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|
## -*- tcl -*-
# ### ### ### ######### ######### #########
## A discrete zoom-control widget based on buttons. The API is similar
## to a scale.
# ### ### ### ######### ######### #########
## Requisites
package require Tcl 8.4 ; # No {*}-expansion :(
package require snit ; #
package require uevent::onidle ; # Some defered actions.
# ### ### ### ######### ######### #########
##
snit::widget canvas::zoom {
# ### ### ### ######### ######### #########
## API
option -orient -default vertical -configuremethod O-orient -type {snit::enum -values {vertical horizontal}}
option -levels -default 0 -configuremethod O-levels -type {snit::integer -min 0}
option -variable -default {} -configuremethod O-variable
option -command -default {} -configuremethod O-command
constructor {args} {
install reconfigure using uevent::onidle ${selfns}::reconfigure \
[mymethod Reconfigure]
$self configurelist $args
return
}
# ### ### ### ######### ######### #########
## Option processing. Any changes force a refresh of the grid
## information, and then a redraw.
method O-orient {o v} {
#puts $o=$v
if {$options($o) eq $v} return
set options($o) $v
$reconfigure request
return
}
method O-levels {o v} {
#puts $o=$v
if {$options($o) == $v} return
set options($o) $v
$reconfigure request
return
}
method O-variable {o v} {
if {$v eq $options(-variable)} return
if {$options(-variable) ne ""} {
# Drop tracing of now disconnected variable.
trace remove variable $options(-variable) write [mymethod ZoomChanged]
}
set options(-variable) $v
if {$options(-variable) ne ""} {
# Start to trace the now connected variable. Also import
# the zoomlevel external value.
upvar #0 $options(-variable) zoomlevel
set myzoomlevel $zoomlevel
trace add variable $options(-variable) write [mymethod ZoomChanged]
}
$reconfigure request
return
}
method O-command {o v} {
if {$v eq $options(-command)} return
set options(-command) $v
# Export current zoom level through the new callback.
$self Callback
return
}
# ### ### ### ######### ######### #########
component reconfigure
method Reconfigure {} {
# (Re)generate the user interface.
eval [linsert [winfo children $win] 0 destroy]
set side $ourside($options(-orient))
set max $options(-levels)
button $win.outz -text - -command [mymethod ZoomOut]
pack $win.outz -side $side -expand 0 -fill both
set mynormalbg [$win.outz cget -bg]
for {set level 0} {$level < $max} {incr level} {
button $win.l$level -text $level -command [mymethod ZoomSet $level]
pack $win.l$level -side $side -expand 0 -fill both
}
button $win.inz -text + -command [mymethod ZoomIn]
pack $win.inz -side $side -expand 0 -fill both
# Validate the current zoom level, it may have become invalid
# due to a change to max allowed levels.
set z [Cap $myzoomlevel]
if {$z == $myzoomlevel} return
$self Update $z
return
}
# ### ### ### ######### ######### #########
## Handle option changes
# ### ### ### ######### ######### #########
## Events from inside and outside which act on the zoomlevel.
method ZoomChanged {args} {
upvar #0 $options(-variable) zoomlevel
set z [Cap $zoomlevel]
if {$myzoomlevel == $z} return
$self Update $z
return
}
method ZoomSet {new} {
if {$new == $myzoomlevel} return
$self Update $new
return
}
method ZoomIn {} {
if {$myzoomlevel >= ($options(-levels)-1)} return
set new $myzoomlevel
incr new
$self Update $new
return
}
method ZoomOut {} {
if {$myzoomlevel <= 0} return
set new $myzoomlevel
incr new -1
$self Update $new
return
}
proc Cap {n} {
upvar 1 options(-levels) max
if {$n < 0 } { return 0 }
if {$n >= $max } { return [expr {$max - 1}] }
return $n
}
# ### ### ### ######### ######### #########
## Helper, update visible widget state for new level, and
## propagate new level to the model as well, via either -variable
## or -command.
method Update {newlevel} {
catch { $win.l$myzoomlevel configure -bg $mynormalbg }
set myzoomlevel $newlevel
catch { $win.l$myzoomlevel configure -bg steelblue }
if {$options(-variable) ne ""} {
upvar #0 $options(-variable) zoomlevel
set zoomlevel $myzoomlevel
}
$self Callback
return
}
method Callback {} {
if {![llength $options(-command)]} return
uplevel #0 [linsert $options(-command) end $win $myzoomlevel]
return
}
# ### ### ### ######### ######### #########
## State
variable mynormalbg {} ; # Color of non-highlighted button.
variable myzoomlevel 0 ; # Currently chosen zoom level.
# Map from the -orientation to the widget -side to use for
# pack'ing.
typevariable ourside -array {
vertical bottom
horizontal right
}
# ### ### ### ######### ######### #########
}
# ### ### ### ######### ######### #########
## Ready
package provide canvas::zoom 0.1
return
# ### ### ### ######### ######### #########
## Scrap yard.
|
