Bug 91240

Well, the same happens to Firefox. Displaying a few animated gifs like these:

http://www.gifs.net/animate/pagelett.htm

take 70% of my 800 MHz, no matter if the window is minimised or not.

Could it be the responsibility of the window manager to unmap a window when minimized?

A window manager DOES unmap a window when it's minimized.

I develop X11 drivers (DDX modules) for OpenWindows (Sun's X server under Solaris), and when we were trying to get certification from Sun, one of the 'problems' they reported back to us was that with our DDX, the X server was using a non-trivial amount of CPU time when an application was drawing with a planemask of zero, with a rop of GXnoop, or to a window which was iconified.  We fixed that, and now, very little CPU time is used by Xsun when doing these pathological things.

I would definately agree with anyone that says that drawing to a minimized window is an X server internals issue.  However, there are two reasons why it's also a Konqueror/Qt issue:

1) X11 apps need to be well-behaved, and something as important as KDE should be a paragon of 'well behaved'.

2) You'll die before the X.org people will get around to fixing this problem themselves.

*** Bug 91283 has been marked as a duplicate of this bug. ***

*** Bug 103345 has been marked as a duplicate of this bug. ***

*** Bug 34134 has been marked as a duplicate of this bug. ***

SVN commit 618069 by mkoller:

BUG: 91240

Pause animations whenever a HTML view is hidden and resume animations
when it's shown again. This greatly reduces CPU usage when there are
a lot of animated images in hidden tabs or minimized windows


 M  +5 -0      khtmlview.cpp  
 M  +33 -0     misc/loader.cpp  
 M  +4 -0      misc/loader.h  


--- branches/KDE/3.5/kdelibs/khtml/khtmlview.cpp #618068:618069
@@ -50,6 +50,7 @@
 #include "css/csshelper.h"
 #include "misc/htmlhashes.h"
 #include "misc/helper.h"
+#include "misc/loader.h"
 #include "khtml_settings.h"
 #include "khtml_printsettings.h"
 
@@ -571,11 +572,15 @@
 void KHTMLView::hideEvent(QHideEvent* e)
 {
     QScrollView::hideEvent(e);
+    if ( m_part && m_part->xmlDocImpl() )
+        m_part->xmlDocImpl()->docLoader()->pauseAnimations();
 }
 
 void KHTMLView::showEvent(QShowEvent* e)
 {
     QScrollView::showEvent(e);
+    if ( m_part && m_part->xmlDocImpl() )
+        m_part->xmlDocImpl()->docLoader()->resumeAnimations();
 }
 
 void KHTMLView::resizeEvent (QResizeEvent* e)
--- branches/KDE/3.5/kdelibs/khtml/misc/loader.cpp #618068:618069
@@ -794,6 +794,17 @@
     }
 }
 
+void CachedImage::pauseAnimations()
+{
+    if ( m ) m->pause();
+}
+
+void CachedImage::resumeAnimations()
+{
+    if ( m ) m->unpause();
+}
+
+
 void CachedImage::deleteMovie()
 {
     delete m; m = 0;
@@ -1088,6 +1099,28 @@
         }
 }
 
+void DocLoader::pauseAnimations()
+{
+    for ( QPtrDictIterator<CachedObject> it( m_docObjects ); it.current(); ++it )
+        if ( it.current()->type() == CachedObject::Image )
+        {
+            CachedImage *img = const_cast<CachedImage*>( static_cast<const CachedImage *>( it.current() ) );
+
+            img->pauseAnimations();
+        }
+}
+
+void DocLoader::resumeAnimations()
+{
+    for ( QPtrDictIterator<CachedObject> it( m_docObjects ); it.current(); ++it )
+        if ( it.current()->type() == CachedObject::Image )
+        {
+            CachedImage *img = const_cast<CachedImage*>( static_cast<const CachedImage *>( it.current() ) );
+
+            img->resumeAnimations();
+        }
+}
+
 // ------------------------------------------------------------------------------------------
 
 Loader::Loader() : QObject()
--- branches/KDE/3.5/kdelibs/khtml/misc/loader.h #618068:618069
@@ -287,6 +287,8 @@
 #endif
 
         void setShowAnimations( KHTMLSettings::KAnimationAdvice );
+        void pauseAnimations();
+        void resumeAnimations();
 
         virtual bool schedule() const { return true; }
 
@@ -363,6 +365,8 @@
         void setAutoloadImages( bool );
         void setCachePolicy( KIO::CacheControl cachePolicy ) { m_cachePolicy = cachePolicy; }
         void setShowAnimations( KHTMLSettings::KAnimationAdvice );
+        void pauseAnimations();
+        void resumeAnimations();
         void insertCachedObject( CachedObject* o ) const;
         void removeCachedObject( CachedObject* o) const { m_docObjects.remove( o ); }
 

*** Bug 132932 has been marked as a duplicate of this bug. ***