本文实例汇总了Delphi基本图像处理方法。分享给大家供大家参考。具体分析如下：
//浮雕 procedure Emboss(SrcBmp,DestBmp:TBitmap;AzimuthChange:integer);overload; var i, j, Gray, Azimuthvalue, R, G, B: integer; SrcRGB, SrcRGB1, SrcRGB2, DestRGB: pRGBTriple; begin for i := 0 to SrcBmp.Height - 1 do begin SrcRGB := SrcBmp.ScanLine[i]; DestRGB := DestBmp.ScanLine[i]; if (AzimuthChange >= -180) and (AzimuthChange < -135) then begin if i > 0 then SrcRGB1 := SrcBmp.ScanLine[i-1] else SrcRGB1 := SrcRGB; Inc(SrcRGB1); SrcRGB2 := SrcRGB; Inc(SrcRGB2); end else if (AzimuthChange >= -135) and (AzimuthChange < -90) then begin if i > 0 then SrcRGB1 := SrcBmp.ScanLine[i-1] else SrcRGB1 := SrcRGB; SrcRGB2 := SrcRGB1; Inc(SrcRGB2); end else if (AzimuthChange >= -90) and (AzimuthChange < -45) then begin if i > 0 then SrcRGB1 := SrcBmp.ScanLine[i-1] else SrcRGB1 := SrcRGB; SrcRGB2 := SrcRGB1; end else if (AzimuthChange >= -45) and (AzimuthChange < 0) then begin SrcRGB1 := SrcRGB; if i > 0 then SrcRGB2 := SrcBmp.ScanLine[i-1] else SrcRGB2 := SrcRGB; end else if (AzimuthChange >= 0) and (AzimuthChange < 45) then begin SrcRGB2 := SrcRGB; if (i < SrcBmp.Height - 1) then SrcRGB1 := SrcBmp.ScanLine[i+1] else SrcRGB1 := SrcRGB; end else if (AzimuthChange >= 45) and (AzimuthChange < 90) then begin if (i < SrcBmp.Height - 1) then SrcRGB1 := SrcBmp.ScanLine[i+1] else SrcRGB1 := SrcRGB; SrcRGB2 := SrcRGB1; end else if (AzimuthChange >= 90) and (AzimuthChange < 135) then begin if (i < SrcBmp.Height - 1) then SrcRGB1 := SrcBmp.ScanLine[i+1] else SrcRGB1 := SrcRGB; SrcRGB2 := SrcRGB1; Inc(SrcRGB1); end else if (AzimuthChange >= 135) and (AzimuthChange <= 180) then begin if (i < SrcBmp.Height - 1) then SrcRGB2 := SrcBmp.ScanLine[i+1] else SrcRGB2 := SrcRGB; Inc(SrcRGB2); SrcRGB1 := SrcRGB; Inc(SrcRGB1); end; for j := 0 to SrcBmp.Width - 1 do begin if (AzimuthChange >= -180) and (AzimuthChange < -135) then begin Azimuthvalue := AzimuthChange + 180; R:=SrcRGB.rgbtRed-((SrcRGB1.rgbtRed)*Azimuthvalue div 45)-((SrcRGB2.rgbtRed)*(45-Azimuthvalue) div 45)+78; G:=SrcRGB.rgbtGreen-((SrcRGB1.rgbtGreen)*Azimuthvalue div 45)-((SrcRGB2.rgbtGreen)*(45-Azimuthvalue) div 45)+78; B:=SrcRGB.rgbtBlue-((SrcRGB1.rgbtBlue)*Azimuthvalue div 45)-((SrcRGB2.rgbtBlue)*(45-Azimuthvalue) div 45)+78; end else if (AzimuthChange >= -135) and (AzimuthChange < -90) then begin Azimuthvalue := AzimuthChange + 135; R:=SrcRGB.rgbtRed-((SrcRGB1.rgbtRed)*Azimuthvalue div 45)-((SrcRGB2.rgbtRed)*(45-Azimuthvalue) div 45)+78; G:=SrcRGB.rgbtGreen-((SrcRGB1.rgbtGreen)*Azimuthvalue div 45)-((SrcRGB2.rgbtGreen)*(45-Azimuthvalue) div 45)+78; B:=SrcRGB.rgbtBlue-((SrcRGB1.rgbtBlue)*Azimuthvalue div 45)-((SrcRGB2.rgbtBlue)*(45-Azimuthvalue) div 45)+78; end else if (AzimuthChange >= -90) and (AzimuthChange < -45) then begin if j=1 then Inc(SrcRGB1,-1); Azimuthvalue := AzimuthChange + 90; R:=SrcRGB.rgbtRed-((SrcRGB1.rgbtRed)*Azimuthvalue div 45)-((SrcRGB2.rgbtRed)*(45-Azimuthvalue) div 45)+78; G:=SrcRGB.rgbtGreen-((SrcRGB1.rgbtGreen)*Azimuthvalue div 45)-((SrcRGB2.rgbtGreen)*(45-Azimuthvalue) div 45)+78; B:=SrcRGB.rgbtBlue-((SrcRGB1.rgbtBlue)*Azimuthvalue div 45)-((SrcRGB2.rgbtBlue)*(45-Azimuthvalue) div 45)+78; end else if (AzimuthChange >= -45) and (AzimuthChange < 0) then begin if j=1 then begin Inc(SrcRGB1,-1); Inc(SrcRGB2,-1); end; Azimuthvalue := AzimuthChange + 45; R:=SrcRGB.rgbtRed-((SrcRGB1.rgbtRed)*Azimuthvalue div 45)-((SrcRGB2.rgbtRed)*(45-Azimuthvalue) div 45)+78; G:=SrcRGB.rgbtGreen-((SrcRGB1.rgbtGreen)*Azimuthvalue div 45)-((SrcRGB2.rgbtGreen)*(45-Azimuthvalue) div 45)+78; B:=SrcRGB.rgbtBlue-((SrcRGB1.rgbtBlue)*Azimuthvalue div 45)-((SrcRGB2.rgbtBlue)*(45-Azimuthvalue) div 45)+78; end else if (AzimuthChange >= 0) and (AzimuthChange < 45) then begin if j=1 then begin Inc(SrcRGB1,-1); Inc(SrcRGB2,-1); end; Azimuthvalue := AzimuthChange; R:=SrcRGB.rgbtRed-((SrcRGB1.rgbtRed)*Azimuthvalue div 45)-((SrcRGB2.rgbtRed)*(45-Azimuthvalue) div 45)+78; G:=SrcRGB.rgbtGreen-((SrcRGB1.rgbtGreen)*Azimuthvalue div 45)-((SrcRGB2.rgbtGreen)*(45-Azimuthvalue) div 45)+78; B:=SrcRGB.rgbtBlue-((SrcRGB1.rgbtBlue)*Azimuthvalue div 45)-((SrcRGB2.rgbtBlue)*(45-Azimuthvalue) div 45)+78; end else if (AzimuthChange >= 