7GUIs is an interesting project to analyse the usability of different GUI toolkits. The 7 mini-application examples give focussed examples of important GUI patterns, such that the implementation should serve as a guide to how the language and toolkit under use help or hinder the programmer. The linked page includes several interesting references and sample implementations.
I hope to see some interesting Tk implementations to appear, perhaps leading to some discussions of where Tk is not so strong and how it could be improved. Solutions using Tk wrappers such as GRIDPLUS2, Dynaforms and TAO/Tk are particularly welcome.
Please add your implementations to this page, or critique ones already here. Adding a single solution (instead of all 7) is welcome, particularly if it highlights a beautiful technique. While showing off 3rd-party libraries is encouraged, at least one "naive Tk" implementation of each example should exist. Though for Cells I fully endorse the use of tablelist, purely on the assumption that no Tk programmer should be without it!
aspect: These are intended to highlight how to use core Tcl/Tk features without relying on 3rd-party libraries. The code should be self-contained, though relying on bundled extensions such as ttk, sqlite3 is not discouraged and tcllib / tklib dependencies are not out of the question.
Enough "good practice" should be present to make the examples easy to extend or incorporate into a larger program without butchery. Thus doing everything inside a namespace, despite the extra verbosity of namespace which.
The first 5 examples included below (all but Flight Booker and Crud) were hacked together somewhat hastily on a Sunday afternoon, the same day I saw the original article. The two remaining I shied away from, as a significant part of their challenge is "Form layout", which I find to be one of Tk's weaknesses. A solution based on WJD's Dynaforms (link below) makes these much nicer to write, but my version is currently in "over-engineered" state and not yet ready for release.
#!/usr/bin/env tclsh package require Tk namespace eval app { variable c 0 entry .e -state readonly -textvariable [namespace which -variable c] button .b -text Count -command [list incr [namespace which -variable c]] pack .e .b -side left wm title . Counter } wm protocol . WM_DELETE_WINDOW exit vwait forever
#!/usr/bin/env tclsh package require Tk package require lambda namespace eval app { variable c 0 variable f 32 proc c2f {} { puts c2f variable c variable f set f [format %.1f [expr {$c * 9 / 5.0 + 32}]] } proc f2c {} { puts f2c variable f variable c set c [format %.1f [expr {($f - 32) * 5 / 9.0}]] } entry .c -textvariable [namespace which -variable c] entry .f -textvariable [namespace which -variable f] label .cl -text "\u00b0 Celcius" label .fl -text "\u00b0 Fahrenheit" trace add variable c write [lambda@ [namespace current] args c2f] trace add variable f write [lambda@ [namespace current] args f2c] pack .c .cl .f .fl -side left } wm title . "Temperature Converter" wm protocol . WM_DELETE_WINDOW exit vwait forever
This is an example of dependent widgets (whose readonly status is a function of other widgets' values), which is fun with an approach like WJD's dynaforms (paper here ), but a little cumbersome in ordinary Tk (imo). Example Coming Soon.
Naïve solutions #1 and #2 above are already beginning to show that namespace management easily become distracting. TclOO helps a lot:
#!/usr/bin/env tclsh package require Tk package require lambda oo::class create Timer { variable percent 0 variable started [clock milliseconds] variable seconds 0s variable duration 10.0 constructor {} { set duration 10.0 label .pl -text "Elapsed Time:" ttk::progressbar .p -variable [my varname percent] -orient h label .l -textvariable [my varname seconds] label .sl -text "Duration:" scale .s -variable [my varname duration] -orient h -from 0.0 -to 15.0 -resolution 0.1 button .r -text "Reset" -command [namespace code {my reset}] grid .pl .p -sticky nsew grid .l - -sticky nsew grid .sl .s -sticky nsew grid .r - -sticky nsew grid columnconfigure . 1 -weight 1 wm title . Timer my reset after idle [namespace code {my tick}] } method reset {} { set started [clock milliseconds] } method tick {} { set now [clock milliseconds] set elapsed [expr {($now - $started) / 100 / 10.0}] set percent [expr {$elapsed * 100 / $duration}] if {$percent <= 100} { set seconds [format %.1fs $elapsed] } else { set started [expr {$now - int($duration * 1000)}] } after idle [namespace code {my tick}] } } Timer create t wm protocol . WM_DELETE_WINDOW exit vwait forever
EG There are a few problems in this code.
Pretty sure we've all written more than plenty of these, but a concise, readable example using modern features will be fun.
This is a nice little demo of canvas, but also calls for some helper code. The most interesting part is an undo facility.
The code below is very rough, but it demonstrates some patterns that really ought to be factored out for reuse .. unless anyone has something better pre-rolled? ;-)
The verbosity of this implementation suggests that it's showing some gaps where Tk could help some more. Still, 200 lines isn't terrible.
