图像拉伸，放大缩小算法函数
平滑放大缩小拉伸图像，本函数同时具有很高的效率。
其中BITMAP24结构和BITMAP 结构类似，在这里你可以假设两者相同。
pMapX,pMapY用于建立积卷映射表，同时将浮点运算转换成浮点运算。
其中BITMAP24结构和BITMAP 结构类似，在这里你可以假设两者相同。
pMapX,pMapY用于建立积卷映射表，同时将浮点运算转换成浮点运算。
- void ImageStretch(BITMAP24 & dest,const BITMAP24 & src)
- {
- ASSERT(dest.bmWidth>0 && dest.bmHeight>0);
- ASSERT(src.bmWidth>0 && src.bmHeight>0);
- double fZoomX = (double)dest.bmWidth/(double)src.bmWidth;
- double fZoomY = (double)dest.bmHeight/(double)src.bmHeight;
- LONG i;
- POINTMAP * pMapX;
- POINTMAP * pMapY;
- double fMin,fMax;
- pMapX = CImageDataMgr::instance().AllocXPointMap(dest.bmWidth);
- pMapY = CImageDataMgr::instance().AllocYPointMap(dest.bmHeight);
- // 初始化pMapX
- if (fZoomX<1.0f)
- {
- for (i=0;i
- {
- fMin = i/fZoomX;
- fMax = (i+1)/fZoomX;
- pMapX[i].ps = (int)fMin;
- pMapX[i].pe = (int)fMax;
- if (pMapX[i].ps>=src.bmWidth) pMapX[i].ps=src.bmWidth-1;
- if (pMapX[i].pe>=src.bmWidth) pMapX[i].pe=src.bmWidth-1;
- pMapX[i].ws = (int)((pMapX[i].ps+1.0f-fMin)*fZoomX*256);
- pMapX[i].we = (int)((fMax-pMapX[i].pe)*fZoomX*256);
- pMapX[i].wi = 256-pMapX[i].ws-pMapX[i].we;
- }
- } else if (fZoomX==1.0f)
- {
- for (i=0;i
- {
- pMapX[i].ps = i;
- pMapX[i].pe = i;
- pMapX[i].ws = 256;
- pMapX[i].we = 0;
- }
- } else if (fZoomX>1.0f)
- {
- for (i=0;i
- {
- fMin = i/fZoomX;
- pMapX[i].ps = (LONG)fMin;
- pMapX[i].pe = pMapX[i].ps+1;
- if (pMapX[i].ps>=src.bmWidth) pMapX[i].ps=src.bmWidth-1;
- if (pMapX[i].pe>=src.bmWidth) pMapX[i].pe=src.bmWidth-1;
- fMin -= pMapX[i].ps;
- pMapX[i].we = (LONG)(fMin * 256);
- pMapX[i].ws = 256 - pMapX[i].we;
- }
- }
- // 初始化pMapY
- if (fZoomY<1.0f)
- {
- for (i=0;i
- {
- fMin = i/fZoomY;
- fMax = (i+1)/fZoomY;
- pMapY[i].ps = (int)fMin;
- pMapY[i].pe = (int)fMax;
- if (pMapY[i].ps>=src.bmHeight) pMapY[i].ps=src.bmHeight-1;
- if (pMapY[i].pe>=src.bmHeight) pMapY[i].pe=src.bmHeight-1;
- pMapY[i].ws = (int)((pMapY[i].ps+1.0f-fMin)*fZoomY*256);
- pMapY[i].we = (int)((fMax-pMapY[i].pe)*fZoomY*256);
- pMapY[i].wi = 256-pMapY[i].ws-pMapY[i].we;
- }
- } else if (fZoomY==1.0f)
- {
- for (i=0;i
- {
- pMapY[i].ps = i;
- pMapY[i].pe = i;
- pMapY[i].ws = 256;
- pMapY[i].we = 0;
- }
- } else if (fZoomY>1.0f)
- {
- for (i=0;i
- {
- fMin = i/fZoomY;
