'Graphics' Methods

[Virtual24]

I'm trying to make a fun little game with java, because java make it so easy to manipulate graphics, except that i am hitting a road block!! for example: when you use the

public void paint( Graphics g )
{
    Image firstImage = createImage( 500, 400 );
    anImage = getImage( getCodeBase(), "theImage.bmp" );
    offScreen.getGraphics( firstImage )
    offScreen.drawImage( anImage, 10, 30, this );
    g.clearRect( 500, 400 );
    g.drawImage( firstImage, 0, 0, this );
}

this draws an image ("theImage.bmp") just fine to the screen, BUT... if i were to draw two images, the background of the second image covers up the first image. Understand what i mean? How do i get it so that i can only paint just the 'Image' and not the surrounding black background which is required cuz you have to do something with that space in a .bmp file. There has to be a way to so this, no in fact i know there is a way to do it!!! Any Ideas???? Please Help!! Thanx in advance.

[billrogers]

I did a multiplayer connect 4 game a year and half ago. I think you can have it just repaint certain coordinates.

[Virtual24]

yeah, sure you can... thats not what I mean at all (sorry)... Lets say that you draw a circle that fills up most of the bitmap in paint. then you use paint bucket to make the rest of the area black that the circle doesn't take up. Thwn, when i get into my program, i want to put the circle on the screen, say for an animation. BUT... i dont want the computer to paint the BLACK part ont the screen, just the circle. I know this is possible because people have done it! Does anyone know how???

[Mrs Kensington]

Are you trying to make some part of your image transparent?

if so then this code should help...

public static BufferedImage makeTransparent(BufferedImage image, Color c)
{
    //create the pixel but make the alpha channel 0 for transparent
    int[] TRANSPARENT_COLOR = {c.getRed(), c.getGreen(), c.getBlue(), 0}; 
    WritableRaster raster = image.getRaster (); 
    int[] pixel = new int [4];
    //go through every pixel
&nbsp;&nbsp;&nbsp;&nbsp;for (int y=0; y < image.getHeight (); y++)
&nbsp;&nbsp;&nbsp;&nbsp;{
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (int x=0; x < image.getWidth (); x++)
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//get the pixel
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;pixel = raster.getPixel (x, y, pixel);
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//if the RGB value equals the RGB of the Color we want to make transparent
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//write new pixel over top
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (pixel[0] == TRANSPARENT_COLOR[0] && pixel[1] == TRANSPARENT_COLOR[1] && pixel[2] == TRANSPARENT_COLOR[2])
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;raster.setPixel (x, y, TRANSPARENT_COLOR);
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}
&nbsp;&nbsp;&nbsp;&nbsp;}
&nbsp;&nbsp;&nbsp;&nbsp;//return new image	
&nbsp;&nbsp;&nbsp;&nbsp;return image;
}

as you see you need a BufferedImage. To create one from a normal Image use...

public static BufferedImage createBufferedImage(Image source, ImageObserver io)
{
    //get images dimenions
    int sourceWidth = source.getWidth(io);
    int sourceHeight = source.getHeight(io);
    //create new BufferedImage
    BufferedImage image = new BufferedImage (sourceWidth, sourceHeight, BufferedImage.TYPE_INT_ARGB);
    //draw old image over new image
    image.getGraphics().drawImage(source, 0, 0, null);
    //return image
    return image;
}

for the ImageObserver you can just use a Component.

Hope this answers your question

[Virtual24]

Well it turns out i dont need any of that, sorry thanx for the info anyway. I figured out that if i use a .gif file with a transparent background, then java does all the rest.