调整mask背景透明度从150降低到80，让图像在暂停时仍可见

Windows/CS/Framework4.0/Toprie/Toprie/Camera.cs

@@ -135,8 +135,8 @@ namespace JoyD.Windows.CS.Toprie
                         g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
                         g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.ClearTypeGridFit;
                         
-                        // 设置半透明背景
-                        using (Brush brush = new SolidBrush(Color.FromArgb(150, Color.Black)))
+                        // 设置更透明的背景，50是透明度值，0完全透明，255不透明
+                        using (Brush brush = new SolidBrush(Color.FromArgb(80, Color.Black)))
                         {   
                             g.FillRectangle(brush, 0, 0, bitmapWidth, bitmapHeight);
                         }