gistfile1.m

    NSImage* lightImage;
    {
        lightImage=[[NSImage alloc]initWithSize:[image size]];
        [lightImage lockFocus];
        NSRect rect=NSZeroRect;
        rect.size=[image size];
        [image drawAtPoint:NSZeroPoint fromRect:rect operation:NSCompositeCopy fraction:0.4];
        [lightImage unlockFocus];
    }

    NSImage* lightImage=({
        NSImage* lightImage=[[NSImage alloc]initWithSize:[image size]];
        [lightImage lockFocus];
        NSRect rect=NSZeroRect;
        rect.size=[image size];
        [image drawAtPoint:NSZeroPoint fromRect:rect operation:NSCompositeCopy fraction:0.4];
        [lightImage unlockFocus];
        lightImage;
    });