flashing flickering Canvas Blinking delphi

 

Double Buffering is one way but not always sufficient. Imagine you paint a shape at runtime, it depends on your repaint method. Forces the control to repaint its image on the screen could be crucial.

Call Repaint to force the control to repaint its image immediately. If the ControlStyle property includes csOpaque, the control paints itself directly. So double buffering plus invalidate and [csOpaque] as controlstyle could be an improvement:

var Compass: TPaintBox;
procedure TForm1ForceRepaint(Sender: TObject);
{Called when display type or compass angle changes}
begin
  compass.controlstyle:= [csOpaque];
  while heading.value<0 do heading.Value:=heading.Value+360;
  while heading.value>360 do heading.Value:=heading.Value-360;
  compass.Invalidate;
end;
https://stackoverflow.com/questions/1954491/stop-flickering

https://delphi-bar.blogspot.com/2012/11/prevent-screen-refresh-and-flickering.html
LockWindowUpdate(Handle);
try
    // Code goes here
finally
    LockWindowUpdate(0);
end;

Solution 2

SendMessage(Handle, WM_SETREDRAW, WPARAM(False), 0);
try
     // Code goes here
finally
    SendMessage(Handle, WM_SETREDRAW, WPARAM(True), 0);
    RedrawWindow(Self.Handle, nil, 0, RDW_ERASE or RDW_FRAME or RDW_INVALIDATE or RDW_ALLCHILDREN);
end;
https://delphi-bar.blogspot.com/2012/11/prevent-screen-refresh-and-flickering.html

https://stackoverflow.com/questions/15308077/delphi-custom-animation-collision-detection

 

https://www.codeproject.com/Articles/33/Flicker-Free-Drawing-In-MFC
https://stackoverflow.com/questions/6363954/best-way-to-do-non-flickering-segmented-graphics-updates-in-delphi
https://stackoverflow.com/questions/17483147/flicker-does-not-reduce-after-double-buffering-in-mfc-cpaintdc
https://stackoverflow.com/questions/17483147/flicker-does-not-reduce-after-double-buffering-in-mfc-cpaintdc