L_DispContainerSetRequestedImage

#include "l_bitmap.h"

L_LTIVW_API L_INT EXT_FUNCTION L_DispContainerSetRequestedImage(hCon, nCellIndex, pBitmaps, pBitmapIndexes, nLength, uFlags)

HDISPCONTAINER hCon;	/* handle to the container */
L_INT nCellIndex;	/* index of a cell */
pBITMAPHANDLE pBitmaps;	/* pointer to bitmaps array */
L_INT * pBitmapIndexes;	/* pointer to bitmap indexes array */
L_INT nLength;	/* length of the bitmap indexes array */
L_UINT uFlags;	/* flag */

Sends the requested images to the control; this function is used when the low memory usage feature is enabled (for more information see the L_DispContainerEnableCellLowMemoryUsage function).

Parameter	Description
hCon	Handle to the container.
nCellIndex	A zero-based index of the cell for which to pass the requested image.
pBitmaps	Array of a BITMAPHANDLE structure that contains the requested frames.
pBitmapIndexes	Array of Integers containing the index of each bitmap in pBitmaps in respective manner.
nLength	Length of the pBitmapIndexes array.
uFlags	Flag that indicate how to handle the images set. Possible values are:
	Value	Meaning
	CONTAINER_SETIMAGE_INSERT	[0x00000000] Insert the requested image.
	CONTAINER_SETIMAGE_REPLACE	[0x00000001] Replace the requested image with the corresponding index.

Returns

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

Comments

The low memory usage feature works by making the control stop from loading all of 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 frames, etc. For example, suppose the cell layout is a 2X2 (See L_DispContainerSetCellProperties), and the user needs to load more than 100000 frames. Instead of loading them all, this function will send a callback (DISPCONTAINERFRAMEREQUESTEDCALLBACK) 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 view 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 function L_DispContainerSetRequestedImage.

nHiddenCount allows the control load a specified number of frames ahead (so if you have a 2X2 cell and you set nHiddenCount to 3, the method will request (1, 2, 3, 4, 5, 6, 7). The function will normally request also 0, -1, -2. but since those indexes are not valid, the control will not request them.

To get the current frames request callback function, call L_DispContainerGetLowMemoryUsageCallBack.
To set the current frames request callback function, call L_DispContainerSetLowMemoryUsageCallBack

If the user doesnt need to use the low memory usage to load the images, he can use the direct way by sending a bitmap list to the control using the L_DispContainerSetCellBitmapList 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.

Platforms

Windows 95 / 98 / Me; Windows 2000 / XP; Windows CE.

See Also

Functions:	L_DispContainerCreate, L_DispContainerDestroy, L_DispContainerInsertCell, L_DispContainerEnableCellLowMemoryUsage, L_DispContainerSetLowMemoryUsageCallBack, L_DispContainerGetLowMemoryUsageCallBack, L_DispContainerSetCellBitmapList
Topics:	Using the Image Viewer
	Image Viewer Functions: Using the Image Viewer

Example

For an example, refer to L_DispContainerSetLowMemoryUsageCallBack.