Add conditional redrawing

This covers most of the previous functionality, but separating the input
handling and rendering functions. Only cursor drawing and a few corner
cases missing.

1 files changed, 5 insertions, 2 deletions

diff --git a/src/drawing.c b/src/drawing.c
index b790595..89d3ef6 100644
--- a/src/drawing.c
+++ b/src/drawing.c
@@ -29,7 +29,7 @@ draw_channels(void) {
         }
         u8 clr = active ? COL_FG : COL_GREY;
         size_t y = CHAN_START_Y + i * CHAN_OFFSET_Y;
-        draw_channel_sprite(CHAN_START_X, y, active, i);
+        draw_channel_sprite(CHAN_START_X, y, clr, i);
     }
 }
 
@@ -175,8 +175,12 @@ draw_bank_buttons() {
 
 void
 draw_pattern_buttons() {
+    // Clear patterns.
     size_t x = PAT_START_X;
     size_t y = PAT_START_Y;
+
+    draw_filled_rect(x, y, x + PAT_W, y + PAT_H * 8, COL_BG);
+
     txt_drawf_small("PAT", x, y - 10, COL_FG);
     char pat_names[] = {
         'A', 'B', 'C', 'D',
@@ -190,7 +194,6 @@ draw_pattern_buttons() {
         if (i == next_pattern && current_pattern != next_pattern) {
             color = COL_BLUE;
         }
-        draw_filled_rect(x, y, x + PAT_W, y + PAT_H, COL_BG);
         draw_rect(x, y, x + PAT_W, y + PAT_H, color);
         txt_drawc(pat_names[i], x + 4, y + 2, color);
         y += PAT_OFFSET_Y;