{"id":1947,"date":"2025-02-23T14:39:26","date_gmt":"2025-02-23T06:39:26","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=1947"},"modified":"2025-02-23T14:39:26","modified_gmt":"2025-02-23T06:39:26","slug":"html5-canvas","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/02\/23\/html5-canvas\/","title":{"rendered":"HTML5\u00a0Canvas"},"content":{"rendered":"\n

HTML5 <canvas><\/code> \u5143\u7d20\u63d0\u4f9b\u4e86\u4e00\u4e2a\u7528\u4e8e\u7ed8\u5236\u56fe\u5f62\u7684\u533a\u57df\uff0c\u53ef\u4ee5\u901a\u8fc7 JavaScript \u5728\u8fd9\u4e2a\u533a\u57df\u8fdb\u884c\u52a8\u6001\u6e32\u67d3\u3002\u5b83\u5e38\u7528\u4e8e\u7ed8\u5236\u56fe\u8868\u3001\u6e38\u620f\u56fe\u5f62\u3001\u56fe\u50cf\u7f16\u8f91\u3001\u6570\u636e\u53ef\u89c6\u5316\u7b49\u3002<\/p>\n\n\n\n

1. Canvas \u57fa\u7840<\/strong><\/h3>\n\n\n\n

<canvas><\/code> \u5143\u7d20\u672c\u8eab\u662f\u4e00\u4e2a\u5bb9\u5668\uff0c\u5b83\u6ca1\u6709\u663e\u793a\u4efb\u4f55\u5185\u5bb9\uff0c\u9664\u975e\u4f60\u4f7f\u7528 JavaScript \u6765\u7ed8\u5236\u3002\u4f60\u53ef\u4ee5\u5728 <canvas><\/code> \u5143\u7d20\u4e2d\u5b9a\u4e49\u56fe\u5f62\u7684\u5bbd\u5ea6\u548c\u9ad8\u5ea6\u3002<\/p>\n\n\n\n

\u793a\u4f8b\uff1a<\/h4>\n\n\n\n
<!DOCTYPE html>\n<html lang=\"en\">\n<head>\n    <meta charset=\"UTF-8\">\n    <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">\n    <title>Canvas \u57fa\u7840\u793a\u4f8b<\/title>\n<\/head>\n<body>\n    <h1>HTML5 Canvas \u793a\u4f8b<\/h1>\n    <canvas id=\"myCanvas\" width=\"500\" height=\"500\" style=\"border:1px solid #000000;\">\n        \u4f60\u7684\u6d4f\u89c8\u5668\u4e0d\u652f\u6301 Canvas\u3002\n    <\/canvas>\n\n    <script>\n        var canvas = document.getElementById(\"myCanvas\");\n        var ctx = canvas.getContext(\"2d\");\n\n        \/\/ \u7ed8\u5236\u4e00\u4e2a\u7ea2\u8272\u7684\u77e9\u5f62\n        ctx.fillStyle = \"red\";\n        ctx.fillRect(50, 50, 150, 100);\n    <\/script>\n<\/body>\n<\/html><\/code><\/pre>\n\n\n\n
\u5728\u4e0a\u8ff0\u793a\u4f8b\u4e2d\uff0c\u6211\u4eec\u9996\u5148\u521b\u5efa\u4e86\u4e00\u4e2a <canvas><\/code> \u5143\u7d20\uff0c\u8bbe\u7f6e\u4e86\u5176\u5bbd\u5ea6\u548c\u9ad8\u5ea6\u3002\u63a5\u7740\u4f7f\u7528 JavaScript \u83b7\u53d6\u8be5\u5143\u7d20\u7684 context<\/code>\uff0c\u5b83\u662f\u4e00\u4e2a\u7528\u6765\u7ed8\u5236\u56fe\u5f62\u7684\u5bf9\u8c61\u3002getContext(\"2d\")<\/code> \u8fd4\u56de\u4e00\u4e2a 2D \u7ed8\u56fe\u4e0a\u4e0b\u6587\uff0c\u5141\u8bb8\u6211\u4eec\u5728\u753b\u5e03\u4e0a\u7ed8\u5236\u56fe\u5f62\u3002<\/p>\n\n\n\n
2. \u7ed8\u5236\u57fa\u672c\u56fe\u5f62<\/strong><\/h3>\n\n\n\n
canvas<\/code> \u63d0\u4f9b\u4e86\u5f88\u591a\u7ed8\u5236\u65b9\u6cd5\uff0c\u53ef\u4ee5\u7ed8\u5236\u77e9\u5f62\u3001\u5706\u5f62\u3001\u7ebf\u6761\u3001\u8def\u5f84\u7b49\u3002<\/p>\n\n\n\n
