diff --git a/libc3/window/cairo/demo/flies.c b/libc3/window/cairo/demo/flies.c
index b4cde1c..571cfb8 100644
--- a/libc3/window/cairo/demo/flies.c
+++ b/libc3/window/cairo/demo/flies.c
@@ -162,11 +162,14 @@ bool flies_render (s_sequence *seq, s_window_cairo *window,
fly_in = &map->values[1].data.uw;
fly_out = &map->values[2].data.uw;
fly_time = &map->values[3].data.f64;
- board_item_h = (f64) (window->h - 60) / BOARD_SIZE;
+ board_item_h = (f64) (window->h - 60) / (BOARD_SIZE + 1);
board_item_w = board_item_h * g_xy_ratio;
board_w = board_item_w * BOARD_SIZE;
board_h = board_item_h * BOARD_SIZE;
board_x = (window->w - board_w) / 2.0;
+ cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
+ cairo_rectangle(cr, board_x, 0, board_w, board_h);
+ cairo_fill(cr);
cairo_set_source_rgb(cr, 1.0, 1.0, 1.0);
cairo_set_font_size(cr, board_item_h);
cairo_select_font_face(cr, "Courier New",
@@ -199,21 +202,17 @@ bool flies_render (s_sequence *seq, s_window_cairo *window,
assert(board_item);
switch (*board_item) {
case BOARD_ITEM_SPACE:
- cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
- cairo_rectangle(cr, 0, 0, board_item_w + 0.5,
- board_item_h + 0.5);
- cairo_fill(cr);
break;
case BOARD_ITEM_BLOCK:
cairo_set_source_rgb(cr, 0.0, 0.0, 1.0);
- cairo_rectangle(cr, 0, 0, board_item_w + 0.5,
- board_item_h + 0.5);
+ cairo_rectangle(cr, 0, 0, board_item_w + 1.0,
+ board_item_h + 1.0);
cairo_fill(cr);
break;
case BOARD_ITEM_FLY:
cairo_set_source_rgb(cr, 1.0, 0.0, 0.0);
- cairo_rectangle(cr, 0, 0, board_item_w + 0.5,
- board_item_h + 0.5);
+ cairo_rectangle(cr, 0, 0, board_item_w + 1.0,
+ board_item_h + 1.0);
cairo_fill(cr);
if (address[0] == BOARD_SIZE / 2 &&
address[1] == BOARD_SIZE - 1) {
@@ -270,8 +269,8 @@ bool flies_render (s_sequence *seq, s_window_cairo *window,
break;
case BOARD_ITEM_DEAD_FLY:
cairo_set_source_rgb(cr, 0.5, 0.5, 0.5);
- cairo_rectangle(cr, 0, 0, board_item_w + 0.5,
- board_item_h + 0.5);
+ cairo_rectangle(cr, 0, 0, board_item_w + 1.0,
+ board_item_h + 1.0);
cairo_fill(cr);
break;
}