libcucul canvas drawing(3caca)

NAME
libcucul canvas drawing -

  Defines
#define CUCUL_MAGIC_FULLWIDTH 0x000ffffe

  Functions
int cucul_gotoxy (cucul_canvas_t *, int, int)
Set cursor position.
int cucul_get_cursor_x (cucul_canvas_t *)
Get X cursor position.
int cucul_get_cursor_y (cucul_canvas_t *)
Get Y cursor position.
int cucul_put_char (cucul_canvas_t *, int, int, unsigned long int)
Print an ASCII or Unicode character.
unsigned long int cucul_get_char (cucul_canvas_t *, int, int)
Get the Unicode character at the given coordinates.
int cucul_put_str (cucul_canvas_t *, int, int, char const *)
Print a string.
unsigned long int cucul_get_attr (cucul_canvas_t *, int, int)
Get the text attribute at the given coordinates.
int cucul_set_attr (cucul_canvas_t *, unsigned long int)
Set the default character attribute.
int cucul_put_attr (cucul_canvas_t *, int, int, unsigned long int)
Set the character attribute at the given coordinates.
int cucul_set_color_ansi (cucul_canvas_t *, unsigned char, unsigned char)
Set the default colour pair for text (ANSI version).
int cucul_set_color_argb (cucul_canvas_t *, unsigned int, unsigned int)
Set the default colour pair for text (truecolor version).
int cucul_printf (cucul_canvas_t *, int, int, char const *,...)
Print a formated string.
int cucul_clear_canvas (cucul_canvas_t *)
Clear the canvas.
int cucul_set_canvas_handle (cucul_canvas_t *, int, int)
Set cursor handle.
int cucul_get_canvas_handle_x (cucul_canvas_t *)
Get X handle position.
int cucul_get_canvas_handle_y (cucul_canvas_t *)
Get Y handle position.
int cucul_blit (cucul_canvas_t *, int, int, cucul_canvas_t const *, cucul_canvas_t const *)
Blit a canvas onto another one.
int cucul_set_canvas_boundaries (cucul_canvas_t *, int, int, unsigned int, unsigned int)
Set a canvas' new boundaries.

Detailed Description

These functions provide low-level character printing routines and higher level graphics functions.

Define Documentation

  #define CUCUL_MAGIC_FULLWIDTH 0x000ffffe

Used to indicate that the previous character was a fullwidth glyph.

Function Documentation

  int cucul_gotoxy (cucul_canvas_t * cv, int x, int y)

Put the cursor at the given coordinates. Functions making use of the cursor will use the new values. Setting the cursor position outside the canvas is legal but the cursor will not be shown.

This function never fails.

Parameters:
    cv A handle to the libcucul canvas.
    x X cursor coordinate.
    y Y cursor coordinate.

Returns:
    This function always returns 0.

  int cucul_get_cursor_x (cucul_canvas_t * cv)

Retrieve the X coordinate of the cursor's position.

This function never fails.

Parameters:
    cv A handle to the libcucul canvas.

Returns:
    The cursor's X coordinate.

  int cucul_get_cursor_y (cucul_canvas_t * cv)

Retrieve the Y coordinate of the cursor's position.

This function never fails.

Parameters:
    cv A handle to the libcucul canvas.

Returns:
    The cursor's Y coordinate.

  int cucul_put_char (cucul_canvas_t * cv, int x, int y, unsigned long int ch)

Print an ASCII or Unicode character at the given coordinates, using the default foreground and background colour values.

If the coordinates are outside the canvas boundaries, nothing is printed. If a fullwidth Unicode character gets overwritten, its remaining visible parts are replaced with spaces. If the canvas' boundaries would split the fullwidth character in two, a space is printed instead.

The behaviour when printing non-printable characters or invalid UTF-32 characters is undefined. To print a sequence of bytes forming an UTF-8 character instead of an UTF-32 character, use the cucul_put_str() function.

This function never fails.

