Improve calculation of line height and baseline.

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/gui/trunk@15907 72102866-910b-0410-8b05-ffd578937521

ChangeLog

@@ -1,3 +1,10 @@
+2003-02-08 22:53  Alexander Malmberg <alexander@malmberg.org>
+
+	* Source/GSFontInfo.m (-defaultLineHeightForFont),
+	Source/GSHorizontalTypesetter.m (-layoutLineNewParagraph:): Improve
+	calculation of line height and make it match the baseline calculation
+	when typesetting.
+
 2003-02-08 22:29  Alexander Malmberg <alexander@malmberg.org>
 
 	* Source/NSWindow.m (-sendEvent:): On right mouse down, check if

Source/GSFontInfo.m

@@ -342,8 +342,16 @@ static GSFontEnumerator *sharedEnumerator = nil;
 
 - (float) defaultLineHeightForFont
 {
-  // ascent plus descent plus some suitable linegap
-  return [self ascender] - [self descender] + ceil([self pointSize]/ 11.0);
+  /*
+  Generally, roman text is centered in the line disregarding the descender,
+  and the descender height is added above and below. Thus, the line height
+  should be ascender_height+2*descender_height. (Note that descender is
+  negative below the baseline.)
+
+  This calculation should match the baseline calculation in
+  GSHorizontalTypesetter, or text will look odd.
+  */
+  return [self ascender] - 2 * [self descender];
 }
 
 - (NSSize) advancementForGlyph: (NSGlyph)aGlyph

Source/GSHorizontalTypesetter.m

@@ -367,10 +367,14 @@ typedef struct
   (TODO (optimization): if we're dealing with a "simple rectangular
   text container", we should try to extend the existing line frag in place
   before jumping back to do all the expensive checking).
-
-  Normally, baseline==ascender.
   */
 
+  /*
+  This calculation should match the calculation in [GSFontInfo
+  -defaultLineHeightForFont], or text will look odd.
+  */
+#define COMPUTE_BASELINE  baseline = line_height - descender
+
   line_frag_t *line_frags = NULL;
   int num_line_frags = 0;
 
@@ -394,8 +398,6 @@ typedef struct
     ascender = [cache->font ascender];
     descender = -[cache->font descender];
 
-#define COMPUTE_BASELINE  baseline = ascender
-
     COMPUTE_BASELINE;
 
     if (line_height < min)