\u793a\u4f8b\uff1a\u7ed8\u5236\u5706\u5f62\u548c\u7ebf\u6761<\/h4>\n\n\n\n
<!DOCTYPE html>\n<html lang=\"en\">\n<head>\n    <meta charset=\"UTF-8\">\n    <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">\n    <title>Canvas \u7ed8\u5236\u5706\u5f62\u548c\u7ebf\u6761<\/title>\n<\/head>\n<body>\n    <h1>HTML5 Canvas \u793a\u4f8b<\/h1>\n    <canvas id=\"myCanvas\" width=\"500\" height=\"500\" style=\"border:1px solid #000000;\">\n        \u4f60\u7684\u6d4f\u89c8\u5668\u4e0d\u652f\u6301 Canvas\u3002\n    <\/canvas>\n\n    <script>\n        var canvas = document.getElementById(\"myCanvas\");\n        var ctx = canvas.getContext(\"2d\");\n\n        \/\/ \u7ed8\u5236\u5706\u5f62\n        ctx.beginPath();\n        ctx.arc(200, 200, 50, 0, 2 * Math.PI);\n        ctx.fillStyle = \"blue\";\n        ctx.fill();\n\n        \/\/ \u7ed8\u5236\u7ebf\u6761\n        ctx.beginPath();\n        ctx.moveTo(50, 400);\n        ctx.lineTo(450, 400);\n        ctx.strokeStyle = \"green\";\n        ctx.lineWidth = 5;\n        ctx.stroke();\n    <\/script>\n<\/body>\n<\/html><\/code><\/pre>\n\n\n\n
\u8bf4\u660e\uff1a<\/h4>\n\n\n\n
    \n
  • ctx.beginPath()<\/code><\/strong>\uff1a\u5f00\u59cb\u7ed8\u5236\u8def\u5f84\u3002<\/li>\n\n\n\n
  • ctx.arc(x, y, radius, startAngle, endAngle)<\/code><\/strong>\uff1a\u7ed8\u5236\u4e00\u4e2a\u5706\u5f62\uff0cx<\/code> \u548c y<\/code> \u662f\u5706\u5fc3\u7684\u5750\u6807\uff0cradius<\/code> \u662f\u5706\u7684\u534a\u5f84\uff0cstartAngle<\/code> \u548c endAngle<\/code> \u8868\u793a\u5706\u7684\u8d77\u59cb\u548c\u7ed3\u675f\u89d2\u5ea6\u3002<\/li>\n\n\n\n
  • ctx.fill()<\/code><\/strong>\uff1a\u586b\u5145\u5f53\u524d\u8def\u5f84\u3002<\/li>\n\n\n\n
  • ctx.moveTo(x, y)<\/code><\/strong>\uff1a\u79fb\u52a8\u753b\u7b14\u5230\u6307\u5b9a\u7684\u5750\u6807\u3002<\/li>\n\n\n\n
  • ctx.lineTo(x, y)<\/code><\/strong>\uff1a\u7ed8\u5236\u4ece\u5f53\u524d\u70b9\u5230\u6307\u5b9a\u70b9\u7684\u76f4\u7ebf\u3002<\/li>\n\n\n\n
  • ctx.stroke()<\/code><\/strong>\uff1a\u6cbf\u7740\u8def\u5f84\u7ed8\u5236\u7ebf\u6761\u3002<\/li>\n<\/ul>\n\n\n\n
    3. \u7ed8\u5236\u6587\u672c<\/strong><\/h3>\n\n\n\n
    Canvas \u4e5f\u53ef\u4ee5\u7528\u6765\u7ed8\u5236\u6587\u672c\u3002\u4f60\u53ef\u4ee5\u901a\u8fc7 fillText()<\/code> \u6216 strokeText()<\/code> \u65b9\u6cd5\u6765\u7ed8\u5236\u6587\u672c\u3002<\/p>\n\n\n\n
    \u793a\u4f8b\uff1a\u7ed8\u5236\u6587\u672c<\/h4>\n\n\n\n
    <!DOCTYPE html>\n<html lang=\"en\">\n<head>\n    <meta charset=\"UTF-8\">\n    <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">\n    <title>Canvas \u7ed8\u5236\u6587\u672c<\/title>\n<\/head>\n<body>\n    <h1>HTML5 Canvas \u793a\u4f8b<\/h1>\n    <canvas id=\"myCanvas\" width=\"500\" height=\"500\" style=\"border:1px solid #000000;\">\n        \u4f60\u7684\u6d4f\u89c8\u5668\u4e0d\u652f\u6301 Canvas\u3002\n    <\/canvas>\n\n    <script>\n        var canvas = document.getElementById(\"myCanvas\");\n        var ctx = canvas.getContext(\"2d\");\n\n        \/\/ \u8bbe\u7f6e\u5b57\u4f53\n        ctx.font = \"30px Arial\";\n        ctx.fillStyle = \"black\";\n        ctx.fillText(\"Hello, Canvas!