# Drawing children widgets in a Gtk::Layout **URL:** \ **Category:** Ruby-Gnome 2\ **Created:** [December 5, 2013, 4:10pm UTC](https://www.ruby-forum.com/t/drawing-children-widgets-in-a-gtk-layout/237906 "2013-12-05T16:10:24Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Post date:** [December 5, 2013, 4:10pm UTC](https://www.ruby-forum.com/t/drawing-children-widgets-in-a-gtk-layout/237906/1 "2013-12-05T16:10:24Z")
Hello ! I’m dealing with a problem that I can’t find any solution on the net. I got a Gtk::Layout where I load multiples Gtk::Image created with .png images files. I stock each of those Image in a Gtk::EventBox to capture mouse clicks and drag them everywhere on the Layout, and use event\_box.set\_visble\_window(false) cause I need the background of images to be transparent. Until there, all works fine. The problems comes when I want to implement a system of rubberbanding selection of the images. As soon as I use Cairo to draw my dashed rectangle unvisible windowed images aren’t drawn anymore (although, there are if i set their window visible, but that’s not what I want). I assume I have to add in my ‘draw’ method line(s) that tell the program to (re)draw children widget of the layout. But I can’t find in the documentation (even in other languages than Ruby) how to achieve that. Can someone help me, please ? NB : I’m using cairo1.12.6, gtk2-2.0.2 and Ruby1.9.3 on Windows7 if that could be of some help EDIT : Found a way to achieve that : while dealing with the expose\_event of the layout, I used img.event\_box.send\_expose(event) to propagate the expose\_event. That works quite well. Next step, would be to show when an Image is selected. For that, i implement two methods select and unselect to switch the visibility of their even\_box.window. I then get another problem, not really important but still…; When the rubberband selection rectangle moves fast in and out of images, it causes sometimes a little glitch where the image is visible in the upper-left corner of the Gtk::Layout instead of its x, y position for a fraction of second. So if someone can figure a way to improve that, it will be great. ---
**Author:** ![67daidalos\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/6/7ba0ec/32.png) [@67daidalos\_S](https://www.ruby-forum.com/u/67daidalos_S)\ **Post date:** [December 6, 2013, 1:25pm UTC](https://www.ruby-forum.com/t/drawing-children-widgets-in-a-gtk-layout/237906/2 "2013-12-06T13:25:11Z")
Hi, In [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) “[ruby-gnome2-devel-en] drawing children widgets in a Gtk::Layout” on Thu, 05 Dec 2013 16:10:24 +0100, “67Daidalos ..” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Cairo to draw my dashed rectangle unvisible windowed images aren’t drawn > anymore (although, there are if i set their window visible, but that’s > not what I want). I assume I have to add in my ‘draw’ method line(s) > that tell the program to (re)draw children widget of the layout. But I > can’t find in the documentation (even in other languages than Ruby) how > to achieve that. > > Can someone help me, please ? Could you show a sample program that can be ran by us? If you provide it, we can try to tackle your problem easily. 🙂 ## Thanks, kou ---
**Author:** ![67daidalos\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/6/7ba0ec/32.png) [@67daidalos\_S](https://www.ruby-forum.com/u/67daidalos_S)\ **Post date:** [December 6, 2013, 3:59pm UTC](https://www.ruby-forum.com/t/drawing-children-widgets-in-a-gtk-layout/237906/3 "2013-12-06T15:59:19Z")
Here you have a sample program showing the problem, and two PNG I used to do this little test. I commented the main aspects, especially those related to the two problem I mentioned above. If you run it and move the rubberband fast in and out of the two images, you should occasionnaly see them appear for a split second in the upper-left corner of the layout ---
**Author:** ![67daidalos\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/6/7ba0ec/32.png) [@67daidalos\_S](https://www.ruby-forum.com/u/67daidalos_S)\ **Post date:** [December 7, 2013, 4:16am UTC](https://www.ruby-forum.com/t/drawing-children-widgets-in-a-gtk-layout/237906/4 "2013-12-07T04:16:11Z")
Hi, In [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) “Re: [ruby-gnome2-devel-en] drawing children widgets in a Gtk::Layout” on Fri, 06 Dec 2013 15:59:19 +0100, “67Daidalos ..” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Here you have a sample program showing the problem, and two PNG I used > to do this little test. Thanks! You don’t need to call send\_expose. You just return “false” from expose-event callback. If you don’t return not “false” value, other expose callbacks are not called. They will be have image draw callbacks. See also: [https://developer.gnome.org/gtk2/2.24/GtkWidget.html#GtkWidget-expose-event](https://developer.gnome.org/gtk2/2.24/GtkWidget.html#GtkWidget-expose-event) — essai2.0.rb.orig 2013-12-06 23:52:54.000000000 +0900 +++ essai2.0.rb 2013-12-07 12:11:49.902475686 +0900 @@ -146,14 +146,14 @@ cr = widget.bin\_window.create\_cairo\_context draw(cr, widget, select\_rect) [@spr1, @spr2].each do |spr| - spr.e\_box.send\_expose(event) #before posting yesterday, I didn’t have thought to add this line… as people say, sleep on first ! That resolve - ``` # the visibility problem I had. ``` if select\_rect.intersect(spr.rectangle) spr.select else spr.unselect end end - stop\_propagation = false - stop\_propagation end scwin = ScrolledWindow.new > I commented the main aspects, especially those related to the two > problem I mentioned above. > If you run it and move the rubberband fast in and out of the two images, > you should occasionnaly see them appear for a split second in the > upper-left corner of the layout It is reproduced on my environment too. Umm, why… ## Thanks, kou ---
**Author:** ![67daidalos\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/6/7ba0ec/32.png) [@67daidalos\_S](https://www.ruby-forum.com/u/67daidalos_S)\ **Post date:** [December 10, 2013, 8:01pm UTC](https://www.ruby-forum.com/t/drawing-children-widgets-in-a-gtk-layout/237906/5 "2013-12-10T20:01:01Z")
Can you post the fixed, working version of your program? It looks like it works to me. Thanks, Eric ---
**Author:** ![67daidalos\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/6/7ba0ec/32.png) [@67daidalos\_S](https://www.ruby-forum.com/u/67daidalos_S)\ **Post date:** [December 7, 2013, 9:53pm UTC](https://www.ruby-forum.com/t/drawing-children-widgets-in-a-gtk-layout/237906/6 "2013-12-07T21:53:03Z")
Thank you Kou-san, I didn’t knew about the return value for signals. Kouhei S. wrote in post #1129960: > > I commented the main aspects, especially those related to the two > > problem I mentioned above. > > If you run it and move the rubberband fast in and out of the two images, > > you should occasionnaly see them appear for a split second in the > > upper-left corner of the layout > > It is reproduced on my environment too. > Umm, why… I thought I have a beginning of explanation. As I tried to start dragging a rubberbanding rectangle from inside one of the images, I saw it draws on the upper-left corner too… I assume the events that occurs in EventBoxes are passed somehow to the parent container (i.e. the Gtk::Layout) but with coordinates relative to the EventBox.