45) and (AzimuthChange < 90) then begin if j=1 then Inc(SrcRGB2,-1); Azimuthvalue := AzimuthChange - 45; R:=SrcRGB.rgbtRed-((SrcRGB1.rgbtRed)*Azimuthvalue div 45)-((SrcRGB2.rgbtRed)*(45-Azimuthvalue) div 45)+78; G:=SrcRGB.rgbtGreen-((SrcRGB1.rgbtGreen)*Azimuthvalue div 45)-((SrcRGB2.rgbtGreen)*(45-Azimuthvalue) div 45)+78; B:=SrcRGB.rgbtBlue-((SrcRGB1.rgbtBlue)*Azimuthvalue div 45)-((SrcRGB2.rgbtBlue)*(45-Azimuthvalue) div 45)+78; end else if (AzimuthChange >= 90) and (AzimuthChange < 135) then begin Azimuthvalue := AzimuthChange - 90; R:=SrcRGB.rgbtRed-((SrcRGB1.rgbtRed)*Azimuthvalue div 45)-((SrcRGB2.rgbtRed)*(45-Azimuthvalue) div 45)+78; G:=SrcRGB.rgbtGreen-((SrcRGB1.rgbtGreen)*Azimuthvalue div 45)-((SrcRGB2.rgbtGreen)*(45-Azimuthvalue) div 45)+78; B:=SrcRGB.rgbtBlue-((SrcRGB1.rgbtBlue)*Azimuthvalue div 45)-((SrcRGB2.rgbtBlue)*(45-Azimuthvalue) div 45)+78; end else if (AzimuthChange >= 135) and (AzimuthChange <= 180) then begin Azimuthvalue := AzimuthChange - 135; R:=SrcRGB.rgbtRed-((SrcRGB1.rgbtRed)*Azimuthvalue div 45)-((SrcRGB2.rgbtRed)*(45-Azimuthvalue) div 45)+78; G:=SrcRGB.rgbtGreen-((SrcRGB1.rgbtGreen)*Azimuthvalue div 45)-((SrcRGB2.rgbtGreen)*(45-Azimuthvalue) div 45)+78; B:=SrcRGB.rgbtBlue-((SrcRGB1.rgbtBlue)*Azimuthvalue div 45)-((SrcRGB2.rgbtBlue)*(45-Azimuthvalue) div 45)+78; end; R:=Min(R,255); R:=Max(R,0); G:=Min(G,255); G:=Max(G,0); B:=Min(B,255); B:=Max(B,0); Gray := (R shr 2) + (R shr 4) + (G shr 1) + (G shr 4) + (B shr 3); DestRGB.rgbtRed:=Gray; DestRGB.rgbtGreen:=Gray; DestRGB.rgbtBlue:=Gray; if (j=-180) and (AzimuthChange<-135)) or ((AzimuthChange>=90) and (AzimuthChange<=180))) then begin Inc(SrcRGB1); end; if (j=135) and (AzimuthChange<180)) or ((AzimuthChange>=-180) and (AzimuthChange<=-90))) then begin Inc(SrcRGB2); end; Inc(SrcRGB); Inc(DestRGB); end; end; end; procedure Emboss(Bmp:TBitmap;AzimuthChange:integer;ElevationChange:integer;WeightChange:integer);overload; var DestBmp:TBitmap; begin DestBmp:=TBitmap.Create; DestBmp.Assign(Bmp); Emboss(Bmp,DestBmp,AzimuthChange,ElevationChange,WeightChange); Bmp.Assign(DestBmp); end; //反色 procedure Negative(Bmp:TBitmap); var i, j: Integer; PRGB: pRGBTriple; begin Bmp.PixelFormat:=pf24Bit; for i := 0 to Bmp.Height - 1 do begin PRGB := Bmp.ScanLine[i]; for j := 0 to Bmp.Width - 1 do begin PRGB^.rgbtRed :=not PRGB^.rgbtRed ; PRGB^.rgbtGreen :=not PRGB^.rgbtGreen; PRGB^.rgbtBlue :=not PRGB^.rgbtBlue; Inc(PRGB); end; end; end; //曝光 procedure Exposure(Bmp:TBitmap); var i, j: integer; PRGB: pRGBTriple; begin Bmp.PixelFormat:=pf24Bit; for i := 0 to Bmp.Height - 1 do begin PRGB := Bmp.ScanLine[i]; for j := 0 to Bmp.Width - 1 do begin if PRGB^.rgbtRed<128 then PRGB^.rgbtRed :=not PRGB^.rgbtRed ; if PRGB^.rgbtGreen<128 then PRGB^.rgbtGreen :=not PRGB^.rgbtGreen; if PRGB^.rgbtBlue<128 then PRGB^.rgbtBlue :=not PRGB^.rgbtBlue; Inc(PRGB); end; end; end; //模糊 procedure Blur(SrcBmp:TBitmap); var i, j:Integer; SrcRGB:pRGBTriple; SrcNextRGB:pRGBTriple; SrcPreRGB:pRGBTriple; Value:Integer; procedure IncRGB; begin Inc(SrcPreRGB); Inc(SrcRGB); Inc(SrcNextRGB); end; procedure DecRGB; begin Inc(SrcPreRGB,-1); Inc(SrcRGB,-1); Inc(SrcNextRGB,-1); end; begin SrcBmp.PixelFormat:=pf24Bit; for i := 0 to SrcBmp.Height - 1 do begin if i > 0 then SrcPreRGB:=SrcBmp.ScanLine[i-1] else SrcPreRGB := SrcBmp.ScanLine[i]; SrcRGB := SrcBmp.ScanLine[i]; if i < SrcBmp.Height - 1 then SrcNextRGB:=SrcBmp.ScanLine[i+1] else SrcNextRGB:=SrcBmp.ScanLine[i]; for j := 0 to SrcBmp.Width - 1 do begin if j > 0 then DecRGB; Value:=SrcPreRGB.rgbtRed+SrcRGB.rgbtRed+SrcNextRGB.rgbtRed; if j > 0 then IncRGB; Value:=Value+SrcPreRGB.rgbtRed+SrcRGB.rgbtRed+SrcNextRGB.rgbtRed; if j < SrcBmp.Width - 1 then IncRGB; Value:=(Value+SrcPreRGB.rgbtRed+SrcRGB.rgbtRed+SrcNextRGB.rgbtRed) div 9; DecRGB; SrcRGB.rgbtRed:=value; if j > 0 then DecRGB; Value:=SrcPreRGB.rgbtGreen+SrcRGB.rgbtGreen+SrcNextRGB.rgbtGreen; if j > 0 then IncRGB; Value:=Value+SrcPreRGB.rgbtGreen+SrcRGB.rgbtGreen+SrcNextRGB.rgbtGreen; if j < SrcBmp.Width - 1 then IncRGB; Value:=(Value+SrcPreRGB.rgbtGreen+SrcRGB.rgbtGreen+SrcNextRGB.rgbtGreen) div 9; DecRGB; SrcRGB.rgbtGreen:=value; if j > 0 then