feat(canvas): 增加 toBlob/toDataURL 测试

pages/component/canvas/canvas.test.js

+let page
+
+beforeAll(async () => {
+  page = await program.reLaunch('/pages/component/canvas/canvas')
+  await page.waitFor(2000)
+})
+
+describe('Canvas.uvue', () => {
+  it('toBlob', async () => {
+    if (process.env.uniTestPlatformInfo.toLowerCase().startsWith('web')) {
+      const {
+        testToBlobResult,
+        testToDataURLResult
+      } = await page.data()
+
+      expect(testToBlobResult).toBe(true)
+      expect(testToDataURLResult).toBe(true)
+    }
+  })
+})

pages/component/canvas/canvas.uvue

@@ -33,6 +33,9 @@
         canvasWidth: 0,
         canvasHeight: 0,
         image: null as Image | null,
+        // 仅测试
+        testToBlobResult: false,
+        testToDataURLResult: false
       }
     },
     onReady() {
@@ -41,6 +44,13 @@
       hidpi(canvas);
       this.canvasWidth = this.canvasContext!.canvas.width;
       this.canvasHeight = this.canvasContext!.canvas.height;
+
+      // #ifdef WEB
+      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
     },
     methods: {
       handleCanvasButton(name : string) {
@@ -630,15 +640,14 @@
         context.restore()
       },
       restore() {
-        const context = this.canvasContext!
-
-        ;[3, 2, 1].forEach((item) => {
-          context.save()
-          context.beginPath()
-          context.scale(item, item)
-          context.rect(10, 10, 100, 100)
-          context.stroke()
-          context.restore()
+        const context = this.canvasContext!;
+        [3, 2, 1].forEach((item) => {
+          context.save()
+          context.beginPath()
+          context.scale(item, item)
+          context.rect(10, 10, 100, 100)
+          context.stroke()
+          context.restore()
         })
       },
       drawImageLocal() {