quick bitmap font format, borrowing new default font from X

1 files changed, 43 insertions, 0 deletions

diff --git a/src/user/libfont/pbf.c b/src/user/libfont/pbf.c
new file mode 100644
index 0000000..34d5be5
--- /dev/null
+++ b/src/user/libfont/pbf.c
@@ -0,0 +1,43 @@
+#include <libfont/fonts.h>
+
+#include <knob/panic.h>
+#include <knob/file.h>
+#include <knob/heap.h>
+
+#include <stdbool.h>
+
+bool try_load_pbf(struct file *f, struct font_info *into) {
+  uint8_t head[4];
+  if (read_from_file(f, 4, head) != 4)
+    return false;
+
+  into->space_width  = head[0] + head[2];
+  into->space_height = head[1] + head[3];
+  into->char_width   = head[0];
+  into->char_height  = head[1];
+
+  const uint16_t bm_size  =  head[0] * head[1];
+  const uint16_t bm_bytes = (bm_size - 1) / 8 + 1;
+
+  uint32_t bm_offsets[256];
+  if (read_from_file(f, 4 * 256, bm_offsets) != 4 * 256)
+    return false;
+
+  uint8_t bm_buf[256 * 256 / 8];
+
+  for (uint16_t i = 0; i < 256; ++i)
+    if (bm_offsets[i] == 0xffffffff)
+      into->bitmaps[i] = 0;
+    else {
+      bool *bp = get_block(bm_size);
+      if (!bp)
+        PANIC("couldn't allocate memory in pbf loader (todo: fail gracefully)");
+      seek_file_to(f, 4 + 4 * 256 + bm_offsets[i]);
+      read_from_file(f, bm_bytes, bm_buf);
+      for (uint16_t j = 0; j < bm_size; ++j)
+        bp[j] = (bm_buf[j / 8] >> (j % 8)) & 1;
+      into->bitmaps[i] = bp;
+    }
+
+  return true;
+}
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