Check if point belongs to the plot

问题

I'm using JFreeChart to draw XYPlot. What I'm currently trying to do:

1. User clicks on the plot and the app gives him back the coordinates of the chosen point; I think that I've got it right. Here is some code:

       public void chartMouseClicked(ChartMouseEvent arg0) {
              Rectangle2D plotArea = chPanel.getScreenDataArea();
              XYPlot plot = (XYPlot) chart.getPlot();
              double chartX = plot.getDomainAxis().java2DToValue(arg0.getTrigger().getPoint().getX(), plotArea, plot.getDomainAxisEdge());
              double chartY = plot.getRangeAxis().java2DToValue(arg0.getTrigger().getPoint().getY(), plotArea, plot.getRangeAxisEdge());
              JOptionPane.showMessageDialog(null, "   x: "+chartX+ "  y: "+chartY);}       
   

2. I need to determine if user clicked on the line or not. The target is to mark the clicked spot if it is on the drawn graph.

I would be grateful for any clue.

回答1:

Instead of working with coordinates, add a ChartMouseListener as shown here. You can examine the ChartMouseEvent and any corresponding ChartEntity for a variety of details.

回答2:

ShapeUtilities.intersects(java.awt.geom.Rectangle2D rect1, java.awt.geom.Rectangle2D rect2) 

where rect2 can be "0" rectangle (for your points).

来源：https://stackoverflow.com/questions/10156338/check-if-point-belongs-to-the-plot