Some optimization methods for UI Application of Qt5 on Hisilicon security platform

　　　 Develop on Hisilicon security platform , Generally, there is a demand for video , Here's a summary , In the use of ＱT.5.5 when , Some processing methods for the platform .

1. Video layer display

        Video uses chip decoding , When it is displayed , Displayed on the video layer ,ＵＩ Use FB Operation display , Display on the graphics layer , This needs to go through the graphics layer , Show video layer , There are two ways on the chip , One is colorkey, One is alpha Transparent approach , If ＱＴ Use ARGB8888 Just use colorkey Method ,ARGB1555 have access to colorkey or alpha Method .

      2.  Graphics layer refresh method

　　QT Need to use buff The way to draw and display UI, However, some drawing processes can be clearly seen on the platform , This can be done using the... Of the Hisilicon platform FB The dual cache method is used to solve the problem , stay QT Of Linuxfb The plug-in calls the... Of the Hisilicon platform FB Operation to refresh the drawn results , The effect looks much better , There will be no ＱT The drawing feels that the whole graphic layer is moving , Of course, after this treatment , There will be a certain sense of delay , But it's not obvious .

       3. Adaptive resolution

　　 Self adaptation can be handled in its own application , You can also use the... Of the Hisilicon platform TDE Function to do , Each has its own advantages and disadvantages , Make trouble in application , Each interface needs to consider different resolutions ;

　　 Use here ＴＤＥ The way to do it , Of course, this approach , If the design is a large resolution effect , Font and icon blurring may occur when adapting to small resolution . Here, press... When setting 1024*768 Minimum resolution design , In the use of TDE Enlarge output to 1280*1024, 1440*900,1080P,2K,4K The output is clearly visible . Use ＴＤＥ Of surface The zoom function in the , Performance aspect １ seconds ５ There is no problem above the frame ！

     4. Mouse jam problem

　　 When operating the mouse in use , If ＵＩ The main interface has refresh operation , Often the mouse movement is not smooth , Here, because the mouse is also in ＵＩ Updated in the main thread , There is a special mouse graphics layer on the Hisilicon platform , The way to deal with it is in ＱＴ Of input In the plug-in of the peripheral , Start a thread to read the mouse device and update the mouse position .

     ５. The problem of switching resolution at runtime

　　 Such a question , No solution has been found , The reason is that we didn't find ＱＴ The method of dynamic reconstruction linuxfb The object in the plug-in , So when switching resolution , The user is required to restart the device , The experience is very bad , If you know the method, please give me some advice ！   

　　QT The library is still very powerful , Compared with the previous writing UI library , Or use UCGUI,　MINIGUI These libraries , Full of happiness ！ However qt Compiled is still a little big if you use 16MB Of flash I can't put it down ！