canvas: 移除 CanvasRenderingContext2D 相关API，API/create-canvas-context-async...

canvas: 移除 CanvasRenderingContext2D 相关API，API/create-canvas-context-async 下已有相同逻辑，仅保留toBlob/dataBase64 方法

pages/component/canvas/canvas.uvue

@@ -2,11 +2,9 @@
   <view class="page" id="page-canvas">
     <canvas id="canvas" class="canvas-element"></canvas>
     <scroll-view class="scroll-view">
-      <view class="grid-view">
-        <view class="grid-item" v-for="(name, index) in names" :key="index">
-          <button class="canvas-drawing-button" @click="handleCanvasButton(name)">{{name}}</button>
-        </view>
-      </view>
+      <button class="canvas-drawing-button" @click="canvasToBlob">canvasToBlob</button>
+      <button class="canvas-drawing-button" @click="canvasToDataURL">canvasToDataURL</button>
+      <text>{{dataBase64}}</text>
     </scroll-view>
   </view>
 </template>
@@ -22,17 +20,13 @@
 
   export default {
     data() {
-      const API_PATH = ["arc", "arcTo", "bezierCurveTo", "quadraticCurve", "moveTo", "lineTo", "rect", "clip", "pattern"]
-      const API_DRAW = ["stroke", "strokeRect", "strokeText", "fill", "fillRect", "fillText", "drawImage", "drawImageLocal", "clearRect"]
-      const API_STATE = ["beginPath", "closePath",  "reset", "transform", "rotate", "resetTransform", "save", "restore", "scale", "translate"]
-      const API_PROPERTIES = ["setLineCap", "setLineJoin", "setLineWidth", "setMiterLimit", "setFillStyle", "setStrokeStyle", "setGlobalAlpha", "lineDash", "linearGradient", "radialGradient", "textAlign"]
       return {
-        title: 'Context2D',
-        names: [...API_PATH, ...API_DRAW, ...API_STATE, ...API_PROPERTIES, "measureText"] as string[],
+        title: 'Context2D',
+        canvas: null as UniCanvasElement | null,
         canvasContext: null as CanvasRenderingContext2D | null,
         canvasWidth: 0,
-        canvasHeight: 0,
-        image: null as Image | null,
+        canvasHeight: 0,
+        dataBase64: '',
         // 仅测试
         testToBlobResult: false,
         testToDataURLResult: false
@@ -49,844 +43,21 @@
       canvas.toBlob((blob : Blob) => {
         this.testToBlobResult = (blob.size > 0 && blob.type == 'image/jpeg')
       }, 'image/jpeg', 0.95)
-      this.testToDataURLResult = canvas.toDataURL().startsWith('data:image/png;base64')
       // #endif
+      this.testToDataURLResult = canvas.toDataURL().startsWith('data:image/png;base64')
+
+      this.canvas = canvas;
     },
-    methods: {
-      handleCanvasButton(name : string) {
-        switch (name) {
-          case "arc":
-            this.arc();
-            break;
-          case "arcTo":
-            this.arcTo();
-            break;
-          case "beginPath":
-            this.beginPath();
-            break;
-          case "bezierCurveTo":
-            this.bezierCurveTo();
-            break;
-          case "clearRect":
-            this.clearRect();
-            break;
-          case "clip":
-            this.clip();
-            break;
-          case "closePath":
-            this.closePath();
-            break;
-          case "pattern":
-            this.pattern()
-            break;
-          case "linearGradient":
-            this.createLinearGradient();
-            break;
-          case "radialGradient":
-            this.createRadialGradient();
-            break;
-          case "fill":
-            this.fill();
-            break;
-          case "fillRect":
-            this.fillRect();
-            break;
-          case "fillText":
-            this.fillText();
-            break;
-          case "lineTo":
-            this.lineTo();
-            break;
-          case "moveTo":
-            this.moveTo();
-            break;
-          case "quadraticCurve":
-            this.quadraticCurveTo();
-            break;
-          case "rect":
-            this.rect();
-            break;
-          case "reset":
-            this.reset();
-            break;
-          case "resetTransform":
-            this.resetTransform();
-            break;
-          case "restore":
-            this.restore();
-            break;
-          case "rotate":
-            this.rotate();
-            break;
