Posted 8 September 2017, 2:46 pm EST
When I initially display my fpChart I size it to fit the window and it displays quickly.
The size will change if the window is resized since it is anchored on all 4 sides.
This also seems to work quite fast.
I then allow the user to 'zoom' the chart to a larger size. This initially displays the top left part of the chart and works quite quickly.
I then allow them to 'scroll' down or right by simply resetting the Location property. (using negative values)
I would expect this to be fast, but it is very slow.
I can see it repainting the chart in sections.
I see similar performance problems if the window (an MDI child) is maximized and I switch to/from the chart window.
It is so slow that I can see that switching windows apparently causes it to reset the size of the one that is being hidden back to its 'normal state size' before the new window is displayed maximized. Switching the chart window between normal and maximized seems to be a little faster, but still slow.
Is this a bug or is there a property I need to set to improve the repainting performance?
Note that the source of the data is an fpSpread sheetview. However the sheet is read only so the data never changes.
(I would not expect it to be rebuilding the chart model anyway for a resize or 'move' action.)