[Uml-devel] kdesdk/umbrello

[Sebastian Stein]

CVS commit by sstein: 

patch by Achim Spangler:

I found the reason for the high CPU load - and fixed it.

Detect:
Simply check with kdbg where the operation is currently, if the program is
interrupted in invisible-state.

=> always something with Qt update events
As I have this high load only with a lot of diagrams, the QCanvas and
QCanvasView classes were suspectible.

Solution:
Switch the update OFF for the QCanvas of a hidden diagram
( QT-Doc states for QCanvas::setUpdatePeriod()
  "If ms is less than 0 automatic updating will be stopped. " ),
and switch it back to ON on show event.

Result:
Now even my large project is at a very low CPU load!

Now the work with my project is again smart and quick.

##
Changes:
UMLView::init() :
---------------------
Switch update OFF, as this is started by show event.
( Change call of "canvas() -> setUpdatePeriod( 20 );"
   to "canvas() -> setUpdatePeriod( -1 );" )


UMLView::showEvent(QShowEvent* /*se*/) :
----------------------------------------------------------
Start update again with the well working rate of 20msec.
Call "canvas() -> setUpdatePeriod( 20 );" immediately after
"canvas()->setDoubleBuffering( true );"


UMLView::hideEvent(QHideEvent* /*he*/) :
--------------------------------------------------------
Stop update again with "-1" as update rate.
Call "canvas() -> setUpdatePeriod( -1 );" immediately after
"canvas()->setDoubleBuffering( false );"


  M +2 -0      ChangeLog   1.24
  M +16 -1     umbrello/umlview.cpp   1.163


--- kdesdk/umbrello/ChangeLog  #1.23:1.24
@@ -1,4 +1,6 @@
 Version 1.3
 
+* heavily reduced memory usage and CPU load on large projects
+
 * reserved keywords added for supported languages
 

--- kdesdk/umbrello/umbrello/umlview.cpp  #1.162:1.163
@@ -146,5 +146,11 @@ void UMLView::init() {
         viewport() -> setBackgroundMode( NoBackground );
         setCanvas( new UMLViewCanvas( this ) );
-        canvas() -> setUpdatePeriod( 20 );
+        // don't set the quite frequent update rate for each
+        // diagram, as that causes also an update of invisible
+        // diagrams, which can cost high CPU load for many
+        // diagrams.
+        // Instead: set the updatePeriod to 20 on Show event,
+        //          and switch update back off on Hide event
+        canvas() -> setUpdatePeriod( -1 );
         resizeContents(defaultCanvasSize, defaultCanvasSize);
         canvas() -> resize(defaultCanvasSize, defaultCanvasSize);
@@ -393,4 +399,8 @@ void UMLView::showEvent(QShowEvent* /*se
         kdWarning() << "Show Event for " << getName() << endl;
         canvas()->setDoubleBuffering( true );
+        // as the diagram gets now visible again,
+        // the update of the diagram elements shall be
+        // at the normal value of 20
+        canvas()-> setUpdatePeriod( 20 );
 #       endif
 
@@ -415,4 +425,9 @@ void UMLView::hideEvent(QHideEvent* /*he
         kdWarning() << "Hide Event for " << getName() << endl;
         canvas()->setDoubleBuffering( false );
+        // a periodic update of all - also invisible - diagrams
+        // can cause a very high CPU load if more than 100diagrams
+        // are inside a project - and this without any need
+        // => switch the update of for hidden diagrams
+        canvas()-> setUpdatePeriod( -1 );
 #       endif
 }