-          case "save":
-            this.save();
-            break;
-          case "scale":
-            this.scale();
-            break;
-          case "stroke":
-            this.stroke();
-            break;
-          case "strokeRect":
-            this.strokeRect();
-            break;
-          case "strokeText":
-            this.strokeText();
-            break;
-          case "transform":
-            this.transform();
-            break;
-          case "translate":
-            this.translate();
-            break;
-          case "drawImageLocal":
-            this.drawImageLocal()
-            break;
-          case "drawImage":
-            this.drawImage();
-            break;
-          case "measureText":
-            this.measureText();
-            break;
-          case "setFillStyle":
-            this.setFillStyle();
-            break;
-          case "setStrokeStyle":
-            this.setStrokeStyle();
-            break;
-          case "setGlobalAlpha":
-            this.setGlobalAlpha();
-            break;
-          case "setFontSize":
-            this.setFontSize();
-            break;
-          case "setLineCap":
-            this.setLineCap();
-            break;
-          case "setLineJoin":
-            this.setLineJoin();
-            break;
-          case "lineDash":
-            this.lineDash();
-            break;
-          case "setLineWidth":
-            this.setLineWidth();
-            break;
-          case "setMiterLimit":
-            this.setMiterLimit();
-            break;
-          case "textAlign":
-            this.textAlign();
-          default:
-            break;
-        }
-      },
-      arc() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.beginPath()
-        context.lineWidth = 2
-        context.arc(75, 75, 50, 0, Math.PI * 2, true)
-        context.moveTo(110, 75)
-        context.arc(75, 75, 35, 0, Math.PI, false)
-        context.moveTo(65, 65)
-        context.arc(60, 65, 5, 0, Math.PI * 2, true)
-        context.moveTo(95, 65)
-        context.arc(90, 65, 5, 0, Math.PI * 2, true)
-        context.stroke()
-
-        context.restore()
-      },
-      arcTo() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.beginPath()
-        context.moveTo(150, 20)
-        context.arcTo(150, 100, 50, 20, 30)
-        context.stroke()
-
-        context.fillStyle = "blue"
-        // base point
-        context.fillRect(150, 20, 10, 10)
-
-        context.fillStyle = "red"
-        // control point one
-        context.fillRect(150, 100, 10, 10)
-        // control point two
-        context.fillRect(50, 20, 10, 10)
-        //
-        context.setLineDash([5, 5])
-        context.moveTo(150, 20)
-        context.lineTo(150, 100)
-        context.lineTo(50, 20)
-        context.stroke()
-        context.beginPath()
-        context.arc(120, 38, 30, 0, 2 * Math.PI, true)
-        context.stroke()
-
-        context.restore()
-      },
-      beginPath() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        // First path
-        context.beginPath()
-        context.strokeStyle = "blue"
-        context.moveTo(20, 20)
-        context.lineTo(200, 20)
-        context.stroke()
-
-        // Second path
-        context.beginPath()
-        context.strokeStyle = "green"
-        context.moveTo(20, 20)
-        context.lineTo(120, 120)
-        context.stroke()
-
-        context.restore()
-      },
-      textAlign() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.beginPath()
-        context.moveTo(150, 0)
-        context.lineTo(150, 150)
-        context.stroke()
-
-        context.font = "30px serif"
-
-        context.textAlign = "left"
-        context.fillText("left-aligned", 150, 40)
-
-        context.textAlign = "center"
-        context.fillText("center-aligned", 150, 85)
-
-        context.textAlign = "right"
-        context.fillText("right-aligned", 150, 130)
-
-        context.restore()
-      },
-      bezierCurveTo() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.beginPath()
-        context.moveTo(50, 20)
-        context.bezierCurveTo(230, 30, 150, 60, 50, 100)
-        context.stroke()
-
-        context.fillStyle = "blue"
