[英]Calculate inner divs width/height in mm (relative to outer div with known width/height in mm.)
What i want to do is to calculate the inner divs width/height in mm. 我想要做的是计算以mm为单位的内部div宽度/高度。 with JavaScript and also take scale into consideration.
使用JavaScript,并且还要考虑规模。
Example 1: the outer divs assigned width/height is 30x30mm, scale is 0.8 and inner divs width/height in px is 600x600px, the result should then be 24x24mm. 示例1:指定的外部div宽度/高度为30x30mm,比例为0.8,内部div的宽度/高度(以px为单位)为600x600px,结果应为24x24mm。
Example 2: the outer divs assigned width/height is 60x30mm, scale is 1.0 and inner divs width/height in px is 300x600px, the result should then be 15x30mm. 示例2:指定的外部div宽度/高度为60x30mm,比例为1.0,内部div的宽度/高度(以px为单位)为300x600px,结果应为15x30mm。
The outer divs width/height in mm is considered max sizes. 以毫米为单位的外部div宽度/高度被认为是最大尺寸。
Guess it's easy, but the fact that the divs/surfaces can have different ratios made it to complicated for me. 猜猜这很容易,但是div /曲面可以具有不同的比率这一事实使我感到复杂。
var calcDimensions = function(scale) {
var surfaceWidth, surfaceHeight, contentWidth, contentHeight, contentRatio, surfaceRatio;
// Output variable holding the result
var dimensions = { width: 0, height: 0 };
surfaceWidth = 30; // outer divs assigned width in mm
surfaceHeight = 14; // outer divs assigned height in mm
contentWidth = 600; // inner divs real width in px
contentHeight = 196; // inner divs real height in px
scale = 0.8; // Can have a value between 0.1 - 1.0
contentRatio = contentWidth > contentHeight ? contentHeight / contentWidth : contentWidth / contentHeight; // Assuming this is needed in the calculation.
surfaceRatio = surfaceWidth > surfaceHeight ? surfaceHeight / surfaceWidth : surfaceWidth / surfaceHeight; // Assuming this is needed in the calculation.
// Calculate stuff here and return calculated dimensions
return dimensions;
} }
You could try to do the folowing: 您可以尝试执行以下操作:
Add a div in your view with width = 100mm 在视图中添加宽度为100mm的div
<div style="width:100mm;height:0" id="measure">
Maybe you have to set z-index or bg-color to make the div invisible. 也许您必须设置z-index或bg-color才能使div不可见。 Now you can calculate the count of pixels per mm on the device like this:
现在,您可以像这样计算设备上每毫米的像素数:
let pxPerMm = document.getElementById('measure').offsetWidth / 100;
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