LBitmapBase::StartDithering
#include "ltwrappr.h"
virtual L_INT LBitmapBase::StartDithering(pPalette, uColors)
LPRGBQUAD pPalette; |
/* pointer to the palette*/ |
L_UINT uColors; |
/* number of colors used in the palette*/ |
Initializes the buffered dithering of a class object's bitmap. The dithering is then carried out by the LBitmapBase::DitherLine function and a callback function that you supply. It is ended by the LBitmapBase::StopDithering function. (Dithering is the process of using error diffusion to reduce the number of colors in an image.)
Parameter |
Description |
pPalette |
Pointer to the palette that the LBitmapBase::DitherLine function will use for dithering. You can specify your own palette, or use NULL for LEAD's fixed palette. |
uColors |
Number of colors used in the palette. If the palette contains more colors, only the first uColors colors are used. Valid values are 2 to 255. |
Returns
SUCCESS |
The function was successful. |
< 1 |
An error occurred. Refer to Return Codes. |
Comments
The following flow chart shows how the functions relate to each other:
Required DLLs and Libraries
LTDIS 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: |
LBitmapBase::DitherLine, LBitmapBase::StopDithering, Class Members |
Topics: |
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Example
This example dithers each line in one bitmap and writes it to another bitmap
L_INT LBitmapBase__StartDitheringExample() { L_INT nRet; LBitmapBase LeadBitmap, TmpBitmap; /* to hold the loaded image */ LBuffer InBuf, OutBuf; RGBQUAD FixedPalette[256]; /* Fixed palette */ int i; /* Loop counter */ /* Load the input bitmap, at 24 bits per pixel */ TmpBitmap.Load (TEXT("C:\\Program Files\\LEAD Technologies, Inc\\LEADTOOLS 15.0\\Images\\IMAGE3.CMP"), 24, ORDER_BGR); /* Create the new bitmap */ LeadBitmap.Create(TmpBitmap.GetWidth(),TmpBitmap.GetHeight(), 8, /* 8 bits per pixel */ 0, /* Color order is not used */ NULL, /* Use the fixed palette */ TmpBitmap.GetViewPerspective()); /* Allocate the input buffer for 24-bit data */ nRet =InBuf.Reallocate(TmpBitmap.GetBytesPerLine()); if(nRet !=SUCCESS) return nRet; /* Allocate the output buffer for 8-bit data */ nRet =OutBuf.Reallocate(TmpBitmap.GetBytesPerLine()); if(nRet !=SUCCESS) return nRet; /* Get the LEAD fixed palette for an 8-bit image */ nRet =TmpBitmap.GetFixedPalette(FixedPalette, 8); if(nRet !=SUCCESS) return nRet; /* Set the dithering method */ TmpBitmap.SetDitheringMethod ( STEVENSON_ARCE_DITHERING); /* Initialize the dithering process */ nRet =TmpBitmap.StartDithering(FixedPalette, 256); if(nRet !=SUCCESS) return nRet; /* Use DitherLine to process each row in the bitmap */ nRet =LeadBitmap.Access(); if(nRet !=SUCCESS) return nRet; nRet =TmpBitmap.Access(); if(nRet !=SUCCESS) return nRet; for(i=0; i < TmpBitmap.GetHeight(); i++) { nRet =(L_INT)TmpBitmap.GetRow(&InBuf, i); if(nRet < 1) return nRet; nRet =TmpBitmap.DitherLine(&InBuf, &OutBuf); if(nRet !=SUCCESS) return nRet; nRet = (L_INT)LeadBitmap.PutRow(OutBuf, i); if(nRet < 1) return nRet; } nRet =TmpBitmap.Release(); if(nRet !=SUCCESS) return nRet; nRet =LeadBitmap.Release(); if(nRet !=SUCCESS) return nRet; /* End the dithering process */ nRet =TmpBitmap.StopDithering(); if(nRet !=SUCCESS) return nRet; return SUCCESS; }