{"id":88,"date":"2025-11-22T09:48:04","date_gmt":"2025-11-22T01:48:04","guid":{"rendered":"https:\/\/www.52runoob.com\/?p=88"},"modified":"2025-11-22T09:48:04","modified_gmt":"2025-11-22T01:48:04","slug":"%e5%9f%ba%e4%ba%8e-html5-canvas-%e5%ae%9e%e7%8e%b0%e5%9b%be%e7%89%87%e6%97%8b%e8%bd%ac%e4%b8%8e%e4%b8%8b%e8%bd%bd%e5%8a%9f%e8%83%bd%e5%ae%8c%e6%95%b4%e4%bb%a3%e7%a0%81%e5%b1%95%e7%a4%ba","status":"publish","type":"post","link":"https:\/\/www.52runoob.com\/index.php\/2025\/11\/22\/%e5%9f%ba%e4%ba%8e-html5-canvas-%e5%ae%9e%e7%8e%b0%e5%9b%be%e7%89%87%e6%97%8b%e8%bd%ac%e4%b8%8e%e4%b8%8b%e8%bd%bd%e5%8a%9f%e8%83%bd%e5%ae%8c%e6%95%b4%e4%bb%a3%e7%a0%81%e5%b1%95%e7%a4%ba\/","title":{"rendered":"\u57fa\u4e8e HTML5 Canvas \u5b9e\u73b0\u56fe\u7247\u65cb\u8f6c\u4e0e\u4e0b\u8f7d\u529f\u80fd(\u5b8c\u6574\u4ee3\u7801\u5c55\u793a)"},"content":{"rendered":"\n

\u4e0b\u9762\u7ed9\u4f60\u4e00\u4e2a \u57fa\u4e8e HTML5 Canvas \u5b9e\u73b0\u201c\u56fe\u7247\u65cb\u8f6c + \u4e0b\u8f7d\u201d\u201d\u7684\u5b8c\u6574\u53ef\u8fd0\u884c\u793a\u4f8b\u4ee3\u7801<\/strong>\uff0c\u5305\u542b\uff1a<\/p>\n\n\n\n

\u2714 \u56fe\u7247\u4e0a\u4f20
\u2714 Canvas \u7ed8\u5236\u56fe\u7247
\u2714 \u65cb\u8f6c 90\u00b0 \/ 180\u00b0 \/ 270\u00b0
\u2714 \u81ea\u7531\u8f93\u5165\u89d2\u5ea6\u65cb\u8f6c
\u2714 \u4e0b\u8f7d\u65cb\u8f6c\u540e\u7684\u56fe\u7247
\u2714 \u7eaf HTML5 + \u539f\u751f JS\uff0c\u65e0\u9700\u4efb\u4f55\u5e93<\/p>\n\n\n\n

\u590d\u5236\u5373\u53ef\u76f4\u63a5\u8fd0\u884c\uff0c\u975e\u5e38\u9002\u5408\u79fb\u52a8\u7aef\u6216 Web \u9879\u76ee\u3002<\/p>\n\n\n\n

