深入了解microwindows(二)---LCD篇

其实在microwindows的LCD部份与按键类似.

回到 ebrmain.c 中 main() 函数中.

 

int main()
{
  GR_EVENT event;
  if (GrOpen() < 0) {
        fprintf (stderr, "GrOpen failed");
        return 0;
  }
  ...

  ...

  ...

  return 0;
}

LCD 的初始化也是在GrOpen() 中实现的.

GrOpen->GsInitialize->GdOpenScreen

GdOpenScreen 在 src/engine/devopen.c 中定义.

现在分析一下 GdOpenScreen() 这个函数

/**
 * Open low level graphics driver.
 *
 * @return The screen drawing surface.
 */
PSD
GdOpenScreen(void)
{
    PSD            psd;
    MWPALENTRY *        stdpal;
    MWSCREENINFO        sinfo;    

    psd = scrdev.Open(&scrdev);
    if (!psd)
        return NULL;
    ...

    ...
}

GrOpen->GsInitialize->GdOpenScreen->scrdev.Open

首先调用 scrdev.Open 进行初始化操作, scrdev 初始化在 src/drivers/scr_fb.c 文件中, 对 open, close, getscreeninfo, ...,ShowWindow, SaveImage等函数进行初始化操作.

GrOpen->GsInitialize->GdOpenScreen->scrdev.Open->Open

/* local functions*/
/* init framebuffer*/
static PSD open(PSD psd)
{
    psd->xres = psd->xvirtres = WIDTH;
    psd->yres = psd->yvirtres = HEIGHT;
    psd->planes = PLANES;
    psd->bpp = BITCOUNT;
    psd->ncolors = (psd->bpp >= 24)? (1 << 24): (1 << psd->bpp); // colors count 
    psd->linelen = psd->xvirtres;
    psd->addr = bmpdata;
    psd->size = MEMSIZE;
    psd->pixtype = MWPF_TRUECOLOR888;
    memset(psd->addr,0x00,psd->size);
    psd->portrait = MWPORTRAIT_NONE;
    /* !EMBEDDEDPLANET*/
    psd->flags = PSF_SCREEN | PSF_HAVEBLIT;
    if (psd->bpp == 16)
        psd->flags |= PSF_HAVEOP_COPY;
    status = 2;  
    open_panel();   
    return psd;    /* success*/
}

在 open 函数里对 LCD的一些参数进行了配置.

GrOpen->GsInitialize->GdOpenScreen->scrdev.Open->Open->open_panel

void open_panel()
{
    pio_fd = open ("/dev/fb0", O_RDONLY | O_NONBLOCK);
}

open_panel 只是打开一个设备文件.