[ulis], 2003-06-28: A hacked package to scroll a frame in pure Tcl/Tk.

2003-11-07, v 0.9.1: automatic scroll on resize.

[http://perso.wanadoo.fr/maurice.ulis/tcl/ScrolledFrame/ScrolledFrame.gif]

----

'''The package'''

  if {[info exists ::scrolledframe::version]} { return }
  namespace eval ::scrolledframe \
  {
  # beginning of ::scrolledframe namespace definition

    namespace export scrolledframe

  # ==============================
  #
  # scrolledframe
  set version 0.9.1
  #
  # a scrolled frame
  #
  # (C) 2003, ulis
  #
  # NOL licence (No Obligation Licence)
  #
  # ==============================
  #
  # Hacked package, no documentation, sorry
  # See example at bottom
  #
  # ------------------------------
  # v 0.9.1
  #  automatic scroll on resize
  # ==============================

    package provide Scrolledframe $version

    # --------------
    #
    # create a scrolled frame
    #
    # --------------
    # parm1: widget name
    # parm2: options key/value list
    # --------------
    proc scrolledframe {w args} \
    {
      variable {}
      # create a scrolled frame
      frame $w
      # trap the reference
      rename $w ::scrolledframe::_$w
      # redirect to dispatch
      interp alias {} $w {} ::scrolledframe::dispatch $w
      # create scrollable internal frame
      frame $w.scrolled -highlightt 0 -padx 0 -pady 0
      # place it
      place $w.scrolled -in $w -x 0 -y 0
      # init internal data
      set ($w:vheight) 0
      set ($w:vwidth) 0
      set ($w:vtop) 0
      set ($w:vleft) 0
      set ($w:xscroll) ""
      set ($w:yscroll) ""
      # configure
      if {$args != ""} { uplevel 1 ::scrolledframe::config $w $args }
      # bind <Configure>
      bind $w <Configure> [namespace code [list vresize $w]]
      bind $w.scrolled <Configure> [namespace code [list resize $w]]
      # return widget ref
      return $w
    }

    # --------------
    #
    # dispatch the trapped command
    #
    # --------------
    # parm1: widget name
    # parm2: operation
    # parm2: operation args
    # --------------
    proc dispatch {w cmd args} \
    {
      variable {}
      switch -glob -- $cmd \
      {
        con*    { uplevel 1 [linsert $args 0 ::scrolledframe::config $w] }
        xvi*    { uplevel 1 [linsert $args 0 ::scrolledframe::xview  $w] }
        yvi*    { uplevel 1 [linsert $args 0 ::scrolledframe::yview  $w] }
        default { uplevel 1 [linsert $args 0 ::scrolledframe::_$w    $cmd] }
      }
    }

    # --------------
    # configure operation
    #
    # configure the widget
    # --------------
    # parm1: widget name
    # parm2: options
    # --------------
    proc config {w args} \
    {
      variable {}
      set options {}
      set flag 0
      foreach {key value} $args \
      {
        switch -glob -- $key \
        {
          -xsc*   \
          {
            # new xscroll option
            set ($w:xscroll) $value
            set flag 1
          }
          -ysc*   \
          {
            # new yscroll option
            set ($w:yscroll) $value
            set flag 1
          }
          default { lappend options $key $value }
        }
      }
      # check if needed
      if {!$flag || $options != ""} \
      { 
        # call frame config
        uplevel 1 [linsert $options 0 ::scrolledframe::_$w config]
      }
    }

    # --------------
    # resize proc
    #
    # resize the scrolled region
    # --------------
    # parm1: widget name
    # --------------
    proc resize {w} \
    {
      variable {}
      # compute new height & width
      set ($w:vheight) [winfo reqheight $w.scrolled]
      set ($w:vwidth) [winfo reqwidth $w.scrolled]
      # resize the scroll bars
      vresize $w
    }

    # --------------
    # vresize proc
    #
    # resize the visible part
    # --------------
    # parm1: widget name
    # --------------
    proc vresize {w} \
    { 
      xview $w scroll 0 unit
      yview $w scroll 0 unit
      xset $w
      yset $w 
    }

    # --------------
    # xset proc
    #
    # resize the visible part
    # --------------
    # parm1: widget name
    # --------------
    proc xset {w} \
    {
      variable {}
      # call the xscroll command
      set cmd $($w:xscroll)
      if {$cmd != ""} { catch { eval $cmd [xview $w] } }
    }

    # --------------
    # yset proc
    #
    # resize the visible part
    # --------------
    # parm1: widget name
    # --------------
    proc yset {w} \
    {
      variable {}
      # call the yscroll command
      set cmd $($w:yscroll)
      if {$cmd != ""} { catch { eval $cmd [yview $w] } }
    }

