This method retrieves the range of possible setting values for a specified functionality of the scan device.
Parameters
capability
The number for the retrieved
functionality in hexidecimal notation (value is of
typeScanCapability)
Return Value
The CapabilityRange class (Returns null[C#] or Nothing[Visual Basic] if unsuccessful).
Explanation
The GetCapabilityRange method retrieves the range of possible setting values for a specified functionality of the scan device. To retrieve the range of possible values for a setting, the DataSourceName property must be set. If the DataSourceName property is blank then prior to executing this method, please execute the SelectDataSource method. (If the OpenDataSource method has been executed, the DataSourceName is disabled and the open scan device will be used.)
Depending on your scanner, the resolution values that are possible may be different according to the pixel type value (i.e. according to whether the pixel type is 1 bit color, 24 bit color, etc.) Because of this, it is recommended that you you set the PixelType property prior to retrieving the possible values for horizontal and vertical resolution.
To execute the GetCapabilityRange method you must first execute the Initialize method. If the OpenDataSource method is executed prior to executing the GetCapRange method then the open datasource cannot be used by another application until that datasource (scan device) is closed.
After executing this method, the value is set into the ContainerType property.
Contents of the return value
| Parameter | Return Value |
|---|---|
| Brightness | Range Information |
| Contrast | Range Information |
| Gamma | Range Information |
| Highlight | Range Information |
| Shadow | Range Information |
| XResolution | Range Information |
| YResolution | Range Information |
| Rotation | Range Information |
| Threshold | Range Information |
| XScaling | Range Information |
| YScaling | Range Information |
| SkipBlankPage (AutoDiscardBlankPages) |
Range Information (including Twain Standard Capability) |
| JpegQuality | Range Information |
| Sharpness | Range Information Enabled when using Canon DR, Epson, or Panasonic scan drivers. In Canon DR drivers this is called "Edge Adjustment". In Epson drivers, it is called "Unsharpness". In Panasonic drivers, it is called "Image Quality". |
| SkipBlankPage | Range Information |
| FocusPosition | Range Information Enabled for Epson scan drivers. |
When ContainerType = 3 or 4, then the number of elements in the list is set into the Maximum property for the CapabilityRange class. Use this number and execute the GetCapabilityEnumToSingle method.
When ContainerType = 5, then the current value is set into the Current property for the CapabilityRange class and the default value is set into the Default property.
When ContainerType = 6, then values are set into the Current, Range, Maximum, Minimum, and Step properties.