CODEWITHSUNDEEP
javagraphics2d
Ruzard
Ruzard

Reputation: 1359

Clear image with transparent background in java

I am drawing images in paintComponent(Graphics g) method in order to make them compatible with Retina displays

g.drawImage(image, 0, 0, imageWidth/2, imageHeight/2, null);

Everything works perfectly but the image's shadows stack on each other. It makes the picture ugly. So I need to clear image before drawing new. Here comes the problem:

I had no problems clearing image, however the problem is to prevent the background of the parent element from being overlapped. Now it looks in such a way http://cl.ly/image/0K1u0q2M150W .

I used methods from other topics:

g2d.setBackground(new Color(255,255,255,0));
g2d.clearRect(0, 0, ICON_WIDTH, ICON_HEIGHT);

as well as 

g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.CLEAR));
g2d.setBackground(new Color(255,255,255,0));
g2d.clearRect(0, 0, ICON_WIDTH, ICON_HEIGHT);
g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER));

and several others.

this is how it should look like http://cl.ly/image/2V1R1v0X452N and this is how it looks after invoking repaint() method several times. I need to call it to change the image from one to another.

my paintComponent method:

Image image;
if (flag) {
    image = image1;
} else {
    image = image2;
}

g2d.drawImage(image, 0, 0, IMAGE_SIZE, IMAGE_SIZE, null);

Upvotes: 1

Views: 7154

Answers (1)

Ruzard
Ruzard

Reputation: 1359

While writing this question I accidentally found the answer. For me calling 

        super.paintComponent(g);

in the beginning of the paintComponnent() method was the solution. Because it clears the image somewhere inside.

The code from super.paintComponent(g) that clears image is the following:

g.setColor(c.getBackground());
g.fillRect(0, 0, c.getWidth(),c.getHeight());

if I put it instead of super.paintComponent - it also works. I just needed not to set my own color before filling the rectangle.

Upvotes: 6

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