Colors - rockcastle/lvgl GitHub Wiki

Written for v5.1

The color module handles all color related functions like changing color depth, creating colors from hex code, converting between color depths, mixing colors etc.

The following variable types are defined by the color module:

lv_color1_t Store monochrome color. For compatibility it also has R,G,B fields but they are always the same (1 byte)
lv_color8_t A structure to store R (3 bit),G (3 bit),B (2 bit) components for 8 bit colors (1 byte)
lv_color16_t A structure to store R (5 bit),G (6 bit),B (5 bit) components for 16 bit colors (2 byte)
lv_color24_t A structure to store R (8 bit),G (8 bit), B (8 bit) components for 24 bit colors (4 byte)
lv_color_t Equal to color1/8/16/24_t according to color depth settings
lv_color_int_t uint8_t, uint16_t or uint32_t according to color depth setting. Used to build color arrays from plain numbers.
lv_opa_t A simple uint8_t type to describe opacity.

The lv_color_t, lv_color1_t__lv_color8_t, lv_color16_t and lv_color24_t types have got four fields:

red red channel
green green channel
blue blue channel
full red + green + blue as one number

You can set the current color depth in lv_conf.h by setting the LV_COLOR_DEPTH define to 1 (monochrome), 8, 16 or 24.

You can convert a color from the current color depth to an other. The converter functions return with a number so you have to use the full field:

lv_color_t c;
c.red   = 0x38;
c.green = 0x70;
c.blue  = 0xCC;

lv_color1_t c1;
c1.full = lv_color_to1(c);		/*Return 1 for light colors, 0 for dark colors*/

lv_color8_t c8;
c8.full = lv_color_to8(c);		/*Give a 8 bit number with the converted color*/ 

lv_color16_t c16;
c16.full = lv_color_to16(c); 	/*Give a 16 bit number with the converted color*/

lv_color24_t c24;
c24.full = lv_color_to24(c);	/*Give a 32 bit number with the converted color*/

You can create a color with the current color depth using the LV_COLOR_MAKE macro. It takes 3 arguments (red, green, blue) as 8 bit numbers. For example to create light red color: my_color = COLOR_MAKE(0xFF,0x80,0x80). Colors can be created from HEX codes too: my_color = LV_COLOR_HEX(0xFF8080) or my_color = LV_COLOR_HEX3(0xF88).

Mixing two colors is possible with mixed_color = lv_color_mix(color1, color2, ratio). Ration can be 0..255. 0 results fully color2, 255 result fully color1.

To describe opacity the lv_opa_t type is created as wrapper to uint8_t. Some defines are also introduced: