CODEWITHSUNDEEP
javaswing
Silentbob
Silentbob

Reputation: 3065

Colors are inverted on JPanel

I am attempting to draw a grid of lines on a JPanel placed insided JFrame using a BufferedImage.

So far I have got the vertical lines working (sort of) but my query is in relation to the Color of the lines and background.

When I run the application the JFrame and JPanel appears but the Color of the background is black and the lines are White. It's as though the Colors are inverted. (see image below)

JPanel view

I haven't set any Color in my Main class and my source code for the JPanel is as follows- 

public class MyPanel extends JPanel {

    boolean[][] grid;
    BufferedImage image;
    Graphics2D imageG;

    public MyPanel(boolean[][] newGrid) {
        grid = newGrid;
        image = new BufferedImage(1000, 1000, BufferedImage.TYPE_INT_RGB);
        imageG = image.createGraphics();
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Integer cellWidth = this.getWidth() / grid.length;

        for (Integer i = 0; i < grid.length + 1; i++) {
            imageG.drawLine(i * cellWidth, 0, i * cellWidth, this.getHeight());
        }

        Graphics2D tempg = (Graphics2D) g;
        tempg.fillRect(0, 0, this.getWidth(), this.getHeight());
        //Draw BufferedImage
        tempg.drawImage(image, 0, 0, this);
        //this.getGraphics().drawImage(lineImage, 0, 0, this);
    }
}

Upvotes: 1

Views: 240

Answers (1)

ArifMustafa
ArifMustafa

Reputation: 4935

Use BufferedImage.TYPE_INT_ARGB which Represents an image with 8-bit RGBA color components packed into integer pixels.

and earlier using BufferedImage.TYPE_INT_RGB which Represents an image with 8-bit RGB color components packed into integer pixels. also it lacks with transparent Colors as well as undefined Colors and thus it illustrates those with Color.BLACK.

rectified source code from above -

    public MyPanel(boolean[][] newGrid) {
        grid = newGrid;
        //Represents an image with 8-bit RGBA color components packed into integer pixels.
        image = new BufferedImage(1000, 1000, BufferedImage.TYPE_INT_ARGB);
        imageG = image.createGraphics();
        //Set the single pixel line color to YELLOW using BufferedImage instance
        imageG.setColor(Color.YELLOW);
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Integer cellWidth = this.getWidth() / grid.length;

        Graphics2D tempg = (Graphics2D) g;
        //Set the blocks and rest of it part to color RED
        tempg.setColor(Color.RED);

        for (Integer i = 0; i < grid.length + 1; i++) {
            imageG.drawLine(i * cellWidth, 0, i * cellWidth, this.getHeight());
        }

        tempg.fillRect(0, 0, this.getWidth(), this.getHeight());
        //Draw BufferedImage
        tempg.drawImage(image, 0, 0, this);
        //this.getGraphics().drawImage(lineImage, 0, 0, this);
    }

hope this will help you, thanks.

Upvotes: 3

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