?? libmng_filter.c
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/* ************************************************************************** *//* * For conditions of distribution and use, * *//* * see copyright notice in libmng.h * *//* ************************************************************************** *//* * * *//* * project : libmng * *//* * file : libmng_filter.c copyright (c) 2000 G.Juyn * *//* * version : 1.0.0 * *//* * * *//* * purpose : Filtering routines (implementation) * *//* * * *//* * author : G.Juyn * *//* * web : http://www.3-t.com * *//* * email : mailto:info@3-t.com * *//* * * *//* * comment : implementation of the filtering routines * *//* * * *//* * changes : 0.5.1 - 05/08/2000 - G.Juyn * *//* * - changed strict-ANSI stuff * *//* * 0.5.1 - 05/12/2000 - G.Juyn * *//* * - changed trace to macro for callback error-reporting * *//* * * *//* * 0.9.2 - 08/05/2000 - G.Juyn * *//* * - changed file-prefixes * *//* * * *//* * 0.9.3 - 09/07/2000 - G.Juyn * *//* * - added support for new filter_types * *//* * * *//* ************************************************************************** */#include "libmng.h"#include "libmng_data.h"#include "libmng_error.h"#include "libmng_trace.h"#ifdef __BORLANDC__#pragma hdrstop#endif#include "libmng_filter.h"#if defined(__BORLANDC__) && defined(MNG_STRICT_ANSI)#pragma option -A /* force ANSI-C */#endif/* ************************************************************************** */#ifdef MNG_INCLUDE_FILTERS/* ************************************************************************** */mng_retcode filter_a_row (mng_datap pData){ mng_retcode iRetcode;#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_FILTER_A_ROW, MNG_LC_START)#endif switch (*(pData->pWorkrow + pData->iFilterofs)) { case 1 : { iRetcode = filter_sub (pData); break; } case 2 : { iRetcode = filter_up (pData); break; } case 3 : { iRetcode = filter_average (pData); break; } case 4 : { iRetcode = filter_paeth (pData); break; } default : iRetcode = MNG_INVALIDFILTER; }#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_FILTER_A_ROW, MNG_LC_END)#endif return iRetcode;}/* ************************************************************************** */mng_retcode filter_sub (mng_datap pData){ mng_uint32 iBpp; mng_uint8p pRawx; mng_uint8p pRawx_prev; mng_int32 iX;#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_FILTER_SUB, MNG_LC_START)#endif iBpp = pData->iFilterbpp; pRawx = pData->pWorkrow + pData->iPixelofs + iBpp; pRawx_prev = pData->pWorkrow + pData->iPixelofs; for (iX = iBpp; iX < pData->iRowsize; iX++) { *pRawx = (mng_uint8)(*pRawx + *pRawx_prev); pRawx++; pRawx_prev++; }#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_FILTER_SUB, MNG_LC_END)#endif return MNG_NOERROR;}/* ************************************************************************** */mng_retcode filter_up (mng_datap pData){ mng_uint8p pRawx; mng_uint8p pPriorx; mng_int32 iX;#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_FILTER_UP, MNG_LC_START)#endif pRawx = pData->pWorkrow + pData->iPixelofs; pPriorx = pData->pPrevrow + pData->iPixelofs; for (iX = 0; iX < pData->iRowsize; iX++) { *pRawx = (mng_uint8)(*pRawx + *pPriorx); pRawx++; pPriorx++; }#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_FILTER_UP, MNG_LC_END)#endif return MNG_NOERROR;}/* ************************************************************************** */mng_retcode filter_average (mng_datap pData){ mng_int32 iBpp; mng_uint8p pRawx; mng_uint8p pRawx_prev; mng_uint8p pPriorx; mng_int32 iX;#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_FILTER_AVERAGE, MNG_LC_START)#endif iBpp = pData->iFilterbpp; pRawx = pData->pWorkrow + pData->iPixelofs; pPriorx = pData->pPrevrow + pData->iPixelofs; pRawx_prev = pData->pWorkrow + pData->iPixelofs; for (iX = 0; iX < iBpp; iX++) { *pRawx = (mng_uint8)(*pRawx + ((*pPriorx) >> 1)); pRawx++; pPriorx++; } for (iX = iBpp; iX < pData->iRowsize; iX++) { *pRawx = (mng_uint8)(*pRawx + ((*pRawx_prev + *pPriorx) >> 1)); pRawx++; pPriorx++; pRawx_prev++; }#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_FILTER_AVERAGE, MNG_LC_END)#endif return MNG_NOERROR;}/* ************************************************************************** */mng_retcode filter_paeth (mng_datap pData){ mng_int32 iBpp; mng_uint8p pRawx; mng_uint8p pRawx_prev; mng_uint8p pPriorx; mng_uint8p pPriorx_prev; mng_int32 iX; mng_uint32 iA, iB, iC; mng_uint32 iP; mng_uint32 iPa, iPb, iPc;#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_FILTER_PAETH, MNG_LC_START)#endif iBpp = pData->iFilterbpp; pRawx = pData->pWorkrow + pData->iPixelofs; pPriorx = pData->pPrevrow + pData->iPixelofs; pRawx_prev = pData->pWorkrow + pData->iPixelofs; pPriorx_prev = pData->pPrevrow + pData->iPixelofs; for (iX = 0; iX < iBpp; iX++) { *pRawx = (mng_uint8)(*pRawx + *pPriorx); pRawx++; pPriorx++; } for (iX = iBpp; iX < pData->iRowsize; iX++) { iA = (mng_uint32)*pRawx_prev; iB = (mng_uint32)*pPriorx; iC = (mng_uint32)*pPriorx_prev; iP = iA + iB - iC; iPa = abs (iP - iA); iPb = abs (iP - iB); iPc = abs (iP - iC); if ((iPa <= iPb) && (iPa <= iPc)) *pRawx = (mng_uint8)(*pRawx + iA); else if (iPb <= iPc) *pRawx = (mng_uint8)(*pRawx + iB); else *pRawx = (mng_uint8)(*pRawx + iC); pRawx++; pPriorx++; pRawx_prev++; pPriorx_prev++; }#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_FILTER_PAETH, MNG_LC_END)#endif return MNG_NOERROR;}/* ************************************************************************** *//* ************************************************************************** */mng_retcode init_rowdiffering (mng_datap pData){ mng_uint8p pRawi, pRawo; mng_int32 iX;#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_INIT_ROWDIFFERING, MNG_LC_START)#endif if (pData->iFilter & 0x40) /* has leveling parameters ? */ { switch (pData->iColortype) /* salvage leveling parameters */ { case 0 : { /* gray */ if (pData->iBitdepth <= 8) pData->iLevel0 = (mng_uint16)*pData->pWorkrow; else pData->iLevel0 = mng_get_uint16 (pData->pWorkrow); break; } case 2 : { /* rgb */ if (pData->iBitdepth <= 8) { pData->iLevel0 = (mng_uint16)*pData->pWorkrow; pData->iLevel1 = (mng_uint16)*(pData->pWorkrow+1); pData->iLevel2 = (mng_uint16)*(pData->pWorkrow+2); } else { pData->iLevel0 = mng_get_uint16 (pData->pWorkrow); pData->iLevel1 = mng_get_uint16 (pData->pWorkrow+2); pData->iLevel2 = mng_get_uint16 (pData->pWorkrow+4); } break; } case 3 : { /* indexed */ pData->iLevel0 = (mng_uint16)*pData->pWorkrow; break; } case 4 : { /* gray+alpha */ if (pData->iBitdepth <= 8) { pData->iLevel0 = (mng_uint16)*pData->pWorkrow; pData->iLevel1 = (mng_uint16)*(pData->pWorkrow+1); } else { pData->iLevel0 = mng_get_uint16 (pData->pWorkrow); pData->iLevel1 = mng_get_uint16 (pData->pWorkrow+2); } break; } case 6 : { /* rgb+alpha */ if (pData->iBitdepth <= 8) { pData->iLevel0 = (mng_uint16)*pData->pWorkrow; pData->iLevel1 = (mng_uint16)*(pData->pWorkrow+1); pData->iLevel2 = (mng_uint16)*(pData->pWorkrow+2); pData->iLevel3 = (mng_uint16)*(pData->pWorkrow+3); } else { pData->iLevel0 = mng_get_uint16 (pData->pWorkrow); pData->iLevel1 = mng_get_uint16 (pData->pWorkrow+2); pData->iLevel2 = mng_get_uint16 (pData->pWorkrow+4); pData->iLevel3 = mng_get_uint16 (pData->pWorkrow+6); } break; } } } /* shift the entire row back in place */ pRawi = pData->pWorkrow + pData->iFilterofs; pRawo = pData->pWorkrow; for (iX = 0; iX < pData->iRowsize + pData->iPixelofs - pData->iFilterofs; iX++) *pRawo++ = *pRawi++; pData->iFilterofs = 0; /* indicate so ! */ if (pData->iFilter & 0x01) /* no adaptive filtering ? */ pData->iPixelofs = pData->iFilterofs; else pData->iPixelofs = pData->iFilterofs + 1;#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_INIT_ROWDIFFERING, MNG_LC_END)#endif return MNG_NOERROR;}/* ************************************************************************** */mng_retcode differ_g1 (mng_datap pData){ mng_uint8p pRawi, pRawo; mng_int32 iX;#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_DIFFER_G1, MNG_LC_START)#endif if (pData->iLevel0 & 0x01) /* is it uneven level ? */ { pRawi = pData->pWorkrow + pData->iPixelofs; pRawo = pData->pPrevrow + pData->iPixelofs; /* just invert every bit */ for (iX = 0; iX < pData->iRowsize; iX++) *pRawo++ = (mng_uint8)(~(*pRawi++)); }#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_DIFFER_G1, MNG_LC_END)#endif return MNG_NOERROR;}/* ************************************************************************** */mng_retcode differ_g2 (mng_datap pData){ mng_uint8p pRawi, pRawo; mng_int32 iX; mng_int32 iC, iS; mng_uint8 iB, iN, iQ;#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_DIFFER_G2, MNG_LC_START)#endif pRawi = pData->pWorkrow + pData->iPixelofs; pRawo = pData->pPrevrow + pData->iPixelofs; iC = 0; iB = 0; iN = 0; iS = 0; for (iX = 0; iX < pData->iRowsamples; iX++) { if (!iC) { iC = 4; iB = *pRawi++; iN = 0; iS = 8; } iS -= 2; iQ = (mng_uint8)(((iB >> iS) + pData->iLevel0) & 0x03); iN = (mng_uint8)((iN << 2) + iQ); iC--; if (!iC) *pRawo++ = iN; } if (iC) *pRawo = (mng_uint8)(iN << iS);#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_DIFFER_G2, MNG_LC_END)#endif return MNG_NOERROR;}/* ************************************************************************** */mng_retcode differ_g4 (mng_datap pData){ mng_uint8p pRawi, pRawo; mng_int32 iX; mng_int32 iC, iS; mng_uint8 iB, iN, iQ;#ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_DIFFER_G4, MNG_LC_START)#endif pRawi = pData->pWorkrow + pData->iPixelofs; pRawo = pData->pPrevrow + pData->iPixelofs; iC = 0; iB = 0; iN = 0; iS = 0;?? 快捷鍵說明
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