如何从卡片组图像中取出特定的卡？

Question

I want to take out a card from my deck image. How can I do that without downloading every single card separately? I don't want to initialize all 52 cards in my class.

Right now, I randomize colour and value and then it finds the picture in my source folder. But is it possible to only take one card out from my single deck image?

bild = ImageIO.read(new File("source folder/" + colour + value + ".png"));      

Answer 1

You still have to load the entire image but when you're drawing, just use

g.drawImage(Image img, int dstx1, int dsty1, int dstx2, int dsty2, int srcx1, int srcy1, int srcx2, int srcy2, ImageObserver observer);

The src (=source) values will be the upper left und lower right coordinates within your image that define the part you want to draw while the dst (=destination) values will decide where it will be drawn.

Answer 2

You should initialize them all but you don't have to do it by hands.

You should create one image that contains every single card and load it. BufferedImage class provides you a getSubImage(int x, int y, int w, int h); and is returning a piece (a card) of your BufferedImage.

You can populate an array of card while looping through the image of your deck.

    for(int i = 0; i<4; i++){
        for(int j = 0; j < 13; j++){
            deckArray[13 * i + j] == image.getSubImage(i * cardWidth,
                                                       j * cardHeight, 
                                                       cardWidth, 
                                                       cardHeight);
        }
    }

Something like this. Note that I'm assuming 4*13 images os sheet and no space between them. You will have to find a way to track you cards, which one is which in your array no matter how you store them, because what you definietly don't want is loading an image every time you want to use it.

It's not tested and not 100% sure I did all the math corretly, just a quick reference how could you achive something like this.