bug with package showtext

[Li-yuhui]

Hello, i got a error, when i use devout package to create picture filled with texture, the text on picture are all black solid, but when i did not library showtext package, the error is gone. Same error happened when i use export package to output file to PowerPoint, so i guess there is a bunch of code needed to be optimized. Thanks for your view, please forgive my poor English.