Christian Heide Damm responded in comp.lang.tcl [L1 ] on how to move the cursor up and down visible lines instead of real text widget lines:
...namely binding up/down to something like this:
# Find the coordinates of the cursor and set the new height
# manually. Note: errors rounding off, since
# coordinates don't match character positions exactly.
lset {lines char} [split [$textWidget index insert] .]
lset {x y textWidth textHeight} [$textWidget bbox [$textWidget
index insert]]
lset {_ maxy _ _} [$textWidget bbox "end - 1 char"]
# When updating position, make sure y is within text boundaries
switch -- $upOrDown {
"up" {
set y [max [expr $y-$textHeight] 0]
}
"down" {
set y [min [expr $y+$textHeight] $maxy]
}
}
lset {newx newy width _} [$textWidget bbox [$textWidget index
@$x,$y]]
# Test on which side of the character
# we should position the cursor
if {$x>[expr $newx+$width/2]} {
set x [expr $newx+$width+1]
}
set newIndex [$textWidget index @$x,$y]Here is the above code in a function, with the non-existent function lset replaced with calls to scan and missing functions min/max defined. Note that this code needs to be modified to handle more than a screenful of text:
proc min args {lindex [lsort -real $args] 0}
proc max args {lindex [lsort -real $args] end}
proc moveUpDown {textWidget upOrDown} {
# Find the coordinates of the cursor and set the new height
# manually. Note: errors rounding off, since
# coordinates don't match character positions exactly.
scan [$textWidget index insert] {%d.%d} lines char
scan [$textWidget bbox [$textWidget index insert]] {%d %d %d %d} x y textWidth textHeight
scan [$textWidget bbox "end - 1 char"] {%*d %d %*d %*d} maxy
# When updating position, make sure y is within text boundaries
switch -- $upOrDown {
"up" {
set y [max [expr $y-$textHeight] 0]
}
"down" {
set y [min [expr $y+$textHeight] $maxy]
}
}
scan [$textWidget bbox [$textWidget index @$x,$y]] {%d %d %d %*d} newx newy width
# Test on which side of the character
# we should position the cursor
if {$x>[expr $newx+$width/2]} {
set x [expr $newx+$width+1]
}
return [$textWidget index @$x,$y]
}
# Replace the default Text widget bindings to try it out
bind Text <Up> {
tkTextSetCursor %W [moveUpDown %W up]
}
bind Text <Down> {
tkTextSetCursor %W [moveUpDown %W down]
}