Created
December 7, 2017 10:31
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// Calc DPI with JS | |
function dpLib(debug) { | |
"use strict"; | |
var div = document.createElement("div"); | |
div.style.width = "1in"; | |
div.style.position = "abolute"; | |
div.style.top = "-100%"; | |
div.style.bottom = "-100%"; | |
document.body.appendChild(div); | |
// | |
this.version = "1.0"; | |
this.cmInInch = 2.54; // 1 in = 2.54 cm | |
this.pixInInch = div.offsetWidth; | |
this.pixInCm = this.pixInInch / this.cmInInch; | |
// | |
document.body.removeChild(div); | |
if (debug) { | |
console.info("Version of dpLib: %s", this.version); | |
console.info("inch = %s pixels \n centimetr = %s pixels", this.pixInInch, this.pixInCm); | |
} | |
} | |
// inches | |
dpLib.prototype.i = function (i) { | |
if (!i) i = 1; | |
return this.pixInInch * i; | |
} | |
// centimetres | |
dpLib.prototype.cm = function (cm) { | |
if (!cm) cm = 1; | |
return this.pixInCm * cm; | |
} | |
// convert centimetres to inches | |
dpLib.prototype.cm2i = function (cm) { | |
if (!cm) cm = 1; | |
return cm / this.cmInInch; | |
} | |
// convert inches to centimetres | |
dpLib.prototype.i2cm = function (i) { | |
if (!i) i = 1; | |
return i * this.cmInInch; | |
} |
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