altos/draw: Add damage tracking

[fw/altos] / src / draw / ao_box.c

diff --git a/src/draw/ao_box.c b/src/draw/ao_box.c
new file mode 100644 (file)
index 0000000..173b720
--- /dev/null
+++ b/src/draw/ao_box.c
@@ -0,0 +1,28 @@
+/*
+ * Copyright © 2023 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include <ao_box.h>
+
+void
+ao_box_union(struct ao_box *dst, int16_t x1, int16_t y1, int16_t x2, int16_t y2)
+{
+       if (x1 < dst->x1) dst->x1 = x1;
+       if (x2 > dst->x2) dst->x2 = x2;
+       if (y1 < dst->y1) dst->y1 = y1;
+       if (y2 > dst->y2) dst->y2 = y2;
+}