Included TEA and Androwish changes by Christian Werner from:

http://www.androwish.org/index.html/info/9fb57bb78476312a

backend_tcl/demo/demo.tcl

@@ -1,20 +1,68 @@
 package require Tk
-lappend auto_path [file dirname [info script]]/../lib
 package require zint
+wm title . "ZINT Demo"
+wm minsize . 480 320
+if {[info command sdltk] eq "sdltk"} {
+    wm attributes . -fullscreen 1
+    set padx 30
+    set pady 20
+} else {
+    wm geometry . 480x320
+    set padx 5
+    set pady 5
+}
 image create photo ::zintimg
-pack [label .l -image ::zintimg] -side left
-pack [ttk::separator .s -orient vertical] -side left
-pack [::ttk::combobox .c -values [lsort [zint symbologies]] -state readonly]\
-        -side top -fill x
+pack [::ttk::combobox .c -values [lsort [zint symbologies]] -state readonly] \
+    -side top -fill x -padx $padx -pady $pady
 .c set Datamatrix
-pack [::ttk::entry .e] -side top -fill x
+pack [::ttk::entry .e] -side top -fill x -padx $padx -pady $pady
 .e insert end 12345
 bind .e <Return> Generate
-pack [::ttk::button .b -text Generate -command Generate] -fill x -side top
+pack [::ttk::button .b -text Generate -command Generate] -fill x -side top \
+    -padx $padx -pady $pady
 proc Generate {} {
     ::zintimg blank
+    ::zintimg configure -width 1 -height 1
+    ::zintimg blank
+    ::zintimg configure -width 0 -height 0
     if {[catch {zint encode [.e get] ::zintimg -barcode [.c get]} e]} {
         tk_messageBox -message $e -title "Zint error"
+    } else {
+	set w [image width ::zintimg]
+	set h [image height ::zintimg]
+	set lw [winfo width .l]
+	set lh [winfo height .l]
+	set sx [expr {int(1.0 * $lw / $w)}]
+	set sy [expr {int(1.0 * $lh / $h)}]
+	if {$sy < $sx} {
+	    set sx $sy
+	}
+	if {$sx <= 0} {
+	    set sx [expr {1.1 * $lw / $w}]
+	    set sy [expr {1.1 * $lh / $h}]
+	    if {$sy < $sx} {
+		set sx $sy
+	    }
+	}
+	::zintimg blank
+	::zintimg configure -width 1 -height 1
+	::zintimg blank
+	::zintimg configure -width 0 -height 0
+	catch {
+	    zint encode [.e get] ::zintimg -barcode [.c get] -scale $sx
+	}
     }
 }
-Generate
+pack [label .l -image ::zintimg -bg white] -side top -fill both -expand 1 \
+    -padx $padx -pady $pady
+bind .e <Configure> {
+    after cancel Generate
+    after idle Generate
+}
+bind .c <<ComboboxSelected>> {
+    after cancel Generate
+    after idle Generate
+}
+bind all <Break> exit
+bind all <Control-q> exit
+bind all <Alt-q> exit