Parameters:
    cv A handle to the libcucul canvas.
    x X coordinate.
    y Y coordinate.
    ch The character to print.

Returns:
    This function always returns 0.

  unsigned long int cucul_get_char (cucul_canvas_t * cv, int x, int y)

Get the ASCII or Unicode value of the character at the given coordinates. If the value is less or equal to 127 (0x7f), the character can be printed as ASCII. Otherise, it must be handled as a UTF-32 value.

If the coordinates are outside the canvas boundaries, a space (0x20) is returned.

A special exception is when CUCUL_MAGIC_FULLWIDTH is returned. This value is guaranteed not to be a valid Unicode character, and indicates that the character at the left of the requested one is a fullwidth character.

This function never fails.

Parameters:
    cv A handle to the libcucul canvas.
    x X coordinate.
    y Y coordinate.

Returns:
    This function always returns 0.

  int cucul_put_str (cucul_canvas_t * cv, int x, int y, char const * s)

Print an UTF-8 string at the given coordinates, using the default foreground and background values. The coordinates may be outside the canvas boundaries (eg. a negative Y coordinate) and the string will be cropped accordingly if it is too long.

See cucul_put_char() for more information on how fullwidth characters are handled when overwriting each other or at the canvas' boundaries.

This function never fails.

Parameters:
    cv A handle to the libcucul canvas.
    x X coordinate.
    y Y coordinate.
    s The string to print.

Returns:
    This function always returns 0.

  unsigned long int cucul_get_attr (cucul_canvas_t * cv, int x, int y)

Get the internal libcucul attribute value of the character at the given coordinates. The attribute value has 32 significant bits, organised as follows from MSB to LSB:

•   3 bits for the background alpha

•   4 bits for the background red component

•   4 bits for the background green component

•   3 bits for the background blue component

•   3 bits for the foreground alpha

•   4 bits for the foreground red component

•   4 bits for the foreground green component

•   3 bits for the foreground blue component

•   4 bits for the bold, italics, underline and blink flags

If the coordinates are outside the canvas boundaries, the current attribute is returned.

This function never fails.

Parameters:
    cv A handle to the libcucul canvas.
    x X coordinate.
    y Y coordinate.

Returns:
    The requested attribute.

  int cucul_set_attr (cucul_canvas_t * cv, unsigned long int attr)

Set the default character attribute for drawing. Attributes define foreground and background colour, transparency, bold, italics and underline styles, as well as blink. String functions such as caca_printf() and graphical primitive functions such as caca_draw_line() will use this attribute.

The value of attr is either:

•   a 32-bit integer as returned by cucul_get_attr(), in which case it also contains colour information,

•   a combination (bitwise OR) of style values (CUCUL_UNDERLINE, CUCUL_BLINK, CUCUL_BOLD and CUCUL_ITALICS), in which case setting the attribute does not modify the current colour information.

To retrieve the current attribute value, use cucul_get_attr(-1,-1).

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

•   EINVAL The attribute value is out of the 32-bit range.

Parameters:
    cv A handle to the libcucul canvas.
    attr The requested attribute value.

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

  int cucul_put_attr (cucul_canvas_t * cv, int x, int y, unsigned long int attr)

Set the character attribute, without changing the character's value. If the character at the given coordinates is a fullwidth character, both cells' attributes are replaced.

The value of attr is either:

•   a 32-bit integer as returned by cucul_get_attr(), in which case it also contains colour information,

•   a combination (bitwise OR) of style values (CUCUL_UNDERLINE, CUCUL_BLINK, CUCUL_BOLD and CUCUL_ITALICS), in which case setting the attribute does not modify the current colour information.

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

•   EINVAL The attribute value is out of the 32-bit range.

Parameters:
    cv A handle to the libcucul canvas.
    x X coordinate.
    y Y coordinate.
    attr The requested attribute value.

