+
+#define COLOUR_SYS_HEX(r, g, b) 0x ## r ## g ## b ## ul
+
+#undef COLOUR_SYSTEM
+#define COLOUR_SYSTEM HEX
+
+/*
+ * Returns true iff this pixel is an "edge" -- that is, either there
+ * is no pixel to the right or below or those pixels are a different
+ * colour.
+ */
+static int is_edge(unsigned x, unsigned y, unsigned w, unsigned h,
+ unsigned long *p, unsigned long colour)
+{
+ return y+1 >= h || x+1 >= w
+ || (p[1] & 0xffffff) != colour
+ || (p[w] & 0xffffff) != colour;
+}
+
+static void print_xpm_w32vga(unsigned long size, unsigned long *icon_buf)
+{
+ unsigned w = size & 0xffff, h = (size >> 16) & 0xffff;
+ unsigned x, y, i, j, n;
+
+ const char colourchars[16] = "#rgybmc-+RGYBMC ";
+ unsigned long palette[16] = {
+ 0x000000, 0x800000, 0x008000, 0x808000,
+ 0x000080, 0x800080, 0x008080, 0xc0c0c0,
+ 0x808080, 0xff0000, 0x00ff00, 0xffff00,
+ 0x0000ff, 0xff00ff, 0x00ffff, 0xffffff
+ };
+
+ unsigned long prev_colour = 0;
+ unsigned used_colours, v;
+
+ size = (unsigned long) w * h;
+ for (i = 0; i < size; i++) {
+ unsigned long *p = &icon_buf[i];
+ char *c;
+
+ x = i%w, y=i/w;
+
+ switch (*p & 0xffffff) {
+ /* red */
+ case COLOUR0_PRIMARY:
+ *p = y&1 ? ( x&1 ? 'r' : 'm' ) : ( x&1 ? 'y' : 'r' );
+ break;
+ case COLOUR0_LIGHT:
+ *p = (x^y)&1 ? '+' : 'r';
+ break;
+ case COLOUR0_DARK:
+ *p = 'r';
+ break;
+ /* orange */
+ case COLOUR1_PRIMARY:
+ *p = y&1 ? 'y' : x&1 ? '+' : 'R';
+ break;
+ case COLOUR1_LIGHT:
+ *p = (x^y)&1 ? '+' : 'y';
+ break;
+ case COLOUR1_DARK:
+ *p = (x^y)&1 ? 'r' : 'y';
+ break;
+ /* yellow */
+ case COLOUR2_PRIMARY:
+ *p = (x^y)&1 ? '+' : 'Y';
+ break;
+ case COLOUR2_LIGHT:
+ *p = (x^y)&1 ? '-' : 'Y';
+ break;
+ case COLOUR2_DARK:
+ *p = (x^y)&1 ? '+' : 'Y';
+ if (is_edge(x, y, w, h, p, COLOUR2_DARK))
+ *p = (x^y)&1 ? '+' : 'y';
+ break;
+ /* green */
+ case COLOUR3_PRIMARY:
+ *p = y&1 ? 'g' : x&1 ? '+' : 'g';
+ break;
+ case COLOUR3_LIGHT:
+ *p = (x^y)&1 ? '+' : 'g';
+ break;
+ case COLOUR3_DARK:
+ *p = 'g';
+ if (is_edge(x, y, w, h, p, COLOUR3_DARK))
+ *p = (x^y)&1 ? '#' : 'g';
+ break;
+ /* blue */
+ case COLOUR4_PRIMARY:
+ *p = (x^y)&1 ? 'b' : 'c';
+ break;
+ case COLOUR4_LIGHT:
+ *p = 'c';
+ if (is_edge(x, y, w, h, p, COLOUR4_LIGHT))
+ *p = (x^y)&1 ? 'b' : 'c';
+ break;
+ case COLOUR4_DARK:
+ *p = 'b';
+ if (is_edge(x, y, w, h, p, COLOUR4_DARK))
+ *p = (x^y)&1 ? '#' : 'b';
+ break;
+ /* white */
+ case COLOUR5_PRIMARY:
+ *p = (x^y)&1 ? '-' : ' ';
+ break;
+ case COLOUR5_LIGHT:
+ *p = ' ';
+ break;
+ case COLOUR5_DARK:
+ *p = (x^y)&1 ? '+' : ' ';
+ break;
+ /* dummy */
+ case 0xff0000: *p = 'R'; break;
+ case 0x00ff00: *p = 'G'; break;
+ case 0x0000ff: *p = 'B'; break;
+ }
+
+ c = strchr(colourchars, *p);
+ assert(c && c - colourchars < 16);
+ used_colours |= 1u << (c-colourchars);
+ }
+
+ for (n = 0, v = used_colours; v; n++)
+ v &= v-1;
+
+ puts("/* XPM */");
+ puts("static char *icon[] = {");
+ printf("\"%u %u %u 1\",\n", w, h, n);
+ for (i = 0; i < sizeof colourchars; i++) {
+ if (!(used_colours & (1u << i)))
+ continue;
+
+ printf("\"%c c #%.6lx\",\n", colourchars[i], palette[i]);
+ }
+
+ for (y = 0; y < h; y++) {
+ putchar('"');
+ for (x = 0; x < w; x++) {
+ putchar(icon_buf[y*h+x]);
+ }
+ printf("\"%.*s\n", y+1<h, ",");
+ }
+
+ puts("};");
+}
+