CODEWITHSUNDEEP
javanetbeansjpanel
Nauris Linde
Nauris Linde

Reputation: 15

Draw line with mouse in JPanel on NetBeans

I need to draw a line in JPanel with mouse, clicking two points in panel. First click would be the start of the line, and second click would be the end of the line.

This is my programm

I have something like this:

    private void jPanel1MouseClicked(java.awt.event.MouseEvent evt) {                                     
    // TODO add your handling code here:
    Graphics g = this.jPanel1.getGraphics();

    int x = evt.getX();
    int y = evt.getY();

    g.drawLine(x, y, x, y);
}

But it only draws pixel. Line with coordinates I need something like this, but just drawing it with mouse clicking.

Upvotes: 0

Views: 4080

Answers (2)

Steve Chaloner
Steve Chaloner

Reputation: 8202

You're drawing a line from (x, y) to (x, y) which is why you're getting just a single pixel. You need to capture the co-ordinates of the first click, and then draw the line on the second click.

private int startX = -1;
private int startY = -1;

private void jPanel1MouseClicked(java.awt.event.MouseEvent evt) {                                     
    if (startX == -1 && startY == -1) {
        startX = evt.getX();
        startY = evt.getY();
    } else {
        Graphics g = this.jPanel1.getGraphics();
        g.drawLine(startX, startY, 
                   evt.getX(), evt.getY());
        // reset the start point
        startX = -1;
        startY = -1;
    }
}

Upvotes: 1

StephaneM
StephaneM

Reputation: 4899

From the doc

Draws a line, using the current color, between the points (x1, y1) and (x2, y2) in this graphics context's coordinate system.

In your case x1=x2 and y1=y2, that's why your line is 1 pixel long. After each click you must record the coordinates of your click so that you can use them as the origin of the line for the next click.

Upvotes: 1

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