DecRGB; Value:=SrcPreRGB.rgbtBlue+SrcRGB.rgbtBlue+SrcNextRGB.rgbtBlue; if j > 0 then IncRGB; Value:=Value+SrcPreRGB.rgbtBlue+SrcRGB.rgbtBlue+SrcNextRGB.rgbtBlue; if j < SrcBmp.Width - 1 then IncRGB; Value:=(Value+SrcPreRGB.rgbtBlue+SrcRGB.rgbtBlue+SrcNextRGB.rgbtBlue) div 9; DecRGB; SrcRGB.rgbtBlue:=value; IncRGB; end; end; end; //锐化 procedure Sharpen(SrcBmp:TBitmap); var i, j: integer; SrcRGB: pRGBTriple; SrcPreRGB: pRGBTriple; Value: integer; begin SrcBmp.PixelFormat:=pf24Bit; for i := 0 to SrcBmp.Height - 1 do begin SrcRGB := SrcBmp.ScanLine[i]; if i > 0 then SrcPreRGB:=SrcBmp.ScanLine[i-1] else SrcPreRGB:=SrcBmp.ScanLine[i]; for j := 0 to SrcBmp.Width - 1 do begin if j = 1 then Dec(SrcPreRGB); Value:=SrcRGB.rgbtRed+(SrcRGB.rgbtRed-SrcPreRGB.rgbtRed) div 2; Value:=Max(0,Value); Value:=Min(255,Value); SrcRGB.rgbtRed:=value; Value:=SrcRGB.rgbtGreen+(SrcRGB.rgbtGreen-SrcPreRGB.rgbtGreen) div 2; Value:=Max(0,Value); Value:=Min(255,Value); SrcRGB.rgbtGreen:=value; Value:=SrcRGB.rgbtBlue+(SrcRGB.rgbtBlue-SrcPreRGB.rgbtBlue) div 2; Value:=Max(0,Value); Value:=Min(255,Value); SrcRGB.rgbtBlue:=value; Inc(SrcRGB); Inc(SrcPreRGB); end; end; end; [图像的旋转和翻转] 以下代码用ScanLine配合指针移动实现，用于24位色！ //旋转90度 procedure Rotate90(const Bitmap:TBitmap); var i,j:Integer; rowIn,rowOut:pRGBTriple; Bmp:TBitmap; Width,Height:Integer; begin Bmp:=TBitmap.Create; Bmp.Width := Bitmap.Height; Bmp.Height := Bitmap.Width; Bmp.PixelFormat := pf24bit; Width:=Bitmap.Width-1; Height:=Bitmap.Height-1; for j := 0 to Height do begin rowIn := Bitmap.ScanLine[j]; for i := 0 to Width do begin rowOut := Bmp.ScanLine[i]; Inc(rowOut,Height - j); rowOut^ := rowIn^; Inc(rowIn); end; end; Bitmap.Assign(Bmp); end; //旋转180度 procedure Rotate180(const Bitmap:TBitmap); var i,j:Integer; rowIn,rowOut:pRGBTriple; Bmp:TBitmap; Width,Height:Integer; begin Bmp:=TBitmap.Create; Bmp.Width := Bitmap.Width; Bmp.Height := Bitmap.Height; Bmp.PixelFormat := pf24bit; Width:=Bitmap.Width-1; Height:=Bitmap.Height-1; for j := 0 to Height do begin rowIn := Bitmap.ScanLine[j]; for i := 0 to Width do begin rowOut := Bmp.ScanLine[Height - j]; Inc(rowOut,Width - i); rowOut^ := rowIn^; Inc(rowIn); end; end; Bitmap.Assign(Bmp); end; //旋转270度 procedure Rotate270(const Bitmap:TBitmap); var i,j:Integer; rowIn,rowOut:pRGBTriple; Bmp:TBitmap; Width,Height:Integer; begin Bmp:=TBitmap.Create; Bmp.Width := Bitmap.Height; Bmp.Height := Bitmap.Width; Bmp.PixelFormat := pf24bit; Width:=Bitmap.Width-1; Height:=Bitmap.Height-1; for j := 0 to Height do begin rowIn := Bitmap.ScanLine[j]; for i := 0 to Width do begin rowOut := Bmp.ScanLine[Width - i]; Inc(rowOut,j); rowOut^ := rowIn^; Inc(rowIn); end; end; Bitmap.Assign(Bmp); end; //任意角度 function RotateBitmap(Bitmap:TBitmap;Angle:Integer;BackColor:TColor):TBitmap; var i,j,iOriginal,jOriginal,CosPoint,SinPoint : integer; RowOriginal,RowRotated : pRGBTriple; SinTheta,CosTheta : Extended; AngleAdd : integer; begin Result:=TBitmap.Create; Result.PixelFormat := pf24bit; Result.Canvas.Brush.Color:=BackColor; Angle:=Angle Mod 360; if Angle<0 then Angle:=360-Abs(Angle); if Angle=0 then Result.Assign(Bitmap) else if Angle=90 then begin Result.Assign(Bitmap); Rotate90(Result);//如果是旋转90度，直接调用上面的代码 end else if (Angle>90) and (Angle<180) then begin AngleAdd:=90; Angle:=Angle-AngleAdd; end else if Angle=180 then begin Result.Assign(Bitmap); Rotate180(Result);//如果是旋转180度，直接调用上面的过程 end else if (Angle>180) and (Angle<270) then begin AngleAdd:=180; Angle:=Angle-AngleAdd; end else if Angle=270 then begin Result.Assign(Bitmap); Rotate270(Result);//如果是旋转270度，直接调用上面的过程 end else if (Angle>270) and (Angle<360) then begin AngleAdd:=270; Angle:=Angle-AngleAdd; end else AngleAdd:=0; if (Angle>0) and (Angle<90) then begin SinCos((Angle + AngleAdd) * Pi / 180, SinTheta, CosTheta); if (SinTheta * CosTheta) < 0 then begin Result.Width := Round(Abs(Bitmap.Width * CosTheta - Bitmap.Height * SinTheta)); Result.Height := Round(Abs(Bitmap.Width * SinTheta - Bitmap.Height * CosTheta)); end else begin Result.Width := Round(Abs(Bitmap.Width * CosTheta + Bitmap.Height * SinTheta)); Result.Height := Round(Abs(Bitmap.Width * SinTheta + Bitmap.Height * CosTheta)); end; CosTheta:=Abs(CosTheta); SinTheta:=Abs(SinTheta); if (AngleAdd=0) or (AngleAdd=180) then begin CosPoint:=Round(Bitmap.Height*CosTheta); SinPoint:=Round(Bitmap.Height*SinTheta); end else begin SinPoint:=Round(Bitmap.Width*CosTheta); CosPoint:=Round(Bitmap.Width*SinTheta); end; for j := 0 to Result.Height-1 do begin RowRotated := Result.Scanline[j]; for i := 0 to Result.Width-1 do begin Case AngleAdd of 0: begin jOriginal := Round((j+1)*CosTheta-(i+1-SinPoint)*SinTheta)-1; iOriginal := Round((i+1)*CosTheta-(CosPoint-j-1)*SinTheta)-1; end; 90: begin iOriginal := Round((j+1)*SinTheta-(i+1-SinPoint)*CosTheta)-1; jOriginal := Bitmap.Height-Round((i+1)*SinTheta-(CosPoint-j-1)*CosTheta); end; 180: begin jOriginal := Bitmap.Height-Round((j+1)*CosTheta-(i+1-SinPoint)*SinTheta); iOriginal := Bitmap.Width-Round((i+1)*CosTheta-(CosPoint-j-1)*SinTheta); end; 270: begin iOriginal := Bitmap.Width-Round((j+1)*SinTheta-(i+1-SinPoint)*CosTheta); jOriginal := Round((i+1)*SinTheta-(CosPoint-j-1)*CosTheta)-1; end; end; if (iOriginal >= 0) and (iOriginal <= Bitmap.Width-1)and (jOriginal >= 0) and (jOriginal <= Bitmap.Height-1) then begin RowOriginal := Bitmap.Scanline[jOriginal]; Inc(RowOriginal,iOriginal); RowRotated^ := RowOriginal^; Inc(RowRotated); end else begin Inc(RowRotated); end; end; end; end; end; //水平翻转 procedure FlipHorz(const Bitmap:TBitmap); var i,j:Integer; rowIn,rowOut:pRGBTriple; Bmp:TBitmap; Width,Height:Integer; begin Bmp:=TBitmap.Create; Bmp.Width := Bitmap.Width; Bmp.Height := Bitmap.Height; Bmp.PixelFormat := pf24bit; Width:=Bitmap.Width-1; Height:=Bitmap.Height-1; for j := 0 to Height do begin rowIn := Bitmap.ScanLine[j]; for i := 0 to Width do begin rowOut := Bmp.ScanLine[j]; Inc(rowOut,Width - i); rowOut^ := rowIn^; Inc(rowIn); end; end; Bitmap.Assign(Bmp); end; //垂直翻转 procedure FlipVert(const Bitmap:TBitmap); var i,j:Integer; rowIn,rowOut:pRGBTriple; Bmp:TBitmap; Width,Height:Integer; begin Bmp:=TBitmap.Create; Bmp.Width := Bitmap.Height; Bmp.Height := Bitmap.Width; Bmp.PixelFormat := pf24bit; Width:=Bitmap.Width-1; Height:=Bitmap.Height-1; for j := 0 to Height do begin rowIn := Bitmap.ScanLine[j]; for i := 0 to Width do begin rowOut := Bmp.ScanLine[Height - j]; Inc(rowOut,i); rowOut^ := rowIn^; Inc(rowIn); end; end; Bitmap.Assign(Bmp); end; [亮度、对比度、饱和度的调整] 以下代码用ScanLine配合指针移动实现！ function Min(a, b: integer): integer; begin if a < b then result := a else result := b; end; function Max(a, b: integer): integer; begin if a > b then result := a else result := b; end; //亮度调整 procedure BrightnessChange(const SrcBmp,DestBmp:TBitmap;ValueChange:integer); var i, j: integer; SrcRGB, DestRGB: pRGBTriple; begin for i := 0 to SrcBmp.Height - 1 do begin SrcRGB := SrcBmp.ScanLine[i]; DestRGB := DestBmp.ScanLine[i]; for j := 0 to SrcBmp.Width - 1 do begin if ValueChange > 0 then begin DestRGB.rgbtRed := Min(255, SrcRGB.rgbtRed + ValueChange); DestRGB.rgbtGreen := Min(255, SrcRGB.rgbtGreen + ValueChange); DestRGB.rgbtBlue := Min(255, SrcRGB.rgbtBlue + ValueChange); end else begin DestRGB.rgbtRed := Max(0, SrcRGB.rgbtRed + ValueChange); DestRGB.rgbtGreen := Max(0, SrcRGB.rgbtGreen + ValueChange); DestRGB.rgbtBlue := Max(0, SrcRGB.rgbtBlue + ValueChange); end; Inc(SrcRGB); Inc(DestRGB); end; end; end; //对比度调整 procedure ContrastChange(const SrcBmp,DestBmp:TBitmap;ValueChange:integer); var i, j: integer; SrcRGB, DestRGB: pRGBTriple; begin for i := 0 to SrcBmp.Height - 1 do begin SrcRGB := SrcBmp.ScanLine[i]; DestRGB := DestBmp.ScanLine[i]; for j := 0 to SrcBmp.Width - 1 do begin if ValueChange>=0 then begin if SrcRGB.rgbtRed >= 128 then DestRGB.rgbtRed := Min(255, SrcRGB.rgbtRed + ValueChange) else DestRGB.rgbtRed := Max(0, SrcRGB.rgbtRed - ValueChange); if SrcRGB.rgbtGreen >= 128 then DestRGB.rgbtGreen := Min(255, SrcRGB.rgbtGreen + ValueChange) else DestRGB.rgbtGreen := Max(0, SrcRGB.rgbtGreen - ValueChange); if SrcRGB.rgbtBlue >= 128 then DestRGB.rgbtBlue := Min(255, SrcRGB.rgbtBlue + ValueChange) else DestRGB.rgbtBlue := Max(0, SrcRGB.rgbtBlue - ValueChange); end else begin if SrcRGB.rgbtRed >= 128 then DestRGB.rgbtRed := Max(128, SrcRGB.rgbtRed + ValueChange) else DestRGB.rgbtRed := Min(128, SrcRGB.rgbtRed - ValueChange); if SrcRGB.rgbtGreen >= 128 then DestRGB.rgbtGreen := Max(128, SrcRGB.rgbtGreen + ValueChange) else DestRGB.rgbtGreen := Min(128, SrcRGB.rgbtGreen - ValueChange); if SrcRGB.rgbtBlue >= 128 then DestRGB.rgbtBlue := Max(128, SrcRGB.rgbtBlue + ValueChange) else DestRGB.rgbtBlue := Min(128, SrcRGB.rgbtBlue - ValueChange); end; Inc(SrcRGB); Inc(DestRGB); end; end; end; //饱和度调整 procedure SaturationChange(const SrcBmp,DestBmp:TBitmap;ValueChange:integer); var Grays: array[0..767] of Integer; Alpha: array[0..255] of Word; Gray, x, y: Integer; SrcRGB,DestRGB: pRGBTriple; i: Byte; begin ValueChange:=ValueChange+255; for i := 0 to 255 do Alpha[i] := (i * ValueChange) Shr 8; x := 0; for i := 0 to 255 do begin Gray := i - Alpha[i]; Grays[x] := Gray; Inc(x); Grays[x] := Gray; Inc(x); Grays[x] := Gray; Inc(x); end; for y := 0 to SrcBmp.Height - 1 do begin SrcRGB := SrcBmp.ScanLine[Y]; DestRGB := DestBmp.ScanLine[Y]; for x := 0 to SrcBmp.Width - 1 do begin Gray := Grays[SrcRGB.rgbtRed + SrcRGB.rgbtGreen + SrcRGB.rgbtBlue]; if Gray + Alpha[SrcRGB.rgbtRed]>0 then DestRGB.rgbtRed := Min(255,Gray + Alpha[SrcRGB.rgbtRed]) else DestRGB.rgbtRed := 0; if Gray + Alpha[SrcRGB.rgbtGreen]>0 then DestRGB.rgbtGreen := Min(255,Gray + Alpha[SrcRGB.rgbtGreen]) else DestRGB.rgbtGreen := 0; if Gray + Alpha[SrcRGB.rgbtBlue]>0 then DestRGB.rgbtBlue := Min(255,Gray + Alpha[SrcRGB.rgbtBlue]) else DestRGB.rgbtBlue := 0; Inc(SrcRGB); Inc(DestRGB); end; end; end; //RGB调整 procedure RGBChange(SrcBmp,DestBmp:TBitmap;RedChange,GreenChange,BlueChange:integer); var SrcRGB, DestRGB: pRGBTriple; i,j:integer; begin for i := 0 to SrcBmp.Height- 1 do begin SrcRGB := SrcBmp.ScanLine[i]; DestRGB :=DestBmp.ScanLine[i]; for j := 0 to SrcBmp.Width - 1 do begin if RedChange> 0 then DestRGB.rgbtRed := Min(255, SrcRGB.rgbtRed + RedChange) else DestRGB.rgbtRed := Max(0, SrcRGB.rgbtRed + RedChange); if GreenChange> 0 then DestRGB.rgbtGreen := Min(255, SrcRGB.rgbtGreen + GreenChange) else DestRGB.rgbtGreen := Max(0, SrcRGB.rgbtGreen + GreenChange); if BlueChange> 0 then DestRGB.rgbtBlue := Min(255, SrcRGB.rgbtBlue + BlueChange) else DestRGB.rgbtBlue := Max(0, SrcRGB.rgbtBlue + BlueChange); Inc(SrcRGB); Inc(DestRGB); end; end; end; [颜色调整] //RGB<=>BGR procedure RGB2BGR(const Bitmap:TBitmap); var X: Integer; Y: Integer; PRGB: pRGBTriple; Color: Byte; begin for Y := 0 to (Bitmap.Height - 1) do begin for X := 0 to (Bitmap.Width - 1) do begin Color := PRGB^.rgbtRed; PRGB^.rgbtRed := PRGB^.rgbtBlue; PRGB^.rgbtBlue := Color; Inc(PRGB); end; end end; end; //灰度化(加权) procedure Grayscale(const Bitmap:TBitmap); var X: Integer; Y: Integer; PRGB: pRGBTriple; Gray: Byte; begin for Y := 0 to (Bitmap.Height - 1) do begin PRGB := Bitmap.ScanLine[Y]; for X := 0 to (Bitmap.Width - 1) do begin Gray := (77 * Red + 151 * Green + 28 * Blue) shr 8; PRGB^.rgbtRed:=Gray; PRGB^.rgbtGreen:=Gray; PRGB^.rgbtBlue:=Gray; Inc(PRGB); end; end; end;
理论篇：
关键词：
绘图区－即窗口显示图像的区域，亦可为全屏幕（在全屏幕下绘图的效果比一般窗口下好）
中心点－即要绘图区显示的中心点在原始图像的坐标（声明：这个概念特别重要）
先说说图像的放大，要放大一张图片，我们一般的做法是直接放大图像，但本文介绍的方法仅放大我们能够看到的部分，放大分两种情况，一种是放大后比绘图区还要小，这种情况没什么好说，当然是显示全部的图像；第二种是放大后的图像比绘图区大，这才是我们今天要讨论的重点话题，这种情况下我们先要确定图像放大后的大小，然后根据“中心点”计算在原始图像的位置和大小，最后把截取的图像放大到绘图区。
再说说图像的漫游，当显示的图像超过绘图区时，我们需要对图像进行漫游，以便看到全部的图像。原理是：当鼠标在绘图区进行单击时，这时开始漫游，先记录鼠标的单击位置，然后检测鼠标的移动，根据鼠标和上次的位移计算出“中心点”（需要将屏幕坐标转换为原始图像坐标），根据在上面放大的原理到原始图像中取出要显示的部分，放大显示到绘图区。
算法实现篇：
1.图像放大
变量定义：
PZoom:放大率(整数:100时为100%，根据需要可以将 100 该为 10000 或者更大些，但不推荐使用浮点数)
a,b:中心点
w,h:要截取原始图像的宽和高
x,y:要截取的位置(左上角)
sw,sh:原始图像的宽和高
p1,p2:放大比例
aw,ah:放大后图像的大小
pw,ph:绘图区大小
vx,vy:在绘图区显示的位置（左上角）
vw,vh:在绘图区显示的大小
ptx,pty:临时变量
已知的变量：PZoom,(a,b),(sw,sh),(p1,p2),(aw,ah),(pw,ph)
要计算的变量：(x,y),(w,h),(vx,vy),(vw,vh)
开始计算：
aw=Round(PZoom*sw/100); ah=Round(PZoom*sh/100); p1=aw/pw p2=ah/ph // 注：Round 用于取整，如其他语言的Int(),Fix()等 if p1>1 then w=Round(sw/p1) else w=sw if p2>1 then h=Round(sh/p2) else h=sh // 注：shr 为右移运算符，可以使用“>>1”、“div 2”、“/2”或“Round(w/2)”代替 x=a-w shr 1 y=b-h shr 1 // 注：div 为整除运算符 ptx=(w*PZoom) div 100 pty=(h*PZoom) div 100 // 以下计算在绘图区显示的图像大小和位置
变量
