此代码是对上一篇代码的修改补充：https://www.haolizi.net/example/view_28275.html（为嵌入WinForm组件，且大小不准确），此代码全部为Wpf方式，生成的气泡宽度高度较为精确。
适用任意字体以及字号，可设置图像字体、字号、行间距、字间距、阴影、气泡宽度等，在RichtextboxHelper.cs内查看。
生成的气泡宽度高度较为精确。
如有高度不一致问题，是因为文字高度超出了插入图像的高度，可对文字大小或图像进行调整。
注意：
green_left_mess.png、green_right_mess.png、white_left_mess.png、white_right_mess.png
4个文件设置为“嵌入的资源”。
本例子附带5种文字，均为外部调用，不用安装或加入资源文件。
附带消息框photoshop文件，除不能调整大小外，可以ps设置任意方向、透明度、颜色、阴影等在程序中调用。
资源文件列表
信息框_white.psd , 35301
Box_Demo/.vs/Box_Demo/v16/.suo , 54784
Box_Demo/.vs/Box_Demo/v16/Server/sqlite3/db.lock , 0
Box_Demo/.vs/Box_Demo/v16/Server/sqlite3/storage.ide , 712704
Box_Demo/.vs/Box_Demo/v16/Server/sqlite3/storage.ide-shm , 32768
Box_Demo/.vs/Box_Demo/v16/Server/sqlite3/storage.ide-wal , 4136512
Box_Demo/Box_Demo.sln , 1136
Box_Demo/WpfApp1/App.config , 189
Box_Demo/WpfApp1/App.xaml , 368
Box_Demo/WpfApp1/App.xaml.cs , 334
Box_Demo/WpfApp1/bin/Debug/BenMoYouYuan-2.ttf , 3583064
Box_Demo/WpfApp1/bin/Debug/ChaoZiSheFengYunJian-2.ttf , 13897516
Box_Demo/WpfApp1/bin/Debug/Lolita.ttf , 10828284
Box_Demo/WpfApp1/bin/Debug/RuiZiWenShuaiKeAiJian-TTF-2.ttf , 6667216
Box_Demo/WpfApp1/bin/Debug/WpfApp1.exe , 489984
Box_Demo/WpfApp1/bin/Debug/WpfApp1.exe.config , 189
Box_Demo/WpfApp1/bin/Debug/WpfApp1.pdb , 60928
Box_Demo/WpfApp1/bin/Debug/ZCOOLtongtong-2.ttf , 8810328
Box_Demo/WpfApp1/Images/1-min.png , 1318
Box_Demo/WpfApp1/Images/10-min.png , 1310
Box_Demo/WpfApp1/Images/11-min.png , 1342
Box_Demo/WpfApp1/Images/12-min.png , 1384
Box_Demo/WpfApp1/Images/13-min.png , 1318
Box_Demo/WpfApp1/Images/14-min.png , 1368
Box_Demo/WpfApp1/Images/15-min.png , 1312
Box_Demo/WpfApp1/Images/16-min.png , 1356
Box_Demo/WpfApp1/Images/17-min.png , 1344
Box_Demo/WpfApp1/Images/18-min.png , 1389
Box_Demo/WpfApp1/Images/19-min.png , 1258
Box_Demo/WpfApp1/Images/2-min.png , 1289
Box_Demo/WpfApp1/Images/20-min.png , 1322
Box_Demo/WpfApp1/Images/21-min.png , 1344
Box_Demo/WpfApp1/Images/22-min.png , 1374
Box_Demo/WpfApp1/Images/23-min.png , 1415
Box_Demo/WpfApp1/Images/24-min.png , 1372
Box_Demo/WpfApp1/Images/25-min.png , 1311
Box_Demo/WpfApp1/Images/26-min.png , 1375
Box_Demo/WpfApp1/Images/27-min.png , 1298
Box_Demo/WpfApp1/Images/28-min.png , 1357
Box_Demo/WpfApp1/Images/29-min.png , 1352
Box_Demo/WpfApp1/Images/3-min.png , 1354
Box_Demo/WpfApp1/Images/30-min.png , 1350
Box_Demo/WpfApp1/Images/4-min.png , 1328
Box_Demo/WpfApp1/Images/5-min.png , 1315
Box_Demo/WpfApp1/Images/6-min.png , 1302
Box_Demo/WpfApp1/Images/7-min.png , 1330
Box_Demo/WpfApp1/Images/8-min.png , 1350
Box_Demo/WpfApp1/Images/9-min.png , 1368
Box_Demo/WpfApp1/Images/background.jpg , 166843
Box_Demo/WpfApp1/Images/BarDown(1).png , 18577
Box_Demo/WpfApp1/Images/BarUp(1).png , 18577
Box_Demo/WpfApp1/Images/BarUp_E(1).png , 18577
Box_Demo/WpfApp1/Images/green_left_mess.png , 19161
Box_Demo/WpfApp1/Images/green_right_mess.png , 18729
Box_Demo/WpfApp1/Images/Nar_Center(1).png , 19913
Box_Demo/WpfApp1/Images/Nar_Center_s(1).png , 19913
Box_Demo/WpfApp1/Images/PageDownBG(1).png , 18581
Box_Demo/WpfApp1/Images/PageUpBG(1).png , 18581
Box_Demo/WpfApp1/Images/Scrollbackground(1).png , 19962
Box_Demo/WpfApp1/Images/white_left_mess.png , 18669
Box_Demo/WpfApp1/Images/white_right_mess.png , 19136
Box_Demo/WpfApp1/MainWindow.xaml , 708
Box_Demo/WpfApp1/MainWindow.xaml.cs , 16124
Box_Demo/WpfApp1/Properties/AssemblyInfo.cs , 2302
Box_Demo/WpfApp1/Properties/Resources.Designer.cs , 2827
Box_Demo/WpfApp1/Properties/Resources.resx , 5612
Box_Demo/WpfApp1/Properties/Settings.Designer.cs , 1094
Box_Demo/WpfApp1/Properties/Settings.settings , 201
Box_Demo/WpfApp1/RichtextboxHelper.cs , 21155
Box_Demo/WpfApp1/ScrollControl.cs , 12346
Box_Demo/WpfApp1/WpfApp1.csproj , 6501
exe/BenMoYouYuan-2.ttf , 3583064
exe/ChaoZiSheFengYunJian-2.ttf , 13897516
exe/Lolita.ttf , 10828284
exe/RuiZiWenShuaiKeAiJian-TTF-2.ttf , 6667216
exe/WpfApp1.exe , 489984
exe/ZCOOLtongtong-2.ttf , 8810328
信息框_Green.psd , 35770