2005 update: At least in version 8.4.11, you can have transparent toplevels in Windows XP, Windows 2000, and Mac OS X with the [wm attributes] command. The following is a neat example I made that demonstrates a transparent toplevel window. The rest of this page is at least two years old. -Paul Walton # Description: This creates a small window demonstrating toplevel transparency in Windows XP, 2000, and Mac OS X. # Author: Paul Walton # Show the console when ctrl+c is pressed. bind . { catch {console show} } # Enable window dragging. bind . { if {"%W" == "."} {dragStart %x %y} } bind . { if {"%W" == "."} {dragTo %X %Y} } # Enable automatic fading/unfading when the mouse enters or leaves the main window. bind . { if {"%W" == "."} {fade start} } bind . { if {"%W" == "."} {unfade start} } # Define some aspects of the main window. wm overrideredirect . 1 wm geometry . 400x200 wm attributes . -alpha .65 -topmost 1 # Global variable that is linked with the scale widget and contains the current alpha level of the main window set AlphaLevel 0.65 # Global variables that are booleans specifing whether the window should currently be fading in or out. set Fading 0 set Unfading 0 # Create small "X" to close the window with. pack [button .close -text "x" -command {destroy .} -relief flat -overrelief groove] -padx 10 -side top -anchor w # Create a slider bar with the scale widget to adjust the transparency. pack [scale .adjust -from 1.0 -to 0.02 -resolution 0.01 -variable AlphaLevel -command {wm attributes . -alpha}] -side top proc dragStart {windowX windowY} { # This sets the anchor point for dragging the window with the cursor. # This should be called whenever the left mouse button is pressed on the window. set ::DragHoldPosition(x) $windowX set ::DragHoldPosition(y) $windowY } proc dragTo {screenX screenY} { # This positions the window to the new coordinates, giving a dragging effect. # This should be called whenever there is mouse motion while the left mouse button is pressed down. set positionX [expr { $screenX - $::DragHoldPosition(x) }] set positionY [expr { $screenY - $::DragHoldPosition(y) }] wm geometry . [winfo width .]x[winfo height .]+$positionX+$positionY } proc fade {mode} { # This slowly fades the window until it is barely visible. # This proc should be called whenever the mouse leaves the main window. # The fading effect stops if the mouse re-enters the window. global Fading AlphaLevel switch -- $mode { start { # Make sure that unfading is stopped. unfade stop # Set the fading flag. set Fading 1 fade more } stop { set Fading 0 return } more { if { $Fading == 0 } { # Fading has been stopped. return } } default { return } } # Get the level of transparency of the window (0 to 1.0). set alphaLevel [wm attributes . -alpha] # Check if the window has faded enough. if { $alphaLevel <= .20 } { # The window has faded enough. set Fading 0 } else { # Fade the window some more. wm attributes . -alpha [expr {$alphaLevel - 0.025} ] set AlphaLevel [wm attributes . -alpha] after 100 fade more } return } proc unfade {mode} { # This slowly unfades the window until it is visible enough. # This proc should be called whenever the mouse enters the main window. # The unfading effect stops if the mouse exit the window. global Unfading AlphaLevel switch -- $mode { start { # Make sure fading is stopped. fade stop # Set the unfading flag. set Unfading 1 unfade more } stop { set Unfading 0 return } more { if { $Unfading == 0 } { # Unfading has been stopped. return } } default { return } } # Get the level of transparency of the window (0 to 1.0). set alphaLevel [wm attributes . -alpha] # Check if the window has unfaded enough. if { $alphaLevel >= 0.90 } { # The window has unfaded enough. set Unfading 0 } else { # Unfade the window some more. wm attributes . -alpha [expr {$alphaLevel + 0.05} ] set AlphaLevel [wm attributes . -alpha] after 100 unfade more } return } Someone was enquiring on the [Tcl'ers Chat] if Tk could do transparent toplevels. It can't natively, but you can simulate them using a canvas. Here is some code which should work on Microsoft Windows systems. It simply gets the wallpaper picture by querying the registry, and then draws the appropriate part of it as a background on the canvas. There are some problems, which should be addressed: * Only works on windows (unix/mac code would be welcome) * Assumes scaled wallpaper (you can check the WallpaperTile value to see if it's actually tiled, and possibly other registry settings - I'll leave