Implement chop_background_layer

[nothing.git] / src / color.c

diff --git a/src/color.c b/src/color.c
index fa43483c954f5e8e73705b2bf318257d48800d81..eb03f55f928a573b9a11d547e136b1efd5d0fbe4 100644 (file)
--- a/src/color.c
+++ b/src/color.c
@@ -1,5 +1,6 @@
 #include <SDL.h>
 #include <string.h>
+#include <math.h>
 
 #include "color.h"
 
@@ -15,6 +16,38 @@ Color rgba(float r, float g, float b, float a)
     return result;
 }
 
+/* TODO(#928): Should the Hue in HSLA representation be in degrees? */
+Color hsla(float h, float s, float l, float a)
+{
+    h = fmodf(h, 360.0f);
+
+    const float c = (1.0f - fabsf(2.0f * l - 1.0f)) * s;
+    const float x = c * (1 - fabsf(fmodf(h / 60.0f, 2.0f) - 1.0f));
+    const float m = l - c / 2.0f;
+
+    Color color = {0.0f, 0.0f, 0.0f, a};
+
+    if (0.0f <= h && h < 60.0f) {
+        color = rgba(c, x, 0.0f, a);
+    } else if (60.0f <= h && h < 120.0f) {
+        color = rgba(x, c, 0.0f, a);
+    } else if (120.0f <= h && h < 180.0f) {
+        color = rgba(0.0f, c, x, a);
+    } else if (180.0f <= h && h < 240.0f) {
+        color = rgba(0.0f, x, c, a);
+    } else if (240.0f <= h && h < 300.0f) {
+        color = rgba(x, 0.0f, c, a);
+    } else if (300.0f <= h && h < 360.0f) {
+        color = rgba(c, 0.0f, x, a);
+    }
+
+    color.r += m;
+    color.g += m;
+    color.b += m;
+
+    return color;
+}
+
 static Uint8 hex2dec_digit(char c)
 {
     if (c >= '0' && c <= '9') {
@@ -50,6 +83,17 @@ Color hexstr(const char *hexstr)
         1.0f);
 }
 
+Color hexs(String input)
+{
+    if (input.count < 6) return COLOR_BLACK;
+
+    return rgba(
+        parse_color_component(input.data) / 255.0f,
+        parse_color_component(input.data + 2) / 255.0f,
+        parse_color_component(input.data + 4) / 255.0f,
+        1.0f);
+}
+
 SDL_Color color_for_sdl(Color color)
 {
     const SDL_Color result = {
@@ -89,3 +133,41 @@ Color color_scale(Color c, Color fc)
         fmaxf(fminf(c.b * fc.b, 1.0f), 0.0f),
         fmaxf(fminf(c.a * fc.a, 1.0f), 0.0f));
 }
+
+int color_hex_to_stream(Color color, FILE *stream)
+{
+    SDL_Color sdl = color_for_sdl(color);
+    return fprintf(stream, "%02x%02x%02x", sdl.r, sdl.g, sdl.b);
+}
+
+int color_hex_to_string(Color color, char *buffer, size_t buffer_size)
+{
+    SDL_Color sdl = color_for_sdl(color);
+    return snprintf(buffer, buffer_size, "%02x%02x%02x", sdl.r, sdl.g, sdl.b);
+}
+
+Color rgba_to_hsla(Color color)
+{
+    const float max = fmaxf(color.r, fmaxf(color.g, color.b));
+    const float min = fminf(color.r, fminf(color.g, color.b));
+    const float c = max - min;
+    float hue = 0.0f;
+    float saturation = 0.0f;
+    const float lightness = (max + min) * 0.5f;
+
+    if (fabsf(c) > 1e-6) {
+        if (fabs(max - color.r) <= 1e-6) {
+            hue = 60.0f * fmodf((color.g - color.b) / c, 6.0f);
+        } else if (fabs(max - color.g) <= 1e-6) {
+            hue = 60.0f * ((color.b - color.r) / c + 2.0f);
+        } else {
+            hue = 60.0f * ((color.r - color.g) / c + 4.0f);
+        }
+
+        saturation = c / (1.0f - fabsf(2.0f * lightness - 1.0f));
+    }
+
+    // TODO(#929): Color struct is used not only for RGBA
+    //   But also for HSLA. We should make another similar struct but for HSLA
+    return rgba(hue, saturation, lightness, color.a);
+}