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\u2b50 \u5b8c\u6574\u4ee3\u7801\uff08HTML + CSS + JavaScript \u4e00\u4f53\uff09<\/strong><\/h1>\n\n\n
\n&lt;!DOCTYPE html>\n&lt;html lang="zh-cn">\n&lt;head>\n&lt;meta charset="UTF-8">\n&lt;meta name="viewport" content="width=device-width, initial-scale=1.0">\n&lt;title>Canvas \u56fe\u7247\u65cb\u8f6c\u4e0e\u4e0b\u8f7d Demo&lt;\/title>\n\n&lt;style>\n    body {\n        font-family: Arial, sans-serif;\n        padding: 12px;\n        background: #f3f3f3;\n    }\n    .box {\n        background: #fff;\n        padding: 15px;\n        border-radius: 10px;\n        box-shadow: 0 2px 10px rgba(0,0,0,.1);\n    }\n    canvas {\n        max-width: 100%;\n        margin-top: 15px;\n        background: #eee;\n        border-radius: 6px;\n    }\n    button {\n        margin: 5px 5px 5px 0;\n        padding: 8px 16px;\n        border: none;\n        border-radius: 6px;\n        background: #007bff;\n        color: #fff;\n    }\n    input[type='number'] {\n        width: 80px;\n        padding: 6px;\n        border-radius: 6px;\n        border: 1px solid #aaa;\n    }\n&lt;\/style>\n&lt;\/head>\n\n&lt;body>\n\n&lt;h2>Canvas \u56fe\u7247\u65cb\u8f6c\u4e0e\u4e0b\u8f7d\u793a\u4f8b&lt;\/h2>\n\n&lt;div class="box">\n    &lt;input type="file" id="upload" accept="image\/*">\n    &lt;br>\n\n    &lt;button onclick="rotate(90)">\u65cb\u8f6c 90\u00b0&lt;\/button>\n    &lt;button onclick="rotate(180)">\u65cb\u8f6c 180\u00b0&lt;\/button>\n    &lt;button onclick="rotate(270)">\u65cb\u8f6c 270\u00b0&lt;\/button>\n\n    &lt;br>\n    &lt;input id="angleInput" type="number" value="45">\n    &lt;button onclick="rotateCustom()">\u81ea\u5b9a\u4e49\u89d2\u5ea6\u65cb\u8f6c&lt;\/button>\n\n    &lt;br>\n    &lt;button onclick="downloadImage()">\u4e0b\u8f7d\u65cb\u8f6c\u540e\u7684\u56fe\u7247&lt;\/button>\n&lt;\/div>\n\n&lt;canvas id="canvas">&lt;\/canvas>\n\n&lt;script>\n    const upload = document.getElementById("upload");\n    const canvas = document.getElementById("canvas");\n    const ctx = canvas.getContext("2d");\n\n    let img = new Image();\n    let currentAngle = 0;\n\n    \/\/ \u4e0a\u4f20\u56fe\u7247\n    upload.onchange = function (e) {\n        const file = e.target.files[0];\n        if (file) {\n            const reader = new FileReader();\n            reader.onload = function (evt) {\n                img.src = evt.target.result;\n            };\n            reader.readAsDataURL(file);\n        }\n    };\n\n    \/\/ \u56fe\u7247\u52a0\u8f7d\u5b8c\u6210\u540e\u7ed8\u5236\n    img.onload = function () {\n        drawImage();\n    };\n\n    \/\/ \u7ed8\u5236\u56fe\u7247\uff08\u5e26\u65cb\u8f6c\uff09\n    function drawImage() {\n        const angleInRad = currentAngle * Math.PI \/ 180;\n\n        \/\/ \u65cb\u8f6c\u540e\u56fe\u7247\u7684\u5bbd\u9ad8\u91cd\u65b0\u8ba1\u7b97\n        const width = img.width;\n        const height = img.height;\n\n        \/\/ \u65cb\u8f6c 90\u00b0 \/ 270\u00b0 \u65f6\u5bbd\u9ad8\u5bf9\u8c03\n        const cw = Math.abs(Math.cos(angleInRad)) * width + Math.abs(Math.sin(angleInRad)) * height;\n        const ch = Math.abs(Math.sin(angleInRad)) * width + Math.abs(Math.cos(angleInRad)) * height;\n\n        canvas.width = cw;\n        canvas.height = ch;\n\n        ctx.clearRect(0, 0, cw, ch);\n\n        ctx.save();\n        \/\/ \u79fb\u52a8 canvas \u539f\u70b9\u5230\u4e2d\u5fc3\n        ctx.translate(cw \/ 2, ch \/ 2);\n        \/\/ \u65cb\u8f6c\u753b\u5e03\n        ctx.rotate(angleInRad);\n        \/\/ \u7ed8\u5236\u56fe\u7247\uff08\u8ba9\u56fe\u7247\u4e2d\u5fc3\u5bf9\u9f50\uff09\n        ctx.drawImage(img, -width \/ 2, -height \/ 2);\n        ctx.restore();\n    }\n\n    \/\/ \u6309\u94ae\u65cb\u8f6c\n    function rotate(angle) {\n        currentAngle = (currentAngle + angle) % 360;\n        drawImage();\n    }\n\n    \/\/ \u81ea\u5b9a\u4e49\u89d2\u5ea6\u65cb\u8f6c\n    function rotateCustom() {\n        const angle = parseFloat(document.getElementById("angleInput").value) || 0;\n        currentAngle = (currentAngle + angle) % 360;\n        drawImage();\n    }\n\n    \/\/ \u4e0b\u8f7d\u56fe\u7247\n    function downloadImage() {\n        const link = document.createElement("a");\n        link.download = "rotated_image.png";\n        link.href = canvas.toDataURL("image\/png");\n        link.click();\n    }\n&lt;\/script>\n\n&lt;\/body>\n&lt;\/html>\n\n<\/pre><\/div>\n\n\n
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\ud83d\udccc \u529f\u80fd\u70b9\u8bf4\u660e<\/h1>\n\n\n\n
\u529f\u80fd<\/th>\u5df2\u5b9e\u73b0<\/th><\/tr><\/thead>
\u4e0a\u4f20\u56fe\u7247<\/td>\u2714<\/td><\/tr>
Canvas \u7ed8\u56fe<\/td>\u2714<\/td><\/tr>
\u81ea\u7531\u65cb\u8f6c\u56fe\u7247<\/td>\u2714<\/td><\/tr>
\u56fe\u7247\u5bbd\u9ad8\u81ea\u9002\u5e94<\/td>\u2714<\/td><\/tr>
\u6309\u94ae\u65cb\u8f6c 90\/180\/270<\/td>\u2714<\/td><\/tr>
\u81ea\u5b9a\u4e49\u89d2\u5ea6\u65cb\u8f6c<\/td>\u2714<\/td><\/tr>
\u4e0b\u8f7d\u65cb\u8f6c\u540e\u56fe\u7247<\/td>\u2714<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
<\/p>\n\n\n\n
\u53ea\u8981\u544a\u8bc9\u6211\u9700\u8981\u54ea\u4e2a\u7248\u672c\uff0c\u6211\u9a6c\u4e0a\u5199\u7ed9\u4f60\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
\u4e0b\u9762\u7ed9\u4f60\u4e00\u4e2a \u57fa\u4e8e HTML5 Canvas \u5b9e\u73b0\u201c\u56fe\u7247\u65cb\u8f6c + \u4e0b\u8f7d\u201d\u201d\u7684\u5b8c\u6574… Continue Reading →<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"class_list":["post-88","post","type-post","status-publish","format-standard","hentry","category-html5"],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts\/88","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/comments?post=88"}],"version-history":[{"count":1,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts\/88\/revisions"}],"predecessor-version":[{"id":89,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts\/88\/revisions\/89"}],"wp:attachment":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/media?parent=88"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/categories?post=88"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/tags?post=88"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}