php - 如何在 PHP 中随机生成图像尺寸？

Question

我想生成一些随机的 placekitten url，如下所示：

http://placekitten.com/200/300

在我目前正在开发的网站上用作领跑者。图片宽度不得小于 100 像素且不得大于 250 像素。我正在生成这样的宽度：

$width = mt_rand(100, 250);

但我不确定如何生成高度。根据生成的随机宽度，高度应具有适当的纵横比。怎么做？

最终目标是：

$thumb = "http://placekitten.com/$width/$height";

Answer 1

应该很简单：

$ratio = 200/300;
$width = mt_rand(100, 250);
$height = round($width / $ratio);

---

看一些例子：

$ratio = 200/300;
echo "base aspect ratio: ", round($ratio, 2), "\n\n";

foreach(range(1,10) as $_) {
  $width = mt_rand(100, 250);
  $height = round($width / $ratio);
  echo "http://placekitten.com/{$width}/{$height}\n";
  echo "aspect ratio: ", round($width / $height, 2), "\n\n";
}

输出

base aspect ratio: 0.67

http://placekitten.com/229/344
aspect ratio: 0.67

http://placekitten.com/112/168
aspect ratio: 0.67

http://placekitten.com/241/362
aspect ratio: 0.67

http://placekitten.com/223/335
aspect ratio: 0.67

http://placekitten.com/196/294
aspect ratio: 0.67

http://placekitten.com/234/351
aspect ratio: 0.67

http://placekitten.com/116/174
aspect ratio: 0.67

http://placekitten.com/157/236
aspect ratio: 0.67

http://placekitten.com/165/248
aspect ratio: 0.67

http://placekitten.com/114/171
aspect ratio: 0.67