Refactoring how we draw on the display.

1 files changed, 19 insertions, 9 deletions

diff --git a/main/main.c b/main/main.c
index f2822a8..97a78b5 100644
--- a/main/main.c
+++ b/main/main.c
@@ -33,14 +33,24 @@
 static uint16_t pattern[NUM_ROW][NUM_COL / 8]; // each column is two bits, so 8 can fit in 16-bit integer
 
 
-void draw_char_at_position(char character, uint16_t col_start, uint16_t row_start, uint16_t color) {
+void setPixel(uint16_t x, uint16_t y, uint16_t color) {
+    pattern[y][x / 8] = pattern[y][x / 8] & ~(0b0000000000000011 << (2 * (x % 8))); // clear this column (note the bitwise inversion)
+    pattern[y][x / 8] = pattern[y][x / 8] | (color << (2 * (x % 8))); // write color to column
+}
+
+
+void drawCharAtPosition(char character, int x_start, int y_start, uint16_t color) {
     uint8_t cur_char_row;
-    for(int row = row_start; (row - row_start) < CHAR_HEIGHT && row < NUM_ROW; row++) {
-        cur_char_row = atascii_font[(uint8_t) character][row - row_start];
-        for(int col = col_start; (col - col_start) < CHAR_WIDTH && col < NUM_COL; col++) {
-            pattern[row][col / 8] = (pattern[row][col / 8] & ~(0b0000000000000011 << (2 * (col - col_start)))); // clear this column (note the bitwise inversion)
-            if((1 << (col - col_start)) & cur_char_row) {
-                pattern[row][col / 8] = ((pattern[row][col / 8]) | color << (2 * (col - col_start))); // write color to column
+    for(int y = y_start; (y - y_start) < CHAR_HEIGHT && y < NUM_ROW; y++) {
+        cur_char_row = atascii_font[(uint8_t) character][y - y_start];
+        for(int x = x_start; (x - x_start) < CHAR_WIDTH && x < NUM_COL; x++) {
+            if(x >= 0) {
+                if((1 << (x - x_start)) & cur_char_row) {
+                    setPixel(x, y, color);
+                }
+                else {
+                    setPixel(x, y, 0);
+                }
             }
         }
     }
@@ -145,13 +155,13 @@ void app_main(void)
 
         char* hello = "Hello World!!";
         for(int i = 0; i < strlen(hello); i++) {
-            draw_char_at_position(hello[i], i * CHAR_WIDTH, 0, j % 2 + 1);
+            drawCharAtPosition(hello[i], i * CHAR_WIDTH, 0, j % 2 + 1);
         }
 
         char* numbers = "0123456789";
         int offset = strlen(hello) + 1;
         for(int i = 0; i < strlen(numbers); i++) {
-            draw_char_at_position(numbers[i], (i + offset) * CHAR_WIDTH, 0, j % 2 + 2);
+            drawCharAtPosition(numbers[i], (i + offset) * CHAR_WIDTH, 0, j % 2 + 2);
         }
 
         j++;