\", 100, 100);\n\n        \/\/ \u8bbe\u7f6e\u6587\u672c\u7684\u8f6e\u5ed3\n        ctx.lineWidth = 2;\n        ctx.strokeStyle = \"red\";\n        ctx.strokeText(\"Hello, Canvas!\", 100, 150);\n    <\/script>\n<\/body>\n<\/html><\/code><\/pre>\n\n\n\n
    \u8bf4\u660e\uff1a<\/h4>\n\n\n\n
      \n
    • ctx.font<\/code><\/strong>\uff1a\u8bbe\u7f6e\u5b57\u4f53\u548c\u5927\u5c0f\u3002<\/li>\n\n\n\n
    • ctx.fillText(text, x, y)<\/code><\/strong>\uff1a\u5728\u6307\u5b9a\u4f4d\u7f6e\u7ed8\u5236\u586b\u5145\u7684\u6587\u672c\u3002<\/li>\n\n\n\n
    • ctx.strokeText(text, x, y)<\/code><\/strong>\uff1a\u7ed8\u5236\u8f6e\u5ed3\u6587\u672c\u3002<\/li>\n<\/ul>\n\n\n\n
      4. \u6e05\u9664\u56fe\u5f62<\/strong><\/h3>\n\n\n\n
      \u5982\u679c\u4f60\u9700\u8981\u6e05\u9664\u753b\u5e03\u4e0a\u7684\u90e8\u5206\u5185\u5bb9\uff0c\u53ef\u4ee5\u4f7f\u7528 clearRect()<\/code> \u65b9\u6cd5\u3002<\/p>\n\n\n\n
      \u793a\u4f8b\uff1a\u6e05\u9664\u753b\u5e03<\/h4>\n\n\n\n
      <!DOCTYPE html>\n<html lang=\"en\">\n<head>\n    <meta charset=\"UTF-8\">\n    <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">\n    <title>Canvas \u6e05\u9664\u56fe\u5f62<\/title>\n<\/head>\n<body>\n    <h1>HTML5 Canvas \u793a\u4f8b<\/h1>\n    <canvas id=\"myCanvas\" width=\"500\" height=\"500\" style=\"border:1px solid #000000;\">\n        \u4f60\u7684\u6d4f\u89c8\u5668\u4e0d\u652f\u6301 Canvas\u3002\n    <\/canvas>\n\n    <script>\n        var canvas = document.getElementById(\"myCanvas\");\n        var ctx = canvas.getContext(\"2d\");\n\n        \/\/ \u7ed8\u5236\u4e00\u4e2a\u84dd\u8272\u77e9\u5f62\n        ctx.fillStyle = \"blue\";\n        ctx.fillRect(50, 50, 150, 100);\n\n        \/\/ \u6e05\u9664\u90e8\u5206\u533a\u57df\n        ctx.clearRect(100, 75, 50, 50);  \/\/ \u6e05\u9664\u77e9\u5f62\u533a\u57df\u4e2d\u7684\u4e00\u4e2a\u90e8\u5206\n    <\/script>\n<\/body>\n<\/html><\/code><\/pre>\n\n\n\n
      5. Canvas \u52a8\u753b<\/strong><\/h3>\n\n\n\n
      \u4f60\u53ef\u4ee5\u4f7f\u7528 requestAnimationFrame<\/code> \u6765\u5b9e\u73b0\u5e73\u6ed1\u7684\u52a8\u753b\u6548\u679c\u3002<\/p>\n\n\n\n
      \u793a\u4f8b\uff1a\u52a8\u753b\u6548\u679c<\/h4>\n\n\n\n
