add 商户详情：二维码海报（高清）

src/_shanghu_detail.css

@@ -42,3 +42,8 @@
 		cursor: pointer;
 		margin-bottom: .4rem;
 	}
+	
+	.hideEle {
+		/* visibility: hidden; */
+		display: none;
+	}
\ No newline at end of file

src/_shanghu_detail.html

@@ -48,11 +48,16 @@
 				<div class="qr-card">
 					<!-- <canvas id="mainCanvas" width="3000" height="4000"></canvas> -->
 					<!-- 基础调试确认版 -->
-					<canvas id="mainCanvas" width="420" height="594"></canvas>
+					<!-- <canvas id="mainCanvas" width="420" height="594"></canvas> -->
 					<!-- 不晃动rev -->
 					<!-- <canvas id="mainCanvas" width="375" height="530"></canvas> -->
+					
+					<canvas id="displayCanvas"></canvas>  <!-- 页面预览用 -->
+					
 				</div>
-				<button class="save-btn" onclick="saveCanvas()" v-if="canvasReady">保存二维码</button>
+				<!-- <button class="save-btn" onclick="saveCanvas()" v-if="canvasReady">保存二维码</button> -->
+				<button class="save-btn" onclick="saveImage()" :class="{'showEle': true}">保存二维码</button>
+				
 			</div>
 	</body>