How to 'dim' the canvas?

[James Hodgkiss]

My midlet uses a canvas where ocassionally a little popup info box may appear in the centre of the canvas.

When it appears, I would like to make the surrounding area go darker.

Does anyone know how I could achieve this?

[Tim Holloway]

The usual approach is to create a translucent window the same size as the screen, overlaying the screen and painted with a gray pattern (alternating black and clear pixels, for example.

Then the actual dialog would be overlaid on to of the translucent window.

[James Hodgkiss]

So the end of my paint method is changing from:

if (toShowInfoBox) {
    drawInfoBoxImage(g, ....);
}

to

if (toShowInfoBox) {
 
    //move this block so it's only executed once
    int numPixels = canvasWidth * canvasHeight;
    int[] pixels = new int[numPixels];
    for (int i = 0; i < numPixels; i++) {
        pixels[i] = 0x80808080; //constant grey looks better than alternating black and white
    }
    Image greyTranslucentImage = Image.createRGBImage(pixels, canvasWidth, canvasHeight, true);
 
    g.drawImage(greyTranslucentImage, 0, 0, Graphics.TOP|Graphics.LEFT);
 
    drawInfoBoxImage(g, ....);
}

...it seems to work ok. Is that the way you meant?

Also, rather than create one large image, is it less memory-intensive to create a smaller image and paint is several times to the canvas?

Cheers,
James

[ November 08, 2007: Message edited by: James Hodgkiss ]
[ November 08, 2007: Message edited by: James Hodgkiss ]