void?DrawWuLine（?CDC?*pDC?int?X0?int?Y0?int?X1?int?Y1?COLORREF?clrLine?）//clrline表示要畫線的顏色?
{????pDC->SetPixel（?X0?Y0?clrLine?）;????
????int?XDir?DeltaX?=?X1?-?X0;?
????if（?DeltaX?>=?0?）????{?
????????XDir?=?1;????}?
????else????{?
????????XDir??=?-1;?
????????DeltaX?=?0?-?DeltaX;?/*?make?DeltaX?positive?*/?
????}?
????XDir?=?1;?
??????????unsigned?short?ErrorAdj;?
????unsigned?short?ErrorAccTemp?Weighting;?
????
????/*?Line?is?not?horizontal?diagonal?or?vertical?*/?
????unsigned?short?ErrorAcc?=?0;??/*?initialize?the?line?error?accumulator?to?0?*/?
????
????BYTE?rl?=?GetRValue（?clrLine?）;?
????BYTE?gl?=?GetGValue（?clrLine?）;?
????BYTE?bl?=?GetBValue（?clrLine?）;?
????double?grayl?=?rl?*?0.299?+?gl?*?0.587?+?bl?*?0.114;?
????
????/*?Is?this?an?X-major?or?Y-major?line??*/?
????if?（DeltaY?>?DeltaX）?
????{?
????/*?Y-major?line;?calculate?16-bit?fixed-point?fractional?part?of?a?
????pixel?that?X?advances?each?time?Y?advances?1?pixel?truncating?the?
????????result?so?that?we?won‘t?overrun?the?endpoint?along?the?X?axis?*/?
????????ErrorAdj?=?（（unsigned?long）?DeltaX?????????/*?Draw?all?pixels?other?than?the?first?and?last?*/?
????????while?（--DeltaY）?{?
????????????ErrorAccTemp?=?ErrorAcc;??/*?remember?currrent?accumulated?error?*/?
????????????ErrorAcc?+=?ErrorAdj;??????/*?calculate?error?for?next?pixel?*/?
????????????if?（ErrorAcc?<=?ErrorAccTemp）?
{?
????????????????/*?The?error?accumulator?turned?over?so?advance?the?X?coord?*/?
????????????????X0?+=?XDir;?
????????????}?
????????????Y0++;?/*?Y-major?so?always?advance?Y?*/?
??????????????????/*?The?IntensityBits?most?significant?bits?of?ErrorAcc?give?us?the?
??????????????????intensity?weighting?for?this?pixel?and?the?complement?of?the?
????????????weighting?for?the?paired?pixel?*/?
????????????Weighting?=?ErrorAcc?>>?8;?
????????????ASSERT（?Weighting?????????????ASSERT（?（?Weighting?^?255?）?????????????
????????????COLORREF?clrBackGround?=?::GetPixel（?pDC->m_hDC?X0?Y0?）;?
????????????BYTE?rb?=?GetRValue（?clrBackGround?）;?
????????????BYTE?gb?=?GetGValue（?clrBackGround?）;?
????????????BYTE?bb?=?GetBValue（?clrBackGround?）;?
????????????double?grayb?=?rb?*?0.299?+?gb?*?0.587?+?bb?*?0.114;?
????????????
????????????BYTE?rr?=?（?rb?>?rl???（?（?BYTE?）（?（?（?double?）（?grayl?????????????BYTE?gr?=?（?gb?>?gl???（?（?BYTE?）（?（?（?double?）（?grayl?????????????BYTE?br?=?（?bb?>?bl???（?（?BYTE?）（?（?（?double?）（?grayl?