Move image onMouseMove
lazarus / 39-Graphics

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bigeno · 2015-02-01 21:55

Hi,

I've some speed problem with shifting image on TImage when use
onMouseMove.
Every time I redraw the image by Image1.Canvas with proper shift. But
it's slow.
I use BGRABtimap to draw on TImage, OnMouseDown I do snapshot and
OnMouseMove I draw with shift
bmpI.Draw(Image1.Canvas,X-MouseXStart, Y-MouseYStart,false);

Can I simply redraw TImage (draw with shift) ? I can have white "not
draw" outlined filed OnMouseMove, I can draw rest image after
OnMouseUP.
Do not know if you understand what I mean, somethink like speed
function Image1.Canvas.Shift(X,Y)

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balazsszekely · 2015-02-02 05:50

I'm not sure, if I understand your correctly, but instead of drawing
each time the image with shift, just draw once to a TImage. Then move
the the image left or right according to the mouse position.

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bigeno · 2015-02-02 20:55

Thanks for the hint.
I checked a simple example and it move image quickly. So I implemented
in my code and surprise   because it was same slow as my previous draw
on canvas.
I had extra code which I did not notice   on mousemove, sorry 
FIXED