graphics!

1 files changed, 99 insertions, 0 deletions

diff --git a/src/user/libfont/bdf.c b/src/user/libfont/bdf.c
new file mode 100644
index 0000000..2c19a15
--- /dev/null
+++ b/src/user/libfont/bdf.c
@@ -0,0 +1,99 @@
+#include <libfont/fonts.h>
+
+#include <knob/format.h>
+#include <knob/panic.h>
+#include <knob/block.h>
+#include <knob/heap.h>
+#include <knob/file.h>
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#define LINE_BUF_SIZE 1000
+char line_buf[LINE_BUF_SIZE];
+
+static inline uint8_t hex_to_n(char ch) {
+  return ch - (ch >= 'A' ? 'A' - 10 : '0');
+}
+
+//very minimal implementation
+bool try_load_bdf(const char *path, struct font_info *into) {
+  struct file *f = open_file(path);
+  if (!f)
+    PANIC("Can't open font file sent by get_font.");
+
+  read_line_from_file(f, line_buf, LINE_BUF_SIZE - 1);
+  if (!strequ(line_buf, "STARTFONT 2.1")) {
+    close_file(f);
+    return false;
+  }
+
+  for (uint16_t i = 0; i < 256; ++i)
+    into->bitmaps[i] = 0;
+  into->space_height = -1;
+  into->space_width = -1;
+  into->char_height = -1;
+  into->char_width = -1;
+
+  uint32_t current = 0;
+
+  while (read_line_from_file(f, line_buf, LINE_BUF_SIZE - 1)) {
+    if (blockequ(line_buf, "FONTBOUNDINGBOX ", 16)) {
+      uint32_t n;
+      uint32_t l = try_swtou(line_buf + 16, &n);
+      if (!l)
+        goto bad_format;
+      into->space_width = n;
+      into->char_width = n;
+      l = try_swtou(line_buf + 16 + l, &n);
+      if (!l)
+        goto bad_format;
+      into->space_height = n;
+      into->char_height = n;
+    }
+    else if (blockequ(line_buf, "ENCODING ", 9)) {
+      if (!try_swtou(line_buf + 9, &current))
+        goto bad_format;
+    }
+    else if (strequ(line_buf, "BITMAP")) {
+      if (current >= 256)
+        continue;
+      bool *bm = get_block(into->char_height * into->char_width);
+      if (!bm)
+        PANIC("could not allocate memory for font character bitmap");
+      into->bitmaps[current] = bm;
+
+      for (uint32_t y = 0; y < into->char_height; ++y) {
+        read_line_from_file(f, line_buf, LINE_BUF_SIZE - 1);
+        for (uint32_t x = 0; x < into->char_width; ++x)
+          bm[y * into->char_width + x] = (hex_to_n(line_buf[x / 4]) >> (3 - x % 4)) & 1;
+      }
+    }
+  }
+
+  close_file(f);
+  f = 0;
+
+  if ((into->char_height  == -1) ||
+      (into->char_width   == -1) ||
+      (into->space_height == -1) ||
+      (into->space_width  == -1))
+    goto bad_format;
+
+  if (!into->bitmaps[0]) {
+    const uint32_t bytes = (into->char_height * into->char_width - 1) / 8 + 1;
+    into->bitmaps[0] = get_block(bytes);
+    for (uint32_t i = 0; i < bytes; ++i)
+      into->bitmaps[0][i] = 0b01011010;
+  }
+
+  return true;
+
+bad_format:
+  if (f)
+    close_file(f);
+  for (uint16_t i = 0; i < 256; ++i)
+    if (into->bitmaps[i])
+      free_block(into->bitmaps[i]);
+  return false;
+}
\ No newline at end of file