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Distance fields (circle shape)
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`// noprotect` | |
### BEGIN ### | |
hcl_linear_rainbow = () -> | |
# H and L are linear, C is quadratic | |
domain = [0,1] | |
hue_range = [340, 340-480] | |
chroma_range = [0, 40] | |
luminance_range = [0, 100] | |
scale = (x) -> | |
ext = domain[1]-domain[0] | |
xn = (x-domain[0]) / ext | |
h = hue_range[0] + (hue_range[1]-hue_range[0])*xn | |
c = chroma_range[0] + (chroma_range[1]-chroma_range[0]) * (1 - Math.pow(1 - 2*xn, 2) ) | |
l = luminance_range[0] + (luminance_range[1]-luminance_range[0]) *xn | |
# clamp | |
h = Math.max( Math.min(h, d3.max(hue_range)), d3.min(hue_range) ) | |
c = Math.max( Math.min(c, d3.max(chroma_range)), d3.min(chroma_range) ) | |
l = Math.max( Math.min(l, d3.max(luminance_range)), d3.min(luminance_range) ) | |
return d3.hcl(h,c,l) | |
scale.domain = (x) -> | |
return domain if(!arguments.length) | |
domain = x | |
return scale | |
scale.hue_range = (x) -> | |
return hue_range if(!arguments.length) | |
hue_range = x | |
return scale | |
scale.chroma_range = (x) -> | |
return chroma_range if(!arguments.length) | |
chroma_range = x | |
return scale | |
scale.luminance_range = (x) -> | |
return luminance_range if(!arguments.length) | |
luminance_range = x | |
return scale | |
return scale | |
### END ### | |
### define the distance function for a circle ### | |
CX = 0.5 | |
CY = 0.5 | |
R = 0.25 | |
dist = (x, y) -> R - ( Math.pow(x-CX, 2) + Math.pow(y-CY, 2) )/R | |
### Draw the distance function ### | |
canvas = d3.select('#left') | |
width = canvas.node().getBoundingClientRect().width | |
height = canvas.node().getBoundingClientRect().height | |
side = Math.min(width, height) - 20 | |
ctx = canvas.node().getContext('2d') | |
image = ctx.createImageData(side, side) | |
### define a default cubehelix-style hcl linear rainbow scale ### | |
MAX_D = Math.sqrt(2)/4 | |
colorize_inner = hcl_linear_rainbow() | |
.domain([MAX_D,0]) | |
.hue_range([200, 200+90]) | |
colorize_outer = hcl_linear_rainbow() | |
.domain([-MAX_D,0]) | |
.hue_range([200-180, 200-180+90]) | |
console.debug 'Coloring...' | |
for pixel_x in [0...side] | |
for pixel_y in [0...side] | |
pixel_i = (pixel_y*side + pixel_x)*4 | |
[r,g,b,a] = [pixel_i+0, pixel_i+1, pixel_i+2, pixel_i+3] | |
[x,y] = [pixel_x/side, pixel_y/side] | |
Fxy = dist(x, y) | |
if Fxy > 0 | |
color = d3.rgb colorize_inner(Fxy) | |
else | |
color = d3.rgb colorize_outer(Fxy) | |
image.data[r] = color.r | |
image.data[g] = color.g | |
image.data[b] = color.b | |
image.data[a] = 255 | |
ctx.putImageData(image,(width-side)/2,(height-side)/2) | |
### Draw the reconstructed shape ### | |
canvas = d3.select('#right') | |
width = canvas.node().getBoundingClientRect().width | |
height = canvas.node().getBoundingClientRect().height | |
side = Math.min(width, height) - 20 | |
ctx = canvas.node().getContext('2d') | |
image = ctx.createImageData(side, side) | |
BLUR = 3 | |
for pixel_x in [0...side] | |
for pixel_y in [0...side] | |
pixel_i = (pixel_y*side + pixel_x)*4 | |
[r,g,b,a] = [pixel_i+0, pixel_i+1, pixel_i+2, pixel_i+3] | |
[x,y] = [pixel_x/side, pixel_y/side] | |
Fxy = dist(x, y) | |
value = Math.min(1+Fxy/(BLUR/side), 1) | |
image.data[r] = 255 | |
image.data[g] = 255 | |
image.data[b] = 255 | |
image.data[a] = value*255 | |
ctx.putImageData(image,(width-side)/2,(height-side)/2) |
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html, body { | |
padding: 0; | |
margin: 0; | |
} | |
canvas { | |
background: #222; | |
position: absolute; | |
} | |
#left { | |
top: 0; | |
left: 0; | |
} | |
#right { | |
top: 0; | |
left: 480px; | |
} |
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<!DOCTYPE html> | |
<html> | |
<head> | |
<meta charset="utf-8"> | |
<meta name="description" content="Distance functions (circle shape)" /> | |
<title>Distance functions (circle shape)</title> | |
<link rel="stylesheet" href="index.css"> | |
<script src="http://d3js.org/d3.v3.min.js"></script> | |
</head> | |
<body> | |
<canvas id="left" width="480" height="500"></canvas> | |
<canvas id="right" width="480" height="500"></canvas> | |
<script src="index.js"></script> | |
</body> | |
</html> |
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(function() { | |
// noprotect; | |
/* BEGIN | |
*/ | |
