altos: Add bitmap drawing code

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

diff --git a/src/draw/ao_pattern.c b/src/draw/ao_pattern.c
new file mode 100644 (file)
index 0000000..0d1dc76
--- /dev/null
+++ b/src/draw/ao_pattern.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright © 2016 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.
+ */
+
+#include "ao.h"
+#include "ao_draw.h"
+#include "ao_draw_int.h"
+
+static inline uint32_t
+ao_pattern_expand(uint8_t v, uint8_t rot)
+{
+       uint32_t        r;
+
+       if (rot)
+               v = ao_left(v, 8-rot) | ao_right(v, rot);
+       r = v;
+       return (r << 24) | (r << 16) | (r << 8) | (r);
+}
+
+static inline int
+min(int a, int b) {
+       return a < b ? a : b;
+}
+
+void
+ao_pattern(const struct ao_bitmap      *dst,
+          int16_t                      x,
+          int16_t                      y,
+          int16_t                      width,
+          int16_t                      height,
+          const struct ao_pattern      *pattern,
+          int16_t                      pat_x,
+          int16_t                      pat_y,
+          uint8_t                      rop)
+{
+       uint32_t        pat[8];
+
+       int16_t x2 = x + width;
+       int16_t y2 = y + height;
+
+       ao_clip(x, 0, dst->width);
+       ao_clip(x2, 0, dst->width);
+       ao_clip(y, 0, dst->height);
+       ao_clip(y2, 0, dst->height);
+
+       if (x < x2 && y < y2) {
+               int     xrot = (x - pat_x) & 7;
+               int     yrot = (y - pat_y) & 7;
+               int     i;
+               int16_t dst_x, dst_y;
+
+               for (i = 0; i < 8; i++)
+                       pat[(i + yrot) & 7] = ao_pattern_expand(pattern->pattern[i], xrot);
+               for (dst_y = y; dst_y < y2; dst_y += 8) {
+                       int     h = min(y2 - dst_y, 8);
+                       for (dst_x = x; dst_x < x2; dst_x += 8) {
+                               int     w = min(x2 - dst_x, 8);
+
+                               ao_blt(pat, 1, 0,
+                                      dst->base + dst_y * dst->stride,
+                                      dst->stride,
+                                      dst_x,
+                                      w, h,
+                                      rop,
+                                      0, 0);
+                       }
+               }
+       }
+}
+