that as an exercise...) * Only scales the image by integer amounts - this is a limitation of Tk's image scaling code. * You have to pack child widgets into $path.c - the canvas. You could use [snit] or some other code to make this more transparent (pun intended). # Creates a "transparent" window on windows... package require Tk package require registry package require Img proc transtop {path args} { uplevel 1 [list toplevel $path] $args # Create a canvas in this toplevel pack [canvas $path.c] -fill both -expand 1 # Find out the desktop wallpaper image set file [registry get HKEY_CURRENT_USER\Control Panel\Desktop Wallpaper] set im [image create photo -file [file normalize $file]] set bg [image create photo] set scalex [expr {int(double([winfo screenwidth $path]) / double([image width $im]) + 0.9)}] set scaley [expr {int(double([winfo screenheight $path]) / double([image height $im]) + 0.9)}] $bg copy $im -zoom $scalex $scaley set id [$path.c create image 0 0 -anchor nw -image $bg] updateBgImage $path.c $id bind $path [list updateBgImage $path.c $id] return $path } proc updateBgImage {c id} { set x [expr {0 - [winfo rootx $c]}] set y [expr {0 - [winfo rooty $c]}] $c coords $id $x $y } if {$argv0 eq [info script]} { # Main transtop .t bind .t { exit } wm withdraw . } [FW] notes this is by [Neil Madden], who seems to have forgotten to ;) And also notes that [TkTrans] is the standard full implementation. [NEM] D'oh! Yes, it is by me. Is TkTrans a compiled extension, or pure Tcl code? Either way, if you can use it instead of this code, I would. Note also, that using transparency in an application is likely to be a hideous usability error. Having a semi-transparent background would probably be better. Also, note that if you pack other widgets (text widgets, buttons, labels etc) onto the canvas, they will ''not'' be transparent... [FW]: It's compiled, for Windows. Any #FF00FF pixel is made transparent, so you can make nonstandardly shaped windows. I've also just noticed [DKF]'s new extension [Shape], however, which has a less trivial code but supports Windows and X (and maybe eventually Mac OSes) and doesn't forbid you from using a shade of bright purple in your applications ;) This one's a really clever idea, but I still don't think it has an application, as a good amount of people won't just have the desktop behind the window. [GS] (031206) Is there a way to save a screenshot in a file from the clipboard ? If it is possible, we can use the [cwind] package do a snapshot of the desktop with: package require cwind ::cwind::send |SNAP| And after we can put the file into the canvas. I have made a test by hand saving the image desktop with MsPaint. The result is funny. ---- [ABU] 28-nov-2005 Paul's idea of fading-windows has been implemented in a full application : '''Sticky 2.0''' - See [Stickies] ---- Paul Walton 02-feb-2006 Cool program, ABU. I also implemented the fading effect into a desktop calendar program I made, which you can download here: [http://www.sanightlife.com/Event%20Calendar.msi] (Windows 2000/NT/XP only) This program's two main functions are keeping track of things in a calendar and displaying collections of photos as your desktop wallpaper. You can download these 'photo packs' through the program. I recommend the photo pack hubbleBig.pics, which is a collection of 45 space images from the Hubble telescope. Some of the other photo packs might not be suitable for work, due to the nature of the website I made the program for, although they haven't put any nudity on it yet that I've seen. ---- [RS] 2006-02-03: Here's a very simple demo that works on Windows XP with Tcl 8.4.9 - see the window fade away, and come back again: package req Tk pack [label .t -font {Helvetica 24} -text "Hello, world"] for {set i 20} {$i>=0} {incr i -1} { wm attributes . -alpha [expr $i/20.] if {$i==19} update after 250 } for {set i 1} {$i<=20} {incr i} { wm attributes . -alpha [expr $i/20.] after 250 } In my tests I found that the ''-alpha'' changes are fully visible when the window is updated the first time it has not the full 1.0 (that's the $i==19 test). More [update]s were apparently not necessary. ---- Paul Walton: The whole window flashes when going from a 1.0 alpha level to a <1.0 level and vice versa. So anytime I implement a fading effect, I always limit the transparency to 99%. Also, at least on XP, the window will disappear if the alpha level is below 0.02, meaning you cannot click on the window. ---- [Category Example] | [Category GUI]