This property sets the compression method used when an image is transferred via memory.
Property Value
| Value | Explanation |
|---|---|
| 0 | Uncompressed |
| 1 | PACKBITS |
| 2 | GROUP3-1D |
| 3 | GROUP3-1DEOL |
| 4 | GROUP3-2D |
| 5 | GROUP4 |
| 6 | JPEG |
| 7 | LZW |
| 8 | JBIG |
| 9 | PNG |
| 10 | RLE4 |
| 11 | RLE8 |
| 12 | BITFIELDS |
2,3,4,5 are in FAX[CCITT] format, and 10,11,12 are in BMP format.
In Visual Basic the following constants can be used: (ikScanNoCompress = 0, ikScanPackbits = 1, ikScanGroup3_1D = 2, ikScanGroup3_1D_EOL = 3, ikScanGroup3_2D = 4, ikScanGroup4 = 5, ikScanJPEG = 6, ikScanLZW = 7, ikScanJBIG = 8, ikScanPNG = 9, ikScanRLE4 = 10, ikScanRLE8 = 11, ikScanBITFIELDS = 12).
Explanation
The Compression property sets the compression method used when an image is transferred via memory. When scanning with a custom user interface (with the scan driver's user interface suppressed), be sure to set appropriate values in the PixelType and the BitDepth properties. For example, Tiff group 3 or 4 compression images must be 1 bit black and white; JPEG compression images must be either 8 bit grayscale or 24 bit color.
For details about the different methods for transferring images, please refer to the TransferMode property. The possible setting values supported by a scan device can be retrieved using the GetCapEnum (GetCapEnumVariant) method. Depending on the datasource, uncompressed may be the only file transfer compression method available.
Setting this value
This value can be set at runtime.
Retrieving this value
This value can be retrieved at runtime.