- pMapY[i].ps = (LONG)fMin;
- pMapY[i].pe = pMapY[i].ps+1;
- if (pMapY[i].ps>=src.bmWidth) pMapY[i].ps=src.bmWidth-1;
- if (pMapY[i].pe>=src.bmWidth) pMapY[i].pe=src.bmWidth-1;
- fMin -= pMapY[i].ps;
- pMapY[i].we = (LONG)(fMin * 256);
- pMapY[i].ws = 256 - pMapY[i].we;
- }
- }
- LONG xd,yd;
- LONG ld,pd;
- LONG ls, ps,pe,pi;
- LONG psY,peY,psX,peX;
- LONG wsY,weY,wiY;
- LONG wsX,weX,wiX;
- LONG rvs, gvs, bvs;
- LONG rve, gve, bve;
- LONG rvi, gvi, bvi;
- LONG rv, gv, bv;
- BYTE * bsDest = dest.bmBits;
- BYTE * bsSrc = src.bmBits;
- LONG xi,yi;
- ld = 0;
- for (yd=0;yd
- {
- psY = pMapY[yd].ps;
- peY = pMapY[yd].pe;
- wsY = pMapY[yd].ws;
- weY = pMapY[yd].we;
- wiY = pMapY[yd].wi;
- pd = ld;
- for (xd=0;xd
- {
- psX = pMapX[xd].ps;
- peX = pMapX[xd].pe;
- wsX = pMapX[xd].ws;
- weX = pMapX[xd].we;
- wiX = pMapX[xd].wi;
- if (psY==peY)
- {
- ls = src.bmWidthBytes * psY;
- ps = ls + psX * 3;
- if (psX==peX)
- {
- bsDest[pd] = bsSrc[ps];
- bsDest[pd+1] = bsSrc[ps+1];
- bsDest[pd+2] = bsSrc[ps+2];
- } else if (peX-1==psX)
- {
- pe = ps + 3;
- bsDest[pd] = (BYTE)((bsSrc[ps] * wsX
- + bsSrc[pe] * weX)>>8);
- bsDest[pd+1] = (BYTE)((bsSrc[ps+1] * wsX
- + bsSrc[pe+1] * weX)>>8);
- bsDest[pd+2] = (BYTE)((bsSrc[ps+2] * wsX
- + bsSrc[pe+2] * weX)>>8);
- } else {
- bv = 0, gv = 0, rv = 0;
- pi = ps +3;
- for (xi = psX+1;xi
- {
- bv += bsSrc[pi];
- gv += bsSrc[pi+1];
- rv += bsSrc[pi+2];
- pi +=3;
- }
- bv = bv*wiX/(peX-psX-1);
- gv = gv*wiX/(peX-psX-1);
- rv = rv*wiX/(peX-psX-1);
- bv += bsSrc[ps] * wsX;
- gv += bsSrc[ps+1] * wsX;
- rv += bsSrc[ps+2] * wsX;
- pe = ls + peX * 3;
- bv += bsSrc[pe] * weX;
- gv += bsSrc[pe+1] * weX;
- rv += bsSrc[pe+2] * weX;
- bsDest[pd] = (BYTE)(bv>>8);
- bsDest[pd+1] = (BYTE)(gv>>8);
- bsDest[pd+2] = (BYTE)(rv>>8);
- }
- } else if (peY-1==psY)
- {
- ls = src.bmWidthBytes * psY;
- ps = ls + psX * 3;
- if (psX==peX)
- {
- bv = bsSrc[ps];
- gv = bsSrc[ps+1];
- rv = bsSrc[ps+2];
- } else if (peX-1==psX)
- {
- pe = ps + 3;
- bv = (BYTE)((bsSrc[ps] * wsX
- + bsSrc[pe] * weX)>>8);
- gv = (BYTE)((bsSrc[ps+1] * wsX
- + bsSrc[pe+1] * weX)>>8);
- rv = (BYTE)((bsSrc[ps+2] * wsX
- + bsSrc[pe+2] * weX)>>8);
- } else {
- bv = 0, gv = 0, rv = 0;
- pi = ps +3;
