[Richard Suchenwirth] 2003-02-25 - [Photo] [image]s can be resized by adding the -zoom or -subsample switches when copying an image. Here is a wrapper that takes only a factor and selects the appropriate switch. The image is scaled in place, the temporary image t is freed when no more needed.

 proc scaleImage {im factor} {
    if {$factor < 1} {
       set factor [expr round(1./$factor)]
       set mode -subsample
    } else {set mode -zoom}
    set t [image create photo]
    $t copy $im
    $im blank
    $im copy $t $mode $factor -shrink
    image delete $t
 }
[http://mini.net/files/ifilezoom.jpg]
Usage example: adding the following lines gives [iFile: a little file system browser] scaling capacities on the image shown on the "File" page:

 .m add casc -label Image -menu [menu .m.image -tearoff 0]
 .m.image add comm -label "Zoom x 3" -command {scaleImage $g(i) 3}
 .m.image add comm -label "Zoom x 2" -command {scaleImage $g(i) 2}
 .m.image add comm -label "Zoom x 0.5" -command {scaleImage $g(i) 0.5}
 .m.image add comm -label "Zoom x 0.33" -command {scaleImage $g(i) 0.33}

For robustness, one might disable this menu when no image is displayed.
----
[Arts and crafts of Tcl-Tk programming]