#!/usr/bin/env tclsh package require Tk package require lambda # wraps a script in a lambda that ignores all its arguments # useful for making traces proc ignoreargs {script} { lambda@ [uplevel 1 {self namespace}] args $script } # list-based stack interp alias {} lpush {} lappend proc lpop {_ls varName args} { upvar 1 $_ls ls set vals [lrange $ls end-[llength $args] end] set ls [lreplace $ls end-[llength $args] end] tailcall ::foreach [list $varName {*}$args] $vals {} } # [incr] that doesn't choke on floats proc incf {varName {expr 1}} { set varName [list $varName] tailcall if "\[info exists $varName\]" " set $varName \[expr {\${$varName} + $expr}\] " "else" " set $varName \[expr {$expr}\] " } # dialog box which handles resizing oo::class create Resizer { variable w variable radius variable id variable obj variable undo constructor {W Obj Id} { set w $W set obj $Obj set id $Id lassign [$obj get_center $id] x y set radius [$obj get_radius $id] set undo [list resize_circle $id $radius] label $w.l -text "Adjust diameter of circle at ($x, $y)" scale $w.s -variable [my varname radius] -orient h -from 10.0 -to 500.0 -resolution 1.0 button $w.b -text "Done" -command [namespace code {my Done}] button $w.c -text "Cancel" -command [namespace code {my Cancel}] grid $w.l - -sticky nsew grid $w.s - -sticky nsew grid $w.b $w.c -sticky nsew trace add variable [my varname radius] write [ignoreargs {my Changed}] } method Changed {} { puts "Resizing $id to $radius" $obj resize_circle $id $radius } method Cancel {} { $obj {*}$undo destroy $w after idle [list [self] destroy] } method Done {} { $obj push_undo $undo destroy $w after idle [list [self] destroy] } } proc resize_circle {obj id} { set w .resize_${id} if {[winfo exists $w]} { raise $w focus $w return } toplevel $w Resizer new $w $obj $id } oo::class create Circles { constructor {} { canvas .c -width 480 -height 320 -background white button .u -text "Undo" -command [namespace code {my undo}] button .r -text "Redo" -command [namespace code {my redo}] grid .c - -sticky nsew grid .u .r -sticky nsew grid columnconfigure . 0 -weight 1 grid columnconfigure . 1 -weight 1 grid rowconfigure . 0 -weight 1 bind .c <Configure> [namespace code {my canvas.configure %w %h}] bind .c <Button-1> [namespace code {my canvas.b1 %x %y}] bind .c <Button-3> [namespace code {my canvas.b3 %x %y}] oo::objdefine [self] forward canvas .c } # event handlers method canvas.configure {w h} { # .c scale all 0 0 [expr {1.0/$w}] [expr {1.0/$h}] } method canvas.b1 {x y} { set item [.c find withtag current] if {$item ne ""} { # do nothing } else { my do add_circle $x $y } } method canvas.b3 args { set item [.c find withtag current] if {$item ne ""} { resize_circle [self] $item } } # undo helpers variable undo_stack variable redo_stack method do {cmd args} { lpush undo_stack [my $cmd {*}$args] } method push_undo {cmd args} { lpush undo_stack $cmd {*}$args } method undo {} { if {$undo_stack eq ""} {return} lpop undo_stack cmd puts "undo: $cmd" lpush redo_stack [my {*}$cmd] } method redo {} { if {$redo_stack eq ""} {return} lpop redo_stack cmd puts "redo: $cmd" lpush undo_stack [my {*}$cmd] } # circle geometry helpers method get_center {item} { foreach {x0 y0} [.c coords $item] { incf x $x0 incf y $y0 incr n } set x [expr {$x / $n}] set y [expr {$y / $n}] list $x $y } method get_radius {item} { lassign [.c coords $item] x0 y0 x1 y1 expr {( ($x1 - $x0) + ($y1 - $y0) ) / 4} } # actions: each of these returns an undo action method add_circle {x y {r 50} args} { set x0 [expr {$x-$r}] set x1 [expr {$x+$r}] set y0 [expr {$y-$r}] set y1 [expr {$y+$r}] set id [.c create oval $x0 $y0 $x1 $y1 -fill white {*}$args -activefill grey] return [list delete_circle $id] } method delete_circle {id} { foreach {x y} [my get_center $id] {} set r [my get_radius $id] set cfg [lmap ci [.c itemconfigure $id] { if {[lindex $ci 4] eq [lindex $ci 3]} { # catches defaults and synonyms continue } list [lindex $ci 0] [lindex $ci 4] }] .c delete $id return [concat add_circle $x $y $r {*}$cfg] } method resize_circle {id radius} { foreach {x y} [my get_center $id] {} set oldr [my get_radius $id] set x0 [expr {$x - $radius}] set x1 [expr {$x + $radius}] set y0 [expr {$y - $radius}] set y1 [expr {$y + $radius}] .c coords $id $x0 $y0 $x1 $y1 return "resize_circle $id $oldr" } } Circles create c wm protocol . WM_DELETE_WINDOW exit
This one uses the brilliant tablelist widget to simulate a spreadsheet UI. In a slight deviation from the normal spec, cell references are prefixed with $: more specifically, formulas are of the form =expr, where expr is a Tcl expression, where $A2, $B6, $Z99 refer to other cells' values.
