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@ajayjayayy
Last active August 10, 2018 02:11
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Animate SVG path on scroll
license: mit

Make sure to pop out to a new window, and then scroll.

An experiment to see if I can get svg paths to animate only to a certain horizontal line while a user scrolls. Used in my unreleased wongfu side project.

Built with blockbuilder.org

forked from sxywu's block: Animate SVG path on scroll

<html>
<head>
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/3.10.1/lodash.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.6/d3.js" charset="utf-8"></script>
<style>
* {
font-family: Helvetica, Verdana, sans-serif;
}
.marker {
position: fixed;
top: 0;
left: 0;
width: 100%;
height: 400px;
border: 1px solid #ccc;
}
</style>
</head>
<body>
<svg width="1000" height="20000"></svg>
<div class="marker"></div>
<script>
var data = {categoryX: 300, points: [{"x":300,"y":161.16},{"x":300,"y":232.58},{"x":200,"y":359.51},{"x":300,"y":360.53},{"x":300,"y":566.63},{"x":300,"y":594.08},{"x":300,"y":650.37},{"x":300,"y":723.46},{"x":300,"y":864.01},{"x":300,"y":879.88},{"x":300,"y":1138.35},{"x":300,"y":1158.8},{"x":300,"y":1220.25},{"x":300,"y":1489.94},{"x":300,"y":1583.51},{"x":300,"y":1627.55},{"x":300,"y":1739.97},{"x":300,"y":1800.63},{"x":300,"y":1885.21},{"x":300,"y":1979.47},{"x":300,"y":2057.81},{"x":150,"y":2059.57},{"x":300,"y":2097.48},{"x":300,"y":2152.41},{"x":300,"y":2152.46},{"x":300,"y":2157.54},{"x":300,"y":2157.56},{"x":300,"y":2174.22},{"x":300,"y":2188.61},{"x":300,"y":2213.54},{"x":300,"y":2231.43},{"x":300,"y":2252},{"x":200,"y":2275.33},{"x":300,"y":2291.35},{"x":300,"y":2319.71},{"x":300,"y":2328.22},{"x":300,"y":2345.74},{"x":250,"y":2345.91},{"x":300,"y":2367.61},{"x":300,"y":2409.25},{"x":300,"y":2429.13},{"x":300,"y":2447.6},{"x":300,"y":2467.67},{"x":300,"y":2473.07},{"x":200,"y":2473.24},{"x":300,"y":2485.47},{"x":300,"y":2528.83},{"x":300,"y":2664.08},{"x":300,"y":2664.16},{"x":250,"y":2665.75},{"x":300,"y":2681.58},{"x":250,"y":2682.98},{"x":250,"y":2683.03},{"x":300,"y":2703.05},{"x":250,"y":2707.75},{"x":300,"y":2719.75},{"x":300,"y":2725.5},{"x":250,"y":2727.59},{"x":300,"y":2741.92},{"x":250,"y":2758.02},{"x":300,"y":2758.88},{"x":300,"y":2766},{"x":250,"y":2768.52},{"x":300,"y":2781.85},{"x":250,"y":2783.5},{"x":300,"y":2790.62},{"x":300,"y":2797.6},{"x":300,"y":2803.05},{"x":300,"y":2822.51},{"x":300,"y":2842.45},{"x":300,"y":2859.41},{"x":250,"y":2861.83},{"x":250,"y":2861.9},{"x":300,"y":2878.11},{"x":300,"y":2899.3},{"x":300,"y":2899.39},{"x":150,"y":2900.16},{"x":300,"y":2915.11},{"x":300,"y":2954.28},{"x":300,"y":2963.22},{"x":300,"y":2993.16},{"x":300,"y":3024.93},{"x":300,"y":3034.73},{"x":300,"y":3053.71},{"x":100,"y":3108.65},{"x":300,"y":3108.78},{"x":100,"y":3170.02},{"x":300,"y":3307.02},{"x":300,"y":3347},{"x":100,"y":3386.84},{"x":300,"y":3388.35},{"x":300,"y":3392.8},{"x":300,"y":3409.08},{"x":200,"y":3482.29},{"x":300,"y":3490.06},{"x":100,"y":3490.08},{"x":300,"y":3521.3},{"x":300,"y":3525.8},{"x":300,"y":3527.47},{"x":100,"y":3527.71},{"x":350,"y":3785.85},{"x":300,"y":3817.04},{"x":100,"y":3879.62},{"x":300,"y":3990.06