BMP에 DPI값 세팅하기 및 알아오기

BMP에 DPI값 세팅

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unit MyGraphic;

 

interface

 

uses  SysUtils, Classes, Graphics, Dialogs;

 

function GetBMPFileDPI(FileName: String): LongInt;

procedure SetBMPFileDPI(FileName: String; DPI: Integer);

function GetBmpDPI(Bitmap: TBitmap): LongInt;

procedure SetBmpDPI(Bitmap: TBitmap; DPI: Integer);

 

implementation

 

function GetBMPFileDPI(FileName: String): LongInt;

var

  Stream: TFileStream;

  Data: Word;

  A: Double;

begin

  try

    Result := 0;

    Stream := TFileStream.Create(FileName, fmOpenRead or fmShareDenyWrite);

    Stream.Position := 38;

    if Stream.Read(Data,2) = 2 then

    begin

    A := Data;

    Result := Round(A / 39.370079);

    end;

    finally

      Stream.Free;

    end;

  end;

 

procedure SetBMPFileDPI(FileName: String; DPI: Integer);

var

  Stream: TFileStream; Data: Word;

begin

  try

    Stream := TFileStream.Create(FileName, fmOpenWrite or fmShareExclusive);

    Data := Round(DPI * 39.370079);   

    Stream.Position := 38;

 

    if Stream.Write(Data, 2) = 2 then

    begin

      Stream.Position := 42;

    end

    else

      {Error writing to Stream...}

      ShowMessage('Error writing to Stream. Data not written.');

  finally

    Stream.Free;

  end;

end;

 

function GetBmpDPI(Bitmap: TBitmap): LongInt;

var

  Stream: TMemoryStream;

  Data: Word;

  A: Double;

begin

  try

  Result := 0;

  Stream := TMemoryStream.Create; Bitmap.SaveToStream(Stream);

  Stream.Position := 38;

 

  if Stream.Read(Data,2) = 2 then

  begin

    A := Data;

    Result := Round(A / 39.370079);

  end;

  finally

    Stream.Free;

  end;

end;

 

procedure SetBmpDPI(Bitmap: TBitmap; DPI: Integer);

var

  Stream: TMemoryStream;

  Data: Word;

begin

  try

    Stream := TMemoryStream.Create;

    Bitmap.SaveToStream(Stream);

    Data := Round(DPI * 39.370079);

    Stream.Position := 38;

   

    if Stream.Write(Data, 2) = 2 then

    begin

      Stream.Position := 42;

      if Stream.Write(Data, 2) = 2 then

      begin

        Stream.Position := 0;

        Bitmap.LoadFromStream(Stream);

      end

      else

        {Error writing to Stream...}

        ShowMessage('Error writing to Stream. Data not written.');

    end

    else

      {Error writing to Stream...}

      ShowMessage('Error writing to Stream. Data not written.');

    finally

      Stream.Free;

    end;

  end;

end.