table of contents
libcaca attribute conversions(3caca) | libcaca | libcaca attribute conversions(3caca) |
NAME¶
libcaca attribute conversions -Functions¶
__extern uint32_t caca_get_attr (caca_canvas_t const *, int, int)
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
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- 4 bits for the background green component
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- 3 bits for the background blue component
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- 3 bits for the foreground alpha
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- 4 bits for the foreground red component
- •
- 4 bits for the foreground green component
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- 3 bits for the foreground blue component
- •
- 4 bits for the bold, italics, underline and blink flags
cv A handle to the libcaca canvas.
x X coordinate.
y Y coordinate.
Returns:
The requested attribute.
__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.
cv A handle to the libcaca canvas.
attr The requested attribute value.
Returns:
This function always returns 0.
__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.
cv A handle to the libcaca canvas.
x X coordinate.
y Y coordinate.
attr The requested attribute value.
Returns:
This function always returns 0.
__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.
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.
__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.
__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.
__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.
__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:¶
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- 8-11 most significant bits: red
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- 4-7 most significant bits: green
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- least significant bits: blue
attr The requested attribute
value.
Returns:
The corresponding 12-bit RGB foreground
value.
__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
attr The requested attribute
value.
Returns:
The corresponding 12-bit RGB background
value.
__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:¶
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- argb[0]: background alpha value
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- argb[1]: background red value
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- argb[2]: background green value
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- argb[3]: background blue value
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- argb[4]: foreground alpha value
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- argb[5]: foreground red value
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- argb[6]: foreground green value
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- argb[7]: foreground blue value
attr The requested attribute value.
argb An array of 8-bit integers.
Author¶
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