Pencent:double; // 缩放比 wx:double; // 宽缩放比 hx:double; // 高缩放比 // 获得缩放比 wx:=pw/ptx hx:=ph/pty if wx>hx then Pencent:=hx else Pencent:=wx; // 获得图片最后的大小 vw:=Round(Pencent*ptx); vh:=Round(Pencent*pty); // 计算出图片的位置 vx:=(pw-vw) div 2; vy:=(ph-vh) div 2; // ------------------------------------
好了，两个重要的任务完成(x,y),(w,h),(vx,vy),(vw,vh)已经全部计算得出，下面的工作就是显示了，我们选择 Windows API 进行操作
变量
sDC 为原始图片的设备句柄(DC) tDC 为临时设备句柄 dDC 最终设备句柄 BitBlt(tDC,0,0,w,h,sDC,0,0,SRCCOPY); SetStretchBltMode(dDC,STRETCH_DELETESCANS); StretchBlt(dDC,0,0,vw,vh,tDC,0,0,w,h,SRCCOPY);
最后绘制到显示的区域即可：
例如：
BitBlt(GetDC(0),vx,vy,vx+vw,xy+vh,dDC,0,0,SRCCOPY);
2.图像漫游
先定义三个全局变量：
FBeginDragPoint :TPoint; // 记录鼠标开始拖动的位置 FBeginDragSBPoint :TPoint; // 记录“中心点”位置 FBeginDrag :boolean; // 是否已经开始“拖动” a,b :integer; // “中心点”位置
在鼠标左键点击时，记录鼠标的位置和“中心点”的位置，同时设置 FBeginDrag 为真
当鼠标右键弹起时，设置 FBeginDrag 为假
鼠标移动时，判断 FBeginDrag ，如果为假不进行处理，如果为真进行下面处理：
假设 X,Y 为鼠标当前的位置
a=FBeginDragPoint.X-((X-FBeginDragPoint.X)*100) div PZoom b=FBeginDragPoint.Y-((Y-FBeginDragPoint.Y)*100) div PZoom
最后使用上面介绍的图像放大显示出图像
技巧篇：
1.如果图像较大，使用 delphi 的 位图对象会出现内存溢出错误，这时可以进行如下设置：
bitImage:=TBitmap.Create; bitImage.PixelFormat:=pf24bit; bitImage.ReleaseHandle;
2.如果要让图像自动适应窗口的大小，参考以下代码：
var p1,p2 :double; begin p1:=pw/sw; p2:=ph/sw; if p1>p2 then PZoom:=Round(p2*100) else PZoom:=Round(p1*100); if PZoom=0 then PZoom:=100; end;
Delphi灰度图像像素颜色亮度处理
在图像处理中，速度是很重要的。因此，我们得重新处理一下TBitmap,得到TVczhBitmap。这只是因为GetPixels和SetPixels的速度太慢，换一个方法而已。
unit untBitmapProc; interface uses Graphics, SysUtils; type TVczhBitmap=class(TBitmap) private Data:PByteArray; Line:Integer; procedure SetFormat; function GetBytePointer(X,Y:Integer):PByte; procedure SetBytes(X,Y:Integer;Value:Byte); function GetBytes(X,Y:Integer):Byte; protected published constructor Create; public property Bytes[X,Y:Integer]:Byte read GetBytes write SetBytes; procedure LoadFromFile(FileName:String); procedure ToGray; end; implementation procedure TVczhBitmap.SetFormat; begin HandleType:=bmDIB; PixelFormat:=pf24bit; end; function TVczhBitmap.GetBytePointer(X,Y:Integer):PByte; begin if Line<>Y then begin Line:=Y; Data:=ScanLine[Y]; end; Longint(result):=Longint(Data)+X; end; procedure TVczhBitmap.SetBytes(X,Y:Integer;Value:Byte); begin GetBytePointer(X,Y)^:=Value; end; function TVczhBitmap.GetBytes(X,Y:Integer):Byte; begin result:=GetBytePointer(X,Y)^; end; constructor TVczhBitmap.Create; begin inherited Create; SetFormat; Line:=-1; end; procedure TVczhBitmap.LoadFromFile(FileName:String); begin inherited LoadFromFile(FileName); SetFormat; Line:=-1; end; procedure TVczhBitmap.ToGray; var X,Y,R:Integer; B:Byte; begin for Y:=0 to Height-1 do for X:=0 to Width-1 do begin R:=0; for B:=0 to 2 do R:=R+GetBytes(X*3+B,Y); for B:=0 to 2 do SetBytes(X*3+B,Y,R div 3); end; end; end.
此后，我们需要建立几个窗体。第一个用来显示图片，第二个用来处理图片，其他的窗体都继承自第二个窗体，包含实际的处理方法。
先看第二个窗口：
unit untProc; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, ExtCtrls, untBitmapProc, StdCtrls, ComCtrls; type TfrmProcessor = class(TForm) pbBar: TPaintBox; gpProc: TGroupBox; Button1: TButton; procedure FormCreate(Sender: TObject); procedure FormDestroy(Sender: TObject); procedure FormShow(Sender: TObject); procedure pbBarPaint(Sender: TObject); procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } BarData:array[0..255]of Byte; Bar:TVczhBitmap; procedure DrawBar; end; var frmProcessor: TfrmProcessor; implementation {$R *.dfm} uses untViewer; procedure TfrmProcessor.DrawBar; var I:Integer; begin Bar.Canvas.FillRect(Bar.Canvas.ClipRect); Bar.Canvas.MoveTo(0,255-BarData[0]); for I:=1 to 255 do Bar.Canvas.LineTo(I,255-BarData[I]); end; procedure TfrmProcessor.FormCreate(Sender: TObject); begin Bar:=TVczhBitmap.Create; Bar.Width:=256; Bar.Height:=256; Bar.Canvas.Brush.Color:=clWhite; Bar.Canvas.Brush.Style:=bsSolid; end; procedure TfrmProcessor.FormDestroy(Sender: TObject); begin Bar.Free; end; procedure TfrmProcessor.FormShow(Sender: TObject); var I:Integer; begin for I:=0 to 255 do BarData[I]:=I; DrawBar; end; procedure TfrmProcessor.pbBarPaint(Sender: TObject); begin pbBar.Canvas.Draw(0,0,Bar); end; procedure TfrmProcessor.Button1Click(Sender: TObject); var X,Y:Integer; begin for Y:=0 to Buffer.Height-1 do for X:=0 to Buffer.Width*3-1 do Played.Bytes[X,Y]:=BarData[Buffer.Bytes[X,Y]]; frmViewer.FormPaint(frmViewer); end; end.
