/*
* $Id: gnuplot_dashedlines.js,v 1.2 2010/11/26 23:39:16 sfeam Exp $
*/
/*
* Ethan Merritt November 2010
* Add a dashed line method to gnuplot's HTML5 canvas toolset.
* To start a path use DS(x0,y0) instead of M(x0,y0)
* To draw line segments use DL(x,y) instead of L(x,y)
* Finish as usual with ctx.stroke(); ctx.closePath();
*/
gnuplot.solid = [];
gnuplot.dashpattern1 = gnuplot.solid;
gnuplot.dashpattern2 = [ 0.5, 1.0 ];
gnuplot.dashpattern3 = [ .12, .25, .37, .50, .62, .75, .87, 1.0 ];
gnuplot.dashpattern4 = [ 0.50, 0.70, 0.80, 1.0 ];
gnuplot.dashpattern5 = [ 0.30, 0.50, 0.60, 0.75, 0.85, 1.0 ];
gnuplot.dashlength = 200.; // length of one complete pattern
gnuplot.dashfraction = 0; // how far in the pattern we got last time
gnuplot.dash_x = 0;
gnuplot.dash_y = 0;
gnuplot.dashtype = function(dt) {
gnuplot.pattern = dt;
}
gnuplot.dashstart = function(x,y) {
gnuplot.dash_x = x;
gnuplot.dash_y = y;
gnuplot.dashfraction = 0;
gnuplot.M(x,y);
}
gnuplot.dashstep = function(x,y) {
var delx = x - gnuplot.dash_x;
var dely = y - gnuplot.dash_y;
var stride = Math.sqrt(delx*delx + dely*dely) / gnuplot.dashlength;
var this_step;
if (gnuplot.pattern.length == 0) {gnuplot.L(x,y); return;}
while (stride > 0) {
// Find which piece of the pattern we are in
for (i=0; gnuplot.pattern[i] <= gnuplot.dashfraction; i++);
this_step = gnuplot.pattern[i] - gnuplot.dashfraction;
if (stride > this_step) {
new_x = gnuplot.dash_x + delx*this_step/stride;
new_y = gnuplot.dash_y + dely*this_step/stride;
stride = stride - this_step;
gnuplot.dashfraction = gnuplot.pattern[i];
delx = x - new_x;
dely = y - new_y;
} else {
new_x = x;
new_y = y;
gnuplot.dashfraction = gnuplot.dashfraction + stride;
stride = 0;
}
if (i%2==0) gnuplot.L(new_x,new_y);
else gnuplot.M(new_x,new_y);
gnuplot.dash_x = new_x;
gnuplot.dash_y = new_y;
if (gnuplot.dashfraction >= 1.0) gnuplot.dashfraction = 0;
}
}
