The GDI Graphics Engine And Print Principle And Realization Under Windows 2k Or XP

Responding to the government call for environmental protection about paperless office, most of enterprise and public institution is making a maximizing use of OA systems. Even then the printer is still our daily office essential modern facilities. Because some important files must be saved in the form of papers and the form of paper can only achieve our purpose affected by the device shortage. But there is still another point in real life: sometimes we do not need to print out something, but only want to print preview function to see the output results. However, if the printer is not installed on your computer, the application software does not have print preview function and can't see the effect. this brought a lot of inconvenience to us who have no a printer.There are a lot of virtual printer software, but their function is a signal: only The current file format has been converted into PDF format. Its essence is PDF conversion software, and not really the function of the printer driver, such as setting page properties, etc. Therefore, i design and development of this virtual printer software: bitmap virtual printer.The software is based on Windows 2000/XP as a platform, with Windows GDI graphics engine and some graphics algorithms, and DDI function called to generate high-resolution (600 or 1200 DPI), black and white, gray by dithering raster simulation. Then generated in the graphics page, it uses the RLE compression algorithm compresses the bitmap, concurrent to the spooler and print port monitor.According to the different function, the software is making up of three modules: print process module, driver module and UI module. The function of print process module is spooling and playback about printer jobs; Driver module is the kernel modules of the software and realizes the most functions, as initialization of the virtual page, print control, dithering of bitmap, compressing and so on. UI module is human-computer interaction and shall be responsible for the setting of parameters about the attributes of printer and printer jobs.