之后，做一个窗口继承自它，则调整BarData[]后，按Apply即可看到结果。
现在开始将图像处理。具体效果见示例程序。
一、颜色反转。
灰度图像的颜色都是从0~255，所以，为了使颜色反转，我们可以用255减去该颜色值以得到反转后的颜色
var I:Integer; begin inherited; for I:=0 to 255 do BarData[I]:=255-I;//用255减去该颜色值 DrawBar; pbBarPaint(pbBar); end;
二、缩小颜色范围以增强或减弱亮度
颜色本来是从0~255的。如果调节它的范围，例如从0~16，则会是图像明显变暗。我们可以把起始值设为a，把终止值设为b，则新的颜色值New=a+(b-1)*Old/255。这样做的话可以改变亮度，并且不会破坏原先颜色的顺序。代码如下
var I:Integer; begin for I:=0 to 255 do BarData[I]:=(255-sbMin.Position)+Round((sbMin.Position-sbMax.Position)/255*I); DrawBar; pbBarPaint(pbBar); Button1Click(Button1); end;
这里的sbMin.Position和sbMaxPosition都是反转过的。所以使用时要用255去减
三、增加某个范围内的颜色范围
如果图像本身的颜色范围很小的画，你可以通过这种方法来加大图像的对比度，有利于对图像的分析。具体做法：
选取一个值a做为起始值，选取一个值b做为终止值，然后按以下公式变形：
| 0 (X<=a)
f(X)= | 255/(b-a)*(X-a)
| 255(X>=b)
var I:Integer; begin for I:=0 to 255 do begin if I<=sbMin.Position then BarData[I]:=0 else if I>=sbMax.Position then BarData[I]:=255 else BarData[I]:=Round(255/(sbMax.Position-sbMin.Position)*(I-sbMin.Position)); end; DrawBar; pbBarPaint(pbBar); Button1Click(Button1); end;
四、变为黑白图片
在使用第三个功能的时候，你会发现当b<=a时，图像上的颜色除了黑色就是白色。这样操作的好处是不能直接显示出来的。这只要到了比较高级的图像处理如边缘检测等，才有作用。本例可以拿第三种方法的公式再变形，因此不作详细阐述。
五、指数级亮度调整
我们假设这个图的定义域是[0,1]，值域也是[0,1]。那么，定义函数f(x)=x^c，则f(x)的图像有一段如上图。我们再用鼠标操作时，可以在上面取一点P(a,b)，然后使f(x)通过点P，则c=ln(b)/ln(a)。有了c之后，我们就可以对颜色进行操作了：
New=(Old/255)^c*255=exp(ln(old/255)*c)*255 var ea,eb,ec:Extended; I:Integer; begin ea:=A/255; eb:=B/255; ec:=Ln(eb)/Ln(ea); for I:=1 to 255 do BarData[I]:=Round(Exp(Ln((I/255))*ec)*255); DrawBar; pbBarPaint(pbBar); Button1Click(Button1); end;
这样做可以调节图像的亮度。
Delphi图形显示特效的技巧
概述
----目前在许多学习软件、游戏光盘中，经常会看到各种
图形显示技巧，凭着图形的移动、交错、雨滴状、百页窗、积木堆叠等显现方式，使画面变得更为生动活泼，更 能吸引观众。本文将探讨如何在delphi中实现各种图形显示技巧。
基本原理
----在delphi中，实现一副图象的显示是非常简单的，只要在form中定义一个timage组件，设置其picture属性，然后选 择任何有效的.ico、.bmp、.emf或.wmf文件，进行load，所选文 件就显示在timage组件中了。但这只是直接将图形显示在窗体中，毫无技巧可言。为了使图形显示具有别具一格的效果，可以按下列步骤实现：
----定义一个timage组件，把要显示的图形先装入到timage组件中，也就是说，把图形内容从磁盘载入内存中， 做为图形缓存。
----创建一新的位图对象，其尺寸跟timage组件中的图形一样。
----利用画布(canvas)的copyrect功能(将一个画布的矩形区域拷贝到另一个画布的矩形区域)，使用技巧，动态形
成位图文件内容，然后在窗体中显示位图。
----实现方法
下面介绍各种图形显示技巧：
1.推拉效果
将要显示的图形由上、下、左、右方向拉进屏幕内显示，同时将屏幕上原来的旧图盖掉，此种效果可分为四种，上拉、下拉、左拉、右拉，但原理都差不多，以上拉 效果为例。
原理：首先将放在暂存图形的第一条水平线，搬移至要显示的位图的最后一条，接着再将暂存图形的前两条水平线，依序搬移至要显示位图的最后两条水平线，然后搬移前三条、前四条叄?直到全部图形数据搬完为止。在搬移的过程中即可看到显示的位图由下而上浮起，而达到上拉的效果。
程序算法：
procedure tform1.button1click(sender: tobject); var newbmp: tbitmap; i,bmpheight,bmpwidth:integer; begin newbmp:= tbitmap.create; newbmp.width:=image1.width; newbmp.height:=image1.height; bmpheight:=image1.height; bmpwidth:=image1.width; for i:=0 to bmpheight do begin newbmp.canvas.copyrect(rect (0,bmpheight-i,bmpwidth,bmpheight), image1.canvas, rect(0,0,bmpwidth,i)); form1.canvas.draw(120,100,newbmp); end; newbmp.free; end;
2.垂直交错效果
原理：将要显示的图形拆成两部分，奇数条扫描线由上往下搬移，偶数条扫描线的部分则由下往上搬移，而且两者同时进行。从屏幕上便可看到分别由上下两端出现的较淡图形向屏幕中央移动，直到完全清楚为止。
程序算法：
procedure tform1.button4click(sender: tobject); var newbmp:tbitmap; i,j,bmpheight,bmpwidth:integer; begin newbmp:= tbitmap.create; newbmp.width:=image1.width; newbmp.height:=image1.height; bmpheight:=image1.height; bmpwidth:=image1.width; i:=0; while i< =bmpheight do begin j:=i; while j >0 do begin newbmp.canvas.copyrect(rect(0,j-1,bmpwidth,j), image1.canvas, rect(0,bmpheight-i+j-1,bmpwidth,bmpheight-i+j)); newbmp.canvas.copyrect(rect (0,bmpheight-j,bmpwidth,bmpheight-j+1), image1.canvas, rect(0,i-j,bmpwidth,i-j+1)); j:=j-2; end; form1.canvas.draw(120,100,newbmp); i:=i+2; end; newbmp.free; end;
3.水平交错效果
原理：同垂直交错效果原理一样，只是将分成两组后的图形分别由左右两端移进屏幕。
程序算法：
