drawContourLine method

void drawContourLine (double startX, double startY, double endX, double endY, double contourLevel, int levelNumber)

This method gets called by ContourFinder.findContour each time a contour line was found. Its purpose is to draw the detected contour line, which is a piece of an entire contour. Drawing can e.g. be performed using the respective methods of CanvasRenderingContext2D to draw into a CanvasElement. Or you may use webgl. In that case this method would just fill a buffer with the provided coordinates. This method receives the start and end coordinates of the contour line to be drawn: startX, startY, endX, endY (numbers between 0 and 1). Assume you want to draw the contours of a matrix with ncols columns and nrows rows. Then the start/end coordinates below and a matrix element (i,j) are related by j / (ncols - 1), i / (nrows - 1) to give normalized coordinates between 0 and 1. contourLevel is the value of the current level to be drawn, levelNumber is the number of this level in the list specified to contour finder.

Implementation

void drawContourLine(double startX, double startY, double endX, double endY,
    double contourLevel, int levelNumber);