[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [ft] a confusing problem when using FT_Library_SetLcdFilterWeights()
From: |
Werner LEMBERG |
Subject: |
Re: [ft] a confusing problem when using FT_Library_SetLcdFilterWeights(); |
Date: |
Sun, 29 Apr 2018 06:49:57 +0200 (CEST) |
国梁,
> I am a chinese programmer. I want to output text on OpenGLES with
> freetype(C++). What's more, I want to use that class (C++) in our
> production. It's handle frequency spectrum analyzer. But now I an
> confused about a problem. I set the subpixel choice before building
> lib and my display is LCD display.
>
> Firstly, I write a small demo in our WindowCE7.0 platform and it
> works correctly. I use the LCD filter like this.
>
> FT_Library_SetLcdFilter(library, FT_LCD_FILTER_LIGHT);
> unsigned char weight = 0x55;
> FT_Library_SetLcdFilterWeights(library, &weight);
>
> The result is picture1.
Unfortunately, such hand-held camera snapshots are not very helpful in
analyzing your problem. Can't you simply press the `PrtScr' button to
get real screen snapshots that you can further process to get PNG
images?
> However, when I add the Class to our spectrum analyzer, it seems not
> working correctly. The result is picture2. It seem like more
> darker than picture1. [...]
I doubt that such an issue happens on your WindowCE platform only.
Please compile your program on standard Windows, say, and check
whether you have the same issues – and maybe this enables you to get
real screendumps...
I also suggest that you play around with the `ftview' demo program
(which allows full control over LCD weights), also checking its source
code.
Werner