ImageGear for C and C++ on Linux v18.10 - Updated
Device-Dependent Bitmaps (DDBs)
User Guide > Concepts > Understanding Bitmap Images > Device-Independent/Device-Dependent Bitmaps > Device-Dependent Bitmaps (DDBs)

Device-Dependent Bitmaps are bitmaps whose pixel data is organized for convenient dispatch to a particular device or group of devices, such as to a particular type of display monitor or printer. Normally you will not need to concern yourself with DDBs. ImageGear is designed to hold in-memory images in DIBs by default, and to process the image data of DIBs efficiently. But when the speed with which images are displayed is an important factor in your application, keeping large or often-displayed images in memory in DDB format may improve performance. For such cases, ImageGear provides several ways to create or import DDBs, and to display DDBs. Please refer to Using ImageGear.

If your application is intensive in the use of in-memory DDB's, we suggest you refer to Microsoft Windows documentation of Device-Dependent Bitmaps and Device Contexts.