Java swing how to draw an image as a quadrilateral by using 4 points

Question

I want to draw an image as a quadrilateral by using the points of the 4 corners as parameters. Does Java have anything already built in for that? I've seen a similar post but the solution given did not seem to do what I want. The function call would look like this:

wall.drawTexture(Point topLeft, Point topRight, Point bottomLeft, Point bottomRight);

My wall class already contains an attribute "BufferedImage texture".

Context: I'm doing a raycaster engine. I can split my image into smaller columns to correspond to my pixel columns on the 3D view but the texture integrity isn't very high. I thought by only using the first and last ray to hit the same wall face and convert to a parallelogram instead would solve my problem. It would also probably be faster than drawing column by column.

Please post a [mre] that is compilable and demonstrates the problem. — WJS, May 25 '20 at 20:44
i dont have any code, im just looking for a function that could make what you see in the drawing and what i explained. — Frédéric Bélanger, May 25 '20 at 21:03
Read the section from the Swing tutorial on [Transformations](https://docs.oracle.com/javase/tutorial/2d/advanced/transforming.html). I think you would want the shear transform. — camickr, May 26 '20 at 03:07

score 1 · Accepted Answer · answered May 25 '20 at 19:55

1

You could use drawLine. Something where it draws a line between 1-2, 1-3, 4-2, 4-3 .

answered May 25 '20 at 19:55

Smartsav10

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9

Im not sure i understand what you are suggesting. Im trying to take an image and draw it as a quadrilateral. Ive added an image to help clarify. – Frédéric Bélanger May 25 '20 at 20:23
Once you get your 4 points from the image, use draw line to connect them maybe. – Smartsav10 May 25 '20 at 21:20
yes, i think i can use a double shear to get the desired result. Some math would be needed to get the proper scale factors in order for the image to align with my points but i believe it can work. Big tks! Edit: actually i dont need to shear twice, even better. – Frédéric Bélanger May 26 '20 at 15:54

score 1 · Answer 2 · answered May 25 '20 at 21:16

All I can suggest is that you consider the following:

paintComponent(Graphics g) {
     super.paintComponent(g);

    Graphics2D g2d = (Graphics2D) g;
    // Rendering hints can visually smooth out the graphics with
    // anti aliasing.
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);
}

Other possibilities would be looking at the AffineTransform and related classes where you can manipulate various aspects of a graphics context (e.g. shearing, blurring, etc).

Java swing how to draw an image as a quadrilateral by using 4 points

2 Answers2