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cool-unix/cool/utils/file.ts

@@ -0,0 +1,74 @@
+import { base64ToBlob, uuid } from "./comm";
+
+/**
+ * 将canvas转换为png图片
+ * @param options 转换参数
+ * @returns 图片路径
+ */
+export function canvasToPng(canvasRef: UniElement): Promise<string> {
+	return new Promise((resolve) => {
+		// #ifdef APP
+		canvasRef.parentElement!.takeSnapshot({
+			success(res) {
+				resolve(res.tempFilePath);
+			},
+			fail(err) {
+				console.error(err);
+				resolve("");
+			}
+		});
+		// #endif
+
+		// #ifdef H5
+		const url = URL.createObjectURL(
+			base64ToBlob(
+				(canvasRef as unknown as HTMLCanvasElement)?.toDataURL("image/png", 1) ?? ""
+			)
+		);
+
+		resolve(url);
+		// #endif
+
+		// #ifdef MP
+		uni.createCanvasContextAsync({
+			id: canvasRef.id,
+			component: canvasRef.$vm,
+			success(context) {
+				// 获取2D绘图上下文
+				const ctx = context.getContext("2d")!;
+
+				// 获取canvas对象
+				const canvas = ctx.canvas;
+
+				// 将canvas转换为base64格式的PNG图片数据
+				const data = canvas.toDataURL("image/png", 1);
+
+				// 获取文件系统管理器
+				const fileMg = uni.getFileSystemManager();
+
+				// 生成临时文件路径
+				// @ts-ignore
+				const filepath = `${wx.env.USER_DATA_PATH}/${uuid()}.png`;
+
+				// 将base64数据写入文件
+				fileMg.writeFile({
+					filePath: filepath,
+					data: data.split(",")[1],
+					encoding: "base64",
+					success() {
+						resolve(filepath);
+					},
+					fail(err) {
+						console.error(err);
+						resolve("");
+					}
+				});
+			},
+			fail(err) {
+				console.error(err);
+				resolve("");
+			}
+		});
+		// #endif
+	});
+}