      <!DOCTYPE html>\n<html lang=\"en\">\n<head>\n    <meta charset=\"UTF-8\">\n    <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">\n    <title>Canvas \u52a8\u753b\u793a\u4f8b<\/title>\n<\/head>\n<body>\n    <h1>HTML5 Canvas \u52a8\u753b\u793a\u4f8b<\/h1>\n    <canvas id=\"myCanvas\" width=\"500\" height=\"500\" style=\"border:1px solid #000000;\">\n        \u4f60\u7684\u6d4f\u89c8\u5668\u4e0d\u652f\u6301 Canvas\u3002\n    <\/canvas>\n\n    <script>\n        var canvas = document.getElementById(\"myCanvas\");\n        var ctx = canvas.getContext(\"2d\");\n\n        var x = 50;\n        var y = 50;\n        var dx = 2;\n        var dy = 2;\n\n        function drawBall() {\n            ctx.clearRect(0, 0, canvas.width, canvas.height); \/\/ \u6e05\u9664\u753b\u5e03\n            ctx.beginPath();\n            ctx.arc(x, y, 20, 0, Math.PI * 2);\n            ctx.fillStyle = \"red\";\n            ctx.fill();\n            ctx.closePath();\n\n            \/\/ \u79fb\u52a8\u5c0f\u7403\n            x += dx;\n            y += dy;\n\n            \/\/ \u68c0\u67e5\u662f\u5426\u78b0\u5230\u8fb9\u754c\uff0c\u53cd\u8f6c\u65b9\u5411\n            if (x + 20 > canvas.width || x - 20 < 0) {\n                dx = -dx;\n            }\n            if (y + 20 > canvas.height || y - 20 < 0) {\n                dy = -dy;\n            }\n\n            \/\/ \u8bf7\u6c42\u4e0b\u4e00\u5e27\u52a8\u753b\n            requestAnimationFrame(drawBall);\n        }\n\n        drawBall();  \/\/ \u5f00\u59cb\u52a8\u753b\n    <\/script>\n<\/body>\n<\/html><\/code><\/pre>\n\n\n\n
      \u5c0f\u7ed3<\/h3>\n\n\n\n
      <canvas><\/code> \u662f HTML5 \u63d0\u4f9b\u7684\u5f3a\u5927\u5de5\u5177\uff0c\u7528\u4e8e\u5728\u7f51\u9875\u4e0a\u52a8\u6001\u7ed8\u5236\u56fe\u5f62\u548c\u52a8\u753b\u3002\u4f60\u53ef\u4ee5\u901a\u8fc7\u5b83\u7ed8\u5236\u56fe\u50cf\u3001\u7ebf\u6761\u3001\u77e9\u5f62\u3001\u5706\u5f62\u3001\u6587\u672c\u3001\u56fe\u8868\u7b49\uff0c\u751a\u81f3\u53ef\u4ee5\u521b\u5efa\u590d\u6742\u7684\u6e38\u620f\u548c\u4ea4\u4e92\u5f0f\u56fe\u5f62\u3002\u4e3a\u4e86\u4f18\u5316\u6027\u80fd\uff0c\u52a8\u753b\u901a\u5e38\u4f7f\u7528 requestAnimationFrame<\/code> \u6765\u8fdb\u884c\u5e73\u6ed1\u7684\u5e27\u66f4\u65b0\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
      HTML5 <canvas> \u5143\u7d20\u63d0\u4f9b\u4e86\u4e00\u4e2a\u7528\u4e8e\u7ed8\u5236\u56fe\u5f62\u7684\u533a\u57df\uff0c\u53ef\u4ee5\u901a\u8fc7 JavaScript \u5728 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[75],"tags":[],"class_list":["post-1947","post","type-post","status-publish","format-standard","hentry","category-html5"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/1947","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/comments?post=1947"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/1947\/revisions"}],"predecessor-version":[{"id":1948,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/1947\/revisions\/1948"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=1947"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=1947"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=1947"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}