package require Tk
package require Img

grid [frame .f] -column 0 -row 0 -sticky nswe
grid columnconfigure . 0 -weight 1; grid rowconfigure . 0 -weight 1
grid columnconfigure .f 0 -weight 1; grid rowconfigure .f 0 -weight 1

set img [image create photo -data {iVBORw0KGgoAAAANSUhEUgAAACAAAAAgAQMAAABJtOi3AAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAGUExURQAAAP///6XZn90AAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAPSURBVBjTY/gP
BAyDlwAA2ul/gcqaQMAAAAAASUVORK5CYII=}]

grid [text .f.t -height 10 -width 20] -column 0 -row 0 -sticky nswe
grid [button .f.b -image $img] -column 0 -row 0 -sticky nw

set w [expr {[image width $img]+8}]
set h [expr {[image height $img]+4}]

.f.t tag configure tag1 -lmargin1 $w -lmargin2 $w

.f.t insert end "qwertyuiopasdfghjklzxcvbnm1234567890qwertyuiopasdfghjklzxcvbnm1234567890qwertyuiopasdfghjklzxcvbnm1234567890qwertyuiopasdfghjklzxcvbnm1234567890"

update

bind .f.t <Key> {+mod}
bind .f.t <Configure> {+mod}

proc mod {} {
  .f.t tag add tag1 1.0 end
  .f.t mark set offset @[winfo width .f.t],$::h
  .f.t tag remove tag1 1.0 end
  .f.t tag add tag1 1.0 offset
}

mod