procedure tform1.button5click(sender: tobject); var newbmp:tbitmap; i,j,bmpheight,bmpwidth:integer; begin newbmp:= tbitmap.create; newbmp.width:=image1.width; newbmp.height:=image1.height; bmpheight:=image1.height; bmpwidth:=image1.width; i:=0; while i< =bmpwidth do begin j:=i; while j >0 do begin newbmp.canvas.copyrect(rect(j-1,0,j,bmpheight), image1.canvas, rect(bmpwidth-i+j-1,0,bmpwidth-i+j,bmpheight)); newbmp.canvas.copyrect(rect (bmpwidth-j,0,bmpwidth-j+1,bmpheight), image1.canvas, rect(i-j,0,i-j+1,bmpheight)); j:=j-2; end; form1.canvas.draw(120,100,newbmp); i:=i+2; end; newbmp.free; end;
4.雨滴效果
原理：将暂存图形的最后一条扫描线，依序搬移到可视位图的第一条到最后一条扫描线，让此条扫描线在屏幕上留下它的轨迹。接着再把暂存图形的倒数第二条扫描线，依序搬移到可视位图的第一条到倒数第二条扫描线。其余的扫描线依此类推。
程序算法：
procedure tform1.button3click(sender: tobject); var newbmp:tbitmap; i,j,bmpheight,bmpwidth:integer; begin newbmp:= tbitmap.create; newbmp.width:=image1.width; newbmp.height:=image1.height; bmpheight:=image1.height; bmpwidth:=image1.width; for i:=bmpheight downto 1 do for j:=1 to i do begin newbmp.canvas.copyrect(rect(0,j-1,bmpwidth,j), image1.canvas, rect(0,i-1,bmpwidth,i)); form1.canvas.draw(120,100,newbmp); end; newbmp.free; end;
5.百叶窗效果
原理：将放在暂存图形的数据分成若干组，然后依次从第一组到最后一组搬移，第一次每组各搬移第一条扫描线到可视位图的相应位置，第二次搬移第二条扫描线，接着搬移第三条、第四条扫描线.
程序算法：
procedure tform1.button6click(sender: tobject); var newbmp:tbitmap; i,j,bmpheight,bmpwidth:integer; xgroup,xcount:integer; begin newbmp:= tbitmap.create; newbmp.width:=image1.width; newbmp.height:=image1.height; bmpheight:=image1.height; bmpwidth:=image1.width; xgroup:=16; xcount:=bmpheight div xgroup; for i:=0 to xcount do for j:=0 to xgroup do begin newbmp.canvas.copyrect(rect (0,xcount*j+i-1,bmpwidth,xcount*j+i), image1.canvas, rect(0,xcount*j+i-1,bmpwidth,xcount*j+i)); form1.canvas.draw(120,100,newbmp); end; newbmp.free; end;
6.积木效果
原理：是雨滴效果的一种变化，不同之处在于，积木效果每次搬移的是一块图形，而不只是一根扫描线。
程序算法：
procedure tform1.button7click(sender: tobject); var newbmp:tbitmap; i,j,bmpheight,bmpwidth:integer; begin newbmp:= tbitmap.create; newbmp.width:=image1.width; newbmp.height:=image1.height; bmpheight:=image1.height; bmpwidth:=image1.width; i:=bmpheight; while i>0 do begin for j:=10 to i do begin newbmp.canvas.copyrect(rect(0,j-10,bmpwidth,j), image1.canvas, rect(0,i-10,bmpwidth,i)); form1.canvas.draw(120,100,newbmp); end; i:=i-10; end; newbmp.free; end;
结束语
上述图形显示效果均已上机通过。使用效果很好。
用Delphi实现图像放大镜
向窗体上添加两个TImage组件，其中一个TImage组件的Name属性设置为Image1，它充当原图片显示的载体。另一个TImage组件的Name属性设置为Image2，它可以显示放大后的图像。
本例的核心是StretchBlt函数，利用StretchBlt函数实现局部图像放大，响应代码如下：
procedure TForm1.Image1MouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer); begin StretchBlt(Image2.Canvas.Handle,0,0,Image2.Width,Image2.Height, Image1.Canvas.Handle, X-20,Y-20,40,40,SRCCOPY); Image2.Refresh; Screen.Cursors[1]:=LoadCursorFromFile(‘MAGNIFY.CUR‘); Self.Cursor:=1; end;
程序首先会调用StretchBlt函数，以鼠标当前位置作为中心点，以边长为40选中Image1组件上的局部图像，并放大此局部图像到Image2组件上。然后通过调用Image2组件的Refresh方法以刷新Image2组件的显示。最后设置鼠标指针为新的形状。
程序代码如下：
unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, ExtCtrls, StdCtrls; type TForm1 = class(TForm) Image1: TImage; Image2: TImage; procedure Image1MouseMove(Sender: TObject; Shift: TShiftState; X,Y: Integer); procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X,Y: Integer); private { Private declarations } public { Public declarations } end; var Form1: TForm1; implementation {$R *.dfm} procedure TForm1.Image1MouseMove(Sender:TObject;Shift:TShiftState;X,Y: Integer); begin StretchBlt(Image2.Canvas.Handle,0,0,Image2.Width,Image2.Height,Image1.Canvas.Handle, X-20,Y-20,40,40,SRCCOPY); Image2.Refresh; Screen.Cursors[1]:=LoadCursorFromFile(‘MAGNIFY.CUR‘); Self.Cursor:=1; end; procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,Y: Integer); begin Screen.Cursors[1]:=crDefault; Self.Cursor:=1; end; end.
保存文件，然后按F9键运行程序，程序运行。
放大图像是一个优秀的看图软件必备的功能，本实例提供了一种非常简便易行的方法，不但代码数量少，而且执行效率高。
希望本文所述对大家的Delphi程序设计有所帮助。
