How not to...?
It leaves traces? Do you mean like fingerprints and DNA evidence?
Sherlock Holmes is now on the stage : refreshing the TPaintBox. after a
canvas.Draw with a modified bitmap leaves some foot prints...
Should I take a snapshot of what is under ...?
It's elementary, my dear Watson... clear the canvas before you do the paint.
Then no evidence will be left behind.
Dear Sherlock, you really don't get it, do you. He wants to be caught
and therefor leave some traces behind. ;-)
"David HAROUCHE" <met...@hotmail.com> schreef in bericht
>> Then no evidence will be left behind.
Did you engaged Alfred Hitchcock ?
The problem is that if I draw the bitmap on the Canvas (bitmap;transparent
is set to true) firs as it is, then rotated, the transparency dosent apply
correctly on a transparent TForm :
the form's background is a snapshot of what it was before under the form...
Its going to depend on what it is you are specifically doing. But in
general, draw a rectangle over the canvas with the background color. Then
draw your background image. Then draw your bitmap rotated at its new angle.
>>But in general, draw a rectangle
You surely mean canvas.FillRect !
>>Then draw your background image.
Thats' where I think about a snapshot of the desktop of what is under the
TPaintBox...! But what if a change occurs on the desktop ?
>> Then draw your bitmap rotated at its new angle.
That causes more flickers on screen...
No - I mean what I say, and say what I mean!
And what I mean is draw a rectangle over the background, regardless of what
graphics interface you are using. If you are using vcl drawing routines,
then fillrect will do. I personally dont use the vcl routines much, so am
more likely to use native gdi calls or gdi+ methods.
>>> Then draw your bitmap rotated at its new angle.
> That causes more flickers on screen...
Then it sounds to me your real problem is flickering. I would focus on