LImageViewer::LowMemoryUsageCallBack

#include "ltwrappr.h"

virtual L_INT LImageViewer::LowMemoryUsageCallBack(nCellIndex, puFramesRequested, uLength)

L_INT nCellIndex;	/* index of a cell */
L_UINT * puFramesRequested;	/* table of uLength integers containing frames requested */
L_UINT uLength;	/* length of the frames requested array */

This callback function is called every time a new frame(s) has/have been requested when the low memory usage feature is enabled (for more information see the LImageViewer::EnableCellLowMemoryUsage function).

Parameter	Description
nCellIndex	Index of the cell, which has requested the frames in puFramesRequested.
puFramesRequested	Table of uLength integers containing frames requested
uLength	Length of the frames requested array.

Returns

SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

The low memory usage feature works by stopping the control from loading all the frames at runtime. Instead, the control will load only the frames that are currently visible on the cell. The control will send a request each time the user scrolls down or up, changes the number of visible framesetc. For example, suppose the cell layout is a 2X2 (See LImageViewer::SetCellProperties), and the user needs to load more than 100000 frames. The control will not load them all. This function will send a callback (LImageViewer::LowMemoryUsageCallBack) when the cell is loaded requesting 4 frames (1, 2, 3 and 4) (because the cell is 2X2). Once the user scrolls down the cell to show frame number 5, frame number 1 will be disposed of because it is no longer visible, and the callback will be fired to request frame number 5. When frames are requested, the user is supposed to send them to the control using the LImageViewer::SetRequestedImage function.

For the callback, use the LImageViewer::LowMemoryUsageCallBack function, to use this callback, it must first be set by calling LImageViewer::EnableLowMemoryUsageCallBack function.

Required DLLs and Libraries

LTIVW

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

See Also

Functions:	LImageViewer::EnableLowMemoryUsageCallBack, LImageViewer::RegionCallBack, LImageViewer::EnableRegionCallBack, LImageViewer::MouseCallBack, LImageViewer::ActionCallBack, LImageViewer::TagCallBack, LImageViewer::EnableTagCallBack, LImageViewer::AnnotationCallBack, LImageViewer::EnableAnnotationCallBack, LImageViewer::EnableAnnotationCreatedCallBack, LImageViewer::PrePaintCallBack, LImageViewer::EnablePrePaintCallBack, LImageViewer::EnablePostPaintCallBack, LImageViewer::PostPaintCallBack, Class Members
Topics:	Using the Medical Image Viewer Control
	Image Viewer Functions: Using the Image Viewer
	Image Viewer Functions: Callbacks

Example

For an example, refer to LImageViewer::EnableLowMemoryUsageCallBack.