From 928f675e4ba064bf59dc603fb8df45485bd8472c Mon Sep 17 00:00:00 2001
From: uz <uz@b7a2c559-68d2-44c3-8de9-860c34a00d81>
Date: Sun, 17 Jul 2011 17:15:54 +0000
Subject: [PATCH] Small change in the vector font format.

git-svn-id: svn://svn.cc65.org/cc65/trunk@5088 b7a2c559-68d2-44c3-8de9-860c34a00d81
---
 asminc/tgi-vectorfont.inc   |  4 ++--
 libsrc/tgi/tgi_textheight.s |  9 +++------
 src/chrcvt/main.c           | 20 +++++++++++++++-----
 3 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/asminc/tgi-vectorfont.inc b/asminc/tgi-vectorfont.inc
index b70adcd51..ffe6ac686 100644
--- a/asminc/tgi-vectorfont.inc
+++ b/asminc/tgi-vectorfont.inc
@@ -54,8 +54,8 @@ TGI_VF_CCOUNT           = (TGI_VF_LASTCHAR - TGI_VF_FIRSTCHAR + 1)
 ; Font data loaded directly from file
 .struct TGI_VECTORFONT
         TOP             .byte                   ; Height of char
-        BASELINE        .byte                   ; Character baseline
-        BOTTOM          .byte                   ; Descender
+        BOTTOM          .byte                   ; Descender          
+        HEIGHT          .byte                   ; Maximum char height
         WIDTHS          .byte   ::TGI_VF_CCOUNT ; Char widths
         CHARS           .word   ::TGI_VF_CCOUNT ; Pointer to character defs
         OPS             .byte                   ; Actually dynamic
diff --git a/libsrc/tgi/tgi_textheight.s b/libsrc/tgi/tgi_textheight.s
index 7bd4216bd..7e0aee935 100644
--- a/libsrc/tgi/tgi_textheight.s
+++ b/libsrc/tgi/tgi_textheight.s
@@ -2,7 +2,7 @@
 ; Ullrich von Bassewitz, 2009-10-30
 ;
 
-
+                                        
         .include        "tgi-kernel.inc"
         .include        "tgi-vectorfont.inc"
         .include        "zeropage.inc"
@@ -36,11 +36,8 @@
         stx     ptr1
         lda     _tgi_vectorfont+1
         sta     ptr1+1
-        ldy     #TGI_VECTORFONT::TOP
-        lda     (ptr1),y
-        ldy     #TGI_VECTORFONT::BOTTOM
-        clc
-        adc     (ptr1),y                ; Total font height is top + bottom
+        ldy     #TGI_VECTORFONT::HEIGHT
+        lda     (ptr1),y                ; Get height of font
 
         sta     ptr1
         lda     #0
diff --git a/src/chrcvt/main.c b/src/chrcvt/main.c
index 6c2354cc3..8cc32cc88 100644
--- a/src/chrcvt/main.c
+++ b/src/chrcvt/main.c
@@ -129,15 +129,20 @@
  *      .byte   $54, $43, $48, $00              ; "TCH" version
  *      .word   <size of data portion>
  * Data portion:
- *      .byte   <top>                           ; Value from $88
- *      .byte   <baseline>                      ; Value from $89
- *      .byte   <bottom>                        ; Negative value from $8A
+ *      .byte   <top>                           ; Baseline to top
+ *      .byte   <bottom>                        ; Baseline to bottom
+ *      .byte   <height>                        ; Maximum char height
  *      .byte   <width>, ...                    ; $5F width bytes
  *      .word   <char definition offset>, ...   ; $5F char def offsets
  * Character definitions:
  *      .word   <converted opcode>, ...
  *      .byte   $80
  *
+ * The baseline of the character is assume to be at position zero. top and
+ * bottom are both positive values. The former extends in positive, the other
+ * in negative direction of the baseline. height contains the sum of top and
+ * bottom and is stored here just for easier handling.
+ *
  * The opcodes get converted for easier handling: END is marked by bit 7
  * set in the first byte. The second byte of this opcode is not needed.
  * Bit 7 of the second byte marks a MOVE (bit 7 = 0) or DRAW (bit 7 = 1).
@@ -411,8 +416,13 @@ static void ConvertFile (const char* Input, const char* Output)
     TchHeader[4] = Offs & 0xFF;
     TchHeader[5] = (Offs >> 8) & 0xFF;
     TchHeader[6] = Buf[0x88];
-    TchHeader[7] = Buf[0x89];
-    TchHeader[8] = (unsigned char) -(signed char)(Buf[0x8A]);
+    TchHeader[7] = (unsigned char) -(signed char)(Buf[0x8A]);
+    TchHeader[8] = TchHeader[6] + TchHeader[7];
+
+    /* The baseline must be zero, otherwise we cannot convert */
+    if (Buf[0x89] != 0) {
+        Error ("Baseline of font in `%s' is not zero", Input);
+    }
 
     /* If the output file is NULL, use the name of the input file with ".tch"
      * appended.