git-gui: Allow the user to control the blame/commit split point

At one point I tried to present the blame viewer to an audience of
people on a 640 by 480 pixel LCD projector.  This did not work at
all as the top area (the file data) was taking up all of the screen
realestate and the split point was not adjustable by the user.  In
general locking the user into a specific ratio of display is just
not user friendly.

So we now place a split pane control into the middle of our blame
window, so the user can adjust it to their current needs.  If the
window increases (or decreases) in height we assign the difference
to the file data area, as that is generally the area of the window
that users are trying to see more of when they grow the window.

Unfortunately there appears to be a bug in the "pack" layout manager
in Tcl/Tk 8.4.1.  The status bar and the lower commit pane was being
squashed if the window decreased in height.  I think the pack manager
was just not decreasing the size of the panedwindow slave properly if
the main window shrank.  Switching to the "grid" layout manager fixes
the problem, but is slightly uglier setup code.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

lib/blame.tcl

@@ -13,6 +13,7 @@ field w_load
 field w_file
 field w_cmit
 field status
+field old_height
 
 field highlight_line   -1 ; # current line selected
 field highlight_commit {} ; # sha1 of commit selected
@@ -59,10 +60,22 @@ constructor new {i_commit i_path} {
 		-borderwidth 1 \
 		-relief sunken \
 		-font font_uibold
-	pack $w.path -side top -fill x
 
-	frame $w.out
+	panedwindow $w.file_pane -orient vertical
-	set w_load $w.out.loaded_t
+	frame $w.file_pane.out
+	frame $w.file_pane.cm
+	$w.file_pane add $w.file_pane.out \
+		-sticky nsew \
+		-minsize 100 \
+		-height 100 \
+		-width 100
+	$w.file_pane add $w.file_pane.cm \
+		-sticky nsew \
+		-minsize 25 \
+		-height 25 \
+		-width 100
+
+	set w_load $w.file_pane.out.loaded_t
 	text $w_load \
 		-background white -borderwidth 0 \
 		-state disabled \
@@ -72,7 +85,7 @@ constructor new {i_commit i_path} {
 		-font font_diff
 	$w_load tag conf annotated -background grey
 
-	set w_line $w.out.linenumber_t
+	set w_line $w.file_pane.out.linenumber_t
 	text $w_line \
 		-background white -borderwidth 0 \
 		-state disabled \
@@ -82,7 +95,7 @@ constructor new {i_commit i_path} {
 		-font font_diff
 	$w_line tag conf linenumber -justify right
 
-	set w_cgrp $w.out.commit_t
+	set w_cgrp $w.file_pane.out.commit_t
 	text $w_cgrp \
 		-background white -borderwidth 0 \
 		-state disabled \
@@ -91,18 +104,21 @@ constructor new {i_commit i_path} {
 		-width 4 \
 		-font font_diff
 
-	set w_file $w.out.file_t
+	set w_file $w.file_pane.out.file_t
 	text $w_file \
 		-background white -borderwidth 0 \
 		-state disabled \
 		-wrap none \
 		-height 40 \
 		-width 80 \
-		-xscrollcommand [list $w.out.sbx set] \
+		-xscrollcommand [list $w.file_pane.out.sbx set] \
 		-font font_diff
 
-	scrollbar $w.out.sbx -orient h -command [list $w_file xview]
+	scrollbar $w.file_pane.out.sbx \
-	scrollbar $w.out.sby -orient v \
+		-orient h \
+		-command [list $w_file xview]
+	scrollbar $w.file_pane.out.sby \
+		-orient v \
 		-command [list scrollbar2many [list \
 		$w_load \
 		$w_line \
@@ -114,12 +130,11 @@ constructor new {i_commit i_path} {
 		$w_line \
 		$w_load \
 		$w_file \
-		$w.out.sby \
+		$w.file_pane.out.sby \
 		-sticky nsew
-	grid conf $w.out.sbx -column 3 -sticky we
+	grid conf $w.file_pane.out.sbx -column 3 -sticky we
-	grid columnconfigure $w.out 3 -weight 1
+	grid columnconfigure $w.file_pane.out 3 -weight 1
-	grid rowconfigure $w.out 0 -weight 1
+	grid rowconfigure $w.file_pane.out 0 -weight 1
-	pack $w.out -fill both -expand 1
 
 	label $w.status \
 		-textvariable @status \
@@ -127,18 +142,16 @@ constructor new {i_commit i_path} {
 		-justify left \
 		-borderwidth 1 \
 		-relief sunken
-	pack $w.status -side bottom -fill x
 