},{"x":100,"y":3994.39},{"x":300,"y":4033.28},{"x":150,"y":4040},{"x":300,"y":4168.39},{"x":300,"y":4203.66},{"x":300,"y":4309.47},{"x":300,"y":4355.49},{"x":300,"y":4438.63},{"x":300,"y":4501.4},{"x":300,"y":4527.18},{"x":300,"y":4527.24},{"x":300,"y":4527.32},{"x":300,"y":4705.31},{"x":200,"y":4790.07},{"x":300,"y":4790.17},{"x":300,"y":4831.58},{"x":300,"y":4909.79},{"x":300,"y":4978.06},{"x":300,"y":5024.68},{"x":300,"y":5341.95},{"x":300,"y":5404.04},{"x":300,"y":5707.09},{"x":300,"y":5846.84},{"x":300,"y":5918.93},{"x":300,"y":5956.66},{"x":300,"y":6008.86},{"x":300,"y":6032.41},{"x":300,"y":6074.86},{"x":300,"y":6160.47},{"x":300,"y":6494.77},{"x":300,"y":6544.9},{"x":300,"y":6554.59},{"x":300,"y":6572.89},{"x":300,"y":6620.47},{"x":300,"y":6628.18},{"x":300,"y":6651.49},{"x":300,"y":6690.64},{"x":300,"y":6734.86},{"x":300,"y":6784.42},{"x":300,"y":6897.47},{"x":50,"y":6978.9},{"x":300,"y":7053.46},{"x":300,"y":7064.33},{"x":300,"y":7081.25},{"x":200,"y":7169.69},{"x":300,"y":7169.81},{"x":300,"y":7209.83},{"x":300,"y":7258.2},{"x":100,"y":7352.41},{"x":300,"y":7365.26},{"x":300,"y":7437.33},{"x":300,"y":7556.63},{"x":300,"y":7589.71},{"x":300,"y":7626.93},{"x":300,"y":7649.84},{"x":300,"y":7666.02},{"x":300,"y":7689.28},{"x":300,"y":7705.31},{"x":300,"y":7727.3},{"x":300,"y":7744.38},{"x":300,"y":7766.83},{"x":300,"y":7817.81},{"x":300,"y":7862.84},{"x":400,"y":7882.63},{"x":300,"y":8036.55},{"x":300,"y":8192.58},{"x":300,"y":8419.56},{"x":300,"y":8566.87},{"x":300,"y":8667.14},{"x":300,"y":8780.15},{"x":300,"y":8784.1},{"x":300,"y":8827.76},{"x":300,"y":8855.53},{"x":300,"y":8890.78},{"x":300,"y":8939.6},{"x":300,"y":8997.51},{"x":300,"y":9169.01},{"x":300,"y":9314.37},{"x":300,"y":9399.17},{"x":300,"y":9594.91},{"x":500,"y":9756.56},{"x":200,"y":10109.02}]};
var svg = d3.select('svg');
var distancePath = svg.append('path')
.attr('fill', 'none')
.attr('stroke', 'none').node();
var source;
var target;
var gap = 100;
var totalDistance = 0;
_.each(data.points, function(target) {
if (!source) {
target.d = 'M' + target.x + ',' + target.y;
} else {
if (source.y > target.y - gap) {
// if they're sufficiently close to each other
if (source.x === target.x) {
target.d = drawLine(target.x, target.y);
setDistance(source, target);
} else {
target.d = drawCurve(source.x, source.y, target.x, target.y);
setDistance(source, target);
target.y1 = target.y - source.y;
target.interpolate1 = d3.interpolate(0, target.distance);
}
} else {
target.d = '';
if (source.x !== data.categoryX) {
// if the source repo owner isn't the same as the contributor, move the line back
target.d += drawCurve(source.x, source.y, data.categoryX, source.y + gap / 3);
setDistance(source, target);
target.y1 = gap / 3;
target.interpolate1 = d3.interpolate(0, target.distance);
}
x = target.x;
y = target.y;
if (target.x !== data.categoryX) {
x = data.categoryX;
y = target.y - gap / 3;
}
target.d += drawLine(x, y);
target.y2 = y - (target.y1 || 0);
setDistance(source, target);
if (target.x !== data.categoryX) {
target.d += drawCurve(x, y, target.x, target.y);
var currentDistance = target.distance;
setDistance(source, target);
target.y3 = gap / 3;
target.interpolate2 = d3.interpolate(0, target.distance - currentDistance);
