L'image sur le reçu de l'imprimante thermique epson affiche des lignes horizontales blanches

Question

J'ai imprimé une image bitmap de l'imprimante epson TM-T82 en utilisant le code delphi7. J'envoie des commandes ESCPOS à l'imprimante epson pour imprimer une image bitmap. Cette image bitmap imprimée contient des lignes blanches dans le logo. Lorsque j'utilise l'utilitaire d'impression Epson avec le même logo, il imprime très bien.

Est-ce que quelqu'un sait comment résoudre ce problème?

Voici mon code:

unit ssESCPosPrintBitmap; 

interface 

type 
    // *** ------------------------------------------------------------------------- 
    // *** INTERFACE: IssESCPosPrintBitmap 
    // *** ------------------------------------------------------------------------- 
    IssESCPosPrintBitmap = interface(IInterface) 
    ['{3F279585-6D2E-451F-AF97-76F0E07A70DF}'] 
    function RenderBitmap(const ABitmapFilename: string): string; 
    end; 

    function _ESCPosPrintBitmap(): IssESCPosPrintBitmap; 

implementation 

uses 
    Windows, 
    Graphics, 
    Math; 

type 
    TRGBTripleArray = ARRAY[Word] of TRGBTriple; 
    pRGBTripleArray = ^TRGBTripleArray; // Use a PByteArray for pf8bit color. 

    // *** ------------------------------------------------------------------------- 
    // *** RECORD: TBitmapData 
    // *** ------------------------------------------------------------------------- 
    TBitmapData = record 
    Dots  : array of Boolean; 
    Height : Integer; 
    Width  : Integer; 
    end; 

    // *** ------------------------------------------------------------------------- 
    // *** CLASS: TssESCPosPrintBitmap 
    // *** ------------------------------------------------------------------------- 
    TssESCPosPrintBitmap = class(TInterfacedObject, IssESCPosPrintBitmap) 
    private 
     FLumThreshold : Integer; 
     FBitmap  : TBitmap; 
     FBitmapData : TBitmapData; 
     procedure LoadBitmapData(); 
    public 
     constructor Create(); 
     destructor Destroy; override; 

     function RenderBitmap(const ABitmapFilename: string): string; 
    end; 

const 
    C_DEFAULT_THRESHOLD = 127; 

function _ESCPosPrintBitmap(): IssESCPosPrintBitmap; 
begin 
    Result := TssESCPosPrintBitmap.Create(); 
end; 


{ TssESCPosPrintBitmap } 

{------------------------------------------------------------------------------- 
    Procedure: TssESCPosPrintBitmap.Create 
    Author: bvonfintel 
    DateTime: 2015.01.06 
    Arguments: None 
    Result: None 
-------------------------------------------------------------------------------} 
constructor TssESCPosPrintBitmap.Create; 
begin 
    inherited; 
    FBitmap  := TBitmap.Create(); 
    FLumThreshold := C_DEFAULT_THRESHOLD; 
end; 

procedure TssESCPosPrintBitmap.LoadBitmapData; 
var 
    LIndex : Integer; 
    LX  : Integer; 
    LY  : Integer; 
    LLine : pRGBTripleArray; 
    LPixel : TRGBTriple; 
    LLum : Integer; 
begin 
    LIndex := 0; 
    FBitmapData.Height := FBitmap.Height; 
    FBitmapData.Width := FBitmap.Width; 
    SetLength(FBitmapData.Dots, FBitmap.Width * FBitmap.Height); 

    for LY := 0 to FBitmap.Height-1 do begin 
    LLine := FBitmap.ScanLine[LY]; 

    for LX := 0 to FBitmap.Width-1 do begin 
     LPixel := LLine[LX]; 
     LLum := Trunc((LPixel.rgbtRed * 0.3) + (LPixel.rgbtGreen * 0.59) + (LPixel.rgbtBlue * 0.11)); 

     FBitmapData.Dots[LIndex] := (LLum < FLumThreshold); 

     Inc(LIndex); 
    end; 

    end; 
end; 

function TssESCPosPrintBitmap.RenderBitmap(const ABitmapFilename: string): string; 
var 
    LOffset  : Integer; 
    LX   : Integer; 
    LSlice  : Byte; 
    LB   : Integer; 
    LK   : Integer; 
    LY   : Integer; 
    LI   : Integer; 
    LV   : Boolean; 
    LVI   : Integer; 
begin 
    // *** load the Bitmap from the file 
    FBitmap.LoadFromFile(ABitmapFilename); 
    FBitmap.PixelFormat := pf24bit; 

    // *** Convert the bitmap to an array of B/W pixels 
    LoadBitmapData(); 


    // *** Set the line spacing to 24 dots, the height of each "stripe" of the 
    // *** image that we're drawing 
    Result := #27'3'#24; 

