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L_GetBitmapRowColCompressed

Summary

Retrieves a row (or part of a row) of 1-bit compressed data from a bitmap that has been loaded in its compressed format.

Syntax

#include "l_bitmap.h"

L_LTKRN_API L_SSIZE_T L_GetBitmapRowColCompressed(pBitmap, pWorkBuffer, pRunBuffer, nRow, nCol, uWidth)

Parameters

pBITMAPHANDLE pBitmap

Pointer to the bitmap handle referencing the bitmap to get the image data from.

L_UCHAR * pWorkBuffer

NULL or a pointer to an optional work buffer. Allocating the work buffer speeds processing if you call this function more than once, because if you do not allocate a work buffer, the function allocates and frees a temporary buffer each time it is called. The size of this buffer should be the same as the bitmap handle's BytesPerLine field.

L_UINT16 * pRunBuffer

Pointer to the output buffer, which will be filled with 1-bit compressed image data. Calculate the required size of this buffer as follows: bytes required = (nWidth + 3) * 2.

L_INT nRow

The number of the row to retrieve. The first row is 0, and the last row is 1 less than the bitmap height.

L_INT nCol

The column offset within the row to retrieve. The first column offset is 0, and the last column offset is 1 less than the bitmap width.

L_SIZE_T uWidth

The number of pixels to retrieve.

Returns

Value	Meaning
> 0	The number of pixels processed.
< 1	An error occurred. Refer to Return Codes.

Comments

This function is useful for working with 1-bit images that are loaded in their compressed formats for faster loading and display. For more information, refer to Speeding Up 1-Bit Documents.