feat: add docs/canvas.md

jaywcjlove · Oct 29, 2024 · ad2fd7b · ad2fd7b
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diff --git a/README.md b/README.md
@@ -102,6 +102,7 @@ Quick Reference
 [Emmet](./docs/emmet.md)<!--rehype:style=background: rgb(122 203 23);-->  
 [ES 6](./docs/es6.md)<!--rehype:style=background: rgb(122 203 23);&class=tag&data-lang=JS-->  
 [HTML](./docs/html.md)<!--rehype:style=background: rgb(228 77 39);-->  
+[HTML Canvas](./docs/canvas.md)<!--rehype:style=background: rgb(228 77 39);-->  
 [JavaScript](./docs/javascript.md)<!--rehype:style=background: rgb(203 183 31);-->  
 [jQuery](./docs/jquery.md)<!--rehype:style=background: rgb(203 183 31);-->  
 [Next.js](./docs/nextjs.md)<!--rehype:style=background: rgb(0 0 0);&class=tag&data-lang=React-->  

diff --git a/assets/canvas.svg b/assets/canvas.svg
diff --git a/docs/canvas.md b/docs/canvas.md
@@ -0,0 +1,253 @@
+HTML Canvas 备忘清单
+===
+
+这份 HTML Canvas 快速参考备忘单列出了常见的 HTML5 Canvas 设计标签，以易读的格式呈现。
+
+入门
+---
+<!--rehype:body-class=cols-4-->
+
+### 基本设置
+<!--rehype:wrap-class=col-span-2-->
+
+```html
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Canvas 示例</title>
+  </head>
+  <body>
+    <canvas id="myCanvas" width="500" height="400"
+      style="border:1px solid #000000;">
+    </canvas>
+    <script src="script.js"></script>
+  </body>
+</html>
+```
+
+### 获取上下文
+<!--rehype:wrap-class=col-span-2-->
+
+```js
+const canvas = document.getElementById("myCanvas");
+
+const ctx = canvas.getContext("2d");
+```
+
+绘制形状
+---
+
+### 矩形
+<!--rehype:wrap-class=col-span-2-->
+
+```js
+ctx.fillStyle = "red";
+ctx.fillRect(10, 10, 150, 100); // x, y, 宽度, 高度
+
+ctx.strokeStyle = "blue";
+ctx.lineWidth = 5;
+ctx.strokeRect(200, 10, 150, 100); // x, y, 宽度, 高度
+
+ctx.clearRect(15, 15, 30, 30); // x, y, 宽度, 高度
+```
+
+路径
+---
+
+### 线条
+
+```js
+ctx.beginPath();
+ctx.moveTo(50, 50); // 起始点
+ctx.lineTo(200, 50); // 结束点
+ctx.lineTo(200, 200); // 下一个线条结束点
+ctx.closePath(); // 将结束点连接到起始点
+ctx.stroke();
+```
+
+### 圆形
+
+```js
+ctx.beginPath();
+// x, y, 半径, 起始角度, 结束角度
+ctx.arc(150, 150, 75, 0, 2 * Math.PI);
+ctx.fillStyle = "green";
+ctx.fill();
+ctx.stroke();
+```
+
+### 弧
+
+```js
+ctx.beginPath();
+// x, y, 半径, 起始角度, 结束角度
+ctx.arc(150, 150, 75, 0, Math.PI);
+ctx.stroke();
+```
+
+贝塞尔曲线和二次曲线
+---
+
+### 二次曲线
+
+```js
+ctx.beginPath();
+ctx.moveTo(50, 250);
+// cpX, cpY, 终点X, 终点Y
+ctx.quadraticCurveTo(200, 100, 400, 250); 
+ctx.stroke();
+```
+
+### 贝塞尔曲线
+
+```js
+ctx.beginPath();
+ctx.moveTo(50, 300);
+// cp1X, cp1Y, cp2X, cp2Y, 终点X, 终点Y
+ctx.bezierCurveTo(150, 100, 350, 500, 450, 300); 
+ctx.stroke();
+```
+
+### 文本
+
+```js
+ctx.font = "30px Arial";
+ctx.fillStyle = "black";
+// 文本, x, y
+ctx.fillText("Hello Canvas", 10, 50); 
+// 文本, x, y
+ctx.strokeText("Hello Canvas", 10, 100); 
+```
+
+### 图像
+<!--rehype:wrap-class=col-span-3-->
+
+```js
+const img = new Image();
+img.src = "path/to/image.jpg";
+img.onload = () => {
+  ctx.drawImage(img, 10, 10); // img, x, y
+  ctx.drawImage(img, 50, 50, 100, 100); // img, x, y, 宽度, 高度
+  ctx.drawImage(img, 100, 100, 100, 100, 150, 150, 200, 200); // img, sx, sy, sWidth, sHeight, dx, dy, dWidth, dHeight