var BLUR, CX, CY, Fxy, MAX_D, R, a, b, canvas, color, colorize_inner, colorize_outer, ctx, dist, g, hcl_linear_rainbow, height, image, pixel_i, pixel_x, pixel_y, r, side, value, width, x, y, _i, _j, _k, _l, _ref, _ref1, _ref2, _ref3; | |
hcl_linear_rainbow = function() { | |
var chroma_range, domain, hue_range, luminance_range, scale; | |
domain = [0, 1]; | |
hue_range = [340, 340 - 480]; | |
chroma_range = [0, 40]; | |
luminance_range = [0, 100]; | |
scale = function(x) { | |
var c, ext, h, l, xn; | |
ext = domain[1] - domain[0]; | |
xn = (x - domain[0]) / ext; | |
h = hue_range[0] + (hue_range[1] - hue_range[0]) * xn; | |
c = chroma_range[0] + (chroma_range[1] - chroma_range[0]) * (1 - Math.pow(1 - 2 * xn, 2)); | |
l = luminance_range[0] + (luminance_range[1] - luminance_range[0]) * xn; | |
h = Math.max(Math.min(h, d3.max(hue_range)), d3.min(hue_range)); | |
c = Math.max(Math.min(c, d3.max(chroma_range)), d3.min(chroma_range)); | |
l = Math.max(Math.min(l, d3.max(luminance_range)), d3.min(luminance_range)); | |
return d3.hcl(h, c, l); | |
}; | |
scale.domain = function(x) { | |
if (!arguments.length) { | |
return domain; | |
} | |
domain = x; | |
return scale; | |
}; | |
scale.hue_range = function(x) { | |
if (!arguments.length) { | |
return hue_range; | |
} | |
hue_range = x; | |
return scale; | |
}; | |
scale.chroma_range = function(x) { | |
if (!arguments.length) { | |
return chroma_range; | |
} | |
chroma_range = x; | |
return scale; | |
}; | |
scale.luminance_range = function(x) { | |
if (!arguments.length) { | |
return luminance_range; | |
} | |
luminance_range = x; | |
return scale; | |
}; | |
return scale; | |
}; | |
/* END | |
*/ | |
/* define the distance function for a circle | |
*/ | |
CX = 0.5; | |
CY = 0.5; | |
R = 0.25; | |
dist = function(x, y) { | |
return R - (Math.pow(x - CX, 2) + Math.pow(y - CY, 2)) / R; | |
}; | |
/* Draw the distance function | |
*/ | |
canvas = d3.select('#left'); | |
width = canvas.node().getBoundingClientRect().width; | |
height = canvas.node().getBoundingClientRect().height; | |
side = Math.min(width, height) - 20; | |
ctx = canvas.node().getContext('2d'); | |
image = ctx.createImageData(side, side); | |
/* define a default cubehelix-style hcl linear rainbow scale | |
*/ | |
MAX_D = Math.sqrt(2) / 4; | |
colorize_inner = hcl_linear_rainbow().domain([MAX_D, 0]).hue_range([200, 200 + 90]); | |
colorize_outer = hcl_linear_rainbow().domain([-MAX_D, 0]).hue_range([200 - 180, 200 - 180 + 90]); | |
console.debug('Coloring...'); | |
for (pixel_x = _i = 0; 0 <= side ? _i < side : _i > side; pixel_x = 0 <= side ? ++_i : --_i) { | |
for (pixel_y = _j = 0; 0 <= side ? _j < side : _j > side; pixel_y = 0 <= side ? ++_j : --_j) { | |
pixel_i = (pixel_y * side + pixel_x) * 4; | |
_ref = [pixel_i + 0, pixel_i + 1, pixel_i + 2, pixel_i + 3], r = _ref[0], g = _ref[1], b = _ref[2], a = _ref[3]; | |
_ref1 = [pixel_x / side, pixel_y / side], x = _ref1[0], y = _ref1[1]; | |
Fxy = dist(x, y); | |
if (Fxy > 0) { | |
color = d3.rgb(colorize_inner(Fxy)); | |
} else { | |
color = d3.rgb(colorize_outer(Fxy)); | |
} | |
image.data[r] = color.r; | |
image.data[g] = color.g; | |
image.data[b] = color.b; | |
image.data[a] = 255; | |
} | |
} | |
ctx.putImageData(image, (width - side) / 2, (height - side) / 2); | |
/* Draw the reconstructed shape | |
*/ | |
canvas = d3.select('#right'); | |
width = canvas.node().getBoundingClientRect().width; | |
height = canvas.node().getBoundingClientRect().height; | |
side = Math.min(width, height) - 20; | |
ctx = canvas.node().getContext('2d'); | |
image = ctx.createImageData(side, side); | |
BLUR = 3; | |
for (pixel_x = _k = 0; 0 <= side ? _k < side : _k > side; pixel_x = 0 <= side ? ++_k : --_k) { | |
for (pixel_y = _l = 0; 0 <= side ? _l < side : _l > side; pixel_y = 0 <= side ? ++_l : --_l) { | |
pixel_i = (pixel_y * side + pixel_x) * 4; | |
_ref2 = [pixel_i + 0, pixel_i + 1, pixel_i + 2, pixel_i + 3], r = _ref2[0], g = _ref2[1], b = _ref2[2], a = _ref2[3]; | |
_ref3 = [pixel_x / side, pixel_y / side], x = _ref3[0], y = _ref3[1]; | |
Fxy = dist(x, y); | |
value = Math.min(1 + Fxy / (BLUR / side), 1); | |
image.data[r] = 255; | |
image.data[g] = 255; | |
image.data[b] = 255; | |
image.data[a] = value * 255; | |
} | |
} | |
ctx.putImageData(image, (width - side) / 2, (height - side) / 2); | |
}).call(this); |
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