Fix ability to permanently move icons with rapid presses

src/c/neat_bar.c

@@ -36,50 +36,87 @@ static const GRect s_base_grect_rect = GRect(PBL_DISPLAY_WIDTH - ACTION_BAR_WIDT
 
 static NeatBarLayer *s_current_neat_bar = NULL;
 
-static Animation *s_animate_move(NeatBarLayer *neat_bar, uint8_t button_index, bool move_on_y_axis, int16_t distance) {
-	BitmapLayer *bitmap_layer = NULL;
+static GRect s_get_home_frame(NeatBarLayer *neat_bar, uint8_t button_index) {
+	int16_t y_offset = neat_bar->main_grect.origin.y;
+	int8_t spread = neat_bar->spread;
+	uint16_t width = neat_bar->main_grect.size.w;
+
+	switch (button_index) {
+	case BUTTON_ID_UP:
+		return GRect(ICON_X_OFFSET, UP_Y - spread - y_offset, width, 25);
+	case BUTTON_ID_SELECT:
+		return GRect(ICON_X_OFFSET, SELECT_Y - y_offset, width, 25);
+	case BUTTON_ID_DOWN:
+		return GRect(ICON_X_OFFSET, DOWN_Y + spread - y_offset, width, 25);
+	default:
+		return GRectZero;
+	}
+}
+
+// Performs a press or release animation for a single button, anchored to its
+// home position.  Duplicate events (press when already pressed, release when
+// already released) are ignored so overlapping animations cannot accumulate
+// drift.
+static void s_animate_icon(NeatBarLayer *neat_bar, uint8_t button_index, bool is_press) {
+	BitmapLayer *bitmap_layer;
+	bool *pressed;
 
 	switch (button_index) {
 	case BUTTON_ID_UP:
 		bitmap_layer = neat_bar->up_layer;
+		pressed = &neat_bar->up_pressed;
 		break;
 	case BUTTON_ID_SELECT:
 		bitmap_layer = neat_bar->select_layer;
+		pressed = &neat_bar->select_pressed;
 		break;
 	case BUTTON_ID_DOWN:
 		bitmap_layer = neat_bar->down_layer;
+		pressed = &neat_bar->down_pressed;
 		break;
 	default:
-		return NULL;
+		return;
 	}
 
-	if (!bitmap_layer) {
-		return NULL;
+	if (!bitmap_layer)
+		return;
+	if (is_press) {
+		if (*pressed)
+			return;
+		*pressed = true;
+	} else {
+		if (!*pressed)
+			return;
+		*pressed = false;
 	}
 
 	Layer *layer = bitmap_layer_get_layer(bitmap_layer);
-	GRect from_frame = layer_get_frame(layer);
-	GRect to_frame = from_frame;
-	if (move_on_y_axis) {
-		to_frame.origin.y += distance;
+	GRect home = s_get_home_frame(neat_bar, button_index);
+
+	// off = home shifted by -distance (the "pressed" position)
+	GRect off = home;
+	int16_t distance = neat_bar->animations_move_distance;
+	if (neat_bar->animations_move_on_y_axis) {
+		off.origin.y -= distance;
 	} else {
-		to_frame.origin.x += distance;
+		off.origin.x -= distance;
 	}
 
-	PropertyAnimation *prop_anim = property_animation_create_layer_frame(layer, &from_frame, &to_frame);
-	return property_animation_get_animation(prop_anim);
+	GRect from = is_press ? home : off;
+	GRect to = is_press ? off : home;
+
+	PropertyAnimation *prop_anim = property_animation_create_layer_frame(layer, &from, &to);
+	Animation *anim = property_animation_get_animation(prop_anim);
+	animation_set_duration(anim, neat_bar->animations_duration);
+	animation_schedule(anim);
 }
 
 static void s_icon_down_handler(NeatBarLayer *neat_bar, uint8_t button_index) {
-	Animation *anim = s_animate_move(neat_bar, button_index, neat_bar->animations_move_on_y_axis, -neat_bar->animations_move_distance);
-	animation_set_duration(anim, neat_bar->animations_duration);
-	animation_schedule(anim);
+	s_animate_icon(neat_bar, button_index, true);
 }
 
 static void s_icon_up_handler(NeatBarLayer *neat_bar, uint8_t button_index) {
-	Animation *anim = s_animate_move(neat_bar, button_index, neat_bar->animations_move_on_y_axis, neat_bar->animations_move_distance);
-	animation_set_duration(anim, neat_bar->animations_duration);
-	animation_schedule(anim);
+	s_animate_icon(neat_bar, button_index, false);
 }
 
 static void s_up_down_handler(ClickRecognizerRef recognizer, void *context) {
@@ -332,6 +369,9 @@ NeatBarLayer *neat_bar_layer_create() {
 	neat_bar->animations_move_on_y_axis = false;
 	neat_bar->animations_move_distance = ANIM_DISTANCE;
 	neat_bar->animations_duration = 144;
+	neat_bar->up_pressed = false;
+	neat_bar->select_pressed = false;
+	neat_bar->down_pressed = false;
 	neat_bar->context = NULL;
 	layer_set_update_proc(neat_bar->main_layer, s_main_layer_update_proc);
 	s_current_neat_bar = neat_bar;

src/c/neat_bar.h

@@ -21,6 +21,9 @@ typedef struct {
 	int8_t animations_move_distance;
 	uint8_t animations_duration;
 	//bool use_legacy_animations
+	bool up_pressed;
+	bool select_pressed;
+	bool down_pressed;
 	void *context;
 } NeatBarLayer;