- for (xi = psX+1;xi
- {
- bv += bsSrc[pi];
- gv += bsSrc[pi+1];
- rv += bsSrc[pi+2];
- pi +=3;
- }
- bv = bv*wiX/(peX-psX-1);
- gv = gv*wiX/(peX-psX-1);
- rv = rv*wiX/(peX-psX-1);
- bv += bsSrc[ps] * wsX;
- gv += bsSrc[ps+1] * wsX;
- rv += bsSrc[ps+2] * wsX;
- pe = ls + peX * 3;
- bv += bsSrc[pe] * weX;
- gv += bsSrc[pe+1] * weX;
- rv += bsSrc[pe+2] * weX;
- bv = bv>>8;
- gv = gv>>8;
- rv = rv>>8;
- }
- bvs = bv;
- gvs = gv;
- rvs = rv;
- ls = peY * src.bmWidthBytes;
- ps = ls + psX * 3;
- if (psX==peX)
- {
- bv = bsSrc[ps];
- gv = bsSrc[ps+1];
- rv = bsSrc[ps+2];
- } else if (peX-1==psX)
- {
- pe = ps + 3;
- bv = (BYTE)((bsSrc[ps] * wsX
- + bsSrc[pe] * weX)>>8);
- gv = (BYTE)((bsSrc[ps+1] * wsX
- + bsSrc[pe+1] * weX)>>8);
- rv = (BYTE)((bsSrc[ps+2] * wsX
- + bsSrc[pe+2] * weX)>>8);
- } else {
- bv = 0, gv = 0, rv = 0;
- pi = ps +3;
- for (xi = psX+1;xi
- {
- bv += bsSrc[pi];
- gv += bsSrc[pi+1];
- rv += bsSrc[pi+2];
- pi +=3;
- }
- bv = bv*wiX/(peX-psX-1);
- gv = gv*wiX/(peX-psX-1);
- rv = rv*wiX/(peX-psX-1);
- bv += bsSrc[ps] * wsX;
- gv += bsSrc[ps+1] * wsX;
- rv += bsSrc[ps+2] * wsX;
- pe = ls + peX * 3;
- bv += bsSrc[pe] * weX;
- gv += bsSrc[pe+1] * weX;
- rv += bsSrc[pe+2] * weX;
- bv = bv>>8;
- gv = gv>>8;
- rv = rv>>8;
- }
- bve = bv;
- gve = gv;
- rve = rv;
- bsDest[pd] = (BYTE)((bvs * wsY + bve * weY)>>8);
- bsDest[pd+1] = (BYTE)((gvs * wsY + gve * weY)>>8);
- bsDest[pd+2] = (BYTE)((rvs * wsY + rve * weY)>>8);
- } else {
- // 计算中间部分 bvi;
- bvi = 0, gvi = 0, rvi = 0;
- for (yi = psY+1; yi
- {
- ls = src.bmWidthBytes * yi;
- ps = ls + psX * 3;
- if (psX==peX)
- {
- bv = bsSrc[ps];
- gv = bsSrc[ps+1];
- rv = bsSrc[ps+2];
- } else if (peX-1==psX)
- {
- pe = ps + 3;
- bv = (BYTE)((bsSrc[ps] * wsX
- + bsSrc[pe] * weX)>>8);
- gv = (BYTE)((bsSrc[ps+1] * wsX
- + bsSrc[pe+1] * weX)>>8);
- rv = (BYTE)((bsSrc[ps+2] * wsX
- + bsSrc[pe+2] * weX)>>8);
- } else {
- bv = 0, gv = 0, rv = 0;
- pi = ps +3;
- for (xi = psX+1;xi
- {
- bv += bsSrc[pi];
- gv += bsSrc[pi+1];
- rv += bsSrc[pi+2];
- pi +=3;
- }
- bv = bv*wiX/(peX-psX-1);
- gv = gv*wiX/(peX-psX-1);
- rv = rv*wiX/(peX-psX-1);
- bv += bsSrc[ps] * wsX;
- gv += bsSrc[ps+1] * wsX;
- rv += bsSrc[ps+2] * wsX;
- pe = ls + peX * 3;
