mirror of
https://github.com/ConnectedHumber/Air-Quality-Web
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38 lines
1.3 KiB
JavaScript
38 lines
1.3 KiB
JavaScript
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"use strict";
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// From https://stackoverflow.com/a/15666143/1460422
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let pixel_ratio = (function () {
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let ctx = document.createElement("canvas").getContext("2d"),
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dpr = window.devicePixelRatio || 1,
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bsr = ctx.webkitBackingStorePixelRatio ||
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ctx.mozBackingStorePixelRatio ||
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ctx.msBackingStorePixelRatio ||
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ctx.oBackingStorePixelRatio ||
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ctx.backingStorePixelRatio || 1;
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return dpr / bsr;
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})();
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/**
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* De-blurrificates a canvas on Hi-DPI screens.
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* @param {HTMLCanvasElement} canvas The canvas element to alter.
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* @param {Number} width=canvas.width Optional. The width of the canvas in question.
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* @param {Number} height=canvas.height Optional. The height of the canvas in question.
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* @returns {HTMLCanvasElement} The canvas we operated on. Useful for daisy-chaining.
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*/
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function set_hidpi_canvas(canvas, width, height) {
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width = width || canvas.width;
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height = height || canvas.height;
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canvas.width = width * pixel_ratio;
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canvas.height = height * pixel_ratio;
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canvas.style.width = width + "px";
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canvas.style.height = height + "px";
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// canvas.getContext("2d").setTransform(pixel_ratio, 0, 0, pixel_ratio, 0, 0);
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return canvas;
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}
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export { pixel_ratio, set_hidpi_canvas };
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