-        // start point
-        context.fillRect(50, 20, 10, 10)
-        // end point
-        context.fillRect(50, 100, 10, 10)
-
-        context.fillStyle = "red"
-        // control point one
-        context.fillRect(230, 30, 10, 10)
-        // control point two
-        context.fillRect(150, 70, 10, 10)
-
-        context.restore()
-      },
-      clearRect() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        // 绘制黄色背景
-        context.beginPath()
-        context.fillStyle = "#ff6"
-        context.fillRect(0, 0, 300, 150)
-
-        // 绘制蓝色三角形
-        context.beginPath()
-        context.fillStyle = "blue"
-        context.moveTo(20, 20)
-        context.lineTo(180, 20)
-        context.lineTo(130, 130)
-        context.closePath()
-        context.fill()
-
-        // 清除一部分画布
-        context.clearRect(10, 10, 120, 100)
-
-        context.restore()
-      },
-      clip() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        // Create circular clipping region
-        context.beginPath();
-        context.arc(100, 75, 50, 0, Math.PI * 2, true)
-        context.clip()
-
-        // Draw stuff that gets clipped
-        context.fillStyle = "blue"
-        context.fillRect(0, 0, 300, 150)
-        context.fillStyle = "orange"
-        context.fillRect(0, 0, 100, 100)
-
-        context.restore()
-      },
-      closePath() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.beginPath()
-        context.lineWidth = 10
-        context.moveTo(20, 20)
-        context.lineTo(20, 100)
-        context.lineTo(70, 100)
-        context.closePath()
-        context.stroke()
-
-        context.restore()
-      },
-      pattern() {
-        const context = this.canvasContext!
-
-        this.image = new Image(100, 100)
-        this.image!.src = '../../../static/api.png';
-        // this.image!.src = 'https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/createPattern/canvas_createpattern.png';
-        // Only use the image after it's loaded
-        this.image!.onload = () => {
-          context.save()
-          context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-          const pattern = context.createPattern(this.image!, "repeat")
-          context.fillStyle = pattern
-          context.fillRect(0, 0, 100, 100)
-          context.restore()
-        };
-      },
-      createLinearGradient() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        // Create a linear gradient
-        // The start gradient point is at x=20, y=0
-        // The end gradient point is at x=220, y=0
-        const gradient = context.createLinearGradient(20, 0, 220, 0)
-
-        // Add three color stops
-        gradient.addColorStop(0, "green")
-        gradient.addColorStop(0.5, "cyan")
-        gradient.addColorStop(1, "green")
-
-        // Set the fill style and draw a rectangle
-        context.fillStyle = gradient
-        context.fillRect(20, 20, 200, 100)
-
-        context.restore()
-      },
-      createRadialGradient() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        // Create a radial gradient
-        // The inner circle is at x=110, y=90, with radius=30
-        // The outer circle is at x=100, y=100, with radius=70
-        const gradient = context.createRadialGradient(110, 90, 30, 100, 100, 70)
-
-        // Add three color stops
-        gradient.addColorStop(0, "pink")
-        gradient.addColorStop(0.9, "white")
-        gradient.addColorStop(1, "green")
-
-        // Set the fill style and draw a rectangle
-        context.fillStyle = gradient
-        context.fillRect(20, 20, 160, 160)
-
-        context.restore()
-      },
-      fill() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.beginPath()
-        context.rect(20, 20, 150, 100)
-        context.strokeStyle = '#00ff00'
-        context.fill()
-
-        context.restore()
-      },
-      fillRect() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.fillStyle = "green"
-        context.fillRect(20, 10, 150, 100)
-
-        context.restore()
-      },
-      fillText() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        console.log("fillText")
-        context.strokeStyle = '#ff0000'
-
