The DBImage Component

It's a graphical world out there, and Delphi's darabase supporr for a graphics object is second to none. Nearly all database products sup ported by the BDE support the inclusion of bitmapped graphics in BLOB {Binary Large OBject) data fields within the table. (BLOBs| are not

Chapter B-Delphi's Data-Aware Components |

limited to being containers for graphics but this is one of their most common uses.) If a field type is supported by the BDE you can count ofl Delphi offering a component to work with this type of data. For graphics, that control is the DBImage component, a data-aware version of the-TImage class.

When the DBImage control is enabled, the BLOB graphics images are captured from the dataset and then stored internally in the Windows DIB format. Device-independent bitmaps are an internal data format that is sent to the computer's display adapter driver for translation into a screen display. Because of the size of images and the time needed to process them to and from memory, BLOB fields are cached locally when rows are retrieved from a dataset. This improves the application's performance when a user scrolls through the rows of a table and the images are retrieved from memory rather than a server.

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