I got very interesting problem. I manipulate an image using TImageData however then I need to add a text and modify a few pixels manually. So I do this:
ImgBitmap:=TImagingBitmap.Create;
ImgBitmap.AssignFromImageData(MainImage);
// add text (just an example)
ImgBitmap.Canvas.TextOut(x,y,'some text');
// set some colors (just an example)
ImgBitmap.Canvas.Pixels[x,y]:=col;
// save the changes back to ImageData
ImgBitmap.AssignToImageData(MainImage);
ImgBitmap.Free;
However, my problem is that in some cases (let's say every fifth case) the changes of colors are not visible on the picture when I save it. It seems to me that the Canvas/Handle hasn't been updated yet at the moment I assign the bitmap back to ImageData. Sometimes the part of the image is even partially black. Does anyone have any idea what can be done? I tried to put sleep behind, I tried to use a CriticalSection (it is multithreading appl), I tried to Lock the canvas (although the ImgBitmap is not shared) however nothing works. I also tried to run only one thread but it was the same. Does anyone have any idea?
