drawContourLine method
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);