Here is the source for producing the above images (which also requires downloading beach.jpg).

For the image 1 run wize grad.tcl 1, etc.

#!/usr/bin/env wize
#
# grad.tcl: a script demonstrate use of two winop commands:
# gradient and merge.
#
# In all tests, an image is created and used to setup
# the background tile.  Then a couple of widgets are created.
#

set tst [lindex $argv 0]
wm title . "Winop test: $tst"

switch -- $tst {
  1 - 2 - 3 {
    set img [image create photo -width 400 -height 300]
    if {$tst == "1"} {
      winop image gradient $img Red DarkBlue lines
    } elseif {$tst == "2"} {
      winop image gradient $img Red DarkBlue rectangular
    } else {
      winop image gradient $img DarkBlue Red lines .3
    }
    set img2 [image create photo]
    $img2 copy $img
    . conf -tile $img2
    wm geom . [image width $img2]x[image height $img2]
    option add *tile $img2
    place [button .b -text Begin] -relx .3 -rely .3
    place [text .t -width 20 -height 5] -relx .3 -rely .4
    .t insert end " Enter info..."
  }
  4 - 5 {
    set i [image create photo -file /zvfs/img/tile/tile-swirl.gif]
    set i2 [image create photo -file beach.jpg]
    set i3 [image create photo]
    set img [image create photo]

    if {$tst != 4} {
      $img copy $i -to 0 0 [image width $i2] [image height $i2]
      winop merge $i2 $img $i3 .25
    } else {
      $img copy $i -to 0 0 [image width $i2] [image height $i]
      set i4 [image create photo -width [image width $i2] -height [image height $i]]
      winop image gradient $i4 Cyan Purple lines
      winop image merge $i4 $img $i3 .25
    }
    option add *tile $i3
    . conf -tile $i3 
    wm geom . [image width $i2]x[image height $i2]

    pack [set t [Tabset new . -slant right]] -padx 20 -pady 20 -fill both -expand y 
    set tf [Frame new $t.] 
    pack [set t1 [Text new $tf.]] -fill both -expand y
    Text insert $t1 end [join [info commands *] \n]
    Tabset insert $t end Main -window $tf
    pack [set t1 [Button new $tf. -text Done]] -pady 10

    set t2 [Text new $t.]
    Tabset insert $t end Secondary -window $t2 -fill both

  }
  default {
     puts "usage: $argv0 1 | 2 | 3 | 4 | 5"
     exit 0
  }
}

The following script demonstrates using a canvas to draw an arbitrary polygon upon a white background. This is saved to an image and the White converted to transparent. This image could then be used as a shaped button or toplevel window.

#!/usr/bin/env wize

pack  [frame .f] -fill both -expand 1
canvas [set c .f.c] -bg White  -bd 0 -width 100 -height 100
pack  $c -s top -e 0 -f none -padx 0 -pady 0
set tfile /zvfs/img/tile/blueplasma.gif
if {![file exists $tfile]} {
  $c create polygon "10 10 10 100 50 50" -smooth 1 -fill red
} else {
  set tile [image create photo -file $tfile]
  $c create polygon "10 10 10 100 50 50" -smooth 1 -tile $tile -outline black
}
update
after 1000

set image [image create photo -format window -data .]
set img2 [image create photo]
winop image alpha $image $img2 White
$img2 write -format gif transimg.gif

pack [button .b -bg green -image $img2]

Note that an alternative approach is to use a pixmap.