- bv += bsSrc[pe] * weX;
- gv += bsSrc[pe+1] * weX;
- rv += bsSrc[pe+2] * weX;
- bv = bv>>8;
- gv = gv>>8;
- rv = rv>>8;
- }
- bvi += bv;
- gvi += gv;
- rvi += rv;
- }
- // 计算vs
- ls = src.bmWidthBytes * psY;
- ps = ls + psX * 3;
- if (psX==peX)
- {
- bv = bsSrc[ps];
- gv = bsSrc[ps+1];
- rv = bsSrc[ps+2];
- } else if (peX-1==psX)
- {
- pe = ps + 3;
- bv = (BYTE)((bsSrc[ps] * wsX
- + bsSrc[pe] * weX)>>8);
- gv = (BYTE)((bsSrc[ps+1] * wsX
- + bsSrc[pe+1] * weX)>>8);
- rv = (BYTE)((bsSrc[ps+2] * wsX
- + bsSrc[pe+2] * weX)>>8);
- } else {
- bv = 0, gv = 0, rv = 0;
- pi = ps +3;
- for (xi = psX+1;xi
- {
- bv += bsSrc[pi];
- gv += bsSrc[pi+1];
- rv += bsSrc[pi+2];
- pi +=3;
- }
- bv = bv*wiX/(peX-psX-1);
- gv = gv*wiX/(peX-psX-1);
- rv = rv*wiX/(peX-psX-1);
- bv += bsSrc[ps] * wsX;
- gv += bsSrc[ps+1] * wsX;
- rv += bsSrc[ps+2] * wsX;
- pe = ls + peX * 3;
- bv += bsSrc[pe] * weX;
- gv += bsSrc[pe+1] * weX;
- rv += bsSrc[pe+2] * weX;
- bv = bv>>8;
- gv = gv>>8;
- rv = rv>>8;
- }
- bvs = bv;
- gvs = gv;
- rvs = rv;
- ls = src.bmWidthBytes * peY;
- ps = ls + psX * 3;
- if (psX==peX)
- {
- bv = bsSrc[ps];
- gv = bsSrc[ps+1];
- rv = bsSrc[ps+2];
- } else if (peX-1==psX)
- {
- pe = ps + 3;
- bv = (BYTE)((bsSrc[ps] * wsX
- + bsSrc[pe] * weX)>>8);
- gv = (BYTE)((bsSrc[ps+1] * wsX
- + bsSrc[pe+1] * weX)>>8);
- rv = (BYTE)((bsSrc[ps+2] * wsX
- + bsSrc[pe+2] * weX)>>8);
- } else {
- bv = 0, gv = 0, rv = 0;
- pi = ps +3;
- for (xi = psX+1;xi
- {
- bv += bsSrc[pi];
- gv += bsSrc[pi+1];
- rv += bsSrc[pi+2];
- pi +=3;
- }
- bv = bv*wiX/(peX-psX-1);
- gv = gv*wiX/(peX-psX-1);
- rv = rv*wiX/(peX-psX-1);
- bv += bsSrc[ps] * wsX;
- gv += bsSrc[ps+1] * wsX;
- rv += bsSrc[ps+2] * wsX;
- pe = ls + peX * 3;
- bv += bsSrc[pe] * weX;
- gv += bsSrc[pe+1] * weX;
- rv += bsSrc[pe+2] * weX;
- bv = bv>>8;
- gv = gv>>8;
- rv = rv>>8;
- }
- bve = bv;
- gve = gv;
- rve = rv;
- bv = bvs * wsY + bvi * wiY / (peY - psY -1) + bve * weY;
- gv = gvs * wsY + gvi * wiY / (peY - psY -1) + gve * weY;
- rv = rvs * wsY + rvi * wiY / (peY - psY -1) + rve * weY;
- bsDest[pd] = (BYTE)(bv>>8);
- bsDest[pd+1] = (BYTE)(gv>>8);
- bsDest[pd+2] = (BYTE)(rv>>8);
- }
- pd += 3;
- }
- ld += dest.bmWidthBytes;
- }
- }