I noticed that the resize flicker
gets much better when I set TPanel.FullRepaint
to False
. Since the property exists and is True
by default, there must be some reason for that.
How to decide whether it should be set or not?
The help just states:
FullRepaint controls how the panel responds when it is resized. When FullRepaint is true, the entire panel, including the beveled border repaints when the size changes. When FullRepaint is false, only the area inside the beveled border repaints.
http://docwiki.embarcadero.com/Libraries/XE3/en/Vcl.ExtCtrls.TPanel.FullRepaint
That text says what it does, but not why ...
The effect of a missing Fullrepaint can be shown and you will have to decide if you need it or not.
Run the program and size the form, somtimes the borders of the first panel will not be refreshed.
This happens because in WMWindowPosChanged in case of (FullRepaint or (ShowCaption and (Caption <> ''))) a invalidate will be called, otherwise only InvalidateRect(Handle, Rect, True) of a rects only containing the right and/or bottom border are invalidated. (thanks to Sertac Akyuz for correction)
As you mentioned avoiding invalidate reduces flicker and in many cases the need for a full invalidate is not given, so the user can decide on his own how to proceed.
Panels as the rarely will be used, upper without Fullrepaint
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