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canvasStretch.js
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canvasStretch.js
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/*
* Copyright (C) 2015 Stefano D'Angelo <zanga.mail@gmail.com>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*** Canvas auto-resize utility. ***/
/* Stretches a canvas element to the available size of its parent, within the
* limits of a given width to height ratio, if specified. */
canvasPlot.canvasStretch = function (canvas, ratio) {
var s = window.getComputedStyle(canvas);
var p = canvas.parentNode;
var ps = window.getComputedStyle(p);
var w = p.clientWidth - parseFloat(ps.paddingLeft)
- parseFloat(s.marginLeft) - parseFloat(s.borderLeftWidth)
- parseFloat(s.paddingLeft) - parseFloat(ps.paddingRight)
- parseFloat(s.marginRight) - parseFloat(s.borderRightWidth);
var h = p.clientHeight - parseFloat(ps.paddingTop)
- parseFloat(s.marginTop) - parseFloat(s.borderTopWidth)
- parseFloat(s.paddingTop) - parseFloat(ps.paddingBottom)
- parseFloat(s.marginBottom) - parseFloat(s.borderBottomWidth);
if (ratio) {
var r = w / h;
if (r > ratio)
w = h * ratio;
else if (r < ratio)
h = w / ratio;
}
canvas.width = w;
canvas.height = h;
};