Bug 139790

Summary: Viewer / editor: the center of the photo is moving when zooming in or out
Product: [Applications] digikam Reporter: Kevin Goeser <kevin>
Component: ImageEditor-CanvasAssignee: Digikam Developers <digikam-bugs-null>
Status: RESOLVED FIXED    
Severity: normal    
Priority: NOR    
Version First Reported In: 0.9.0   
Target Milestone: ---   
Platform: Gentoo Packages   
OS: Linux   
Latest Commit: Version Fixed/Implemented In: 0.9.2
Sentry Crash Report:

Description Kevin Goeser 2007-01-08 22:04:37 UTC 
Version:           0.9.0 (using KDE KDE 3.5.5)
Installed from:    Gentoo Packages
Compiler:          GCC 4.1.1 gcc (GCC) 4.1.1 (Gentoo 4.1.1-r1)
OS:                Linux

If zooming in or out using the keyboard or the tool bar buttons, the center of the photo moves. The center of the current projection should be kept as center instead (common usability).

Cheers
   Kevin
Comment 1 Frank Siegert 2007-01-16 23:56:24 UTC 
I can confirm this bug. It happens with 0.9.0 Kubuntu packages as well as with trunk compiled from SVN (r624276). (Is there any way that I can mark this bug as confirmed?)
Comment 2 caulier.gilles 2007-03-19 15:59:03 UTC 
SVN commit 644214 by cgilles:

digikam from trunk : do not move editor viewport content when zoom in/out.
BUG: 139790

 M  +16 -6     canvas.cpp  


--- trunk/extragear/graphics/digikam/utilities/imageeditor/canvas/canvas.cpp #644213:644214
@@ -391,8 +391,8 @@
             emit signalSelected(false);
     }
 
-    int wZ = int(d->im->width());
-    int hZ = int(d->im->height());
+    int wZ = d->im->width();
+    int hZ = d->im->height();
     
     if (visibleWidth() > wZ || visibleHeight() > hZ)
     {
@@ -835,11 +835,16 @@
     if (d->autoZoom || maxZoom())
         return;
 
+    float cpx = (contentsX() + visibleWidth()  / 2.0) / d->zoom; 
+    float cpy = (contentsY() + visibleHeight() / 2.0) / d->zoom; 
+
     d->zoom = d->zoom + 1.0/16.0;
-
     d->im->zoom(d->zoom);
-    
     updateContentsSize();
+
+    viewport()->setUpdatesEnabled(false);
+    center((int)(cpx * d->zoom), (int)(cpy * d->zoom));
+    viewport()->setUpdatesEnabled(true);
     viewport()->update();
 
     emit signalZoomChanged(d->zoom);
@@ -850,11 +855,16 @@
     if (d->autoZoom || minZoom())
         return;
 
+    float cpx = (contentsX() + visibleWidth()  / 2.0) / d->zoom; 
+    float cpy = (contentsY() + visibleHeight() / 2.0) / d->zoom;
+ 
     d->zoom = d->zoom - 1.0/16.0;    
-
     d->im->zoom(d->zoom);
+    updateContentsSize();
 
-    updateContentsSize();
+    viewport()->setUpdatesEnabled(false);
+    center((int)(cpx * d->zoom), (int)(cpy * d->zoom));
+    viewport()->setUpdatesEnabled(true);
     viewport()->update();
 
     emit signalZoomChanged(d->zoom);
Comment 3 Frank Siegert 2007-04-04 23:22:15 UTC 
I believe this problem has been reintroduced with commit 649987.