On Wed, 23 Jan 2013 11:54:13 +0100
duilio foschi <duiliofos...@euplan.com> wrote:
> Hi!
>
> this code
>
> procedure TForm1.DrawBtnClick(Sender: TObject);
> {Draw some ellipses on the canvas - random size and color}
> var
> i:integer;
> cx,cy:integer;
> begin
> with image1, canvas do
> begin
> for i:= 1 to 10 do
> begin
> cx:=random(width);
> cy:=random(height);
> brush.color:=random(256*256*256);
> ellipse(cx,cy,cx+random(100), cy+random(100));
> end;
> end;
> end;
>
> will draw 10 ellipses on Image1.
>
> However, I want to do it interactively, like it is done in Photo-Paint.
>
> The ellipse should be contained in a rectangle R whose upper-left
> corner is given by the original position of the mouse on screen.
>
> And the bottom-right corner of R will be the final position of the mouse.
>
> During dragging, a temporary ellipse should be shown on screen and the
> mouse will be cross-shaped.
>
> Any idea re how to do it ?
Hint: TImage has two Canvas. The Picture.Canvas for the permanent
changes, the Canvas during OnPaint for the temporary drawings.
> An unexpensive well debugged 3th-party library would be the ideal
> solution (as I don't plan to work in graphics in the future).
Mattias
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