libcaca display functions
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## Modules

| libcaca event handling

## Functions

__extern caca_display_t * | caca_create_display (caca_canvas_t *)
| Attach a caca graphical context to a caca canvas. More...
__extern caca_display_t * | caca_create_display_with_driver (caca_canvas_t *, char const *)
| Attach a specific caca graphical context to a caca canvas. More...
__extern char const *const * | caca_get_display_driver_list (void)
| Get available display drivers. More...
__extern char const * | caca_get_display_driver (caca_display_t *)
| Return a caca graphical context's current output driver. More...
__extern int | caca_set_display_driver (caca_display_t *, char const *)
| Set the output driver. More...
__extern int | caca_free_display (caca_display_t *)
| Detach a caca graphical context from a caca backend context. More...
__extern caca_canvas_t * | caca_get_canvas (caca_display_t *)
| Get the canvas attached to a caca graphical context. More...
__extern int | caca_refresh_display (caca_display_t *)
| Flush pending changes and redraw the screen. More...
__extern int | caca_set_display_time (caca_display_t *, int)
| Set the refresh delay. More...
__extern int | caca_get_display_time (caca_display_t const *)
| Get the display's average rendering time. More...
__extern int | caca_get_display_width (caca_display_t const *)
| Get the display width. More...
__extern int | caca_get_display_height (caca_display_t const *)
| Get the display height. More...
__extern int | caca_set_display_title (caca_display_t *, char const *)
| Set the display title. More...
__extern int | caca_set_mouse (caca_display_t *, int)
| Show or hide the mouse pointer. More...
__extern int | caca_set_cursor (caca_display_t *, int)
| Show or hide the cursor. More...

## Detailed Description

These functions provide the basic libcaca routines for display initialisation, system information retrieval and configuration.

## Function Documentation

## caca_create_display()

__extern caca_display_t* caca_create_display | ( | caca_canvas_t * | cv | ) |

Create a graphical context using device-dependent features (ncurses for terminals, an X11 window, a DOS command window...) that attaches to a libcaca canvas. Everything that gets drawn in the libcaca canvas can then be displayed by the libcaca driver.

If no caca canvas is provided, a new one is created. Its handle can be retrieved using caca_get_canvas() and it is automatically destroyed when caca_free_display() is called.

See also caca_create_display_with_driver().

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

- `ENOMEM` Not enough memory.
- `ENODEV` Graphical device could not be initialised.

Parameters

  cv | The caca canvas or NULL to create a canvas automatically.

Returns
  The caca graphical context or NULL if an error occurred.

References caca_create_display_with_driver().

## caca_create_display_with_driver()

__extern caca_display_t* caca_create_display_with_driver | ( | caca_canvas_t * | cv,
|  | char const * | driver
| ) |  |

Create a graphical context using device-dependent features (ncurses for terminals, an X11 window, a DOS command window...) that attaches to a libcaca canvas. Everything that gets drawn in the libcaca canvas can then be displayed by the libcaca driver.

If no caca canvas is provided, a new one is created. Its handle can be retrieved using caca_get_canvas() and it is automatically destroyed when caca_free_display() is called.

If no driver name is provided, libcaca will try to autodetect the best output driver it can.

See also caca_create_display().

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

- `ENOMEM` Not enough memory.
- `ENODEV` Graphical device could not be initialised.

Parameters

  cv | The caca canvas or NULL to create a canvas automatically.
  driver | A string describing the desired output driver or NULL to choose the best driver automatically.

Returns
  The caca graphical context or NULL if an error occurred.

References caca_create_canvas(), caca_free_canvas(), caca_manage_canvas(), and caca_unmanage_canvas().

Referenced by caca_create_display().

## caca_get_display_driver_list()

__extern char const* const* caca_get_display_driver_list | ( | void |  | ) |

Return a list of available display drivers. The list is a NULL-terminated array of strings, interleaving a string containing the internal value for the display driver, and a string containing the natural language description for that driver.

This function never fails.

Returns
  An array of strings.

## caca_get_display_driver()

__extern char const* caca_get_display_driver | ( | caca_display_t * | dp | ) |

Return the given display's current output driver.

This function never fails.

Parameters

  dp | The caca display.

Returns
  A static string.

## caca_set_display_driver()

__extern int caca_set_display_driver | ( | caca_display_t * | dp,
|  | char const * | driver
| ) |  |

Dynamically change the given display's output driver.

FIXME: decide what to do in case of failure

Parameters

  dp | The caca display.
  driver | A string describing the desired output driver or NULL to choose the best driver automatically.

