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Thread: Images (read/write, drawing)

  1. #1
    Super Moderator helloworld922's Avatar
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    Default Images (read/write, drawing)

    Here's a quick and dirty tutorial on how to draw images in Java, then save them to the file system.

    Drawing an image from scratch and saving to a png:
    int width = 1024;
    int height = 768;
    // we're going to use RBG coloring. There are a bunch of different types, though
    BufferedImage image= new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    Graphics g = image.getGraphics();
    // now drawing is just like painting a component
    g.setColor(new Color(0.2f, 0.4f, 0.2f));
    // make the background a slight shade of green
    g.fillRect(0, 0, width, height);
    g.setColor(new Color(1.0f, 0.0f, 0.0f));
    // draw a red circle
    g.drawCircle(0, 0, width, height);
    // now to save the image
    try
    {
         ImageIO.write(image, "png", new File("test.png"));
    }
    catch (IOException exception)
    {
         exception.printStackTrace();
    }

    It is possible to save to multiple file types, for a list of available formats call ImageIO.getWriterFormatNames().

    Reading an image in is as easy as calling the read() method of ImageIO:
    try
    {
         BufferedImage myImage = ImageIO.read(new File("test.png"));
    }
    catch(IOException e)
    {
         e.printStackTrace();
    }

    Happy drawing!

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    JavaPF (June 1st, 2010)


  3. #2
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    Default Re: Images (read/write, drawing)

    very funny!

    import java.io.*;
    import java.awt.image.BufferedImage;
    import javax.imageio.ImageIO;
    import java.awt.Graphics;
    import java.awt.Color;
     
    public class draw {
    	public static void main(String[] args) {
     
    		int width = 200;
    		int height = 200;
    		int circlew = width;
    		int circleh = height;
    		boolean choser = true;
    		int x = width/2;
    		int y = height/2;
     
    		BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    		Graphics g = bi.getGraphics();
     
    		g.setColor(new Color(30,30,30));
    		g.fillRect(0,0, width, height);
    		while(circlew>=25 && circleh>=25){
    			if(choser) {
    				g.setColor(Color.WHITE);
    			}
    			else {
    				g.setColor(Color.black);
    			}
    			if(circlew==25 && circleh==25) {
    				g.setColor(Color.red);
    			}
    			g.fillOval(x-circlew/2,y-circleh/2, circlew, circleh);
    			choser = choser^true;
    			circlew = circlew-25;
    			circleh = circleh-25;
    		}		
     
    		save(bi);
     
    	}
     
    	public static void save(BufferedImage image) {
    		try{
    			ImageIO.write(image, "png", new File("flag.png"));
    		}
    		catch(Exception e) {
    			System.out.println("errore");
    		}
    	}
    }

    flag.png

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