-        context.beginPath()
-        context.moveTo(0, 10)
-        context.lineTo(300, 10)
-        context.stroke()
-        // context.save()
-        // context.scale(1.5, 1.5)
-        // context.translate(20, 20)
-        // context.setFontSize(10)
-        context.fillText('Hello World', 0, 30, 300)
-        // context.setFontSize(20)
-        context.fillText('Hello World', 100, 30, 300)
-
-        // context.restore()
-
-        context.beginPath()
-        context.moveTo(0, 30)
-        context.lineTo(300, 30)
-        context.stroke()
-
-        context.restore()
-      },
-      moveTo() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.beginPath()
-        context.moveTo(0, 0)
-        context.lineTo(300, 150)
-        context.stroke()
-
-        context.restore()
-      },
-      lineTo() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.beginPath()
-        context.moveTo(20, 20)
-        context.lineTo(20, 100)
-        context.lineTo(70, 100)
-        context.stroke()
-
-        context.restore()
-      },
-      stroke() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.beginPath()
-        context.moveTo(20, 20)
-        context.lineTo(20, 100)
-        context.lineTo(70, 100)
-        context.strokeStyle = '#00ff00'
-        context.stroke()
-
-        context.restore()
-      },
-      strokeRect() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.strokeStyle = "green"
-        context.strokeRect(20, 10, 160, 100)
-
-        context.restore()
-      },
-      strokeText() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.font = "10px serif"
-        context.strokeText("Hello world", 50, 90)
-
-        context.font = "30px serif"
-        context.strokeStyle = "blue"
-        context.strokeText("Hello world", 50, 100)
-
-        context.restore()
-      },
-      rotate() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        // Point of transform origin
-        context.arc(0, 0, 5, 0, 2 * Math.PI, true)
-        context.fillStyle = "blue"
-        context.fill()
-
-        // Non-rotated rectangle
-        context.fillStyle = "gray"
-        context.fillRect(100, 0, 80, 20)
-        // Rotated rectangle
-        context.rotate((45 * Math.PI) / 180)
-        context.fillStyle = "red"
-        context.fillRect(100, 0, 80, 20)
-
-        // Reset transformation matrix to the identity matrix
-        context.setTransform(1, 0, 0, 1, 0, 0)
-
-        context.restore()
-      },
-      scale() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        // Scaled rectangle
-        context.scale(9, 3)
-        context.fillStyle = "red"
-        context.fillRect(10, 10, 8, 20)
-
-        // Reset current transformation matrix to the identity matrix
-        context.setTransform(1, 0, 0, 1, 0, 0)
-
-        // Non-scaled rectangle
-        context.fillStyle = "gray"
-        context.fillRect(10, 10, 8, 20)
-
-        context.restore()
-      },
-      reset() {
-        const context = this.canvasContext!
-
-        // Set line width
-        context.lineWidth = 10
-        context.strokeStyle = '#00ff00'
-        // Stroke rect outline
-        context.strokeRect(50, 50, 150, 100)
-
-        // Create filled text
-        context.font = "50px serif";
-        context.fillText("Rect!", 70, 110)
-
-
-        context.lineWidth = 5
-
-        // Stroke out circle
-        context.beginPath();
-        context.arc(300, 100, 50, 0, 2 * Math.PI)
-        context.stroke();
-
-        // Create filled text
-        context.font = "25px sans-serif"
-        context.fillText("Circle!", 265, 100)
-        context.reset()
-
-        hidpi(uni.getElementById("canvas") as UniCanvasElement)
-      },
-      translate() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        // Moved square
-        context.translate(110, 30)
-        context.fillStyle = "red"
-        context.fillRect(0, 0, 80, 80)
-
-        // Reset current transformation matrix to the identity matrix
-        context.setTransform(1, 0, 0, 1, 0, 0)
-
-        // Unmoved square
-        context.fillStyle = "gray"
-        context.fillRect(0, 0, 80, 80)
-
-        context.restore()
-      },
-      save() {
-        const context = this.canvasContext!
