Microsoft Windows CE display drivers and hardware

Microsoft Windows CE operating system version 2.0 graphic style had great changes in version 1.0, the graphical design interface (GDI) directly with the display hardware phase, in version 2.0, GDI and one or more connected to the TFT driver , which in turn is connected with the display hardware. The display technology allows Windows CE to use a variety of display devices without the need to code programs for each device has the hardware, the new Windows CE GDI with the purpose of small steps together.
    This paper first consider a good driver with a Windows CE display characteristics, it discusses the display driver device driver should perform the interface functions, the same graphics the original engine level, can be used to simplify the writing display drivers, GDI support equipment driver is also discussed.
    The paper then lists the Windows CE support for the depth of detail in each pixel, display buffer format, and discuss the display hardware, because the display driver is the passage between the GDI and the display device, the display driver hardware support, also need support for GDI.
Windows CE Display Driver
    Like most of the same Windows CE display driver interface (DDI) DDI for Microsoft Windows NT, a subset, if you are not familiar with the Windows NT DDI, in writing of your Windows CE display driver, it should read the Windows NT device driver package display driver section.
    Windows CE Windows NT DDI only the most basic graphics engine and driver functions. Windows CE and Windows NT differences, has the following details:
Windows CE display drivers always have the same function, GDI does not check the driver capability information;
Windows CE display driver does not refuse to complex operations, it transferred its back to the GDI, so that the operation is divided into simple steps, because all Windows CE display driver support the same features, GD can call the display driver first before the decomposition of complex operations .
Windows CE display drivers are compiled into dynamic link libraries (. DLL files) instead of library functions (. LIB file).
    All Windows CE display driver must implement a set of DDI function, which consists of. GDI call to initialize the display driver and the drawing to show, in addition to DDI function, this set of VC + + class, it calls the primary graphics engine (GPE) classes, show drivers use it to make it easier for hardware acceleration, the standard display driver calls GPE classes and acceleration is based on the S3Trio64 display hardware, if your video display hardware uses a different chip, called in a way you can change to suit your GPE hardware capacity.
    Note that using the GPE class is optional, you do not need them to write to your display driver, the cost of the implementation of the DDI function is more complex, note that the GPE classes provided by Microsoft for your display hardware need to have a flat frame (frame) buffer, if your hardware is not shown, for example, it uses a custom window to connect to the removable memory, it may not use the GPE classes, in order to obtain more detailed information, in this article, part of Windows CE display hardware recommendations, Dirty Rec Drivers in particular sub-section.
    Windows CE display drivers are usually in many ways with different device drivers, the main difference is that they are not exposed to I / O interface. Therefore, they can not be Device Manager to manage, so register can never be their call. Result, no special equipment, documents or other file system records and activities to coordinate the display driver, display driver loading mechanism is a display driver to use application software, called with the display driver names function dynamic Create DC link file. This allows Windows CE to load the lcd display driver, and initializes the device context to be able to return to the calling application of the default display driver, of course, is automatically loaded.

DDI function
    The following table lists the display and print the DDI function driver display driver should be listed here show all the implementation of DDI functions. Implementation of all print driver should print DDI function. However, only Drve Enable Drive must show the driver a dynamic link library (DLL) output. Therefore, only DrvEnableDrive must have a name, other functions are free to call, as they returned from the Drr Enable Driver, function pointer output to GDI, no matter who is called, always follow the definitions file in the Win DDI.H prototype.