LOLWUT: Emit Braille unicode according to pixel pattern.

1 files changed, 23 insertions, 0 deletions

diff --git a/src/lolwut.c b/src/lolwut.c
new file mode 100644
index 000000000..5cef96f33
--- /dev/null
+++ b/src/lolwut.c
@@ -0,0 +1,23 @@
+/* Translate a group of 8 pixels (2x8 vertical rectangle) to the corresponding
+ * braille character. The byte should correspond to the pixels arranged as
+ * follows, where 0 is the least significant bit, and 7 the most significant
+ * bit:
+ *
+ *   0 3
+ *   1 4
+ *   2 5
+ *   6 7
+ *
+ * The corresponding utf8 encoded character is set into the three bytes
+ * pointed by 'output'.
+ */
+#include <stdio.h>
+void lwEmitPixelsGroup(int byte, char *output) {
+    int code = 0x2800 + byte;
+    /* Convert to unicode. This is in the U0800-UFFFF range, so we need to
+     * emit it like this in three bytes:
+     * 1110xxxx 10xxxxxx 10xxxxxx. */
+    output[1] = 0xE0 | (code >> 12);          /* 1110-xxxx */
+    output[2] = 0x80 | ((code >> 6) & 0x3F);  /* 10-xxxxxx */
+    output[3] = 0x80 | (code & 0x3F);         /* 10-xxxxxx */
+}