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| var width = 900,
height = 600,
r1 = -1.80,
r2 = 1.80,
i1 = -1.20,
i2 = 1.20,
rstep,
istep,
ctx,
nmax,
img,
pix,
julias = [
[-0.726895347709114071439, 0.188887129043845954792, 1000],
[-0.156844471694257101941, -0.649707745759247905171, 1000],
[0.285, 0.013, 1000],
[0.285, 0.01, 500],
[0.3, 0.5, 200],
[-0.414, -0.612, 500],
[0.382, 0.147, 200],
[0.284, -0.0122, 1000],
[-0.0519, 0.688, 200],
[-0.577, 0.478, 1000]
],
kr,
ki,
complexe = function(cr, ci){
var zr = 0,
zi = 0,
zr_next,
zi_next;
for (var n = 1; n <= nmax; n++){
if (n == 1){
zr_next = cr;
zi_next = ci;
} else {
zr_next = zr*zr - zi*zi + kr;
zi_next = 2*zr*zi + ki;
}
if ((zr_next*zr_next + zi_next*zi_next) > 4){
return n;
}
zr = zr_next;
zi = zi_next;
}
return 0;
},
draw = function(rmin, imin, rmax, imax){
rstep = (rmax - rmin) / width;
istep = (imax - imin) / height;
var t1 = new Date().getTime(),
t2,
z = -1,
thr = Math.floor(nmax / 5),
eThr,
i,
r,
e;
for(var y = 0; y < height; y++) {
i = imin + y * istep;
for(var x = 0; x < width; x++) {
r = rmin + x * rstep;
e = complexe(r, i);
eThr = e/thr;
if(e > 0) {
if(e <= thr) {
red = Math.floor(eThr * 255);
green = blue = 0;
} else {
e -= thr;
eThr = e/thr;
red = 255 - Math.floor(eThr * 25);
green = Math.floor(eThr * 255);
blue = Math.floor(eThr * 127.5);
}
} else {
red = green = blue = 0;
}
pix[z += 1] = red;
pix[z += 1] = green;
pix[z += 1] = blue;
z += 1;
}
}
ctx.putImageData(img, 0, 0);
t2 = new Date().getTime();
return t2 - t1;
};
$(function(){
var thisLeft = $("#canvas").offset().left,
thisTop = $("#canvas").offset().top,
affiche = function(r1, r2, i1, i2, ms){
$("#coords").html("r1 = " + r1.toExponential(16) +
" | r2 = " + r2.toExponential(16) +
"<br>i1 = " + i1.toExponential(16) +
" | i2 = " + i2.toExponential(16) +
" | ms = " + ms);
},
nbIter = function(){
var n = parseInt($("#maxIter").val(), 10);
if (isNaN(n)){
$("#maxIter").val(50);
n = 50;
} else if (n > 8000) {
n = 8000;
} else if (n < 20){
n = 20;
}
return n;
},
zoom = function(){
var z = parseInt($("#zoom").val(), 10);
if (isNaN(z)) {
$("#zoom").val(5);
z = 5;
} else if (z > 20) {
z = 20;
} else if (z < 1){
z = 1;
}
return z;
},
coefs = function(){
var kn = $("#coefs").val();
kr = julias[kn][0];
ki = julias[kn][1];
$("#maxIter").val(julias[kn][2]);
};
if ($("#canvas")[0].getContext){
ctx = $("#canvas")[0].getContext("2d");
ctx.fillStyle = "#000000";
ctx.fillRect(0, 0, width-1, height-1);
img = ctx.getImageData(0, 0, width, height);
pix = img.data;
coefs();
nmax = nbIter();
affiche(r1, r2, i1, i2, draw(r1, i1, r2, i2));
$("#coefs").change(function(){
coefs();
nmax = nbIter();
$("#zoom").val(5);
r1 = -1.80;
r2 = 1.80;
i1 = -1.20;
i2 = 1.20;
affiche(r1, r2, i1, i2, draw(r1, i1, r2, i2));
});
$("#canvas").click(function(event){
var x = event.pageX - thisLeft,
y = event.pageY - thisTop,
z = zoom(),
w = width/(2*z),
h = height/(2*z),
r = r1,
i = i1;
r1 = r + (x - w) * rstep;
i1 = i + (y - h) * istep;
r2 = r + (x + w) * rstep;
i2 = i + (y + h) * istep;
nmax = nbIter();
affiche(r1, r2, i1, i2, draw(r1, i1, r2, i2));
});
}
}); |
