Add uppermost, current layer status widget to oled (#493)

* Add uppermost, current layer status widget to oled

* Run clang format

* Fixup display widget source includes in CMakeLists

* Update layer widget to only be enabled on primary half of a split keyboard and shuffle some of the options specific to the widget to be enabled via the widget

* Update to latest lvgl/zmk/zephyr ; remove version text from oled per PR

* Fixup file names

* Remove last remenants of the version display text from the oled

* Fixup clang-format

Co-authored-by: KemoNine <mcrosson@kemonine.info>

5 files changed, 86 insertions, 6 deletions

diff --git a/app/src/display/CMakeLists.txt b/app/src/display/CMakeLists.txt
index 3b85fc0..d289f07 100644
--- a/app/src/display/CMakeLists.txt
+++ b/app/src/display/CMakeLists.txt
@@ -4,4 +4,4 @@
 target_sources_ifdef(CONFIG_ZMK_DISPLAY app PRIVATE main.c)
 target_sources_ifdef(CONFIG_ZMK_DISPLAY_STATUS_SCREEN_BUILT_IN app PRIVATE status_screen.c)
 
-add_subdirectory(widgets/)
\ No newline at end of file
+add_subdirectory_ifdef(CONFIG_ZMK_DISPLAY widgets/)
diff --git a/app/src/display/status_screen.c b/app/src/display/status_screen.c
index 9a5c7b4..0c88717 100644
--- a/app/src/display/status_screen.c
+++ b/app/src/display/status_screen.c
@@ -6,6 +6,7 @@
 
 #include <zmk/display/widgets/output_status.h>
 #include <zmk/display/widgets/battery_status.h>
+#include <zmk/display/widgets/layer_status.h>
 #include <zmk/display/status_screen.h>
 
 #include <logging/log.h>
@@ -19,14 +20,15 @@ static struct zmk_widget_battery_status battery_status_widget;
 static struct zmk_widget_output_status output_status_widget;
 #endif
 
+#if IS_ENABLED(CONFIG_ZMK_WIDGET_LAYER_STATUS)
+static struct zmk_widget_layer_status layer_status_widget;
+#endif
+
 lv_obj_t *zmk_display_status_screen() {
     lv_obj_t *screen;
-    lv_obj_t *zmk_version_label;
 
     screen = lv_obj_create(NULL, NULL);
 
-    zmk_version_label = lv_label_create(screen, NULL);
-
 #if IS_ENABLED(CONFIG_ZMK_WIDGET_BATTERY_STATUS)
     zmk_widget_battery_status_init(&battery_status_widget, screen);
     lv_obj_align(zmk_widget_battery_status_obj(&battery_status_widget), NULL, LV_ALIGN_IN_TOP_RIGHT,
@@ -39,8 +41,11 @@ lv_obj_t *zmk_display_status_screen() {
                  0);
 #endif
 
-    lv_label_set_text(zmk_version_label, "ZMK v0.1.0");
-    lv_obj_align(zmk_version_label, NULL, LV_ALIGN_IN_BOTTOM_MID, 0, 0);
+#if IS_ENABLED(CONFIG_ZMK_WIDGET_LAYER_STATUS)
+    zmk_widget_layer_status_init(&layer_status_widget, screen);
+    lv_obj_align(zmk_widget_layer_status_obj(&layer_status_widget), NULL, LV_ALIGN_IN_BOTTOM_LEFT,
+                 0, 0);
+#endif
 
     return screen;
 }
diff --git a/app/src/display/widgets/CMakeLists.txt b/app/src/display/widgets/CMakeLists.txt
index 1d4cca1..ad7e132 100644
--- a/app/src/display/widgets/CMakeLists.txt
+++ b/app/src/display/widgets/CMakeLists.txt
@@ -3,3 +3,4 @@
 
 target_sources_ifdef(CONFIG_ZMK_WIDGET_BATTERY_STATUS app PRIVATE battery_status.c)
 target_sources_ifdef(CONFIG_ZMK_WIDGET_OUTPUT_STATUS app PRIVATE output_status.c)
+target_sources_ifdef(CONFIG_ZMK_WIDGET_LAYER_STATUS app PRIVATE layer_status.c)
diff --git a/app/src/display/widgets/Kconfig b/app/src/display/widgets/Kconfig
index 01bc587..bdb3024 100644
--- a/app/src/display/widgets/Kconfig
+++ b/app/src/display/widgets/Kconfig
@@ -3,6 +3,12 @@
 
 menu "ZMK Display Widgets"
 
+config ZMK_WIDGET_LAYER_STATUS
+    bool "Widget for highest, active layer using small icons"
+    default y
+    depends on !ZMK_SPLIT || ZMK_SPLIT_BLE_ROLE_CENTRAL
+    select LVGL_FONT_MONTSERRAT_12
+
 config ZMK_WIDGET_BATTERY_STATUS
     bool "Widget for battery charge information, using small icons"
     depends on BT
diff --git a/app/src/display/widgets/layer_status.c b/app/src/display/widgets/layer_status.c
new file mode 100644
index 0000000..fb9f689
--- /dev/null
+++ b/app/src/display/widgets/layer_status.c
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2020 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <logging/log.h>
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+#include <zmk/display/widgets/layer_status.h>
+#include <zmk/events/layer_state_changed.h>
+#include <zmk/event_manager.h>
+#include <zmk/endpoints.h>
+#include <zmk/keymap.h>
+
+static sys_slist_t widgets = SYS_SLIST_STATIC_INIT(&widgets);
+static lv_style_t label_style;
+
+static bool style_initialized = false;
+
+void layer_status_init() {
+    if (style_initialized) {
+        return;
+    }
+
+    style_initialized = true;
+    lv_style_init(&label_style);
+    lv_style_set_text_color(&label_style, LV_STATE_DEFAULT, LV_COLOR_BLACK);
+    lv_style_set_text_font(&label_style, LV_STATE_DEFAULT, &lv_font_montserrat_12);
+    lv_style_set_text_letter_space(&label_style, LV_STATE_DEFAULT, 1);
+    lv_style_set_text_line_space(&label_style, LV_STATE_DEFAULT, 1);
+}
+
+void set_layer_symbol(lv_obj_t *label) {
+    int active_layer_index = zmk_keymap_highest_layer_active();
+    char text[6] = {};
+
+    LOG_DBG("Layer changed to %i", active_layer_index);
+    sprintf(text, LV_SYMBOL_KEYBOARD "%i ", active_layer_index);
+
+    lv_label_set_text(label, text);
+}
+
+int zmk_widget_layer_status_init(struct zmk_widget_layer_status *widget, lv_obj_t *parent) {
+    layer_status_init();
+    widget->obj = lv_label_create(parent, NULL);
+    lv_obj_add_style(widget->obj, LV_LABEL_PART_MAIN, &label_style);
+
+    lv_obj_set_size(widget->obj, 40, 15);
+    set_layer_symbol(widget->obj);
+
+    sys_slist_append(&widgets, &widget->node);
+
+    return 0;
+}
+
+lv_obj_t *zmk_widget_layer_status_obj(struct zmk_widget_layer_status *widget) {
+    return widget->obj;
+}
+
+int layer_status_listener(const struct zmk_event_header *eh) {
+    struct zmk_widget_layer_status *widget;
+    SYS_SLIST_FOR_EACH_CONTAINER(&widgets, widget, node) { set_layer_symbol(widget->obj); }
+    return 0;
+}
+
+ZMK_LISTENER(widget_layer_status, layer_status_listener)
+ZMK_SUBSCRIPTION(widget_layer_status, layer_state_changed);
\ No newline at end of file