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.save()
-        context.beginPath()
-        context.strokeStyle = '#00ff00'
-        context.scale(2, 2)
-        context.strokeStyle = '#ff0000'
-        context.rect(0, 0, 100, 100)
-        context.stroke()
-        context.restore()
-
-        context.save()
-        context.rect(0, 0, 50, 50)
-        context.stroke()
-
-        context.restore()
-      },
-      restore() {
-        const context = this.canvasContext!;
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight);
-        [3, 2, 1].forEach((item) => {
-          context.save()
-          context.beginPath()
-          context.scale(item, item)
-          context.rect(10, 10, 100, 100)
-          context.stroke()
-          context.restore()
-        })
-      },
-      drawImageLocal() {
-        const context = this.canvasContext!
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        let image = new Image(100, 100)
-        image.src = '../../../static/uni.png'
-        image.onload = () => {
-          context.drawImage(image, 0, 0, 100, 100)
-        }
-      },
-      drawImage() {
-        const context = this.canvasContext!
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        let image = new Image(100, 100);
-        image.src = 'https://web-ext-storage.dcloud.net.cn/uni-app-x/hello-uniappx-qrcode.png'
-        image.onload = () => {
-          context.drawImage(image, 0, 0, 100, 100)
-          // uni.getElementById("page-canvas")?.appendChild(image)
-        }
-      },
-      rect() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.beginPath()
-        context.rect(20, 20, 150, 100)
-        context.stroke()
-
-        context.restore()
-      },
-      quadraticCurveTo() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        // Quadratic Bézier curve
-        context.beginPath()
-        context.moveTo(50, 20)
-        context.quadraticCurveTo(230, 30, 50, 100)
-        context.stroke()
-
-        // Start and end points
-        context.fillStyle = "blue"
-        context.beginPath()
-        context.arc(50, 20, 5, 0, 2 * Math.PI, true) // Start point
-        context.arc(50, 100, 5, 0, 2 * Math.PI, true) // End point
-        context.fill();
-
-        // Control point
-        context.fillStyle = "red"
-        context.beginPath()
-        context.arc(230, 30, 5, 0, 2 * Math.PI, true)
-        context.fill()
-
-        context.restore()
-      },
-      resetTransform() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        // Draw a rotated rectangle
-        context.rotate((45 * Math.PI) / 180)
-        context.fillRect(60, 0, 100, 30)
-
-        // Reset transformation matrix to the identity matrix
-        context.resetTransform()
-        context.fillStyle = "red"
-        context.fillRect(60, 0, 100, 30)
-
-        context.restore()
-      },
-      transform() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.transform(1, 0.2, 0.8, 1, 0, 0)
-        context.fillRect(0, 0, 100, 100)
-
-        context.restore()
-      },
-      setFillStyle() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight);
-        ['#fef957', 'rgb(242,159,63)', 'rgb(242,117,63)', '#e87e51'].forEach((item : string, index : number) => {
-          context.fillStyle = item
-          context.beginPath()
-          context.rect(0 + 75 * index, 0, 50, 50)
-          context.fill()
-        })
-
-        context.restore()
-      },
-      setStrokeStyle() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight);
-        ['#fef957', 'rgb(242,159,63)', 'rgb(242,117,63)', '#e87e51'].forEach((item : string, index : number) => {
-          context.strokeStyle = item
-          context.beginPath()
-          context.rect(0 + 75 * index, 0, 50, 50)
-          context.stroke()
-        })
-
-        context.restore()
-      },
-      setGlobalAlpha() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.fillStyle = '#000000';
-        [1, 0.5, 0.1].forEach((item : number, index : number) => {
-          context.globalAlpha = item
-          context.beginPath()
-          context.rect(0 + 75 * index, 0, 50, 50)
-          context.fill()
-        })
-        context.globalAlpha = 1
-
-        context.restore()
-      },
-      setFontSize() {
-        const context = this.canvasContext!
