feat(layers): character layer

package.json

@@ -25,6 +25,18 @@
     ],
     "resources": {
       "media": [{
+        "type": "bitmap",
+        "name": "CHARACTER_EVEN",
+        "file": "character_even.png",
+        "memoryFormat": "Smallest",
+        "spaceOptimization": "memory"
+      }, {
+        "type": "bitmap",
+        "name": "CHARACTER_ODD",
+        "file": "character_odd.png",
+        "memoryFormat": "Smallest",
+        "spaceOptimization": "memory"
+      }, {
         "type": "font",
         "name": "CLOCK_FONT_38",
         "file": "clock_font_big.ttf",

src/c/character_layer.c

@@ -0,0 +1,67 @@
+#include "character_layer.h"
+
+#define CHARACTER_H 80
+#define CHARACTER_STEP 4
+
+static Layer *s_character_layer;
+static GBitmap *s_character_even;
+static GBitmap *s_character_odd;
+static int s_character_ticks;
+
+static void character_layer_update_proc(Layer *layer, GContext *ctx) {
+  // Get the character bitmap.
+  GBitmap *bitmap;
+  if (s_character_ticks % 2 == 0) {
+    bitmap = s_character_even;
+  } else {
+    bitmap = s_character_odd;
+  }
+
+  // Get the position of character bitmap and align it to bottom.
+  GRect frame = gbitmap_get_bounds(bitmap);
+  GRect frame_inside = layer_get_unobstructed_bounds(layer);
+  grect_align(&frame, &frame_inside, GAlignBottom, true);
+
+  // Move the character.
+  switch (s_character_ticks) {
+    case 1:
+      frame.origin.x += CHARACTER_STEP;  // to right
+      break;
+    case 3:
+      frame.origin.x -= CHARACTER_STEP;  // to left
+      break;
+  }
+
+  // Draw the character.
+  graphics_context_set_compositing_mode(ctx, GCompOpSet);
+  graphics_draw_bitmap_in_rect(ctx, bitmap, frame);
+}
+
+void character_layer_init(Window *window) {
+  s_character_ticks = 0;
+
+  s_character_even = gbitmap_create_with_resource(RESOURCE_ID_CHARACTER_EVEN);
+  s_character_odd = gbitmap_create_with_resource(RESOURCE_ID_CHARACTER_ODD);
+
+  Layer *window_root_layer = window_get_root_layer(window);
+  GRect window_bounds = layer_get_unobstructed_bounds(window_root_layer);
+
+  s_character_layer =
+      layer_create(GRect(0, window_bounds.size.h - CHARACTER_H, window_bounds.size.w, CHARACTER_H));
+  layer_set_update_proc(s_character_layer, character_layer_update_proc);
+
+  layer_add_child(window_root_layer, s_character_layer);
+}
+
+void character_layer_tick(void) {
+  if (++s_character_ticks == 4) {
+    s_character_ticks = 0;
+  }
+  layer_mark_dirty(s_character_layer);
+}
+
+void character_layer_deinit(void) {
+  layer_destroy(s_character_layer);
+  gbitmap_destroy(s_character_even);
+  gbitmap_destroy(s_character_odd);
+}

src/c/character_layer.h

@@ -0,0 +1,10 @@
+#ifndef CHARACTER_LAYER_H_
+#define CHARACTER_LAYER_H_
+
+#include <pebble.h>
+
+void character_layer_init(Window *window);
+void character_layer_tick(void);
+void character_layer_deinit(void);
+
+#endif

src/c/clock_layer.c

@@ -69,11 +69,10 @@ void clock_layer_init(Window *window, GPoint position) {
   s_clock_layer =
       layer_create(GRect(position.x, position.y, window_bounds.size.w - position.x, 40));
   layer_set_update_proc(s_clock_layer, clock_layer_update_proc);
-
   layer_add_child(window_root_layer, s_clock_layer);
 }
 
-void clock_layer_update(void) {
+void clock_layer_tick(void) {
   layer_mark_dirty(s_clock_layer);
 }
 

src/c/clock_layer.h

@@ -4,7 +4,7 @@
 #include <pebble.h>
 
 void clock_layer_init(Window *window, GPoint position);
-void clock_layer_update(void);
+void clock_layer_tick(void);
 void clock_layer_deinit(void);
 
 #endif

src/c/main_window.c

@@ -1,20 +1,24 @@
 #include "main_window.h"
+#include "character_layer.h"
 #include "clock_layer.h"
 
 static Window *s_main_window;
 
 static void main_window_tick(struct tm *time, TimeUnits units) {
-  clock_layer_update();
+  character_layer_tick();
+  clock_layer_tick();
 }
 
 static void main_window_load(Window *window) {
-  clock_layer_init(s_main_window, GPoint(0, 60));
+  character_layer_init(s_main_window);
+  clock_layer_init(s_main_window, GPoint(0, 40));
   tick_timer_service_subscribe(SECOND_UNIT, main_window_tick);
 }
 
 static void main_window_unload(Window *window) {
   tick_timer_service_unsubscribe();
   clock_layer_deinit();
+  character_layer_deinit();
 }
 
 void main_window_init(void) {