drawContourLine method

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

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.

Implementation

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