    LOffset := 0; 
    while (LOffset < FBitmapData.Height) do begin 
    Result := Result + #27; 
    Result := Result + '*'; // Bit image mode 
    Result := Result + #33; // 24-dot double density 
    Result := Result + Char(Lo(FBitmapData.Width)); 
    Result := Result + Char(Hi(FBitmapData.Width)); 

    for LX := 0 to FBitmapData.Width -1 do begin 
     for LK := 0 to 2 do begin 
     LSlice := 0; 
     for LB := 0 to 7 do begin 
      LY := (((LOffset div 8) + LK) * 8) + LB; 
      LI := (LY * FBitmapData.Width) + LX; 

      LV := False; 
      if (LI < Length(FBitmapData.Dots)) then 
      LV := FBitmapData.Dots[LI]; 

      LVI := IfThen(LV, 1, 0); 

      LSlice := LSlice or (LVI shl (7 - LB)); 
     end; 

     Result := Result + Chr(LSlice); 
     end; 
    end; 

    LOffset := LOffset + 24; 
    Result := Result + sLineBreak; 
    end; 

    // *** Restore the line spacing to the default of 30 dots 
    Result := Result + #27'3'#30 + sLineBreak + sLineBreak + sLineBreak; 
end; 

Function TfrmEpsonPrint.PrintLabel(EPLCode : String): Boolean; 
var 
    ADevice, ADeviceName, ADevicePort: array[0..255]of Char; 
    PrinterHandle: THandle; 
    DocInfo: TDocInfo1; 
    dwJob: cardinal; 
    dwBytesWritten: cardinal; 
    AUtf8: UTF8string; 
    ADeviceMode: THandle; 
    Index: Integer; 
begin 
    Try 
    Try 
     Result := True; 
     //printer 
     Printer.Refresh; 
     Index := Printer.Printers.IndexOf('EPSON TM-T82 Receipt'); 
     If Index >= 0 Then 
     Printer.PrinterIndex := Index 
     Else 
     Begin 
     ShowMessage('EPSON TM-T82 Receipt Printer not found. Please add Generic/Text Only Printer with name 2824'); 
     Result := False; 
     Exit; 
     End; 
     Printer.GetPrinter(ADevice, ADeviceName, ADevicePort, ADeviceMode); 

     //Need a handle to the printer 
     if not OpenPrinter(ADevice, PrinterHandle, nil) Then 
     Exit; 

     //Fill in the structure with info about this "document" 
     DocInfo.pDocName := PChar('Label.txt'); 
     DocInfo.pOutputFile := nil; 
     DocInfo.pDatatype := 'RAW'; 

     //Inform the spooler the document is beginning 
     dwJob := StartDocPrinter(PrinterHandle, 1, @DocInfo); 
     if dwJob = 0 then 
     begin 
     ClosePrinter(PrinterHandle); 
     PrinterHandle := 0; 
     Exit; 
     end; 

     //Start a page 
     if not StartPagePrinter(PrinterHandle) then 
     begin 
     EndDocPrinter(PrinterHandle); 
     ClosePrinter(PrinterHandle); 
     PrinterHandle := 0; 
     Exit; 
     end; 

     EPLCode := _ESCPosPrintBitmap.RenderBitmap('C:\POS\RecTopImage1.bmp'); 
    // EPLCode := EPLCode + #29'V'#1; 

     //epl code... 
     AUtf8 := UTF8string(EPLCode); 
     WritePrinter(PrinterHandle, @AUtf8[1], Length(AUtf8), dwBytesWritten); 

     //End the page 
     if not EndPagePrinter(PrinterHandle) then 
     begin 
     EndDocPrinter(PrinterHandle); 
     ClosePrinter(PrinterHandle); 
     PrinterHandle := 0; 
     Exit; 
     end; 

     //Inform the spooler that the document is ending 
     if not EndDocPrinter(PrinterHandle) then 
     begin 
     ClosePrinter(PrinterHandle); 
     PrinterHandle := 0; 
     Exit; 
     end; 
     //Tidy up the printer handle 
     ClosePrinter(PrinterHandle); 
     PrinterHandle := 0; 
    Except 
    End; 
    Finally 
    PrinterHandle := 0; 
    End; 
End; 

Answer 1

Chaque ligne est de 24 points, 8 lignes étant de 3 points chacun. Mais au moment où vous avez sorti 3 lignes, vous avez déjà réduit de 2 points. Essayez de définir votre interligne à 22 points. Remplacer

Result := #27'3'#24; 

avec

Result := #27'3'#22; 

(Ou si cela ne fonctionne pas, réglez-le sur 21. Je ne sais pas si vous avez entré par 2 points ou par 3.)