如何在JavaScript中獲取Base64編碼圖像的尺寸

Question

我有 REST API 返回 base64 圖片：

API 回復

有什么方法可以獲取此圖像的尺寸（高度，寬度）？

Answer 1

您可以使用給定的src創建Image object 並直接訪問width和height屬性。

 let url = 'data:image/png;base64,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'; // same image as https://via.placeholder.com/50x50 let img = new Image(); img.src = url; img.onload = function() { console.log(img.width, img.height); } document.body.append(img); // just for demonstration