+};
+```
+
+变换
+---
+
+### 平移
+
+```js
+ctx.translate(100, 100); // x, y
+ctx.fillRect(0, 0, 50, 50);
+```
+
+### 旋转
+
+```js
+// 角度（以弧度为单位）
+ctx.rotate((Math.PI / 180) * 45);
+ctx.fillRect(100, 100, 50, 50);
+```
+
+### 缩放
+
+```js
+ctx.scale(2, 2); // x, y
+ctx.fillRect(50, 50, 50, 50);
+```
+
+渐变
+---
+
+### 线性渐变
+<!--rehype:wrap-class=col-span-2-->
+
+```js
+const linearGradient = ctx.createLinearGradient(0, 0, 200, 0); // x0, y0, x1, y1
+linearGradient.addColorStop(0, "red");
+linearGradient.addColorStop(1, "blue");
+ctx.fillStyle = linearGradient;
+ctx.fillRect(10, 10, 200, 100);
+```
+
+### 径向渐变
+
+```js
+const radialGradient = ctx.createRadialGradient(75, 50, 5, 90, 60, 100); // x0, y0, r0, x1, y1, r1
+radialGradient.addColorStop(0, "red");
+radialGradient.addColorStop(1, "blue");
+ctx.fillStyle = radialGradient;
+ctx.fillRect(10, 10, 200, 100);
+```
+
+### 图案
+<!--rehype:wrap-class=col-span-2-->
+
+```js
+const img = new Image();
+img.src = "path/to/image.jpg";
+img.onload = () => {
+  // 'repeat', 'repeat-x', 'repeat-y', 'no-repeat'
+  const pattern = ctx.createPattern(img, "repeat");
+  ctx.fillStyle = pattern;
+  ctx.fillRect(0, 0, 300, 300);
+};
+```
+
+### 阴影
+
+```js
+ctx.shadowColor = "rgba(0, 0, 0, 0.5)";
+ctx.shadowBlur = 10;
+ctx.shadowOffsetX = 5;
+ctx.shadowOffsetY = 5;
+
+ctx.fillStyle = "red";
+ctx.fillRect(100, 100, 100, 100);
+```
+
+合成
+---
+
+### 全局透明度
+
+```js
+ctx.globalAlpha = 0.5;
+ctx.fillStyle = "red";
+ctx.fillRect(100, 100, 100, 100);
+
+ctx.fillStyle = "blue";
+ctx.fillRect(150, 150, 100, 100);
+```
+
+### 全局合成操作
+
+```js
+ctx.globalCompositeOperation = "source-over"; // 默认
+ctx.fillStyle = "red";
+ctx.fillRect(100, 100, 100, 100);
+
+ctx.globalCompositeOperation = "destination-over";
+ctx.fillStyle = "blue";
+ctx.fillRect(150, 150, 100, 100);
+```
+
+### 动画
+
+```js
+let x = 0;
+function draw() {
+  ctx.clearRect(0, 0, canvas.width, canvas.height);
+  ctx.fillStyle = "blue";
+  ctx.fillRect(x, 100, 50, 50);
+  x += 2;
+  requestAnimationFrame(draw);
+}
+draw();
+```
+
+参考阅读
+---
+
+- [MDN 文档](https://developer.mozilla.org/en-US/docs/Web/API/Canvas_API)
diff --git a/docs/quickreference.md b/docs/quickreference.md
@@ -1018,7 +1018,7 @@ H2 部分 - 5列效果展示
 ...
 ```
 
-[#示例](https://github.com/jaywcjlove/reference/blob/ee03850619440e3700ed68ccc2ed21d3591a1490/docs/quickreference.md?plain=1#L986-L991)<!--rehype:target=__blank-->
+[#示例](https://github.com/jaywcjlove/reference/blob/8ae69f23860c1854a81aeceb81a6cc0bc0998fc4/docs/quickreference.md?plain=1#L1012-L1021)<!--rehype:target=__blank-->
 
 ### Two
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+Diff line change
@@ Expand Up / @@ -1018,7 +1018,7 @@ H2 部分 - 5列效果展示 @@
     ...
     ```
-    [#示例](https://github.com/jaywcjlove/reference/blob/ee03850619440e3700ed68ccc2ed21d3591a1490/docs/quickreference.md?plain=1#L986-L991)<!--rehype:target=__blank-->
+    [#示例](https://github.com/jaywcjlove/reference/blob/8ae69f23860c1854a81aeceb81a6cc0bc0998fc4/docs/quickreference.md?plain=1#L1012-L1021)<!--rehype:target=__blank-->
     ### Two
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