gitk: Keep track of font attributes ourselves instead of using font actual

Unfortunately there seems to be a bug in Tk8.5 where font actual -size
sometimes gives the wrong answer (e.g. 12 for Bitstream Vera Sans 9),
even though the font is actually displayed at the right size.  This
works around it by parsing and storing the family, size, weight and
slant of the mainfont, textfont and uifont explicitly.

Signed-off-by: Paul Mackerras <paulus@samba.org>

gitk

@@ -5685,43 +5685,73 @@ proc redisplay {} {
     }
 }
 
-proc fontdescr {f} {
-    set d [list [font actual $f -family] [font actual $f -size]]
-    if {[font actual $f -weight] eq "bold"} {
-	lappend d "bold"
+proc parsefont {f n} {
+    global fontattr
+
+    set fontattr($f,family) [lindex $n 0]
+    set s [lindex $n 1]
+    if {$s eq {} || $s == 0} {
+	set s 10
+    } elseif {$s < 0} {
+	set s [expr {int(-$s / [winfo fpixels . 1p] + 0.5)}]
     }
-    if {[font actual $f -slant] eq "italic"} {
-	lappend d "italic"
+    set fontattr($f,size) $s
+    set fontattr($f,weight) normal
+    set fontattr($f,slant) roman
+    foreach style [lrange $n 2 end] {
+	switch -- $style {
+	    "normal" -
+	    "bold"   {set fontattr($f,weight) $style}
+	    "roman" -
+	    "italic" {set fontattr($f,slant) $style}
+	}
     }
-    if {[font actual $f -underline]} {
-	lappend d "underline"
+}
+
+proc fontflags {f {isbold 0}} {
+    global fontattr
+
+    return [list -family $fontattr($f,family) -size $fontattr($f,size) \
+		-weight [expr {$isbold? "bold": $fontattr($f,weight)}] \
+		-slant $fontattr($f,slant)]
+}
+
+proc fontname {f} {
+    global fontattr
+
+    set n [list $fontattr($f,family) $fontattr($f,size)]
+    if {$fontattr($f,weight) eq "bold"} {
+	lappend n "bold"
     }
-    if {[font actual $f -overstrike]} {
-	lappend d "overstrike"
+    if {$fontattr($f,slant) eq "italic"} {
+	lappend n "italic"
     }
-    return $d
+    return $n
 }
 
 proc incrfont {inc} {
     global mainfont textfont ctext canv phase cflist showrefstop
-    global stopped entries
+    global stopped entries fontattr
+
     unmarkmatches
-    set s [font actual mainfont -size]
+    set s $fontattr(mainfont,size)
     incr s $inc
     if {$s < 1} {
 	set s 1
     }
+    set fontattr(mainfont,size) $s
     font config mainfont -size $s
     font config mainfontbold -size $s
-    set mainfont [fontdescr mainfont]
-    set s [font actual textfont -size]
+    set mainfont [fontname mainfont]
+    set s $fontattr(textfont,size)
     incr s $inc
     if {$s < 1} {
 	set s 1
     }
+    set fontattr(textfont,size) $s
     font config textfont -size $s
     font config textfontbold -size $s
-    set textfont [fontdescr textfont]
+    set textfont [fontname textfont]
     setcoords
     settabs
     redisplay
@@ -8340,15 +8370,17 @@ set selectbgcolor gray85
 catch {source ~/.gitk}
 
 font create optionfont -family sans-serif -size -12
-font create mainfont
-catch {eval font config mainfont [font actual $mainfont]}
-eval font create mainfontbold [font actual mainfont] -weight bold
-font create textfont
-catch {eval font config textfont [font actual $textfont]}
-eval font create textfontbold [font actual textfont]
-font config textfontbold -weight bold
-font create uifont
-catch {eval font config uifont [font actual $uifont]}
+
+parsefont mainfont $mainfont
+eval font create mainfont [fontflags mainfont]
+eval font create mainfontbold [fontflags mainfont 1]
+
+parsefont textfont $textfont
+eval font create textfont [fontflags textfont]
+eval font create textfontbold [fontflags textfont 1]
+
+parsefont uifont $uifont
+eval font create uifont [fontflags uifont]
 
 # check that we can find a .git directory somewhere...
 if {[catch {set gitdir [gitdir]}]} {