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

  int cucul_set_color_ansi (cucul_canvas_t * cv, unsigned char fg, unsigned char bg)

Set the default ANSI colour pair for text drawing. String functions such as caca_printf() and graphical primitive functions such as caca_draw_line() will use these attributes.

Color values are those defined in cucul.h, such as CUCUL_RED or CUCUL_TRANSPARENT.

If an error occurs, 0 is returned and errno is set accordingly:

•   EINVAL At least one of the colour values is invalid.

Parameters:
    cv A handle to the libcucul canvas.
    fg The requested ANSI foreground colour.
    bg The requested ANSI background colour.

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

  int cucul_set_color_argb (cucul_canvas_t * cv, unsigned int fg, unsigned int bg)

Set the default ARGB colour pair for text drawing. String functions such as caca_printf() and graphical primitive functions such as caca_draw_line() will use these attributes.

Colors are 16-bit ARGB values, each component being coded on 4 bits. For instance, 0xf088 is solid dark cyan (A=15 R=0 G=8 B=8), and 0x8fff is white with 50% alpha (A=8 R=15 G=15 B=15).

If an error occurs, 0 is returned and errno is set accordingly:

•   EINVAL At least one of the colour values is invalid.

Parameters:
    cv A handle to the libcucul canvas.
    fg The requested ARGB foreground colour.
    bg The requested ARGB background colour.

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

  int cucul_printf (cucul_canvas_t * cv, int x, int y, char const * format, ...)

Format a string at the given coordinates, using the default foreground and background values. The coordinates may be outside the canvas boundaries (eg. a negative Y coordinate) and the string will be cropped accordingly if it is too long. The syntax of the format string is the same as for the C printf() function.

This function never fails.

Parameters:
    cv A handle to the libcucul canvas.
    x X coordinate.
    y Y coordinate.
    format The format string to print.
    ... Arguments to the format string.

Returns:
    This function always returns 0.

  int cucul_clear_canvas (cucul_canvas_t * cv)

Clear the canvas using the current foreground and background colours.

This function never fails.

Parameters:
    cv The canvas to clear.

Returns:
    This function always returns 0.

  int cucul_set_canvas_handle (cucul_canvas_t * cv, int x, int y)

Set the canvas' handle. Blitting functions will use the handle value to put the canvas at the proper coordinates.

This function never fails.

Parameters:
    cv A handle to the libcucul canvas.
    x X handle coordinate.
    y Y handle coordinate.

Returns:
    This function always returns 0.

  int cucul_get_canvas_handle_x (cucul_canvas_t * cv)

Retrieve the X coordinate of the canvas' handle.

This function never fails.

Parameters:
    cv A handle to the libcucul canvas.

Returns:
    The canvas' handle's X coordinate.

  int cucul_get_canvas_handle_y (cucul_canvas_t * cv)

Retrieve the Y coordinate of the canvas' handle.

This function never fails.

Parameters:
    cv A handle to the libcucul canvas.

Returns:
    The canvas' handle's Y coordinate.

  int cucul_blit (cucul_canvas_t * dst, int x, int y, cucul_canvas_t const * src, cucul_canvas_t const * mask)

Blit a canvas onto another one at the given coordinates. An optional mask canvas can be used.

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

•   EINVAL A mask was specified but the mask size and source canvas size do not match.

Parameters:
    dst The destination canvas.
    x X coordinate.
    y Y coordinate.
    src The source canvas.
    mask The mask canvas.

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

  int cucul_set_canvas_boundaries (cucul_canvas_t * cv, int x, int y, unsigned int w, unsigned int h)

Set new boundaries for a canvas. This function can be used to crop a canvas, to expand it or for combinations of both actions. All frames are affected by this function.

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 resized.

•   ENOMEM Not enough memory for the requested canvas size. If this happens, the canvas handle becomes invalid and should not be used.

Parameters:
    cv The canvas to crop.
    x X coordinate of the top-left corner.
    y Y coordinate of the top-left corner.
    w The width of the cropped area.
    h The height of the cropped area.

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