howto pixel coordinates of points

In GRAL the screen coordinates of the data points are calculated by querying the AxisRenderer of each axis.

For a two-dimensional x-y plot GRAL queries the renderer of x axis for the horizontal position and the renderer of the y axis for the vertical position. Given the data point values x and y, it would as follows:

double pixelX = plot.getAxisRenderer(XYPlot.AXIS_X).worldToView(axisX, x, true);
double pixelY = plot.getAxisRenderer(XYPlot.AXIS_Y).worldToView(axisY, y, true);

The axes are positioned inside a plot area (PlotArea). In order to get the absolute position in the plot area, we have to translate the pixel coordinates:

double pixelX = plot.getAxisRenderer(XYPlot.AXIS_X).worldToView(axisX, x, true);
double pixelY = plot.getAxisRenderer(XYPlot.AXIS_Y).worldToView(axisY, y, true);

double plotAreaHeight = plot.getPlotArea().getHeight();
double plotAreaX = plot.getPlotArea().getX();
double plotAreaY = plot.getPlotArea().getY();

pixelX = plotAreaX + pixelX;
pixelY = plotAreaY + plotAreaHeight - pixelY;