GetLinePointer Method

Description

Return a memory pointer to a line of the image.

Return Type

An ULong object.

A Long value that is actually an in-process 32-bit memory pointer. This return value will NOT be valid out-of-process. Use GetLine and/or PutLine for cross-process safe image access.

Syntax

object.GetLinePointer (y, [bWillModifyLine])

The GetLinePointer Method syntax has these parts:

Part	Description
object	An expression evaluating to an object of type McRegionAccess.
y	Required. A Long value. A 0-based line number, relative to the ROI.Top
bWillModifyLine	Optional. A Boolean value. If True, the line will be marked as modified. Note that a notification of the modification is automatically sent ONLY when the McRegionAccess is fully released. To signal changes before then, use the SignalImageChanged method.

Remarks

The y coordinate is relative to the McRegionAccess ROI, not the image. The pixel values referenced by the returned pointer are in the requested color model, which may differ from the image's native color model.

The pointer points to the ChannelToProcess of the first pixel inside the McRegionAccess -- the ROI 0:y coordinate.

This method may ONLY be called from in-process code that knows how to translate the returned Long value into a pointer to pixel memory.

For non-critical applications, it is recommended the client use GetLine and PutLine instead of this method. Those methods are cross-process safe.

It is critical that the client set bWillModifyLine to TRUE if there is any possibility that the client will be modifying the pixels. This enables any necessary write-backs to the hosting image and activates the “Image Changed” notification process.