (caca_canvas_t *)
           Rotate a canvas.
       __extern int caca_rotate_left (caca_canvas_t *)
           Rotate a canvas, 90 degrees counterclockwise.
       __extern int caca_rotate_right (caca_canvas_t *)
           Rotate a canvas, 90 degrees counterclockwise.
       __extern int caca_stretch_left (caca_canvas_t *)
           Rotate and stretch a canvas, 90 degrees counterclockwise.
       __extern int caca_stretch_right (caca_canvas_t *)
           Rotate and stretch a canvas, 90 degrees clockwise.

Detailed Description

       These functions perform horizontal and vertical canvas flipping.

Function Documentation

   __extern int caca_invert (caca_canvas_t * cv)
       Invert a canvas' colours (black becomes white, red becomes cyan, etc.) without changing
       the characters in it.

       This function never fails.

       Parameters:
           cv The canvas to invert.

       Returns:
           This function always returns 0.

       References caca_add_dirty_rect().

       Referenced by caca_stretch_right().

   __extern int caca_flip (caca_canvas_t * cv)
       Flip a canvas horizontally, choosing characters that look like the mirrored version
       wherever possible. Some characters will stay unchanged by the process, but the operation
       is guaranteed to be involutive: performing it again gives back the original canvas.

       This function never fails.

       Parameters:
           cv The canvas to flip.

       Returns:
           This function always returns 0.

       References caca_add_dirty_rect(), and CACA_MAGIC_FULLWIDTH.

       Referenced by caca_stretch_right().

   __extern int caca_flop (caca_canvas_t * cv)
       Flip a canvas vertically, choosing characters that look like the mirrored version wherever
       possible. Some characters will stay unchanged by the process, but the operation is
       guaranteed to be involutive: performing it again gives back the original canvas.

       This function never fails.

       Parameters:
           cv The canvas to flop.

       Returns:
           This function always returns 0.

       References caca_add_dirty_rect().

       Referenced by caca_stretch_right().

   __extern int caca_rotate_180 (caca_canvas_t * cv)
       Apply a 180-degree transformation to a canvas, choosing characters that look like the
       upside-down version wherever possible. Some characters will stay unchanged by the process,
       but the operation is guaranteed to be involutive: performing it again gives back the
       original canvas.

       This function never fails.

       Parameters:
           cv The canvas to rotate.

       Returns:
           This function always returns 0.

       References caca_add_dirty_rect(), and CACA_MAGIC_FULLWIDTH.

       Referenced by caca_stretch_right().

   __extern int caca_rotate_left (caca_canvas_t * cv)
       Apply a 90-degree transformation to a canvas, choosing characters that look like the
       rotated version wherever possible. Characters cells are rotated two-by-two. Some
       characters will stay unchanged by the process, some others will be replaced by close
       equivalents. Fullwidth characters at odd horizontal coordinates will be lost. The
       operation is not guaranteed to be reversible at all.

       Note that the width of the canvas is divided by two and becomes the new height. Height is
       multiplied by two and becomes the new width. If the original width is an odd number, the
       division is rounded up.

       If an error occurs, -1 is returned and errno is set accordingly:

       • EBUSY The canvas is in use by a display driver and cannot be rotated.

       • ENOMEM Not enough memory to allocate the new canvas size. If this happens, the previous
         canvas handle is still valid.

       Parameters:
           cv The canvas to rotate left.

       Returns:
           0 in case of success, -1 if an error occurred.

       References caca_add_dirty_rect().

       Referenced by caca_stretch_right().

   __extern int caca_rotate_right (caca_canvas_t * cv)
       Apply a 90-degree transformation to a canvas, choosing characters that look like the
       rotated version wherever possible. Characters cells are rotated two-by-two. Some
       characters will stay unchanged by the process, some others will be replaced by close
       equivalents. Fullwidth characters at odd horizontal coordinates will be lost. The
       operation is not guaranteed to be reversible at all.

       Note that the width of the canvas is divided by two and becomes the new height. Height is
       multiplied by two and becomes the new width. If the original width is an odd number, the
       division is rounded up.

       If an error occurs, -1 is returned and errno is set accordingly:

       • EBUSY The canvas is in use by a display driver and cannot be rotated.

       • ENOMEM Not enough memory to allocate the new canvas size. If this happens, the previous
         canvas handle is still valid.

       Parameters:
           cv The canvas to rotate right.

       Returns:
           0 in case of success, -1 if an error occurred.

       References caca_add_dirty_rect().

       Referenced by caca_stretch_right().

   __extern int caca_stretch_left (caca_canvas_t * cv)
       Apply a 90-degree transformation to a canvas, choosing characters that look like the
       rotated version wherever possible. Some characters will stay unchanged by the process,
       some others will be replaced by close equivalents. Fullwidth characters will be lost. The
       operation is not guaranteed to be reversible at all.

       Note that the width and height of the canvas are swapped, causing its aspect ratio to look
       stretched.

       If an error occurs, -1 is returned and errno is set accordingly:

       • EBUSY The canvas is in use by a display driver and cannot be rotated.

       • ENOMEM Not enough memory to allocate the new canvas size. If this happens, the previous
         canvas handle is still valid.

       Parameters:
           cv The canvas to rotate left.

       Returns:
           0 in case of success, -1 if an error occurred.

       References caca_add_dirty_rect().

       Referenced by caca_stretch_right().

   __extern int caca_stretch_right (caca_canvas_t * cv)
       Apply a 270-degree transformation to a canvas, choosing characters that look like the
       rotated version wherever possible. Some characters will stay unchanged by the process,
       some others will be replaced by close equivalents. Fullwidth characters will be lost. The
       operation is not guaranteed to be reversible at all.

       Note that the width and height of the canvas are swapped, causing its aspect ratio to look
       stretched.

       If an error occurs, -1 is returned and errno is set accordingly:

       • EBUSY The canvas is in use by a display driver and cannot be rotated.

       • ENOMEM Not enough memory to allocate the new canvas size. If this happens, the previous
         canvas handle is still valid.

       Parameters:
           cv The canvas to rotate right.

       Returns:
           0 in case of success, -1 if an error occurred.

       References caca_add_dirty_rect(), caca_flip(), caca_flop(), caca_invert(),
       CACA_MAGIC_FULLWIDTH, caca_rotate_180(), caca_rotate_left(), caca_rotate_right(), and
       caca_stretch_left().

Author

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