-	frame $w.cm
+	set w_cmit $w.file_pane.cm.t
-	set w_cmit $w.cm.t
 	text $w_cmit \
 		-background white -borderwidth 0 \
 		-state disabled \
 		-wrap none \
 		-height 10 \
 		-width 80 \
-		-xscrollcommand [list $w.cm.sbx set] \
+		-xscrollcommand [list $w.file_pane.cm.sbx set] \
-		-yscrollcommand [list $w.cm.sby set] \
+		-yscrollcommand [list $w.file_pane.cm.sby set] \
 		-font font_diff
 	$w_cmit tag conf header_key \
 		-tabs {3c} \
@@ -148,12 +161,15 @@ constructor new {i_commit i_path} {
 		-background $active_color \
 		-font font_ui
 	$w_cmit tag raise sel
-	scrollbar $w.cm.sbx -orient h -command [list $w_cmit xview]
+	scrollbar $w.file_pane.cm.sbx \
-	scrollbar $w.cm.sby -orient v -command [list $w_cmit yview]
+		-orient h \
-	pack $w.cm.sby -side right -fill y
+		-command [list $w_cmit xview]
-	pack $w.cm.sbx -side bottom -fill x
+	scrollbar $w.file_pane.cm.sby \
+		-orient v \
+		-command [list $w_cmit yview]
+	pack $w.file_pane.cm.sby -side right -fill y
+	pack $w.file_pane.cm.sbx -side bottom -fill x
 	pack $w_cmit -expand 1 -fill both
-	pack $w.cm -side bottom -fill x
 
 	menu $w.ctxm -tearoff 0
 	$w.ctxm add command \
@@ -172,7 +188,7 @@ constructor new {i_commit i_path} {
 			$w_load \
 			$w_line \
 			$w_file \
-			] yview $w.out.sby]
+			] yview $w.file_pane.out.sby]
 		bind $i <Button-1> "
 			[cb _hide_tooltip]
 			[cb _click $i @%x,%y]
@@ -212,6 +228,29 @@ constructor new {i_commit i_path} {
 	bind $top <Visibility> [list focus $top]
 	bind $top <Destroy> [list delete_this $this]
 
+	grid configure $w.path -sticky ew
+	grid configure $w.file_pane -sticky nsew
+	grid configure $w.status -sticky ew
+	grid columnconfigure $top 0 -weight 1
+	grid rowconfigure $top 0 -weight 0
+	grid rowconfigure $top 1 -weight 1
+	grid rowconfigure $top 2 -weight 0
+
+	set req_w [winfo reqwidth  $top]
+	set req_h [winfo reqheight $top]
+	if {$req_w < 600} {set req_w 600}
+	if {$req_h < 400} {set req_h 400}
+	set g "${req_w}x${req_h}"
+	wm geometry $top $g
+	update
+
+	set old_height [winfo height $w.file_pane]
+	$w.file_pane sash place 0 \
+		[lindex [$w.file_pane sash coord 0] 0] \
+		[expr {int($old_height * 0.70)}]
+	bind $w.file_pane <Configure> \
+	"if {{$w.file_pane} eq {%W}} {[cb _resize %h]}"
+
 	if {$commit eq {}} {
 		set fd [open $path r]
 	} else {
@@ -633,4 +672,19 @@ method _hide_tooltip {} {
 	}
 }
 
+method _resize {new_height} {
+	set diff [expr {$new_height - $old_height}]
+	if {$diff == 0} return
+
+	set my [expr {[winfo height $w.file_pane] - 25}]
+	set o [$w.file_pane sash coord 0]
+	set ox [lindex $o 0]
+	set oy [expr {[lindex $o 1] + $diff}]
+	if {$oy < 0}   {set oy 0}
+	if {$oy > $my} {set oy $my}
+	$w.file_pane sash place 0 $ox $oy
+
+	set old_height $new_height
+}
+
 }