caca_attributes (3caca)

These functions perform conversions between attribute values.

__extern uint32_t caca_get_attr (\fBcaca_canvas_t\fP const *cv, intx, inty)

Get the internal libcaca 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 libcaca canvas.

x X coordinate.

y Y coordinate.

Returns:

The requested attribute.

Referenced by caca_conio_textbackground(), caca_conio_textcolor(), caca_dither_bitmap(), caca_flush_figlet(), and caca_put_figchar().

__extern int caca_set_attr (\fBcaca_canvas_t\fP *cv, uint32_tattr)

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 caca_get_attr(), in which case it also contains colour information,

• a combination (bitwise OR) of style values (CACA_UNDERLINE, CACA_BLINK, CACA_BOLD and CACA_ITALICS), in which case setting the attribute does not modify the current colour information.

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

This function never fails.

Parameters:

cv A handle to the libcaca canvas.

attr The requested attribute value.

Returns:

This function always returns 0.

Referenced by caca_dither_bitmap(), and caca_put_figchar().

__extern int caca_unset_attr (\fBcaca_canvas_t\fP *cv, uint32_tattr)

Unset flags in 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 a combination (bitwise OR) of style values (CACA_UNDERLINE, CACA_BLINK, CACA_BOLD and CACA_ITALICS). Unsetting these attributes does not modify the current colour information.

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

This function never fails.

Parameters:

cv A handle to the libcaca canvas.

attr The requested attribute values to unset.

Returns:

This function always returns 0.

__extern int caca_toggle_attr (\fBcaca_canvas_t\fP *cv, uint32_tattr)

Toggle flags in 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 a combination (bitwise OR) of style values (CACA_UNDERLINE, CACA_BLINK, CACA_BOLD and CACA_ITALICS). Toggling these attributes does not modify the current colour information.

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

This function never fails.

Parameters:

cv A handle to the libcaca canvas.

attr The requested attribute values to toggle.

Returns:

This function always returns 0.

__extern int caca_put_attr (\fBcaca_canvas_t\fP *cv, intx, inty, uint32_tattr)

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 caca_get_attr(), in which case it also contains colour information,

• a combination (bitwise OR) of style values (CACA_UNDERLINE, CACA_BLINK, CACA_BOLD and CACA_ITALICS), in which case setting the attribute does not modify the current colour information.

This function never fails.

Parameters:

cv A handle to the libcaca canvas.

x X coordinate.

y Y coordinate.

attr The requested attribute value.

Returns:

This function always returns 0.

References caca_add_dirty_rect(), and CACA_MAGIC_FULLWIDTH.

Referenced by caca_flush_figlet(), and caca_put_figchar().

__extern int caca_set_color_ansi (\fBcaca_canvas_t\fP *cv, uint8_tfg, uint8_tbg)

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 caca.h, such as CACA_RED or CACA_TRANSPARENT.

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

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

Parameters:

cv A handle to the libcaca canvas.

fg The requested ANSI foreground colour.

bg The requested ANSI background colour.

Returns:

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

Referenced by caca_conio_textbackground(), caca_conio_textcolor(), caca_create_canvas(), and caca_dither_bitmap().

__extern int caca_set_color_argb (\fBcaca_canvas_t\fP *cv, uint16_tfg, uint16_tbg)

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).

This function never fails.

Parameters:

cv A handle to the libcaca canvas.

fg The requested ARGB foreground colour.

bg The requested ARGB background colour.

Returns:

This function always returns 0.

__extern uint8_t caca_attr_to_ansi (uint32_tattr)

Get the ANSI colour pair for a given attribute. The returned value is an 8-bit value whose higher 4 bits are the background colour and lower 4 bits are the foreground colour.

If the attribute has ARGB colours, the nearest colour is used. Special attributes such as CACA_DEFAULT and CACA_TRANSPARENT are not handled and are both replaced with CACA_LIGHTGRAY for the foreground colour and CACA_BLACK for the background colour.

This function never fails. If the attribute value is outside the expected 32-bit range, higher order bits are simply ignored.

Parameters:

attr The requested attribute value.

Returns:

The corresponding DOS ANSI value.

References CACA_BLACK, and CACA_LIGHTGRAY.

__extern uint8_t caca_attr_to_ansi_fg (uint32_tattr)

Get the ANSI foreground colour value for a given attribute. The returned value is either one of the CACA_RED, CACA_BLACK etc. predefined colours, or the special value CACA_DEFAULT meaning the media's default foreground value, or the special value CACA_TRANSPARENT.

If the attribute has ARGB colours, the nearest colour is returned.

This function never fails. If the attribute value is outside the expected 32-bit range, higher order bits are simply ignored.

Parameters:

attr The requested attribute value.

Returns:

The corresponding ANSI foreground value.

Referenced by caca_conio_textbackground().

__extern uint8_t caca_attr_to_ansi_bg (uint32_tattr)

Get the ANSI background colour value for a given attribute. The returned value is either one of the CACA_RED, CACA_BLACK etc. predefined colours, or the special value CACA_DEFAULT meaning the media's default background value, or the special value CACA_TRANSPARENT.

If the attribute has ARGB colours, the nearest colour is returned.

This function never fails. If the attribute value is outside the expected 32-bit range, higher order bits are simply ignored.

Parameters:

attr The requested attribute value.

Returns:

The corresponding ANSI background value.

Referenced by caca_conio_textcolor().

__extern uint16_t caca_attr_to_rgb12_fg (uint32_tattr)

Get the 12-bit foreground colour value for a given attribute. The returned value is a native-endian encoded integer with each red, green and blue values encoded on 8 bits in the following order:

• 8-11 most significant bits: red

• 4-7 most significant bits: green

• least significant bits: blue

This function never fails. If the attribute value is outside the expected 32-bit range, higher order bits are simply ignored.

Parameters:

attr The requested attribute value.

Returns:

The corresponding 12-bit RGB foreground value.

References CACA_DEFAULT, CACA_LIGHTGRAY, and CACA_TRANSPARENT.

__extern uint16_t caca_attr_to_rgb12_bg (uint32_tattr)

Get the 12-bit background colour value for a given attribute. The returned value is a native-endian encoded integer with each red, green and blue values encoded on 8 bits in the following order:

• 8-11 most significant bits: red

• 4-7 most significant bits: green

• least significant bits: blue

This function never fails. If the attribute value is outside the expected 32-bit range, higher order bits are simply ignored.

Parameters:

attr The requested attribute value.

Returns:

The corresponding 12-bit RGB background value.

References CACA_BLACK, CACA_DEFAULT, and CACA_TRANSPARENT.

__extern void caca_attr_to_argb64 (uint32_tattr, uint8_targb[8])

Get the 64-bit colour and alpha values for a given attribute. The values are written as 8-bit integers in the argb array in the following order:

• argb[0]: background alpha value

• argb[1]: background red value

• argb[2]: background green value

• argb[3]: background blue value

• argb[4]: foreground alpha value

• argb[5]: foreground red value

• argb[6]: foreground green value

• argb[7]: foreground blue value

This function never fails. If the attribute value is outside the expected 32-bit range, higher order bits are simply ignored.

Parameters:

attr The requested attribute value.

argb An array of 8-bit integers.

References CACA_BLACK, CACA_DEFAULT, CACA_LIGHTGRAY, and CACA_TRANSPARENT.

Referenced by caca_render_canvas().

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