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--# Opacity
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include GtkEngine.e

constant docs = `<b><u>Opacity</u></b>

    You need to be running a compositing window manager
    to see this demonstrated.
    
    Minimum is set to 20%, so window won't fade away
    completely!
`
constant win = create(GtkWindow,"border_width=10,size=300x300,position=1,$destroy=Quit")

constant panel = create(GtkBox,"orientation=VERTICAL")
    add(win,panel)

constant lbl = create(GtkLabel)
    set(lbl,"markup",docs)
    add(panel,lbl)

constant op_ctl = create(GtkScale,HORIZONTAL,.20,1,0.01) -- values are min, max, step
    set(op_ctl,"value",1.00) -- starting value
    connect(op_ctl,"value-changed","UpdateOpacity") 
    pack(panel,op_ctl)
    
constant btnbox = create(GtkButtonBox)
    pack(panel,-btnbox)

constant btn1 = create(GtkButton,"gtk-quit","Quit")
    add(btnbox,btn1)

show_all(win)
main()

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global function UpdateOpacity(atom ctl)
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    set(win,"opacity",get(ctl,"value"))
return 1
end function