    # -------------
    # xview
    #  
    # called on horizontal scrolling
    # -------------
    # parm1: widget path
    # parm2: optional moveto or scroll
    # parm3: fraction if parm2 == moveto, count unit if parm2 == scroll
    # -------------
    # return: scrolling info if parm2 is empty
    # -------------

    proc xview {w {cmd ""} args} \
    {
      variable {}
      # check args
      set len [llength $args]
      switch -glob -- $cmd \
      {
        ""      {}
        mov*    \
        { if {$len != 1} { error "wrong # args: should be \"$w xview moveto fraction\"" } }
        scr*    \
        { if {$len != 2} { error "wrong # args: should be \"$w xview scroll count unit\"" } }
        default \
        { error "unknown operation \"$cmd\": should be empty, moveto or scroll" }
      }
      # save old values
      set _vleft $($w:vleft)
      set _vwidth $($w:vwidth)
      set _width [winfo width $w]
      # compute new vleft
      set count ""
      switch $len \
      {
        0       \
        { 
          # return fractions
          if {$_vwidth == 0} { return {0 1} }
          set first [expr {double($_vleft) / $_vwidth}]
          set last [expr {double($_vleft + $_width) / $_vwidth}]
          if {$last > 1.0} { return {0 1} }
          return [list [format %g $first] [format %g $last]]
        }
        1       \
        { 
          # absolute movement
          set vleft [expr {int(double($args) * $_vwidth)}]
        }
        2       \
        { 
          # relative movement
          foreach {count unit} $args break
          if {[string match p* $unit]} { set count [expr {$count * 9}] }
          set vleft [expr {$_vleft + $count * 0.1 * $_width}]
        }
      }
      if {$vleft < 0} { set vleft 0 }
      if {$vleft + $_width > $_vwidth} { set vleft [expr {$_vwidth - $_width}] }
      if {$vleft != $_vleft || $count == 0} \
      {
        set ($w:vleft) $vleft
        xset $w
        place $w.scrolled -in $w -x [expr {-$vleft}]
      }
    }

    # -------------
    # yview
    #  
    # called on vertical scrolling
    # -------------
    # parm1: widget path
    # parm2: optional moveto or scroll
    # parm3: fraction if parm2 == moveto, count unit if parm2 == scroll
    # -------------
    # return: scrolling info if parm2 is empty
    # -------------

    proc yview {w {cmd ""} args} \
    {
      variable {}
      # check args
      set len [llength $args]
      switch -glob -- $cmd \
      {
        ""      {}
        mov*    \
        { if {$len != 1} { error "wrong # args: should be \"$w yview moveto fraction\"" } }
        scr*    \
        { if {$len != 2} { error "wrong # args: should be \"$w yview scroll count unit\"" } }
        default \
        { error "unknown operation \"$cmd\": should be empty, moveto or scroll" }
      }
      # save old values
      set _vtop $($w:vtop)
      set _vheight $($w:vheight)
      set _height [winfo height $w]
      # compute new vtop
      set count ""
      switch $len \
      {
        0       \
        { 
          # return fractions
          if {$_vheight == 0} { return {0 1} }
          set first [expr {double($_vtop) / $_vheight}]
          set last [expr {double($_vtop + $_height) / $_vheight}]
          if {$last > 1.0} { return {0 1} }
          return [list [format %g $first] [format %g $last]]
        }
        1       \
        { 
          # absolute movement
          set vtop [expr {int(double($args) * $_vheight)}]
        }
        2       \
        { 
          # relative movement
          foreach {count unit} $args break
          if {[string match p* $unit]} { set count [expr {$count * 9}] }
          set vtop [expr {$_vtop + $count * 0.1 * $_height}]
        }
      }
      if {$vtop < 0} { set vtop 0 }
      if {$vtop + $_height > $_vheight} { set vtop [expr {$_vheight - $_height}] }
      if {$vtop != $_vtop || $count == 0} \
      {
        set ($w:vtop) $vtop
        yset $w
        place $w.scrolled -in $w -y [expr {-$vtop}]
        puts "place $w.scrolled -in $w -y [expr {-$vtop}]"
      }
    }

  # end of ::scrolledframe namespace definition
  }

----

'''The demo'''

  # ==============================
  #
  # demo
  #
  # ==============================

    if {[catch {package require Scrolledframe}]} \
    {
      source [file join [file dirname [info script]] scrolledframe.tcl]
      package require Scrolledframe
    }
    namespace import ::scrolledframe::scrolledframe
    scrolledframe .sf -height 150 -width 100 \
        -xscroll {.hs set} -yscroll {.vs set}
    scrollbar .vs -command {.sf yview}
    scrollbar .hs -command {.sf xview} -orient horizontal
    grid .sf -row 0 -column 0 -sticky nsew
    grid .vs -row 0 -column 1 -sticky ns
    grid .hs -row 1 -column 0 -sticky ew
    grid rowconfigure . 0 -weight 1
    grid columnconfigure . 0 -weight 1
    set f .sf.scrolled
    foreach i {0 1 2 3 4 5 6 7 8 9} \
    { 
      label $f.l$i -text "Hi! I'm the scrolled label $i" -relief groove
      pack $f.l$i -padx 10 -pady 2
    }

----

'''Another demo'''

  # packages
  source ../Scrolledframe/scrolledframe.tcl
  namespace import ::scrolledframe::scrolledframe
  package require Tk
  # create widgets
  set bd 2
  set bd2 [expr {$bd * 2}]
  frame .f0 -bd 1 -relief groove
  frame .f1
  button .f1._A4 -text A4 -width 10 -command {size A4}
  button .f1._A3 -text A3 -width 10 -command {size A3}
  pack .f1._A4 .f1._A3 -padx 10 -pady 10 -side left
  scrolledframe .f2 -xscrollc {.hs set} -yscrollc {.vs set}
  canvas .f2.scrolled.c -bd 1 -relief ridge \
      -highlightt 0 -bg beige
  .f2.scrolled.c create text 0 0 -tags size
  pack .f2.scrolled.c
  scrollbar .vs -command {.f2 yview}
  scrollbar .hs -command {.f2 xview} -orient horizontal
  # place widgets
  grid .f0 -row 1 -column 0 -sticky nsew
  grid .f1 -row 0 -column 0 -columnspan 2
  grid .f2 -row 1 -column 0
  grid .vs -row 1 -column 1 -sticky ns
  grid .hs -row 2 -column 0 -sticky ew
  grid rowconfigure . 1 -weight 1
  grid columnconfigure . 0 -weight 1
  wm geometry . 300x400
  # sizing the canvas
  proc size {size} \
  { 
    switch $size \
    {
      A3    { set width 297; set height 420 }
      A4    { set width 210; set height 297 }
    }
    set c .f2.scrolled.c
    $c config -width $width -height $height 
    set bd [$c cget -bd]
    set bd*2 [expr {$bd * 2}]
    .f2 config -width [incr width ${bd*2}] -height [incr height ${bd*2}]
    $c coords size [expr {$width / 2}] [expr {$height / 2}]
    $c itemconfig size -text $size
  }
  # init
  size A4

----

'''See also'''
   * [Scrolled.frame]
   * [scrolledframe]
----

Roalt, June 30th, 2003

To use the scrolledframe without thinking about adding scrollbars, use the following 
wrapper to replace your "set f [[frame .f]]" call by a "set f [[scrollframe .f]]" call:

[ulis], 2003-06-30: When using the wrapper, be aware to only use the grid geometry manager inside the parent of the frame. This because the wrapper uses it and that geometry managers can't be mixed.

----
  # function to wrap the scrolledframe package
  proc scrollframe { fname args } {
    
    set parent [eval frame $fname $args]

    scrolledframe $parent.sf \
        -xscroll "$parent.hs set" -yscroll "$parent.vs set"
    scrollbar $parent.vs -command "$parent.sf yview"
    scrollbar $parent.hs -command "$parent.sf xview" -orient horizontal
    grid $parent.sf -row 0 -column 0 -sticky nsew
    grid $parent.vs -row 0 -column 1 -sticky ns
    grid $parent.hs -row 1 -column 0 -sticky ew
    grid rowconfigure $parent 0 -weight 1
    grid columnconfigure $parent 0 -weight 1
    return $parent.sf.scrolled
  }

----

A fully wrapped example that also passes the arguments to the scrolled internal frame.

 proc Scrolled_Frame { fname args } {
    set parent [eval frame $fname $args]
    scrolledframe $parent.sf -xscroll [list $parent.hs set] -yscroll [list $parent.vs set]
    foreach {arg1 arg2} $args {
        $parent.sf.scrolled configure $arg1 $arg2
    }
    scrollbar $parent.vs -command [list $parent.sf yview] -orient vertical
    scrollbar $parent.hs -command [list $parent.sf xview] -orient horizontal
    grid $parent.sf -row 0 -column 0 -sticky news
    grid $parent.vs -row 0 -column 1 -sticky ns
    grid $parent.hs -row 1 -column 0 -sticky ew
    grid rowconfigure $parent 0 -weight 1
    grid columnconfigure $parent 0 -weight 1
    return $parent.sf.scrolled
 }
 set blah [Scrolled_Frame .sf -bg #ffffff -relief sunken -bd 50]
 set blah2 [Scrolled_Frame .sf2]
 set blah3 [Scrolled_Frame .sf3 -bg #666666 -relief groove -bd 2]
 set x 0
 while {$x < 100} {
    label $blah.$x -text "This is a Scrolled Frame."
    grid $blah.$x -row $x -column $x -sticky news
    label $blah2.$x -text "This is also a Scrolled Frame."
    grid $blah2.$x -row $x -column $x -sticky news
    label $blah3.$x -text "You guessed it."
    grid $blah3.$x -row $x -column $x -sticky news
    incr x
 }
 pack .sf -fill both -expand true
 pack .sf2 -fill both -expand true
 pack .sf3 -fill both -expand true

----
So, how about some examples of using the above package and proc?

For instance, above, under the screenshot, how about showing the code which
created it?

[ulis]: see '''The demo''' & '''Another demo'''

Will this code be going into [tklib]?
----
[Category Example] 
|
[Category GUI] 
|
[Category Widget]