Problems by double buffer

[SuperSonic]

i have somethink painted in jCanvasPanel1, and i want to use buffer1 as a buffer when painting, but before i send buffer1 to foo procedure, i will, that it has the same painting content as the jCanvasPanel1

so for example : there is a rectangle drawen in jCanvasPanel1. The function DRAW.foo, paints an circle, and i want to have the circle and the rectangle in the final...

i want to copy the graphical content from jCanvasPanel1 to buffer1 before its use in foo

        Image buffer1;
        buffer1 = createImage(1000,1000);
        
        DRAW.foo(buffer1);
                
        jCanvasPanel1.getGraphics().drawImage(buffer1, 0, 0, this);

thanks