图片类型转换 StreachDraw

class function TdbDocImg.ConvertPICintoJPG(cPic: TPicture;

pWidth, pHeight: Integer): TJpegImage;

var

tBMP: TBitmap;

begin

Result := TJpegImage.Create;

   

// if (pWidth > 0) or (pHeight > 0) then

// begin

try

tBMP := TBitmap.Create; // 创建一个过渡性BMP图片,用于更改图片尺寸

if pWidth <= 0 then

pWidth := cPic.width; // 若pWidth为有效值则改变tBMP宽度,否则不变

if pHeight <= 0 then

pHeight := cPic.height; // 若pHeight为有效值则改变tBMP高度,否则不变

tBMP.width := pWidth;

tBMP.height := pHeight;

tBMP.Canvas.StretchDraw(tBMP.Canvas.ClipRect, cPic.Graphic); // 按照新尺寸重画图形

Result.Assign(tBMP);

finally

tBMP.Free;

end;

// end

// else

// Result.Assign(cPic);

end;