Color (lv_color)

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 type lv_color_t is used to store a color in RGB888 format. This type and format is used in almost all APIs regardless to LV_COLOR_DEPTH.

Creating colors

RGB

Create colors from Red, Green and Blue channel values:

/* All channels are 0-255 */
lv_color_t c = lv_color_make(red, green, blue);


/* Same but can be used for const initialization as well */
lv_color_t c = LV_COLOR_MAKE(red, green, blue);

/* From hex code 0x000000..0xFFFFFF interpreted as RED + GREEN + BLUE */
lv_color_t c = lv_color_hex(0x123456);

/* From 3 digits. Same as lv_color_hex(0x112233) */
lv_color_t c = lv_color_hex3(0x123);

HSV

Create colors from Hue, Saturation and Value values:

//h = 0..359, s = 0..100, v = 0..100
lv_color_t c = lv_color_hsv_to_rgb(h, s, v);

//All channels are 0-255
lv_color_hsv_t c_hsv = lv_color_rgb_to_hsv(r, g, b);


//From lv_color_t variable
lv_color_hsv_t c_hsv = lv_color_to_hsv(color);

Palette

LVGL includes Material Design's palette of colors. In this system all named colors have a nominal main color as well as four darker and five lighter variants.

The names of the colors are as follows:

LV_PALETTE_RED
LV_PALETTE_PINK
LV_PALETTE_PURPLE
LV_PALETTE_DEEP_PURPLE
LV_PALETTE_INDIGO
LV_PALETTE_BLUE
LV_PALETTE_LIGHT_BLUE
LV_PALETTE_CYAN
LV_PALETTE_TEAL
LV_PALETTE_GREEN
LV_PALETTE_LIGHT_GREEN
LV_PALETTE_LIME
LV_PALETTE_YELLOW
LV_PALETTE_AMBER
LV_PALETTE_ORANGE
LV_PALETTE_DEEP_ORANGE
LV_PALETTE_BROWN
LV_PALETTE_BLUE_GREY
LV_PALETTE_GREY

To get the main color use lv_color_t c = lv_palette_main(LV_PALETTE_...).

For the lighter variants of a palette color use lv_color_t c = lv_palette_lighten(LV_PALETTE_..., v). v can be 1..5. For the darker variants of a palette color use lv_color_t c = lv_palette_darken(LV_PALETTE_..., v). v can be 1..4.

Modify and mix colors

The following functions can modify a color:

// Lighten a color. 0: no change, 255: white
lv_color_t c = lv_color_lighten(c, lvl);

// Darken a color. 0: no change, 255: black
lv_color_t c = lv_color_darken(lv_color_t c, lv_opa_t lvl);

// Lighten or darken a color. 0: black, 128: no change 255: white
lv_color_t c = lv_color_change_lightness(lv_color_t c, lv_opa_t lvl);


// Mix two colors with a given ratio 0: full c2, 255: full c1, 128: half c1 and half c2
lv_color_t c = lv_color_mix(c1, c2, ratio);

Built-in colors

lv_color_white() and lv_color_black() return 0xFFFFFF and 0x000000 respectively.

Opacity

To describe opacity the lv_opa_t type is created from uint8_t. Some special purpose defines are also introduced:

LV_OPA_TRANSP Value: 0, means no opacity making the color completely transparent
LV_OPA_10 Value: 25, means the color covers only a little
LV_OPA_20 ... OPA_80 follow logically
LV_OPA_90 Value: 229, means the color near completely covers
LV_OPA_COVER Value: 255, means the color completely covers (full opacity)

You can also use the LV_OPA_* defines in lv_color_mix() as a mixing ratio.

API