这个系列的文章在网上到处都是 这里也不清楚谁才是原文作者 我这里做个整理，标注一下希望大家能看的更加舒服一点
目录
DrvEnablePDEV
一旦选定了一种显示模式，这个api就会被调用，它会允许驱动使能”物理设备”。这个API的用途是允许显示驱动创建自己私有的上下文，这个上下文将会被传递给其他的显示入口点。创建私有上下文的原因是一个显示驱动可以管理多个显示设备，使用它可以区分开各个显示设备。这个api的返回值是一个上下文指针或者是显示设备的实例。
选中的显示设置通过DEVMODE参数传递给这个API，然而例子驱动中没有使用这个方法，而是硬编码设置为800 * 600 * 32的显示模式。
这个API除创建一个实例结构外，还必须初始化GDIINFO和DEVINFO这两个数据结构。这些参数是重要的，如果你填写支持某一特征，但实际上并不支持。其副作用就是图形扭曲，甚至是蓝屏。其余两个参数我会在后面提及，他们是hDev和hDriver,参数hDriver实际上是显示驱动的DEVICE_OBJECT，可以用于API,例如：EngDeviceIoControl用它来和迷你小端口驱动通讯。
hDev是GDI的句柄，然而由于hDev是在被创建进程中，实际上这个参数没有用。在保存和使用这个句柄之前，建议等待，直到调用了DrvCompletePDEV。下面的代码来自例子驱动的DrvEnablePDEV。
DHPDEV GdiExample_DrvEnablePDEV(DEVMODEW *pdm, PWSTR pwszLogAddr,
ULONG cPat, HSURF *phsurfPatterns, ULONG cjCaps,
GDIINFO *pGdiInfo, ULONG cjDevInfo, DEVINFO *pDevInfo,
HDEV hdev, PWSTR pwszDeviceName, HANDLE hDriver)
{
PDEVICE_DATA pDeviceData = NULL;
ENGDEBUGPRINT(0, "GdiExample_DrvEnablePDEV Enter \r\n", NULL);
pDeviceData = (PDEVICE_DATA) EngAllocMem(0,
sizeof(DEVICE_DATA), FAKE_GFX_TAG);
if(pDeviceData)
{
memset(pDeviceData, 0, sizeof(DEVICE_DATA));
memset(pGdiInfo, 0, cjCaps);
memset(pDevInfo, 0, cjDevInfo);
{
pGdiInfo->ulVersion = 0x5000;
pGdiInfo->ulTechnology = DT_RASDISPLAY;
pGdiInfo->ulHorzSize = 0;
pGdiInfo->ulVertSize = 0;
pGdiInfo->ulHorzRes = RESOLUTION_X;
pGdiInfo->ulVertRes = RESOLUTION_Y;
pGdiInfo->ulPanningHorzRes = 0;
pGdiInfo->ulPanningVertRes = 0;
pGdiInfo->cBitsPixel = 8;
pGdiInfo->cPlanes = 4;
pGdiInfo->ulNumColors = 20;
pGdiInfo->ulVRefresh = 1;
pGdiInfo->ulBltAlignment = 1;
pGdiInfo->ulLogPixelsX = 96;
pGdiInfo->ulLogPixelsY = 96;
pGdiInfo->flTextCaps = TC_RA_ABLE;
pGdiInfo->flRaster = 0;
pGdiInfo->ulDACRed = 8;
pGdiInfo->ulDACGreen = 8;
pGdiInfo->ulDACBlue = 8;
pGdiInfo->ulAspectX = 0x24;
pGdiInfo->ulNumPalReg = 256;
pGdiInfo->ulAspectY = 0x24;
pGdiInfo->ulAspectXY = 0x33;
pGdiInfo->xStyleStep = 1;
pGdiInfo->yStyleStep = 1;
pGdiInfo->denStyleStep = 3;
pGdiInfo->ptlPhysOffset.x = 0;
pGdiInfo->ptlPhysOffset.y = 0;
pGdiInfo->szlPhysSize.cx = 0;
pGdiInfo->szlPhysSize.cy = 0;
pGdiInfo->ciDevice.Red.x = 6700;
pGdiInfo->ciDevice.Red.y = 3300;
pGdiInfo->ciDevice.Red.Y = 0;
pGdiInfo->ciDevice.Green.x = 2100;
pGdiInfo->ciDevice.Green.y = 7100;
pGdiInfo->ciDevice.Green.Y = 0;
pGdiInfo->ciDevice.Blue.x = 1400;
pGdiInfo->ciDevice.Blue.y = 800;
pGdiInfo->ciDevice.Blue.Y = 0;
pGdiInfo->ciDevice.AlignmentWhite.x = 3127;
pGdiInfo->ciDevice.AlignmentWhite.y = 3290;
pGdiInfo->ciDevice.AlignmentWhite.Y = 0;
pGdiInfo->ciDevice.RedGamma = 20000;
pGdiInfo->ciDevice.GreenGamma = 20000;
pGdiInfo->ciDevice.BlueGamma = 20000;
pGdiInfo->ciDevice.Cyan.x = 1750;
pGdiInfo->ciDevice.Cyan.y = 3950;
pGdiInfo->ciDevice.Cyan.Y = 0;
pGdiInfo->ciDevice.Magenta.x = 4050;
pGdiInfo->ciDevice.Magenta.y = 2050;
pGdiInfo->ciDevice.Magenta.Y = 0;
pGdiInfo->ciDevice.Yellow.x = 4400;
pGdiInfo->ciDevice.Yellow.y = 5200;
pGdiInfo->ciDevice.Yellow.Y = 0;
pGdiInfo->ciDevice.MagentaInCyanDye = 0;
pGdiInfo->ciDevice.YellowInCyanDye = 0;
pGdiInfo->ciDevice.CyanInMagentaDye = 0;
pGdiInfo->ciDevice.YellowInMagentaDye = 0;
pGdiInfo->ciDevice.CyanInYellowDye = 0;
pGdiInfo->ciDevice.MagentaInYellowDye = 0;
pGdiInfo->ulDevicePelsDPI = 0;
pGdiInfo->ulPrimaryOrder = PRIMARY_ORDER_CBA;
pGdiInfo->ulHTPatternSize = HT_PATSIZE_4x4_M;
pGdiInfo->flHTFlags = HT_FLAG_ADDITIVE_PRIMS;
pGdiInfo->ulHTOutputFormat = HT_FORMAT_32BPP;
*pDevInfo = gDevInfoFrameBuffer;
pDevInfo->iDitherFormat = BMF_32BPP;
}
pDeviceData->pVideoMemory = EngMapFile(L"\\??\\c:\\video.dat",
RESOLUTION_X*RESOLUTION_Y*4, &pDeviceData->pMappedFile);
pDeviceData->hDriver = hDriver;
pDevInfo->hpalDefault = EngCreatePalette(PAL_BITFIELDS,
0, NULL, 0xFF0000, 0xFF00, 0xFF);
}
ENGDEBUGPRINT(0, "GdiExample_DrvEnablePDEV Exit \r\n", NULL);
return (DHPDEV)pDeviceData;
}