mirror of https://github.com/dirtbags/moth.git
43 lines
1.0 KiB
JavaScript
43 lines
1.0 KiB
JavaScript
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function Plot(id, width, height) {
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var canvas = document.getElementById(id);
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var ctx = canvas.getContext('2d');
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canvas.width = 800;
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canvas.height = 200;
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// We'll let the canvas do all the tricksy math
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xscale = canvas.width/width;
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yscale = canvas.height/height;
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ctx.lineWidth = 2;
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function moveTo(x, y) {
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ctx.moveTo(Math.round(x * xscale), Math.round(y * yscale));
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}
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function lineTo(x, y) {
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ctx.lineTo(Math.round(x * xscale), Math.round(y * yscale));
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}
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function draw(values) {
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ctx.beginPath();
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moveTo(values[0][0], height);
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var lasty = 0;
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for (i in values) {
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var x = values[i][0];
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var y = values[i][1];
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lineTo(x, height - lasty);
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lineTo(x, height - y);
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lasty = y;
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}
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lineTo(width, height - lasty);
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}
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this.line = function(color, values) {
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ctx.fillStyle = color;
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ctx.strokeStyle = color;
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draw(values);
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ctx.stroke();
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}
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}
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