[英]How to change the width and height of an image JavaScript
我有這段代碼可以在我的網站中添加圖像,但我想調整它的大小
var questionHeader = document.getElementById("a"); var img = new Image(), canvas = document.createElement("canvas"), ctx = canvas.getContext("2d"); img.onload = () => { let width = Math.floor(img.naturalWidth * 0.1), height = Math.floor(img.naturalHeight * 0.1); canvas.width = width; canvas.height = height; ctx.drawImage(img, 0, 0, width, height); }; img.src = "https://cdn-icons-png.flaticon.com/512/7951/7951990.png"; questionHeader.appendChild(img);
<div id="a"></div>
使用此代碼,我想讓圖像更小
let width = Math.floor(img.naturalWidth * 0.1),
height = Math.floor(img.naturalHeight * 0.1);
canvas.width = width;
canvas.height = height;
ctx.drawImage(img, 0, 0, width, height);
出於某種原因,它不起作用。 任何人都知道問題可能是什么?
您可以通過 css class 調整 img 的大小,您可以使用 Z686155AF75A60A0F6EZDEDD80C 為 img 設置 class
您附加了錯誤的元素(img 而不是 canvas)。
var questionHeader = document.getElementById("a");
var img = new Image(),
canvas = document.createElement("canvas"),
ctx = canvas.getContext("2d");
img.onload = () => {
let width = Math.floor(img.naturalWidth * 0.1),
height = Math.floor(img.naturalHeight * 0.1);
canvas.width = width;
canvas.height = height;
canvas.style.border = "1px solid";
ctx.drawImage(img, 0, 0, width, height);
};
img.src = "https://cdn-icons-png.flaticon.com/512/7951/7951990.png";
questionHeader.appendChild(canvas);
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