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TwatchChalice
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Calculate color suitability based on luminosity

This commit is contained in:
Neale Pickett 2016-06-03 08:58:36 -06:00
parent 05acb5a102
commit e8522d9b4b
1 changed files with 20 additions and 1 deletions
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21
src/main.c
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@ -25,6 +25,25 @@ GPoint center;
bool bt_connected;
static int32_t luminosity(GColor c) {
int r = (c.argb & 0b110000) >> 4;
int g = (c.argb & 0b001100) >> 2;
int b = (c.argb & 0b000011) >> 0;
return (2126 * r) + (7152 * g) + (722 * b);
}
static bool visible_against(GColor a, GColor b) {
int32_t la = luminosity(a);
int32_t lb = luminosity(b);
if ((la - lb > 15000) || (lb - la > 15000)) {
return true;
} else {
return false;
}
}
static GPoint point_of_polar(int32_t theta, int r) {
GPoint ret = {
.x = (int16_t)(sin_lookup(theta) * r / TRIG_MAX_RATIO) + center.x,
@ -116,7 +135,7 @@ static void set_configurables() {
do {
uint8_t argb = rand() % 0b00111111;
accent_color = (GColor8){ .argb = argb | 0b11000000 };
} while (gcolor_equal(accent_color, face_color));
} while (! visible_against(accent_color, face_color));
#else
accent_color = gcolor_legible_over(face_color);
#endif