# megawidget.tcl # # Basic megawidget support classes. Experimental for any use other than # the ::tk::IconList megawdget, which is itself only designed for use in # the Unix file dialogs. # # Copyright (c) 2009-2010 Donal K. Fellows # # See the file "license.terms" for information on usage and redistribution of # this file, and for a DISCLAIMER OF ALL WARRANTIES. # package require Tk ::oo::class create ::tk::Megawidget { superclass ::oo::class method unknown {w args} { if {[string match .* $w]} { [self] create $w {*}$args return $w } next $w {*}$args } unexport new unknown self method create {name superclasses body} { next $name [list \ superclass ::tk::MegawidgetClass {*}$superclasses]\;$body } } ::oo::class create ::tk::MegawidgetClass { variable w hull options IdleCallbacks constructor args { # Extract the "widget name" from the object name set w [namespace tail [self]] # Configure things tclParseConfigSpec [my varname options] [my GetSpecs] "" $args # Move the object out of the way of the hull widget rename [self] _tmp # Make the hull widget(s) my CreateHull bind $hull [list [namespace which my] destroy] # Rename things into their final places rename ::$w theWidget rename [self] ::$w # Make the contents my Create } destructor { foreach {name cb} [array get IdleCallbacks] { after cancel $cb unset IdleCallbacks($name) } if {[winfo exists $w]} { bind $hull {} destroy $w } } #################################################################### # # MegawidgetClass::configure -- # # Implementation of 'configure' for megawidgets. Emulates the operation # of the standard Tk configure method fairly closely, which makes things # substantially more complex than they otherwise would be. # # This method assumes that the 'GetSpecs' method returns a description # of all the specifications of the options (i.e., as Tk returns except # with the actual values removed). It also assumes that the 'options' # array in the class holds all options; it is up to subclasses to set # traces on that array if they want to respond to configuration changes. # # TODO: allow unambiguous abbreviations. # method configure args { # Configure behaves differently depending on the number of arguments set argc [llength $args] if {$argc == 0} { return [lmap spec [my GetSpecs] { lappend spec $options([lindex $spec 0]) }] } elseif {$argc == 1} { set opt [lindex $args 0] if {[info exists options($opt)]} { set spec [lsearch -inline -index 0 -exact [my GetSpecs] $opt] return [linsert $spec end $options($opt)] } } elseif {$argc == 2} { # Special case for where we're setting a single option. This # avoids some of the costly operations. We still do the [array # get] as this gives a sufficiently-consistent trace. set opt [lindex $args 0] if {[dict exists [array get options] $opt]} { # Actually set the new value of the option. Use a catch to # allow a megawidget user to throw an error from a write trace # on the options array to reject invalid values. try { array set options $args } on error {ret info} { # Rethrow the error to get a clean stack trace return -code error -errorcode [dict get $info -errorcode] $ret } return } } elseif {$argc % 2 == 0} { # Check that all specified options exist. Any unknown option will # cause the merged dictionary to be bigger than the options array set merge [dict merge [array get options] $args] if {[dict size $merge] == [array size options]} { # Actually set the new values of the options. Use a catch to # allow a megawidget user to throw an error from a write trace # on the options array to reject invalid values try { array set options $args } on error {ret info} { # Rethrow the error to get a clean stack trace return -code error -errorcode [dict get $info -errorcode] $ret } return } # Due to the order of the merge, the unknown options will be at # the end of the dict. This makes the first unknown option easy to # find. set opt [lindex [dict keys $merge] [array size options]] } else { set opt [lindex $args end] return -code error -errorcode [list TK VALUE_MISSING] \ "value for \"$opt\" missing" } return -code error -errorcode [list TK LOOKUP OPTION $opt] \ "bad option \"$opt\": must be [tclListValidFlags options]" } #################################################################### # # MegawidgetClass::cget -- # # Implementation of 'cget' for megawidgets. Emulates the operation of # the standard Tk cget method fairly closely. # # This method assumes that the 'options' array in the class holds all # options; it is up to subclasses to set traces on that array if they # want to respond to configuration reads. # # TODO: allow unambiguous abbreviations. # method cget option { return $options($option) } #################################################################### # # MegawidgetClass::TraceOption -- # # Sets up the tracing of an element of the options variable. # method TraceOption {option method args} { set callback [list my $method {*}$args] trace add variable options($option) write [namespace code $callback] } #################################################################### # # MegawidgetClass::GetSpecs -- # # Return a list of descriptions of options supported by this # megawidget. Each option is described by the 4-tuple list, consisting # of the name of the option, the "option database" name, the "option # database" class-name, and the default value of the option. These are # the same values returned by calling the configure method of a widget, # except without the current values of the options. # method GetSpecs {} { return { {-takefocus takeFocus TakeFocus {}} } } #################################################################### # # MegawidgetClass::CreateHull -- # # Creates the real main widget of the megawidget. This is often a frame # or toplevel widget, but isn't always (lightweight megawidgets might # use a content widget directly). # # The name of the hull widget is given by the 'w' instance variable. The # name should be written into the 'hull' instance variable. The command # created by this method will be renamed. # method CreateHull {} { return -code error -errorcode {TCL OO ABSTRACT_METHOD} \ "method must be overridden" } #################################################################### # # MegawidgetClass::Create -- # # Creates the content of the megawidget. The name of the widget to # create the content in will be in the 'hull' instance variable. # method Create {} { return -code error -errorcode {TCL OO ABSTRACT_METHOD} \ "method must be overridden" } #################################################################### # # MegawidgetClass::WhenIdle -- # # Arrange for a method to be called on the current instance when Tk is # idle. Only one such method call per method will be queued; subsequent # queuing actions before the callback fires will be silently ignored. # The additional args will be passed to the callback, and the callbacks # will be properly cancelled if the widget is destroyed. # method WhenIdle {method args} { if {![info exists IdleCallbacks($method)]} { set IdleCallbacks($method) [after idle [list \ [namespace which my] DoWhenIdle $method $args]] } } method DoWhenIdle {method arguments} { unset IdleCallbacks($method) tailcall my $method {*}$arguments } } #################################################################### # # tk::SimpleWidget -- # # Simple megawidget class that makes it easy create widgets that behave # like a ttk widget. It creates the hull as a ttk::frame and maps the # state manipulation methods of the overall megawidget to the equivalent # operations on the ttk::frame. # ::tk::Megawidget create ::tk::SimpleWidget {} { variable w hull options method GetSpecs {} { return { {-cursor cursor Cursor {}} {-takefocus takeFocus TakeFocus {}} } } method CreateHull {} { set hull [::ttk::frame $w -cursor $options(-cursor)] my TraceOption -cursor UpdateCursorOption } method UpdateCursorOption args { $hull configure -cursor $options(-cursor) } # Not fixed names, so can't forward method state args { tailcall $hull state {*}$args } method instate args { tailcall $hull instate {*}$args } } #################################################################### # # tk::FocusableWidget -- # # Simple megawidget class that makes a ttk-like widget that has a focus # ring. # ::tk::Megawidget create ::tk::FocusableWidget ::tk::SimpleWidget { variable w hull options method GetSpecs {} { return { {-cursor cursor Cursor {}} {-takefocus takeFocus TakeFocus ::ttk::takefocus} } } method CreateHull {} { ttk::frame $w set hull [ttk::entry $w.cHull -takefocus 0 -cursor $options(-cursor)] pack $hull -expand yes -fill both -ipadx 2 -ipady 2 my TraceOption -cursor UpdateCursorOption } } return # Local Variables: # mode: tcl # fill-column: 78 # End: