Simple Block Selection for Text Widget

MEd 2006-02-13: Another feature taken from MetPad (will be available in version 0.7). It adds block-selection capabilities to text widgets. The normal text widget selection is line-based, block selection allows you to select text square-based ...well, not easy to explain, if you are in doubt just try it out ;)

Usage:

1. Control-ButtonPress-1 to activate block selection
2. Control-Button1-Motion to modify (increase/decrease) the selection
3. Control-x to cut selection, Control-c to copy selection to clipboard

Known Issues:

• Troubles when using Tabs
• Selection currently works only from top-left to bottom-right

    ##########################################################
    # Name:  blocksel.tcl
    # Author: Martin Eder, [email protected]
    # Description: Enables block selection for text widgets
    ##########################################################

    variable spos

    proc block_sel {wid x y} {
        $wid tag remove sel 0.0 end
        set fpos [split [$wid index "@$x,$y"] "."]
        for {set sl [lindex $::spos 0]} {$sl <= [lindex $fpos 0]} {incr sl} {
            $wid tag add sel "$sl.[lindex $::spos 1]" "$sl.[lindex $fpos 1]"
        }
    }

    proc mouse_down {wid x y} {
        $wid mark set insert "@$x,$y"
        $wid tag remove sel 0.0 end
        set ::spos [split [$wid index insert] "."]
    }

    proc copy_blocksel {txt {cutit 0}} {
        set starttag [$txt index end]
        set mseltxt ""

        while {[set curmtag [$txt tag prevrange sel $starttag]] != ""} {
            set msta [lindex $curmtag 0]
            set msto [lindex $curmtag 1]
            set mseltxt "[$txt get $msta $msto]\n$mseltxt"
            if {$cutit == 1} {$txt delete $msta $msto}
            set starttag [lindex $curmtag 0]
        }
        if {$mseltxt != ""} {
            clipboard clear
            clipboard append -- $mseltxt
        }
    }

    bind Text <Control-ButtonPress-1> [list mouse_down %W %x %y]
    bind Text <Control-Button1-Motion> [list block_sel %W %x %y]
    bind Text <Control-Key-x> [list copy_blocksel .txt 1]
    bind Text <Control-Key-c> [list copy_blocksel .txt 0]

    # Testing the code:
    pack [text .txt -font "Courier 10"]
    .txt insert end "To activate block-selection press Ctrl + left mouse button
    and keep pressed. Move the mouse to increase/decrease the block.
    Press Ctrl+c to copy the selection to the clipboard.
    Press Ctrl+x to cut the selection.
    Known Issues: -Difficulties with <Tabs>
                  -Selection just works just from top-left to bottom-right"
    ### End Of Script

See also text .

SeS - 2010-02-01 12:09:21

Hi, thank you for the script to enable block selection. I was able to improve the script to enable selection from bottom-right to top-left direction.

(As implemented in tG2 v1.06.01)

proc block_sel {wid x y} {
  $wid tag remove sel 0.0 end
  set fpos [split [$wid index "@$x,$y"] "."]
  catch {
    if {[lindex $fpos 0] > [lindex $::spos 0]} {
      for {set sl [lindex $::spos 0]} {$sl <= [lindex $fpos 0]} {incr sl} {
        $wid tag add sel "$sl.[lindex $::spos 1]" "$sl.[lindex $fpos 1]"
      }
    } else {
      for {set sl [lindex $::spos 0]} {$sl >= [lindex $fpos 0]} {incr sl -1} {
        $wid tag add sel "$sl.[lindex $fpos 1]" "$sl.[lindex $::spos 1]"
      }
    }
  }
}