Add 'compose' animation

app/CMakeLists.txt

@@ -81,6 +81,7 @@ target_sources_ifdef(CONFIG_ZMK_BLE app PRIVATE src/events/battery_state_changed
 target_sources_ifdef(CONFIG_ZMK_BLE app PRIVATE src/battery.c)
 
 target_sources_ifdef(CONFIG_ZMK_ANIMATION app PRIVATE src/animation/color.c)
+target_sources_ifdef(CONFIG_ZMK_ANIMATION app PRIVATE src/animation/animation_compose.c)
 target_sources_ifdef(CONFIG_ZMK_ANIMATION app PRIVATE src/animation/animation_ripple.c)
 target_sources_ifdef(CONFIG_ZMK_ANIMATION app PRIVATE src/animation/animation_solid.c)
 target_sources_ifdef(CONFIG_ZMK_ANIMATION app PRIVATE src/animation/animation.c)

app/dts/bindings/animations/zmk,animation-compose.yaml

@@ -0,0 +1,27 @@
+# Copyright (c) 2020, The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: |
+  Higher-order animation which allows for composing other animation
+  drivers and using different blending modes.
+
+compatible: "zmk,animation-compose"
+
+include: animation_base.yaml
+
+properties:
+  label:
+    type: string
+    required: true
+
+  animations:
+    type: phandles
+    required: true
+    description: |
+      Animations to be combined.
+
+  blending-modes:
+    type: array
+    required: true
+    description: |
+      Blending modes for each animation.

app/include/dt-bindings/zmk/animation_compose.h

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2020 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define BLENDING_MODE_NORMAL 0
+#define BLENDING_MODE_MULTIPLY 1
+#define BLENDING_MODE_LIGHTEN 2
+#define BLENDING_MODE_DARKEN 3
+#define BLENDING_MODE_SCREEN 4
+#define BLENDING_MODE_SUBTRACT 5

app/src/animation/animation_compose.c

@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2020 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define DT_DRV_COMPAT zmk_animation_compose
+
+#include <zephyr.h>
+#include <device.h>
+#include <drivers/animation.h>
+#include <logging/log.h>
+
+#include <zmk/animation.h>
+#include <dt-bindings/zmk/animation_compose.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+// Zephyr 2.7.0 comes with DT_INST_FOREACH_PROP_ELEM
+// that we can't use quite yet as we're still on 2.5.*
+#define ZMK_DT_INST_FOREACH_PROP_ELEM(inst, prop, fn)                                              \
+    UTIL_LISTIFY(DT_INST_PROP_LEN(inst, prop), fn, DT_DRV_INST(inst), prop)
+
+#define PHANDLE_TO_DEVICE(idx, node_id, prop) DEVICE_DT_GET(DT_PHANDLE_BY_IDX(node_id, prop, idx)),
+
+struct animation_compose_config {
+    const struct device **animations;
+    const size_t animations_size;
+    const uint8_t *blending_modes;
+};
+
+static void animation_compose_render_pixel(const struct device *dev,
+                                           const struct animation_pixel *pixel,
+                                           struct zmk_color_rgb *value) {
+    const struct animation_compose_config *config = dev->config;
+
+    const struct device **animations = config->animations;
+    const uint8_t *blending_modes = config->blending_modes;
+
+    struct zmk_color_rgb rgb = {
+        .r = 0,
+        .g = 0,
+        .b = 0,
+    };
+
+    for (size_t i = 0; i < config->animations_size; ++i) {
+        animation_render_pixel(animations[i], pixel,
+                               blending_modes[i] == BLENDING_MODE_NORMAL ? value : &rgb);
+
+        switch (blending_modes[i]) {
+        case BLENDING_MODE_MULTIPLY:
+            value->r = value->r * rgb.r;
+            value->g = value->g * rgb.g;
+            value->b = value->b * rgb.b;
+            break;
+        case BLENDING_MODE_LIGHTEN:
+            value->r = value->r > rgb.r ? value->r : rgb.r;
+            value->g = value->g > rgb.g ? value->g : rgb.g;
+            value->b = value->b > rgb.b ? value->b : rgb.b;
+            break;
+        case BLENDING_MODE_DARKEN:
+            value->r = value->r > rgb.r ? rgb.r : value->r;
+            value->g = value->g > rgb.g ? rgb.g : value->g;
+            value->b = value->b > rgb.b ? rgb.b : value->b;
+            break;
+        case BLENDING_MODE_SCREEN:
+            value->r = value->r + (1.0f - value->r) * rgb.r;
+            value->g = value->g + (1.0f - value->g) * rgb.g;
+            value->b = value->b + (1.0f - value->b) * rgb.b;
+            break;
+        case BLENDING_MODE_SUBTRACT:
+            value->r = value->r - value->r * rgb.r;
+            value->g = value->g - value->g * rgb.g;
+            value->b = value->b - value->b * rgb.b;
+            break;
+        }
+    }
+}
+
+static int animation_compose_init(const struct device *dev) { return 0; }
+
+static const struct animation_api animation_compose_api = {
+    .on_before_frame = NULL,
+    .on_after_frame = NULL,
+    .render_pixel = animation_compose_render_pixel,
+};
+
+#define ANIMATION_COMPOSE_DEVICE(idx)                                                              \
+                                                                                                   \
+    static const uint8_t animation_compose_##idx##_blending_modes[] =                              \
+        DT_INST_PROP(idx, blending_modes);                                                         \
+                                                                                                   \
+    static const struct device *animation_compose_##idx##_animations[] = {                         \
+        ZMK_DT_INST_FOREACH_PROP_ELEM(idx, animations, PHANDLE_TO_DEVICE)};                        \
+                                                                                                   \
+    static struct animation_compose_config animation_compose_##idx##_config = {                    \
+        .animations = animation_compose_##idx##_animations,                                        \
+        .animations_size = DT_INST_PROP_LEN(idx, animations),                                      \
+        .blending_modes = animation_compose_##idx##_blending_modes,                                \
+    };                                                                                             \
+                                                                                                   \
+    DEVICE_DT_INST_DEFINE(idx, &animation_compose_init, NULL, NULL,                                \
+                          &animation_compose_##idx##_config, POST_KERNEL,                          \
+                          CONFIG_APPLICATION_INIT_PRIORITY, &animation_compose_api);
+
+DT_INST_FOREACH_STATUS_OKAY(ANIMATION_COMPOSE_DEVICE);