| Summary: | zoom in previewwidget has poor behaviour | ||
|---|---|---|---|
| Product: | [Applications] digikam | Reporter: | brandon <brandon> |
| Component: | Preview-Image | Assignee: | Digikam Developers <digikam-bugs-null> |
| Status: | RESOLVED INTENTIONAL | ||
| Severity: | normal | CC: | brandon, marcel.wiesweg |
| Priority: | NOR | ||
| Version: | 0.10.0 | ||
| Target Milestone: | --- | ||
| Platform: | Microsoft Windows | ||
| OS: | Microsoft Windows | ||
| Latest Commit: | Version Fixed In: | 1.0.0 | |
| Sentry Crash Report: | |||
| Attachments: | Patch to improve scroll zooming. | ||
|
Description
brandon
2008-12-23 04:45:19 UTC
brandon, just attach the patch to this bugzilla file. That all... We will review later... Gilles Caulier Created attachment 29594 [details]
Patch to improve scroll zooming.
Here is the code I am playing around with so far. It will be less verbose after I test it a little more.
Basically to re-state the problem:
You should be able to put the mouse over a point on an image and use the scroll wheel to zoom all the way to max zoom right to that point without having to move the mouse.
As previewwidget.cpp works now you have to keep re-centering the mouse on the point you are trying to zoom in on.
This is because there are limitations to Q3ScrollView. It can't for example scroll negatively or, scroll so far that the right edge of an image is in the center of the viewport.
To overcome this you need to either 'bump' the mouse cursor, to keep it centered on the zoomCenterPoint, or adjust the pixmap x/y co-ordinates.
Right now I am only, 'bumping' the cursor, so you can smoothly zoom right in to any point on the image even the edges without having to reposition the mouse.
In the future it might be worth adjusting the pixmap location as well, especially for the right and bottom edges. However the problem with adjusting the pixmap location is, it is once it has been adjusted it's impossible to know when the user would want the image be re-centered.
Anyway hope somebody likes using scroll-zoom and finds this useful.
I'm new to Qt/Kde so don't be shy about pointing out things I could have done better.
I forgot to mention, this patch was created from the <svn-workspace>/graphics/digikam directory. Is this the correct location to create patches from? <svn-workspace>/graphics/digikam directory sound fine... if you use trunk not branches : http://websvn.kde.org/trunk/extragear/graphics/digikam/ Gilles Caulier Brandon, I think we are positive about applying your patch, if you have it well tested and give us a version that you call final we will commit it. (There is a comment in your code calling for configurability of the Ctrl modifier. I think this was chosen due to being KDE standard, and we cannot endlessly add options) Andi, Are you tested this patch ? Gilles Not now, I will test it soon, just fixing something with the menu entries in digiKam. After that I will do it. Andi The patch seems to work quite well, but sometimes the point I'm focusing is not centered when zooming in, although it should be possible to center the image. When I select a point I want to zoom to, it can happen that this point moves out of the visible area. In general I would say the patch is fine, maybe Q3ScrollView is not capable of doing it better? Andi Well I'm afraid but I have to say that the current implementation works much better for me than with the patch applied. With the patch there is a tendency of the cursor to move top-left. E.g. if I start in the bottom-right corner and zoom in and out ten or fifteen times, the cursor finally ends up in the top-left corner. This does not happen with the current implementation. Maybe there's a difference between Linux and Windows? Apart from this, I get these compilation warnings: /home/marcel/freshmeat/multimedia/kde4/src/extragear/graphics/digikam/libs/widgets/common/previewwidget.cpp: In member function ‘void Digikam::PreviewWidget::setZoomFactor(double, bool)’: /home/marcel/freshmeat/multimedia/kde4/src/extragear/graphics/digikam/libs/widgets/common/previewwidget.cpp:252: warning: unused variable ‘oldZoom’ /home/marcel/freshmeat/multimedia/kde4/src/extragear/graphics/digikam/libs/widgets/common/previewwidget.cpp: In member function ‘virtual void Digikam::PreviewWidget::contentsWheelEvent(QWheelEvent*)’: /home/marcel/freshmeat/multimedia/kde4/src/extragear/graphics/digikam/libs/widgets/common/previewwidget.cpp:680: warning: comparison between signed and unsigned integer expressions /home/marcel/freshmeat/multimedia/kde4/src/extragear/graphics/digikam/libs/widgets/common/previewwidget.cpp: In member function ‘void Digikam::PreviewWidget::setZoomFactor(double, bool)’: /home/marcel/freshmeat/multimedia/kde4/src/extragear/graphics/digikam/libs/widgets/common/previewwidget.cpp:253: warning: ‘cpy’ may be used uninitialized in this function /home/marcel/freshmeat/multimedia/kde4/src/extragear/graphics/digikam/libs/widgets/common/previewwidget.cpp:253: warning: ‘cpx’ may be used uninitial Well, closed as won't fix ??? Gilles Caulier Push.... :) |