GdPictureImaging.TwainGetCapRangeNumeric Method

Returns the three parameters that define a Range for a TWAIN capability. Many capabilities allow users to select their current value from a range of regularly spaced values. The capability can specify the minimum and maximum acceptable values and the incremental step size between values. For example, resolution might be supported from 100 to 600 in steps of 50 (100, 150, 200, ..., 550, 600).

public Boolean TwainGetCapRangeNumeric(
    TwainCapabilities Cap, 
    ref Double nMinValue, 
    ref Double nMaxValue, 
    ref Double nStepValue
);

Visual Basic

Public Function TwainGetCapRangeNumeric(
    ByVal Cap As TwainCapabilities, 
    ByRef nMinValue As Double, 
    ByRef nMaxValue As Double, 
    ByRef nStepValue As Double
) As Boolean

Parameters

Parameters	Description
Cap	A member of the TwainCapabilities enumeration.
nMinValue	Output parameter. Starting value in the range.
nMaxValue	Output parameter. Final value in the range.
nStepValue	Output parameter. Increment from nMinValue to nMaxValue.

Returns

True if success, else False -> use TwainGetLastResultCode() and TwainGetLastConditionCode() functions for diagnosing the error.

Remarks

Before using this function check that the TWAIN state is >= 4 (TWAIN_SOURCE_OPEN)

To get the TWAIN state, use the TwainGetState() function.

This function can be used to set the following types of capabilities: TWTY_INT8 , TWTY_INT16, TWTY_INT32, TWTY_UINT8, TWTY_UINT16, TWTY_UINT32, TWTY_BOOL, TWTY_FIX32, TWTY_FRAME.

You can determine the type of each TWAIN capability using the TwainGetCapItemType function or looking the twain references from http://www.twain.org

Example

Gets supported Brightness values

Copy Code

Dim bSuccess As Boolean
Dim MinValue As Double, MaxValue As Double, StepValue As Double
Dim i As Integer
 
oGdPictureImaging.TwainOpenDefaultSource(Me.Handle)
bSuccess = oGdPictureImaging.TwainGetCapRangeNumeric(TwainCapabilities.ICAP_BRIGHTNESS, MinValue, MaxValue, StepValue)
If bSuccess Then
    For i = CInt(MinValue) To CInt(MaxValue) Step CInt(StepValue)
'Here, you can catch & store the i value somewhere
MsgBox("A supported value is: " + Str(i))
    Next i
End If