screenshots and extraction

datapoint/datapoint-8x12.pas

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+
+{ -----------------------------------------------------------------------------
+
+  A small tool to extract 8x12 bitmap fonts from
+  Datapoint 8600 CP/RIM card ROMs
+
+  Compile with the Freepascal Compiler: fpc datapoint-8x12.pas
+
+  Usage: datapoint-8x12 905-008-1.bin Datapoint-8600.draw
+
+----------------------------------------------------------------------------- }
+
+{
+
+This tool designed to extract the font data from the ROM contents of
+a Datapoint 8600 machine. Font data is not directly mapped as a character
+generator but is read by the "bios" of the machine and stored into the actual
+character RAM area. The font is a 8x12 font, but only uppercase characters
+were available, with the lowercase characters later loaded by the operating
+system (RMS 2.8.J).
+
+The font data is organised as nine bytes for each charater, with the MSB
+of these data bytes always 0 for inter-character spacing. Therefore, data exists
+for 7x9 bitmaps. Three empty lines are added when loading this font, one line on
+top and two lines at the bottom as seen when comparing with the cursor in
+the screenshot of the date/time prompt which has all twelve lines set.
+
+Bytes with MSB set denote the place in the character table (when masked with $7F).
+Then nine bytes of graphics data follow.
+
+When no place-in-the-character-table byte appears, continue with the next place.
+
+Note that the shape of "," on the screenshot with lowercase letters differs
+from the data in the ROM, so this might be a completely different font for which
+unfortunately no further data exists.
+
+}
+
+uses sysutils;
+
+function byte2hex(zahl : byte) : string;
+const
+    hexa : array [0..15] of char = '0123456789ABCDEF';
+begin
+  byte2hex := hexa[zahl shr 4] + hexa[zahl and 15];
+end;
+
+function byte2str(c : byte) : string;
+var h : string = '';
+var i : integer;
+begin
+  for i := 7 downto 0 do
+  begin
+    if (c shr i) and 1 = 1 then h := h + '#' else h := h + '-';
+  end;
+  byte2str := h;
+end;
+
+var binary : file of byte;
+    fontfile : text;
+    i, k : integer;
+    character : array[1..9] of byte;
+    asciioffset : integer = 0;
+
+begin
+  assign(binary, paramstr(1));
+  reset(binary);
+
+  assign(fontfile, paramstr(2));
+  rewrite(fontfile);
+
+  seek(binary, $10AF);
+
+  for k := 0 to 73 do
+  begin
+    read(binary, character[1]);
+
+    if (character[1] and $80) = $80 then
+    begin
+      asciioffset := character[1] and $7F;
+      read(binary, character[1]);
+    end;
+
+    for i := 2 to 9 do read(binary, character[i]);
+
+    write(fontfile, byte2hex(asciioffset), ':');
+
+                       writeln(fontfile, #9, byte2str(0));
+    for i := 1 to 9 do writeln(fontfile, #9, byte2str(character[i]));
+                       writeln(fontfile, #9, byte2str(0));
+                       writeln(fontfile, #9, byte2str(0));
+
+    writeln(fontfile);
+    inc(asciioffset);
+  end;
+
+  close(fontfile);
+  close(binary);
+end.