计算给定纵横比的包围矩形

Given the height and the width of a rectangle of any size and an aspect ratio, how can I calculate the height and width of a minimum enclosing rectangle of the given aspect ratio?

给定任意大小和纵横比的矩形的高度和宽度,如何计算给定纵横比的最小包围矩形的高度和宽度?

In code, the function signature would look like this

在代码中,函数签名看起来像这样

public Size getMinimumEnclosingRectangle(Size originalRectangle, float aspectNumerator, float aspectDenomiator);

Calls to this function would look like

调用此函数看起来像

originalRectangle    AspectRatio     Result
-------------------------------------------
100x100              1:2             100x200
64x32                1:1             64x64
125x100              3:2             150x100
100x345              1:3             115x345

1 个解决方案

#1

This may not be the best way, but the way I do this calculation is to calculate the change in aspect ratio and then base the resulting width/height calculation of of that. Here is some code to illustrate this algorithm in practice:

这可能不是最好的方法,但我进行此计算的方法是计算纵横比的变化,然后根据结果的宽度/高度计算。以下是一些在实践中说明此算法的代码:

var sourceImages = [
	{width: 100, height: 100, toAspectRatio:1/2  },
	{width: 64,  height: 32,  toAspectRatio:1/1  },
	{width: 125, height: 100, toAspectRatio:3/2  },
	{width: 100, height: 345, toAspectRatio:1/3 },
	{width: 345, height: 100, toAspectRatio:1/3 }
];


function calculateNewSize( sourceWidth, sourceHeight, toAspectRatio )
{
	var aspectRatioChange = (sourceWidth / sourceHeight) / toAspectRatio;
	var fitWidth = aspectRatioChange < 1 ? sourceHeight * toAspectRatio : sourceWidth;
	var fitHeight = aspectRatioChange >= 1 ? sourceWidth / toAspectRatio : sourceHeight;

	console.log('(' + aspectRatioChange + ') ' + sourceWidth + " x " + sourceHeight + " -> " 
				+ toAspectRatio + ' -> ' + fitWidth + ' x ' + fitHeight); 
}

sourceImages.forEach(function(source) {
	calculateNewSize(source.width, source.height, source.toAspectRatio);
});