#include "l_bitmap.h"
L_LTKRN_API L_SSIZE_T L_PutBitmapRowColCompressed(pBitmap, pWorkBuffer, pRunBuffer, nRow, nCol, uWidth)
Puts a row (or part of a row) of 1-bit compressed data from a buffer to a bitmap that is maintained in its compressed format.
Pointer to the bitmap handle referencing the bitmap to be updated.
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.
Pointer to the input buffer, which contains 1-bit compressed image data.
The number of the row to update. The first row is 0, and the last row is 1 less than the bitmap height.
The column offset within the row to update. The first column offset is 0, and the last column offset is 1 less than the bitmap width.
The number of pixels to retrieve.
Value | Meaning |
---|---|
> 0 | The number of pixels processed. |
< 1 | An error occurred. Refer to Return Codes. |
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.
Required DLLs and Libraries
Win32, x64, Linux.
This example demonstrates the low-level functions for accessing
1-bit compressed bitmap data. It demonstrates the ability to get and put
partial rows, and the ability to process partial rows in buffer-to-buffer
processing. The result of the function is an inverted rectangle in the
middle of the image.
L_INT PutBitmapRowColCompressedExample(L_TCHAR* pszFilename,
HWND hWnd,
pBITMAPHANDLE pLeadBitmap)
{
L_INT nRet;
L_INT XOffset; /* Column offset of the rectangle to process */
L_INT XSize; /* Pixel width of the rectangle to process */
L_INT YOffset; /* Row offset of the rectangle to process */
L_INT YSize; /* Pixel height of the rectangle to process */
L_UCHAR* pBuffer; /* Buffer to hold the expanded row */
L_UINT16* pRunBuffer; /* Buffer to hold the compressed row */
L_UCHAR* pWorkBuffer; /* Work buffer */
HGLOBAL hBuffer; /* Handle to the pBuffer */
HGLOBAL hRunBuffer; /* Handle to the pRunBuffer */
HGLOBAL hWorkBuffer; /* Handle to the pWorkBuffer */
L_INT i, n; /* Counters */
/* Load the bitmap, at 1 bit per pixel */
if(pLeadBitmap->Flags.Allocated)
L_FreeBitmap(pLeadBitmap);
nRet = L_LoadFile( pszFilename, pLeadBitmap, sizeof(BITMAPHANDLE),1,0,
LOADFILE_COMPRESSED | LOADFILE_ALLOCATE | LOADFILE_STORE,
NULL, NULL, NULL, NULL);
if(nRet != SUCCESS)
return nRet;
/* This example does not work with rotated view perspectives */
if ( (pLeadBitmap->ViewPerspective != TOP_LEFT) || (pLeadBitmap->ViewPerspective != BOTTOM_LEFT) )
{
nRet = L_ChangeBitmapViewPerspective ( NULL, pLeadBitmap, sizeof(BITMAPHANDLE), TOP_LEFT );
if(nRet != SUCCESS)
{
L_FreeBitmap(pLeadBitmap);
return nRet;
}
}
/* Specify a rectangle in the middle right part of the displayed image */
XOffset = pLeadBitmap->Width / 3;
XSize = pLeadBitmap->Width * 2 / 3;
YOffset = pLeadBitmap->Height / 3;
YSize = pLeadBitmap->Height / 3;
/* Adjust the YOffset if the view perspective is bottom left */
if (pLeadBitmap->ViewPerspective == BOTTOM_LEFT)
{
YOffset = pLeadBitmap->Height - YOffset - YSize;
}
/* Allocate the buffers */
hBuffer = GlobalAlloc(GMEM_MOVEABLE, ( XSize + 7) / 8);
pBuffer = (L_UCHAR*)GlobalLock( hBuffer );
hRunBuffer = GlobalAlloc(GMEM_MOVEABLE, (XSize + 3) * 2);
pRunBuffer = (L_UINT16*)GlobalLock( hRunBuffer );
hWorkBuffer = GlobalAlloc(GMEM_MOVEABLE, pLeadBitmap->BytesPerLine);
pWorkBuffer = (L_UCHAR* )GlobalLock( hWorkBuffer );
/* Invert the colors of pixels in the left half of the rectangle. */
/* Notice that we get the whole rectangle, but process only half of it. */
L_AccessBitmap(pLeadBitmap);
for(i=YOffset; i < (YOffset + YSize); i++)
{
nRet = (L_INT)L_GetBitmapRowColCompressed(pLeadBitmap, pWorkBuffer,
pRunBuffer, i, XOffset, XSize);
if(nRet < 1)
{
L_FreeBitmap(pLeadBitmap);
return nRet;
}
nRet = L_ExpandRow(pRunBuffer, pBuffer, 0, XSize/2);
if(nRet != SUCCESS)
{
L_FreeBitmap(pLeadBitmap);
return nRet;
}
for(n=0; n < (XSize /16); n++)
pBuffer[n] = pBuffer[n] ^ 0xFF;
nRet = L_CompressRow(pRunBuffer, pBuffer, 0, XSize/2);
if(nRet < 1 )
{
L_FreeBitmap(pLeadBitmap);
return nRet;
}
nRet =(L_INT)L_PutBitmapRowColCompressed(pLeadBitmap, pWorkBuffer, pRunBuffer, i,
XOffset, XSize/ 2);
if(nRet < 1)
{
L_FreeBitmap(pLeadBitmap);
return nRet;
}
}
L_ReleaseBitmap(pLeadBitmap);
/* Free memory that we no longer need */
GlobalFree(hBuffer);
GlobalFree(hRunBuffer);
GlobalFree(hWorkBuffer);
/* Update the paint palette to force a repaint */
SendMessage (hWnd, WM_QUERYNEWPALETTE, 0, 0L);
return SUCCESS;
}
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