libcucul canvas transformation


Functions

__extern int cucul_invert (cucul_canvas_t *)
 Invert a canvas' colours.
__extern int cucul_flip (cucul_canvas_t *)
 Flip a canvas horizontally.
__extern int cucul_flop (cucul_canvas_t *)
 Flip a canvas vertically.
__extern int cucul_rotate_180 (cucul_canvas_t *)
 Rotate a canvas.
__extern int cucul_rotate_left (cucul_canvas_t *)
 Rotate a canvas, 90 degrees counterclockwise.
__extern int cucul_rotate_right (cucul_canvas_t *)
 Rotate a canvas, 90 degrees counterclockwise.
__extern int cucul_stretch_left (cucul_canvas_t *)
 Rotate and stretch a canvas, 90 degrees counterclockwise.
__extern int cucul_stretch_right (cucul_canvas_t *)
 Rotate and stretch a canvas, 90 degrees clockwise.

Detailed Description

These functions perform horizontal and vertical canvas flipping.

Function Documentation

__extern int cucul_invert ( cucul_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.

__extern int cucul_flip ( cucul_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 CUCUL_MAGIC_FULLWIDTH.

__extern int cucul_flop ( cucul_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.

__extern int cucul_rotate_180 ( cucul_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 CUCUL_MAGIC_FULLWIDTH.

__extern int cucul_rotate_left ( cucul_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.

__extern int cucul_rotate_right ( cucul_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.

__extern int cucul_stretch_left ( cucul_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.

__extern int cucul_stretch_right ( cucul_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.