NAME

       libcaca attribute conversions -

   Functions
       __extern uint32_t caca_get_attr (caca_canvas_t const *, int, int)
           Get the text attribute at the given coordinates.
       __extern int caca_set_attr (caca_canvas_t *, uint32_t)
           Set the default character attribute.
       __extern int caca_unset_attr (caca_canvas_t *, uint32_t)
           Unset flags in the default character attribute.
       __extern int caca_toggle_attr (caca_canvas_t *, uint32_t)
           Toggle flags in the default character attribute.
       __extern int caca_put_attr (caca_canvas_t *, int, int, uint32_t)
           Set the character attribute at the given coordinates.
       __extern int caca_set_color_ansi (caca_canvas_t *, uint8_t, uint8_t)
           Set the default colour pair for text (ANSI version).
       __extern int caca_set_color_argb (caca_canvas_t *, uint16_t, uint16_t)
           Set the default colour pair for text (truecolor version).
       __extern uint8_t caca_attr_to_ansi (uint32_t)
           Get DOS ANSI information from attribute.
       __extern uint8_t caca_attr_to_ansi_fg (uint32_t)
           Get ANSI foreground information from attribute.
       __extern uint8_t caca_attr_to_ansi_bg (uint32_t)
           Get ANSI background information from attribute.
       __extern uint16_t caca_attr_to_rgb12_fg (uint32_t)
           Get 12-bit RGB foreground information from attribute.
       __extern uint16_t caca_attr_to_rgb12_bg (uint32_t)
           Get 12-bit RGB background information from attribute.
       __extern void caca_attr_to_argb64 (uint32_t, uint8_t[8])
           Get 64-bit ARGB information from attribute.

Detailed Description

       These functions perform conversions between attribute values.

Function Documentation

   __extern uint32_t caca_get_attr (caca_canvas_t 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 (caca_canvas_t *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 (caca_canvas_t *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 (caca_canvas_t *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 (caca_canvas_t *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 (caca_canvas_t *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, 0 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 (caca_canvas_t *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().

Author

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