1 files changed, 67 insertions, 0 deletions
diff --git a/usr/ansi.c b/usr/ansi.c
new file mode 100644
index 0000000..0e73ff8
--- /dev/null
+++ b/usr/ansi.c
@@ -0,0 +1,67 @@
+#include "gbos.h"
+/* ansi - show the terminal's 7-color ANSI support. Also stress-tests per-glyph
+ * coloring: adjacent characters (which share an 8x8 tile) get different colors.
+ *
+ * NB: no initialized statics / pointer arrays here - SDCC would place them in
+ * the _INITIALIZED area at $A000 (the RAM window), overflowing the 16K image. */
+
+static void sgr(unsigned char n) {   /* emit ESC [ n m */
+    putc(27);
+    putc('[');
+    putu(n);
+    putc('m');
+}
+
+void main(void) {
+    unsigned char i, c;
+    const char *s;
+
+    puts("ANSI 7-color test"); nl();
+
+    /* each color name printed in its own color (31..37) */
+    sgr(31); puts("red ");
+    sgr(32); puts("green ");
+    sgr(33); puts("yellow ");
+    sgr(34); puts("blue ");
+    sgr(35); puts("magenta ");
+    sgr(36); puts("cyan ");
+    sgr(37); puts("white");
+    sgr(0); nl();
+
+    /* per-glyph stress: 40 bars, color changes every single character, so the
+     * left/right halves of one tile differ - impossible with a per-tile palette */
+    c = 31;
+    for (i = 0; i < 40; i++) {
+        sgr(c);
+        putc('#');
+        if (++c > 37) c = 31;
+    }
+    sgr(0); nl();
+
+    /* one word, one color per letter */
+    c = 31;
+    s = "RAINBOW!";
+    for (i = 0; s[i]; i++) {
+        sgr(c);
+        putc(s[i]);
+        if (++c > 37) c = 31;
+    }
+    sgr(0); nl();
+
+    /* background colors: a block of each (SGR 41..47), default white text */
+    puts("backgrounds:"); nl();
+    c = 41;
+    for (i = 0; i < 7; i++) {
+        putc(27); putc('['); putc('4'); putc((char)('0' + (c - 40))); putc('m');
+        puts(" bg ");
+        if (++c > 47) c = 41;
+    }
+    sgr(0); nl();
+
+    /* foreground-on-background combos (one CSI carries both: ESC[fg;bg m) */
+    puts("\033[37;41m wht/red \033[33;44m yel/blu \033[34;43m blu/yel "
+         "\033[32;45m grn/mag \033[36;41m cyn/red \033[0m"); nl();
+
+    /* per-glyph fg over a shared bg: adjacent letters differ, bg stays green */
+    puts("\033[42m\033[31mR\033[33mA\033[34mI\033[35mN\033[37mBOW\033[0m"); nl();
+}