Cast Method

Syntax

CWIMAQVision.Cast SourceImage, DestImage, Type [, LookupTable] [, Shift = 0]

Return Type

Long

On success, this method returns 0. On failure, this method returns a negative number.

Purpose

Changes the type of an image.

Remarks

This method operates with all image types.

This method can perform the change directly on the source image, or it can leave the source image unchanged and instead copy the source image to a destination image and then convert the destination image. If the destination image is the same as the source image, the method changes the type of the source image. Otherwise, the method resizes the destination image to the size of source image and then copies the pixels.

To change the type of an image in-place without supplying a shift value or a lookup table, you can set the Type property to the required type. If the source image type and the Type parameter are the same, the method copies pixels unmodified. You can also use Copy to copy pixels without modifying them. If the source image type and the Type parameter are not the same, the method casts the pixel values to the new type as follows:

Parameters

SourceImage As CWIMAQImage

The source image.

DestImage As CWIMAQImage

The destination image.

Type As CWIMAQImageTypes

The new type for the image.

LookupTable As Variant

[Optional] A lookup table. See Remarks for a description of how the method employs the lookup table.

Shift As Variant

[Optional] The shift value for converting 16-bit images to 8-bit images. The method ignores this value for all other conversions. The method executes this conversion by shifting the 16-bit pixel values to the right by the specified number of shift operations, up to a maximum of 8 shift operations, and then truncating to get an 8-bit value. Enter a value of –1 to ignore the bit depth and shift 0. Enter a value of 0 to use the bit depth to cast the image. See Remarks for a description of how the function employs the shift value.

This parameter has a default value of 0.

Example

Dim i As New CWIMAQImage
Dim lookupTable(0 to 255) As Long
Dim index

' Change the image in Viewer1 to an RGB32 image and 
' store the results in i
CWIMAQVision1.Cast CWIMAQViewer1.Image, i, cwimaqImageTypeRGB32

' Populate the lookupTable with a form of inverse transformation
For index = 0 to 255
    lookupTable(index) = 32767 - (index * 16)
Next

' Change the image in Viewer1 to a 16-bit image using the lookup table
CWIMAQVision1.Cast CWIMAQViewer1.Image, CWIMAQViewer1.Image, _
                   cwimaqImageTypeI16, lookupTable

' Change the image in Viewer1 to an SGL image
' You can use the Type property on the image since there is no need
' for a lookup table or shift value.
CWIMAQViewer1.Image.Type = cwimaqImageTypeSGL

See Also

Copy

CWIMAQImage.Type