initial commit

libraries/FastLED/src/fl/rgbw.cpp

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+/// @file rgbw.cpp
+/// Functions for red, green, blue, white (RGBW) output
+
+#include "fl/stdint.h"
+
+#define FASTLED_INTERNAL
+#include "FastLED.h"
+
+#include "rgbw.h"
+
+
+namespace fl {
+
+
+namespace {
+inline uint8_t min3(uint8_t a, uint8_t b, uint8_t c) {
+    if (a < b) {
+        if (a < c) {
+            return a;
+        } else {
+            return c;
+        }
+    } else {
+        if (b < c) {
+            return b;
+        } else {
+            return c;
+        }
+    }
+}
+
+inline uint8_t divide_by_3(uint8_t x) {
+    uint16_t y = (uint16_t(x) * 85) >> 8;
+    return static_cast<uint8_t>(y);
+}
+} // namespace
+
+// @brief Converts RGB to RGBW using a color transfer method
+// from color channels to 3x white.
+// @author Jonathanese
+void rgb_2_rgbw_exact(uint16_t w_color_temperature, uint8_t r, uint8_t g,
+                      uint8_t b, uint8_t r_scale, uint8_t g_scale,
+                      uint8_t b_scale, uint8_t *out_r, uint8_t *out_g,
+                      uint8_t *out_b, uint8_t *out_w) {
+    (void)w_color_temperature;
+    r = scale8(r, r_scale);
+    g = scale8(g, g_scale);
+    b = scale8(b, b_scale);
+    uint8_t min_component = min3(r, g, b);
+    *out_r = r - min_component;
+    *out_g = g - min_component;
+    *out_b = b - min_component;
+    *out_w = min_component;
+}
+
+void rgb_2_rgbw_max_brightness(uint16_t w_color_temperature, uint8_t r,
+                               uint8_t g, uint8_t b, uint8_t r_scale,
+                               uint8_t g_scale, uint8_t b_scale, uint8_t *out_r,
+                               uint8_t *out_g, uint8_t *out_b, uint8_t *out_w) {
+    (void)w_color_temperature;
+    *out_r = scale8(r, r_scale);
+    *out_g = scale8(g, g_scale);
+    *out_b = scale8(b, b_scale);
+    *out_w = min3(r, g, b);
+}
+
+void rgb_2_rgbw_null_white_pixel(uint16_t w_color_temperature, uint8_t r,
+                                 uint8_t g, uint8_t b, uint8_t r_scale,
+                                 uint8_t g_scale, uint8_t b_scale,
+                                 uint8_t *out_r, uint8_t *out_g, uint8_t *out_b,
+                                 uint8_t *out_w) {
+    (void)w_color_temperature;
+    *out_r = scale8(r, r_scale);
+    *out_g = scale8(g, g_scale);
+    *out_b = scale8(b, b_scale);
+    *out_w = 0;
+}
+
+void rgb_2_rgbw_white_boosted(uint16_t w_color_temperature, uint8_t r,
+                              uint8_t g, uint8_t b, uint8_t r_scale,
+                              uint8_t g_scale, uint8_t b_scale, uint8_t *out_r,
+                              uint8_t *out_g, uint8_t *out_b, uint8_t *out_w) {
+    (void)w_color_temperature;
+    r = scale8(r, r_scale);
+    g = scale8(g, g_scale);
+    b = scale8(b, b_scale);
+    uint8_t min_component = min3(r, g, b);
+    uint8_t w;
+    bool is_min = true;
+    if (min_component <= 84) {
+        w = 3 * min_component;
+    } else {
+        w = 255;
+        is_min = false;
+    }
+    uint8_t r_prime;
+    uint8_t g_prime;
+    uint8_t b_prime;
+    if (is_min) {
+        r_prime = r - min_component;
+        g_prime = g - min_component;
+        b_prime = b - min_component;
+    } else {
+        uint8_t w3 = divide_by_3(w);
+        r_prime = r - w3;
+        g_prime = g - w3;
+        b_prime = b - w3;
+    }
+
+    *out_r = r_prime;
+    *out_g = g_prime;
+    *out_b = b_prime;
+    *out_w = w;
+}
+
+rgb_2_rgbw_function g_user_function = rgb_2_rgbw_exact;
+
+void set_rgb_2_rgbw_function(rgb_2_rgbw_function func) {
+    if (func == nullptr) {
+        g_user_function = rgb_2_rgbw_exact;
+        return;
+    }
+    g_user_function = func;
+}
+
+void rgb_2_rgbw_user_function(uint16_t w_color_temperature, uint8_t r,
+                              uint8_t g, uint8_t b, uint8_t r_scale,
+                              uint8_t g_scale, uint8_t b_scale, uint8_t *out_r,
+                              uint8_t *out_g, uint8_t *out_b, uint8_t *out_w) {
+    g_user_function(w_color_temperature, r, g, b, r_scale, g_scale, b_scale,
+                    out_r, out_g, out_b, out_w);
+}
+
+void rgbw_partial_reorder(EOrderW w_placement, uint8_t b0, uint8_t b1,
+                          uint8_t b2, uint8_t w, uint8_t *out_b0,
+                          uint8_t *out_b1, uint8_t *out_b2, uint8_t *out_b3) {
+
+    uint8_t out[4] = {b0, b1, b2, 0};
+    switch (w_placement) {
+    // unrolled loop for speed.
+    case W3:
+        out[3] = w;
+        break;
+    case W2:
+        out[3] = out[2];  // memmove and copy.
+        out[2] = w;
+        break;
+    case W1:
+        out[3] = out[2];
+        out[2] = out[1];
+        out[1] = w;
+        break;
+    case W0:
+        out[3] = out[2];
+        out[2] = out[1];
+        out[1] = out[0];
+        out[0] = w;
+        break;
+    }
+    *out_b0 = out[0];
+    *out_b1 = out[1];
+    *out_b2 = out[2];
+    *out_b3 = out[3];
+}
+
+} // namespace fl