feat(display): Add modifiers widget

app/include/zmk/display/widgets/mods_status.h

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2022 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <lvgl.h>
+#include <kernel.h>
+
+struct zmk_widget_mods_status {
+    sys_snode_t node;
+    lv_obj_t *obj;
+};
+
+int zmk_widget_mods_status_init(struct zmk_widget_mods_status *widget, lv_obj_t *parent);
+lv_obj_t *zmk_widget_mods_status_obj(struct zmk_widget_mods_status *widget);

app/src/display/status_screen.c

@@ -9,6 +9,7 @@
 #include <zmk/display/widgets/battery_status.h>
 #include <zmk/display/widgets/layer_status.h>
 #include <zmk/display/widgets/wpm_status.h>
+#include <zmk/display/widgets/mods_status.h>
 #include <zmk/display/status_screen.h>
 
 #include <zephyr/logging/log.h>
@@ -34,6 +35,10 @@ static struct zmk_widget_layer_status layer_status_widget;
 static struct zmk_widget_wpm_status wpm_status_widget;
 #endif
 
+#if IS_ENABLED(CONFIG_ZMK_WIDGET_MODS_STATUS)
+static struct zmk_widget_mods_status mods_status_widget;
+#endif
+
 lv_obj_t *zmk_display_status_screen() {
     lv_obj_t *screen;
     screen = lv_obj_create(NULL);
@@ -65,5 +70,14 @@ lv_obj_t *zmk_display_status_screen() {
     zmk_widget_wpm_status_init(&wpm_status_widget, screen);
     lv_obj_align(zmk_widget_wpm_status_obj(&wpm_status_widget), LV_ALIGN_BOTTOM_RIGHT, 0, 0);
 #endif
+
+#if IS_ENABLED(CONFIG_ZMK_WIDGET_MODS_STATUS)
+    zmk_widget_mods_status_init(&mods_status_widget, screen);
+    lv_obj_set_style_local_text_font(zmk_widget_mods_status_obj(&mods_status_widget),
+                                     LV_LABEL_PART_MAIN, LV_STATE_DEFAULT,
+                                     lv_theme_get_font_small());
+    lv_obj_align(zmk_widget_mods_status_obj(&mods_status_widget), NULL, LV_ALIGN_IN_BOTTOM_RIGHT, 0,
+                 0);
+#endif
     return screen;
 }

app/src/display/widgets/CMakeLists.txt

@@ -6,3 +6,4 @@ target_sources_ifdef(CONFIG_ZMK_WIDGET_OUTPUT_STATUS app PRIVATE output_status.c
 target_sources_ifdef(CONFIG_ZMK_WIDGET_PERIPHERAL_STATUS app PRIVATE peripheral_status.c)
 target_sources_ifdef(CONFIG_ZMK_WIDGET_LAYER_STATUS app PRIVATE layer_status.c)
 target_sources_ifdef(CONFIG_ZMK_WIDGET_WPM_STATUS app PRIVATE wpm_status.c)
+target_sources_ifdef(CONFIG_ZMK_WIDGET_MODS_STATUS app PRIVATE mods_status.c)

app/src/display/widgets/Kconfig

@@ -36,4 +36,9 @@ config ZMK_WIDGET_WPM_STATUS
     select LV_USE_LABEL
     select ZMK_WPM
 
+config ZMK_WIDGET_MODS_STATUS
+    bool "Widget for displaying active modifiers"
+    depends on !ZMK_SPLIT || ZMK_SPLIT_ROLE_CENTRAL
+    select LV_USE_LABEL
+
 endmenu

app/src/display/widgets/mods_status.c

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2022 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <logging/log.h>
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+#include <zmk/display.h>
+#include <zmk/display/widgets/mods_status.h>
+#include <zmk/events/keycode_state_changed.h>
+#include <zmk/event_manager.h>
+#include <zmk/endpoints.h>
+#include <zmk/hid.h>
+
+static sys_slist_t widgets = SYS_SLIST_STATIC_INIT(&widgets);
+
+struct mods_status_state {
+    uint8_t mods;
+};
+
+struct mods_status_state mods_status_get_state(const zmk_event_t *eh) {
+    return (struct mods_status_state){.mods = zmk_hid_get_explicit_mods()};
+};
+
+void set_mods_symbol(lv_obj_t *label, struct mods_status_state state) {
+    char text[5] = {};
+
+    LOG_DBG("mods changed to %i", state.mods);
+    if (state.mods & (MOD_LCTL | MOD_RCTL))
+        strcat(text, "C");
+    if (state.mods & (MOD_LSFT | MOD_RSFT))
+        strcat(text, "S");
+    if (state.mods & (MOD_LALT | MOD_RALT))
+        strcat(text, "A");
+    if (state.mods & (MOD_LGUI | MOD_RGUI))
+        strcat(text, "G");
+
+    lv_label_set_text(label, text);
+    lv_obj_align(label, NULL, LV_ALIGN_IN_BOTTOM_RIGHT, -1, 0);
+}
+
+void mods_status_update_cb(struct mods_status_state state) {
+    struct zmk_widget_mods_status *widget;
+    SYS_SLIST_FOR_EACH_CONTAINER(&widgets, widget, node) { set_mods_symbol(widget->obj, state); }
+}
+
+ZMK_DISPLAY_WIDGET_LISTENER(widget_mods_status, struct mods_status_state, mods_status_update_cb,
+                            mods_status_get_state)
+ZMK_SUBSCRIPTION(widget_mods_status, zmk_keycode_state_changed);
+
+int zmk_widget_mods_status_init(struct zmk_widget_mods_status *widget, lv_obj_t *parent) {
+    widget->obj = lv_label_create(parent, NULL);
+    lv_label_set_align(widget->obj, LV_LABEL_ALIGN_RIGHT);
+
+    lv_obj_set_size(widget->obj, 40, 15);
+
+    sys_slist_append(&widgets, &widget->node);
+
+    widget_mods_status_init();
+    return 0;
+}
+
+lv_obj_t *zmk_widget_mods_status_obj(struct zmk_widget_mods_status *widget) { return widget->obj; }