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

## caca_free_display()

__extern int caca_free_display | ( | caca_display_t * | dp | ) |

Detach a graphical context from its caca backend and destroy it. The libcaca canvas continues to exist and other graphical contexts can be attached to it afterwards.

If the caca canvas was automatically created by caca_create_display(), it is automatically destroyed and any handle to it becomes invalid.

This function never fails.

Parameters

  dp | The libcaca graphical context.

Returns
  This function always returns 0.

References caca_free_canvas(), and caca_unmanage_canvas().

## caca_get_canvas()

__extern caca_canvas_t* caca_get_canvas | ( | caca_display_t * | dp | ) |

Return a handle on the caca_canvas_t object that was either attached or created by caca_create_display().

This function never fails.

Parameters

  dp | The libcaca graphical context.

Returns
  The libcaca canvas.

## caca_refresh_display()

__extern int caca_refresh_display | ( | caca_display_t * | dp | ) |

Flush all graphical operations and print them to the display device. Nothing will show on the screen until this function is called.

If caca_set_display_time() was called with a non-zero value, caca_refresh_display() will use that value to achieve constant framerate: if two consecutive calls to caca_refresh_display() are within a time range shorter than the value set with caca_set_display_time(), the second call will be delayed before performing the screen refresh.

This function never fails.

Parameters

  dp | The libcaca display context.

Returns
  This function always returns 0.

References caca_clear_dirty_rect_list().

## caca_set_display_time()

__extern int caca_set_display_time | ( | caca_display_t * | dp,
|  | int | usec
| ) |  |

Set the refresh delay in microseconds. The refresh delay is used by caca_refresh_display() to achieve constant framerate. See the caca_refresh_display() documentation for more details.

If the argument is zero, constant framerate is disabled. This is the default behaviour.

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

- `EINVAL` Refresh delay value is invalid.

Parameters

  dp | The libcaca display context.
  usec | The refresh delay in microseconds.

Returns
  0 upon success, -1 if an error occurred.

## caca_get_display_time()

__extern int caca_get_display_time | ( | caca_display_t const * | dp | ) |

Get the average rendering time, which is the average measured time between two caca_refresh_display() calls, in microseconds. If constant framerate was activated by calling caca_set_display_time(), the average rendering time will be close to the requested delay even if the real rendering time was shorter.

This function never fails.

Parameters

  dp | The libcaca display context.

Returns
  The render time in microseconds.

## caca_get_display_width()

__extern int caca_get_display_width | ( | caca_display_t const * | dp | ) |

If libcaca runs in a window, get the usable window width. This value can be used for aspect ratio calculation. If libcaca does not run in a window or if there is no way to know the font size, most drivers will assume a 6x10 font is being used. Note that the units are not necessarily pixels.

This function never fails.

Parameters

  dp | The libcaca display context.

Returns
  The display width.

## caca_get_display_height()

__extern int caca_get_display_height | ( | caca_display_t const * | dp | ) |

If libcaca runs in a window, get the usable window height. This value can be used for aspect ratio calculation. If libcaca does not run in a window or if there is no way to know the font size, assume a 6x10 font is being used. Note that the units are not necessarily pixels.

This function never fails.

Parameters

  dp | The libcaca display context.

Returns
  The display height.

## caca_set_display_title()

__extern int caca_set_display_title | ( | caca_display_t * | dp,
|  | char const * | title
| ) |  |

If libcaca runs in a window, try to change its title. This works with the ncurses, S-Lang, OpenGL, X11 and Win32 drivers.

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

- `ENOSYS` Display driver does not support setting the window title.

Parameters

  dp | The libcaca display context.
  title | The desired display title.

Returns
  0 upon success, -1 if an error occurred.

## caca_set_mouse()

__extern int caca_set_mouse | ( | caca_display_t * | dp,
|  | int | flag
| ) |  |

Show or hide the mouse pointer. This function works with the ncurses, S-Lang and X11 drivers.

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

- `ENOSYS` Display driver does not support hiding the mouse pointer.

Parameters

  dp | The libcaca display context.
  flag | 0 hides the pointer, 1 shows the system's default pointer (usually an arrow). Other values are reserved for future use.

Returns
  0 upon success, -1 if an error occurred.

## caca_set_cursor()

__extern int caca_set_cursor | ( | caca_display_t * | dp,
|  | int | flag
| ) |  |

Show or hide the cursor, for devices that support such a feature.

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

- `ENOSYS` Display driver does not support showing the cursor.

Parameters

  dp | The libcaca display context.
  flag | 0 hides the cursor, 1 shows the system's default cursor (usually a white rectangle). Other values are reserved for future use.

Returns
  0 upon success, -1 if an error occurred.