Add automatic scaling by an integer factor

src/card_layer.c

@@ -27,7 +27,7 @@ CardLayer *card_layer_create(GRect frame) {
     layer_set_update_proc(card_layer->layer, background_update_proc);
     *(CardLayer **)layer_get_data(card_layer->layer) = card_layer;
 
-    card_layer->name_text_layer = text_layer_create(GRect(0, 0, PEBBLE_WIDTH, 22)); // TODO: Fix magic number
+    card_layer->name_text_layer = text_layer_create(GRect(0, 0, PEBBLE_WIDTH, NAME_LAYER_HEIGHT));
     text_layer_set_background_color(card_layer->name_text_layer, GColorBlack);
     text_layer_set_font(card_layer->name_text_layer, fonts_get_system_font(FONT_KEY_GOTHIC_18_BOLD));
     text_layer_set_overflow_mode(card_layer->name_text_layer, GTextOverflowModeTrailingEllipsis);
@@ -43,7 +43,7 @@ CardLayer *card_layer_create(GRect frame) {
     text_layer_set_text_alignment(card_layer->value_text_layer, GTextAlignmentCenter);
     text_layer_set_text_color(card_layer->value_text_layer, GColorBlack);
     layer_add_child(card_layer->layer, (Layer *)card_layer->value_text_layer);
-
+	
     return card_layer;
 }
 
@@ -69,6 +69,25 @@ static void draw_barcode_matrix(CardLayer *card_layer, GContext* ctx) {
 
     int16_t img_pixels = card_layer->barcode_width * card_layer->barcode_height;
 
+	// name_text_layer and pager_layer need to be subtracted from the pebble height
+	// as does twice the WHITE_BORDER
+	const int16_t MAX_HEIGHT = PEBBLE_HEIGHT - NAME_LAYER_HEIGHT - PAGER_LAYER_HEIGHT;
+
+	// The mid point between the black border at the top (name_layer) and at the bottom (pager_layer)
+	// is not exactly in the middle of the screen
+	const int16_t MID_HEIGHT = (PEBBLE_HEIGHT - NAME_LAYER_HEIGHT - PAGER_LAYER_HEIGHT) / 2 + NAME_LAYER_HEIGHT;
+
+	// Non-linear barcodes are scaled to save persistent storage space. Dynamically calculate
+	// the maximum integer scaling factor, keep a white border of 2 units around.
+
+	const int16_t SCALING_FACTOR_X = PEBBLE_WIDTH / (card_layer->barcode_width + 2 + 2);
+	const int16_t SCALING_FACTOR_Y = MAX_HEIGHT / (card_layer->barcode_height + 2 + 2);
+
+	// actual scaling factor is the least of x and y scaling, but at least 1
+	const int16_t SCALING_FACTOR = MAX( MIN(SCALING_FACTOR_X, SCALING_FACTOR_Y), 1);
+
+	APP_LOG(APP_LOG_LEVEL_DEBUG, "image size %ix%i, scaling by %i", card_layer->barcode_width, card_layer->barcode_height, SCALING_FACTOR);
+
     // The comparison part of this loop adds 7 to the barcode width to allow C
     // to ceil the byte count. Since the server will always pad incomplete bytes
     // with 0, this is reasonably safe.
@@ -80,15 +99,15 @@ static void draw_barcode_matrix(CardLayer *card_layer, GContext* ctx) {
 
         for (int8_t p = 0; p < 8; p++) {
             if (card_layer->barcode_data[current_byte] & (1 << p)) {
-                // Non-linear barcodes are scaled 2x to save persistent storage space.
-
-                point_x = ( PEBBLE_WIDTH/2 - card_layer->barcode_width ) + raw_x * 2;
-                point_y = ( PEBBLE_HEIGHT/2 - card_layer->barcode_height ) + raw_y * 2;
 
-                graphics_draw_pixel(ctx, GPoint(point_x, point_y));
-                graphics_draw_pixel(ctx, GPoint(point_x + 1, point_y));
-                graphics_draw_pixel(ctx, GPoint(point_x + 1, point_y + 1));
-                graphics_draw_pixel(ctx, GPoint(point_x, point_y + 1));
+                for(int8_t s_x = 0; s_x < SCALING_FACTOR; s_x++) {
+                    for(int8_t s_y = 0; s_y < SCALING_FACTOR; s_y++) {
+                        point_x = ( PEBBLE_WIDTH/2 - (SCALING_FACTOR * card_layer->barcode_width)/2 ) + SCALING_FACTOR*raw_x + s_x;
+                        point_y = ( MID_HEIGHT - (SCALING_FACTOR * card_layer->barcode_height)/2 ) + SCALING_FACTOR*raw_y + s_y;
+
+                        graphics_draw_pixel(ctx, GPoint(point_x, point_y));
+                    }
+                }
             }
 
             raw_x++;
@@ -107,6 +126,10 @@ static void draw_barcode_linear(CardLayer *card_layer, GContext* ctx) {
 
     int16_t img_pixels = card_layer->barcode_width;
 
+	// Try to do an integer scale if possible, keep white border of 2 units on each side
+	const int16_t SCALING_FACTOR_X = PEBBLE_WIDTH / (card_layer->barcode_width + 2 + 2);
+	const int16_t SCALING_FACTOR = MAX( SCALING_FACTOR_X, 1);
+
     // The comparison part of this loop adds 7 to the barcode width to allow C
     // to ceil the byte count. Since the server will always pad incomplete bytes
     // with 0, this is reasonably safe.
@@ -118,11 +141,14 @@ static void draw_barcode_linear(CardLayer *card_layer, GContext* ctx) {
 
         for (int16_t current_pixel = 0; current_pixel < 8; current_pixel++) {
             if (card_layer->barcode_data[current_byte] & (1 << current_pixel)) {
-                for (int16_t current_vertical = 0; current_vertical < card_layer->barcode_height; current_vertical++) {
-                    point_x = ( PEBBLE_WIDTH / 2 - card_layer->barcode_width / 2 ) + raw_x;
-                    point_y = ( PEBBLE_HEIGHT / 2 - card_layer->barcode_height / 2 ) + current_vertical;
-
-                    graphics_draw_pixel(ctx, GPoint(point_x, point_y));
+                for(int8_t s_x = 0; s_x < SCALING_FACTOR; s_x++) {
+                    point_x = ( PEBBLE_WIDTH/2 - (SCALING_FACTOR * card_layer->barcode_width)/2 ) + SCALING_FACTOR*raw_x + s_x;
+
+                    for (int16_t current_vertical = 0; current_vertical < card_layer->barcode_height; current_vertical++) {
+                        point_y = ( PEBBLE_HEIGHT / 2 - card_layer->barcode_height / 2 ) + current_vertical;
+
+                        graphics_draw_pixel(ctx, GPoint(point_x, point_y));
+                    }
                 }
             }
 

src/defines.h

@@ -3,6 +3,8 @@
 #define PEBBLE_HEIGHT 168
 #define PEBBLE_WIDTH 144
 #define STATUS_HEIGHT 16
+#define NAME_LAYER_HEIGHT 22
+#define PAGER_LAYER_HEIGHT 30
 
 #define IMG_HEADER_OFFSET 3
 #define IMG_BIT_SIZE 8