+# Adjust the progress bar for a change in requested extent or canvas size
+proc adjustprogress {} {
+ global progresscanv progressitem progresscoords
+ global fprogitem fprogcoord lastprogupdate progupdatepending
+
+ set w [expr {[winfo width $progresscanv] - 4}]
+ set x0 [expr {$w * [lindex $progresscoords 0]}]
+ set x1 [expr {$w * [lindex $progresscoords 1]}]
+ set h [winfo height $progresscanv]
+ $progresscanv coords $progressitem $x0 0 $x1 $h
+ $progresscanv coords $fprogitem 0 0 [expr {$w * $fprogcoord}] $h
+ set now [clock clicks -milliseconds]
+ if {$now >= $lastprogupdate + 100} {
+ set progupdatepending 0
+ update
+ } elseif {!$progupdatepending} {
+ set progupdatepending 1
+ after [expr {$lastprogupdate + 100 - $now}] doprogupdate
+ }
+}
+
+proc doprogupdate {} {
+ global lastprogupdate progupdatepending
+
+ if {$progupdatepending} {
+ set progupdatepending 0
+ set lastprogupdate [clock clicks -milliseconds]
+ update
+ }
+}
+