SECTNBitmap Class

class SECTNBitmap: public CBitmap

SECTNBitmap encapsulates a thumbnail bitmap. A thumbnail bitmap is basically an in-memory DIB that knows how to serialize itself to an archive through the MFC standard Serialize() member function.

Defined in: SECTNBMP.H

Comments

When an SECTNDocument is serialized, it first creates an SECTNBitmap from the current view and serializes that. After the thumbnail, the document continues to serialize application-specific data as normal. SECTNView takes care of creating the SECTNBitmap and SECTNFileDialog handles reading in and displaying the SECTNBitmap in the thumbnail-enabled open file common dialog.

One side effect of Objective Toolkit using the DIB format to store the thumbnail is that the Windows 95 Explorer will automatically display a thumbnail of the thumbnail in the Explorer and common dialogs. To turn off this feature, change the signature of the first two bytes from DIB (0x4d42) to another non-DIB value. This signature is written and checked in the Serialize member funtion.

In most cases the application will never have to deal directly with SECTNBitmap.

The THUMBNL sample in the \SAMPLES\TOOLKIT\STANDARD\UIEXT\THUMBNL directory demonstrates how to use SECTNBitmap and the other Objective Toolkit thumbnail support classes.