-
-        context.save();
-        [10, 20, 30, 40].forEach((item : number, index : number) => {
-          // context.fontSize(item)
-          context.fillText('Hello, world', 20, 20 + 40 * index)
-        })
-
-        context.restore()
-      },
-      setLineCap() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.lineWidth = 10;
-        ['butt', 'round', 'square'].forEach((item : string, index : number) => {
-          context.beginPath()
-          context.lineCap = item
-          context.moveTo(20, 20 + 20 * index)
-          context.lineTo(100, 20 + 20 * index)
-          context.stroke()
-        })
-
-        context.restore()
-      },
-      setLineJoin() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.lineWidth = 10;
-        ['bevel', 'round', 'miter'].forEach((item : string, index : number) => {
-          context.beginPath()
-          context.lineJoin = item
-          context.moveTo(20 + 80 * index, 20)
-          context.lineTo(100 + 80 * index, 50)
-          context.lineTo(20 + 80 * index, 100)
-          context.stroke()
-        })
-
-        context.restore()
-      },
-      setLineWidth() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight);
-        [2, 4, 6, 8, 10].forEach((item : number, index : number) => {
-          context.beginPath()
-          context.lineWidth = item
-          context.moveTo(20, 20 + 20 * index)
-          context.lineTo(100, 20 + 20 * index)
-          context.stroke()
-        })
-
-        context.restore()
-      },
-      lineDash() {
-        const context = this.canvasContext!
-
-        context.save();
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.setLineDash([4, 16])
-
-        // Dashed line with no offset
-        context.beginPath()
-        context.moveTo(0, 50)
-        context.lineTo(300, 50)
-        context.stroke()
-
-        // Dashed line with offset of 4
-        context.beginPath()
-        context.strokeStyle = "red"
-        context.lineDashOffset = 4
-        context.moveTo(0, 100)
-        context.lineTo(300, 100)
-        context.stroke()
-
-        context.restore()
-      },
-      setMiterLimit() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        context.lineWidth = 4;
-        [2, 4, 6, 8, 10].forEach((item : number, index : number) => {
-          context.beginPath()
-          context.miterLimit = item
-          context.moveTo(20 + 80 * index, 20)
-          context.lineTo(100 + 80 * index, 50)
-          context.lineTo(20 + 80 * index, 100)
-          context.stroke()
-        })
-
-        context.restore()
-      },
-      measureText() {
-        const context = this.canvasContext!
-
-        context.save()
-        context.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
-        const text = "uni-app x，是下一代 uni-app，是一个跨平台应用开发引擎"
-
-        context.font = "20px 宋体"
-
-        context.fillStyle = "red"
-        context.fillText(text, 0, 60)
-        const textMetrics = context.measureText(text)
-        context.strokeText(text, 40, 100)
-        context.fillText("measure text width:" + textMetrics.width, 40, 80)
-
-        context.restore()
+    methods: {
+      canvasToBlob() {
+        // #ifdef WEB
+        this.canvas!.toBlob((blob : Blob) => {
+          this.testToBlobResult = (blob.size > 0 && blob.type == 'image/jpeg')
+        }, 'image/jpeg', 0.95)
+        // #endif
+      },
+      canvasToDataURL() {
+        this.dataBase64 = this.canvas!.toDataURL()
       }
     }
   }
@@ -915,11 +86,6 @@
     flex-wrap: wrap;
   }
 
-  .grid-item {
-    width: 50%;
-    padding: 5px;
-  }
-
   .btn-to-image {
     margin: 10px;
   }