It features a clever unbound command, which colin once shared with the chat.
Keyboard bindings and the size of the edit window could be improved.
Other examples like this exist on the wiki .. see A bigger spreadsheet for one.
#!/usr/bin/env tclsh # package require Tk package require tablelist # REQUIRES: # [lremove] proc lremove {_ls args} { upvar 1 $_ls ls foreach a $args { set ls [lsearch -exact -not -all -inline $ls $a] } } # [unbound] -- originally from colin proc unbound {__text} { set __unbound {} while {$__text ne ""} { try { dict with __unbound { subst -nocommands -nobackslashes $__text } } trap {TCL LOOKUP VARNAME} {__e __eo} { dict set __unbound [lindex [dict get $__eo -errorcode] end] \$[lindex [dict get $__eo -errorcode] end] } on error {e eo} { puts stderr "$e ($eo)" return -options $eo $e ;# improvement due to dgp } on ok {} { return [dict keys $__unbound] } } } variable Alphabet " ABCDEFGHIJKLMNOPQRSTUVWXYZ" oo::class create Sheet { variable W variable Values ;# list of lists of values, bound to display variable Formulas ;# array(CellId) -> "=$expr" variable Depends ;# array(CellId) -> {dependent cellids ..} constructor {{w .}} { if {$w eq "."} {set w ""} set W $w # create widgets tablelist::tablelist ${W}.tl -selecttype cell ttk::sizegrip ${W}.z -takefocus 0 scrollbar ${W}.sy -orient v -command [list ${W}.tl yview] scrollbar ${W}.sx -orient h -command [list ${W}.tl xview] ${W}.tl configure -xscrollcommand [list ${W}.sx set] ${W}.tl configure -yscrollcommand [list ${W}.sy set] # set up tablelist $W.tl configure -columntitles [split $::Alphabet ""] $W.tl configure -editstartcommand [namespace code {my EditStart}] $W.tl configure -editendcommand [namespace code {my EditEnd}] for {set i 1} {$i < 27} {incr i} { $W.tl columnconfigure $i -editable 1 } # columns don't support -relief or -border .. FIXME! foreach opt {background foreground font } { $W.tl columnconfigure 0 -${opt} [$W.tl cget -label${opt}] } # set up Values set 26 [lrepeat 26 {}] for {set i 0} {$i < 99} {incr i} { lappend Values [list $i {*}$26] } $W.tl configure -listvariable [my varname Values] # lay out: grid ${W}.tl ${W}.sy -sticky nsew grid ${W}.sx ${W}.z -sticky nsew set w .[string trimleft $W .] grid columnconfigure $w 0 -weight 1 grid rowconfigure $w 0 -weight 1 } method Eval {script} { ;# debugging helper try $script } method CellId {x y} { return [string index $::Alphabet $x]$y } method CellRef {id} { regexp {([A-Z]+)([0-9]+)} $id -> x y set x [string first $x $::Alphabet] list $x $y } method EditStart {tl y x dispvalue} { set cellid [my CellId $x $y] if {[info exists Formulas($cellid)]} { set f $Formulas($cellid) unset Formulas($cellid) foreach ub [unbound $f] { lremove Depends($ub) $cellid } return $f } return $dispvalue } method EditEnd {tl y x newvalue} { set cellid [my CellId $x $y] after idle [namespace code [list my Recalculate $cellid]] if {[string match =* $newvalue]} { set Formulas($cellid) $newvalue foreach ub [unbound $newvalue] { if {![info exists Depends($ub)] || $cellid ni $Depends($ub)} { lappend Depends($ub) $cellid } } return -1 } # $tl rejectinput return $newvalue } method Evaluate {expr} { set expr [string trimleft $expr =] set env [lmap name [unbound $expr] { lassign [my CellRef $name] x y list $name [lindex $Values $y $x] }] try { apply [list $env [list expr $expr]] } on error {e o} { return "#!ERROR" } } method Recalculate {cellid} { lassign [my CellRef $cellid] x y if {[info exists Formulas($cellid)]} { set expr $Formulas($cellid) set val [my Evaluate $expr] lset Values $y $x $val } if {[info exists Depends($cellid)]} { foreach dep $Depends($cellid) { after idle [namespace code [list my Recalculate $dep]] } } } } Sheet create s wm protocol . WM_DELETE_WINDOW exit