caca_font

Section: libcaca (3caca)
Updated: Tue Jan 26 2021
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NAME

caca_font - libcaca bitmap font handling

SYNOPSIS

Modules

libcaca FIGfont handling

Functions

__extern caca_font_t * caca_load_font (void const *, size_t)
Load a font from memory for future use.
__extern char const *const * caca_get_font_list (void)
Get available builtin fonts.
__extern int caca_get_font_width (caca_font_t const *)
Get a font's standard glyph width.
__extern int caca_get_font_height (caca_font_t const *)
Get a font's standard glyph height.
__extern uint32_t const * caca_get_font_blocks (caca_font_t const *)
Get a font's list of supported glyphs.
__extern int caca_render_canvas (caca_canvas_t const *, caca_font_t const *, void *, int, int, int)
Render the canvas onto an image buffer.
__extern int caca_free_font (caca_font_t *)
Free a font structure.

Detailed Description

These functions provide bitmap font handling routines and high quality canvas to bitmap rendering.

Function Documentation

__extern caca_font_t* caca_load_font (void const * data, size_t size)

This function loads a font and returns a handle to its internal structure. The handle can then be used with caca_render_canvas() for bitmap output.

Internal fonts can also be loaded: if size is set to 0, data must be a string containing the internal font name.

If size is non-zero, the size bytes of memory at address data are loaded as a font. This memory are must not be freed by the calling program until the font handle has been freed with caca_free_font().

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

•: ENOENT Requested built-in font does not exist.
•: EINVAL Invalid font data in memory area.
•: ENOMEM Not enough memory to allocate font structure.

Parameters

: data The memory area containing the font or its name.
size The size of the memory area, or 0 if the font name is given.

Returns

: A font handle or NULL in case of error.

References caca_load_font().

Referenced by caca_load_font().

__extern char const* const* caca_get_font_list (void)

Return a list of available builtin fonts. The list is a NULL-terminated array of strings.

This function never fails.

Returns

: An array of strings.

__extern int caca_get_font_width (caca_font_t const * f)

Return the standard value for the current font's glyphs. Most glyphs in the font will have this width, except fullwidth characters.

This function never fails.

Parameters

: f The font, as returned by caca_load_font()

Returns

: The standard glyph width.

__extern int caca_get_font_height (caca_font_t const * f)

Returns the standard value for the current font's glyphs. Most glyphs in the font will have this height.

This function never fails.

Parameters

: f The font, as returned by caca_load_font()

Returns

: The standard glyph height.

__extern uint32_t const* caca_get_font_blocks (caca_font_t const * f)

This function returns the list of Unicode blocks supported by the given font. The list is a zero-terminated list of indices. Here is an example:

{
   0x0000, 0x0080,   // Basic latin: A, B, C, a, b, c
   0x0080, 0x0100,   // Latin-1 supplement: "A, 'e, ^u
   0x0530, 0x0590,   // Armenian
   0x0000, 0x0000,   // END
};

This function never fails.

Parameters

: f The font, as returned by caca_load_font()

Returns

: The list of Unicode blocks supported by the font.

__extern int caca_render_canvas (caca_canvas_t const * cv, caca_font_t const * f, void * buf, int width, int height, int pitch)

This function renders the given canvas on an image buffer using a specific font. The pixel format is fixed (32-bit ARGB, 8 bits for each component).

The required image width can be computed using caca_get_canvas_width() and caca_get_font_width(). The required height can be computed using caca_get_canvas_height() and caca_get_font_height().

Glyphs that do not fit in the image buffer are currently not rendered at all. They may be cropped instead in future versions.

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

•: EINVAL Specified width, height or pitch is invalid.

Parameters

: cv The canvas to render
f The font, as returned by caca_load_font()
buf The image buffer
width The width (in pixels) of the image buffer
height The height (in pixels) of the image buffer
pitch The pitch (in bytes) of an image buffer line.

Returns

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

References caca_attr_to_argb64().

__extern int caca_free_font (caca_font_t * f)

This function frees all data allocated by caca_load_font(). The font structure is no longer usable by other libcaca functions. Once this function has returned, the memory area that was given to caca_load_font() can be freed.

This function never fails.

Parameters

: f The font, as returned by caca_load_font()

Returns

: This function always returns 0.

Author

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