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cohort
Joined: 07 Feb 2006
Posts: 47
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 Posted: Wed Apr 05, 2006 10:54 pm Post subject: Scrolling/resizing a GtkImage object |
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I'm trying to build an app that requires having a viewport with a large image to be held within, resized to fit by default, scrolled if "zoomed in".
Is there any easy way to do it?
(I got the viewport scrolling worked out, I just need zooming) |
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cweiske
Joined: 08 Dec 2005
Posts: 454
Location: Leipzig/Germany
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cohort
Joined: 07 Feb 2006
Posts: 47
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| Posted: Thu Apr 06, 2006 7:55 am Post subject: |
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In other words, "no."
So, how do I get the size of my viewport?
And yes, I did look through the docs. |
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cweiske
Joined: 08 Dec 2005
Posts: 454
Location: Leipzig/Germany
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| Posted: Thu Apr 06, 2006 8:01 am Post subject: |
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| You can zoom it. The viewport will adjust itself if you add the image to it. You just need to scale the image correctly, and that's possible with the methods. |
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cohort
Joined: 07 Feb 2006
Posts: 47
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| Posted: Thu Apr 06, 2006 8:13 am Post subject: |
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| cweiske wrote: | | You just need to scale the image correctly |
Which is why I need to know the size of my viewport (which can change if the user resizes the app).. |
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cweiske
Joined: 08 Dec 2005
Posts: 454
Location: Leipzig/Germany
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| Posted: Thu Apr 06, 2006 8:18 am Post subject: |
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| get_size_request() doesn't help? Maybe there are width and height properties you can read. |
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cohort
Joined: 07 Feb 2006
Posts: 47
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| Posted: Thu Apr 06, 2006 9:10 am Post subject: |
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From the GTK docs: "the size request is not necessarily the size a widget will actually be allocated."
I can't find any "actual size" properties anywhere. Only found "requested size" properties, which are "not to be trusted"... |
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cweiske
Joined: 08 Dec 2005
Posts: 454
Location: Leipzig/Germany
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| Posted: Thu Apr 06, 2006 1:05 pm Post subject: |
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| Use the allocation property, it should have x and y subproperties. |
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scott
Joined: 16 Feb 2006
Posts: 35
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cohort
Joined: 07 Feb 2006
Posts: 47
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| Posted: Sun Apr 30, 2006 12:54 pm Post subject: |
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| cweiske wrote: | | Use the allocation property, it should have x and y subproperties. |
That was it.
I created a little function to determine the scale while keeping the aspect ratio, and uploaded it to the gnope channel -- perhaps it may help out someone else, too.
I'll make a usage example later, I'm in a bit of a crunch now. |
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cohort
Joined: 07 Feb 2006
Posts: 47
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| Posted: Tue May 02, 2006 2:45 am Post subject: |
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Now the question is, how do I capture the resize event?
I tried:
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$this->manip_viewport->connect("size-allocate", array($this, 'resize_imagewin'));
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but get an infinite loop...
Shouldn't it only fire once? |
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scott
Joined: 16 Feb 2006
Posts: 35
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| Posted: Tue May 02, 2006 3:05 pm Post subject: |
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| The signal should be fired once for each time the size is allocated. What is happening in your callback? Are you resizing the image again? Also, have you tried the 'size-request' signal? I think that is probably the better signal to use in this case. |
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cohort
Joined: 07 Feb 2006
Posts: 47
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| Posted: Wed May 03, 2006 12:31 am Post subject: |
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| I manually resize the child object (a GtkImage), not the viewport. |
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scott
Joined: 16 Feb 2006
Posts: 35
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| Posted: Wed May 03, 2006 2:38 pm Post subject: |
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| Yes but when you resize the child, doesn't the view port get resized? A container's size is determined by the size of its children. And when you resize a container, the resizing is propogated to its children. I think you are inadvertenly creating an infinite loop by setting a size while setting a size. |
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cohort
Joined: 07 Feb 2006
Posts: 47
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| Posted: Thu May 04, 2006 3:36 am Post subject: |
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It does the same thing using both signals ('size-allocation' and 'size-request').
However, you pointed me in the right direction -- I put a test in the resize-imagewin() function that checks to see if the size of the viewport has changed -- if no, it "returns" having done nothing. (basically, checks to see if either height OR width matches -- if it does, it doesn't need to be resized.)
Problem fixed. |
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