RGB matrix effect - left-right gradient (#7742)

* Left-right gradient.

* Update the comment to match the new functionality.

* CPP does integer division so this round is not necessary.

* The x-range is actually 224, update comment and use bit-shifting again.

* Update docs with gradient left-right effect and associated "DISABLE" option.

4 files changed, 25 insertions, 0 deletions

diff --git a/docs/feature_rgb_matrix.md b/docs/feature_rgb_matrix.md
index 5695acc508..92fd62b32a 100644
--- a/docs/feature_rgb_matrix.md
+++ b/docs/feature_rgb_matrix.md
@@ -199,6 +199,7 @@ enum rgb_matrix_effects {
     RGB_MATRIX_SOLID_COLOR = 1,     // Static single hue, no speed support
     RGB_MATRIX_ALPHAS_MODS,         // Static dual hue, speed is hue for secondary hue
     RGB_MATRIX_GRADIENT_UP_DOWN,    // Static gradient top to bottom, speed controls how much gradient changes
+    RGB_MATRIX_GRADIENT_LEFT_RIGHT,    // Static gradient left to right, speed controls how much gradient changes
     RGB_MATRIX_BREATHING,           // Single hue brightness cycling animation
     RGB_MATRIX_BAND_SAT,        // Single hue band fading saturation scrolling left to right
     RGB_MATRIX_BAND_VAL,        // Single hue band fading brightness scrolling left to right
diff --git a/keyboards/crkbd/keymaps/dsanchezseco/config.h b/keyboards/crkbd/keymaps/dsanchezseco/config.h
index 14efb7d4ec..033173defb 100644
--- a/keyboards/crkbd/keymaps/dsanchezseco/config.h
+++ b/keyboards/crkbd/keymaps/dsanchezseco/config.h
@@ -36,6 +36,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //disable effects
 #define DISABLE_RGB_MATRIX_ALPHAS_MODS         // Static dual hue speed is hue for secondary hue
 #define DISABLE_RGB_MATRIX_GRADIENT_UP_DOWN    // Static gradient top to bottom speed controls how much gradient changes
+#define DISABLE_RGB_MATRIX_CYCLE_LEFT_RIGHT    // Static gradient left to right speed controls how much gradient changes
 #define DISABLE_RGB_MATRIX_BAND_SAT        // Single hue band fading saturation scrolling left to right
 #define DISABLE_RGB_MATRIX_BAND_VAL        // Single hue band fading brightness scrolling left to right
 #define DISABLE_RGB_MATRIX_BAND_PINWHEEL_SAT   // Single hue 3 blade spinning pinwheel fades saturation
diff --git a/quantum/rgb_matrix_animations/gradient_left_right_anim.h b/quantum/rgb_matrix_animations/gradient_left_right_anim.h
new file mode 100644
index 0000000000..2eab2eb759
--- /dev/null
+++ b/quantum/rgb_matrix_animations/gradient_left_right_anim.h
@@ -0,0 +1,22 @@
+#ifndef DISABLE_RGB_MATRIX_GRADIENT_LEFT_RIGHT
+RGB_MATRIX_EFFECT(GRADIENT_LEFT_RIGHT)
+#    ifdef RGB_MATRIX_CUSTOM_EFFECT_IMPLS
+
+bool GRADIENT_LEFT_RIGHT(effect_params_t* params) {
+    RGB_MATRIX_USE_LIMITS(led_min, led_max);
+
+    HSV     hsv   = rgb_matrix_config.hsv;
+    uint8_t scale = scale8(64, rgb_matrix_config.speed);
+    for (uint8_t i = led_min; i < led_max; i++) {
+        RGB_MATRIX_TEST_LED_FLAGS();
+        // The x range will be 0..224, map this to 0..7
+        // Relies on hue being 8-bit and wrapping
+        hsv.h   = rgb_matrix_config.hsv.h + (scale * g_led_config.point[i].x >> 5);
+        RGB rgb = hsv_to_rgb(hsv);
+        rgb_matrix_set_color(i, rgb.r, rgb.g, rgb.b);
+    }
+    return led_max < DRIVER_LED_TOTAL;
+}
+
+#    endif  // RGB_MATRIX_CUSTOM_EFFECT_IMPLS
+#endif      // DISABLE_RGB_MATRIX_GRADIENT_LEFT_RIGHT
diff --git a/quantum/rgb_matrix_animations/rgb_matrix_effects.inc b/quantum/rgb_matrix_animations/rgb_matrix_effects.inc
index 01332ed0dd..4c1723d933 100644
--- a/quantum/rgb_matrix_animations/rgb_matrix_effects.inc
+++ b/quantum/rgb_matrix_animations/rgb_matrix_effects.inc
@@ -2,6 +2,7 @@
 #include "rgb_matrix_animations/solid_color_anim.h"
 #include "rgb_matrix_animations/alpha_mods_anim.h"
 #include "rgb_matrix_animations/gradient_up_down_anim.h"
+#include "rgb_matrix_animations/gradient_left_right_anim.h"
 #include "rgb_matrix_animations/breathing_anim.h"
 #include "rgb_matrix_animations/colorband_sat_anim.h"
 #include "rgb_matrix_animations/colorband_val_anim.h"