[SOLVED] BGRABitmap, CanvasBGRA

[petevick]

I'm trying to get to grips with using BGRABitmap. I want to draw on the BGRABitmap.CanvasBGRA. With a TCanvas I can use the Clear procedure to clear any drawn lines etc, but there doesn't appear to be an equivalent for the CanvasBGRA, am I missing something ?

[paweld]

Maybe FillRect

Code: Pascal  [Select][+][-]

1. var
2.   bmp: TBGRABitmal;
3. begin
4.   // ...
5.   bmp.CanvasBGRA.Brush.Color := clWhite;  
6.   bmp.CanvasBGRA.FillRect(bmp.CanvasBGRA.ClipRect); // "clear" :-)
7.   // ...
8. end;
9.  

[petevick]

Maybe FillRect

Code: Pascal  [Select][+][-]

1. var
2.   bmp: TBGRABitmal;
3. begin
4.   // ...
5.   bmp.CanvasBGRA.Brush.Color := clWhite;  
6.   bmp.CanvasBGRA.FillRect(bmp.CanvasBGRA.ClipRect); // "clear" :-)
7.   // ...
8. end;
9.  

Yep that does it, but it's not giving  what I'm after, I need to delve deeper I think.
Thanks for the help pawekd 

[circular]

It is a good point, CanvasBGRA provides methods do draw as the regular Canvas, bit it does not provide a Clear method nor methods to erase according to a certain shape.

As a workaround, you can do bmp.FillTransparent.

I am wondering what would be the methods. Clear seem rather straightforward to clear the whole canvas. Regarding the shapes, maybe we could add a property to the Pen and the Brush to express that they are suppose to erase instead of draw.

[petevick]

It is a good point, CanvasBGRA provides methods do draw as the regular Canvas, bit it does not provide a Clear method nor methods to erase according to a certain shape.

As a workaround, you can do bmp.FillTransparent.

I am wondering what would be the methods. Clear seem rather straightforward to clear the whole canvas. Regarding the shapes, maybe we could add a property to the Pen and the Brush to express that they are suppose to erase instead of draw.

The Pen/Brush property sounds like the better way to me.