}
}
target.totalDistance = (totalDistance += target.distance);
}
source = target;
});
var path = svg.append('path')
.attr('d', _.pluck(data.points, 'd').join(' '))
.attr('fill-opacity', 0)
.attr('stroke', '#3FB8AF')
.attr('stroke-width', 4)
.attr('stroke-linecap', 'round')
.attr('stroke-dasharray', totalDistance)
.attr('stroke-dashoffset', totalDistance);
var circle = svg.selectAll('circle')
.data(data.points).enter().append('circle')
.attr('fill', '#fff')
.attr('stroke', '#3FB8AF')
.attr('stroke-width', 2)
.attr('cx', function(d) {return d.x})
.attr('cy', function(d) {return d.y})
.attr('r', 4);
window.addEventListener('scroll', _.throttle(windowScroll, 200));
function windowScroll() {
var top = scrollY + 400;
var source;
var target = _.find(data.points, function(point) {
if (point.y >= top) {
return true;
}
source = point;
return false;
});
if (source && target) {
var distance = 0;
var distanceFromSource = top - source.y;
if (!target.interpolate1) {
// if there's no interpolate1
if (!target.interpolate2) {
// and there's no interpolate2, must mean it's a straight line
distance = distanceFromSource + source.totalDistance;
} else {
// if there's a interpolate2, must mean there's a straight line
// and then a curve at the end, so figure out if we're in straight line or curve part
if (distanceFromSource <= target.y2) {
// it's in straight line part
distance = distanceFromSource + source.totalDistance;
} else {
// if it's in last curve part, first interpolate the curve
// and then add that back to the straight part and the previous total distance
var partialDistance = (distanceFromSource - target.y2) / target.y3;
distance = target.interpolate2(partialDistance) + target.y2 + source.totalDistance;
}
}
} else {
// if there's interpolate1, must mean there's a first curve
if (distanceFromSource <= target.y1) {
// so if it's within the first curve, interpolate that and add it to total distance
var partialDistance = distanceFromSource / target.y1;
distance = target.interpolate1(partialDistance) + source.totalDistance;
} else if (distanceFromSource <= (target.y1 + target.y2)) {
// if we're in line part, add curve to it
distance = target.interpolate1(1) + (distanceFromSource - target.y1) + source.totalDistance;
} else if (interpolate2) {
var partialDistance = (distanceFromSource - target.y2 - target.y1) / target.y3;
distance = target.interpolate1(1) + target.y2 + target.interpolate2(partialDistance);
}
}
// var partialDistance = (top - source.y) / (target.y - source.y);
// var distance = target.interpolater(partialDistance) + source.totalDistance;
path.transition().duration(200)
.attr('stroke-dashoffset', totalDistance - (distance || 0));
}
};
function drawLine(x, y) {
return 'L' + x + ',' + y;
}
function drawCurve(x1, y1, x2, y2) {
var cy = (y1 + y2) / 2;
return 'C' + x1 + ',' + cy + ' ' + x2 + ',' + cy + ' ' + x2 + ',' + y2;
}
function setDistance(source, target) {
var distancePathD = 'M' + source.x + ',' + source.y + ' ' + target.d;
distancePath.setAttribute('d', distancePathD);
target.distance = parseFloat(distancePath.getTotalLength().toFixed(2));
}
</script>
</body>
</html>
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