Method: DrawTo - Syntax 1

Draws a barcode symbol on the specified canvas. The barcode symbol is specified by the properties of this barcode component.

Syntax:

function DrawTo(Canvas: TCanvas; Left, Top: Integer; Module: Integer = 0; Angle: Integer = -1; HDPI: Integer = 0; VDPI: Integer = 0): Integer; overload; virtual;

Description:

On the specified canvas, draws current barcode symbol that is specified by the properties of this barcode component.

Parameters:

• Canvas: TCanvas; Specifies target canvas to represent the barcode symbol on it.

  For the TBarcode2D_CCA, TBarcode2D_CCB, and TBarcode2D_CCC barcode components, if the Linear property is set, the 2D symbol and the linear symbol are assembled to generate an EAN.UCC composite barcode symbol. Both of them will be drawn on the specified canvas.

• Left: Integer; Specifies the margin between the rotated barcode symbol and the left side of the canvas in logical dots or pixels in the horizontal direction. If the quiet zones are represented (please read the ShowQuietZone property about whether or not the quiet zones will be represented), they are included in the barcode symbol. See diagram (the SpaceColor property is set to clSilver in order to accentuate the quiet zones):

  

  For the TBarcode2D_Code16K barcode component, the leading quiet zone and the trailing quiet zone are included always, even if the ShowQuietZone property is set to false. See diagram (the SpaceColor property is set to clSilver in order to accentuate the quiet zones):

  

  For the TBarcode2D_CCA, TBarcode2D_CCB, and TBarcode2D_CCC components, if the Linear property is set, the 2D symbol and the linear symbol are assembled to generate an EAN.UCC composite barcode symbol. The linear symbol is included in the composite barcode symbol, and the parameter specifies the left margin for entire rotated EAN.UCC composite barcode symbol not for the 2D symbol. See diagram (the SpaceColor property is set to clSilver in order to accentuate the quiet zones):

  

  When the linear component of TBarcode2D_CCA, TBarcode2D_CCB, or TBarcode2D_CCC component is TBarcode1D_UPCA, TBarcode1D_UPCE, TBarcode1D_UPCE0, TBarcode1D_UPCE1, TBarcode1D_EAN8, TBarcode1D_EAN13, or TBarcode1D_EAN128, and its human readable text is represented. The human readable text and the vertical spacing between the text and linear symbol are included in the symbol. If the TextAlignment property isn't set to taCustom, and the human readable text exceeds entire EAN.UCC composite barcode symbol in horizontal direction, the excess is included in the symbol. If the TextAlignment property is set to taCustom, the width of quiet zone marks and their horizontal spacing (LeftQuietZoneSpacing and RightQuietZoneSpacing) are included in the symbol too (if they are represented, this does not apply to TBarcode1D_EAN128). The parameter always specifies the left margin for entire rotated EAN.UCC composite symbol. See diagram (the SpaceColor property is set to clSilver in order to accentuate the quiet zones):

   

  See also the "LeftMargin" property.

• Top: Integer; Specifies the margin between the rotated barcode symbol and the top side of the canvas in logical dots or pixels in the vertical direction. If the quiet zones are represented (please read the ShowQuietZone property about whether or not the quiet zones will be represented), they are included in the barcode symbol. See diagram (the SpaceColor property is set to clSilver in order to accentuate the quiet zones):

  

  For the TBarcode2D_Code16K barcode component, the leading quiet zone and the trailing quiet zone are included always, even if the ShowQuietZone property is set to false. See diagram (the SpaceColor property is set to clSilver in order to accentuate the quiet zones):

  

  For the TBarcode2D_CCA, TBarcode2D_CCB, and TBarcode2D_CCC components, if the Linear property is set, the 2D symbol and the linear symbol are assembled to generate an EAN.UCC composite barcode symbol. The linear symbol is included in the composite barcode symbol, and the parameter specifies the top margin for entire rotated EAN.UCC composite barcode symbol not for the 2D symbol. See diagram (the SpaceColor property is set to clSilver in order to accentuate the quiet zones):

  

  When the linear component of TBarcode2D_CCA, TBarcode2D_CCB, or TBarcode2D_CCC component is TBarcode1D_UPCA, TBarcode1D_UPCE, TBarcode1D_UPCE0, TBarcode1D_UPCE1, TBarcode1D_EAN8, TBarcode1D_EAN13, or TBarcode1D_EAN128, and its human readable text is represented. The human readable text and the vertical spacing between the text and linear symbol are included in the symbol. If the TextAlignment property isn't set to taCustom, and the human readable text exceeds entire EAN.UCC composite barcode symbol in horizontal direction, the excess is included in the symbol. If the TextAlignment property is set to taCustom, the width of quiet zone marks and their horizontal spacing (LeftQuietZoneSpacing and RightQuietZoneSpacing) are included in the symbol too (if they are represented, this does not apply to TBarcode1D_EAN128). The parameter always specifies the top margin for entire rotated EAN.UCC composite symbol. See diagram (the SpaceColor property is set to clSilver in order to accentuate the quiet zones):

   

  See also the "TopMargin" property.

• Module: Integer; Specifies the module size in logical dots or pixels in the horizontal direction. It defaults to 0 if the Module parameter is not provided, and the value of Module property will be used.

  • For the Matrix 2D barcode symbology (excluding the TBarcode2D_MaxiCode barcode symbology), the module is single cell (a suqare shape) used to encode one bit data. The parameter specifies the module width and height. See diagram:

    

  • For the TBarcode2D_MaxiCode barcode symbology, the module is single cell (a regular hexagonal shape) used to encode one bit data. The parameter specifies the horizonal width of a module. Also, it's the center to center horizontal distance between adjacent modules. See diagram:

    

  • For the Stacked 2D barcode symbology and Linear 1D barcode symbology, the module is the thinest bar (or space) in the barcode symbol. The parameter specifies the module width. See diagram:

    

  • For the 2D component TBarcode2D_CCA, TBarcode2D_CCB, or TBarcode2D_CCC, if its Linear property is set, the 2D symbol and the linear symbol are assembled to generate an EAN.UCC composite barcode symbol, the parameter specifies the module width for entire EAN.UCC composite barcode symbol (including both 2D and linear symbols). See diagram:

    

  See also the "Module" property.

• Angle: Integer; Specifies an angle in degrees to rotate the barcode symbol and its quiet zones (if they are represented, please read the ShowQuietZone property about whether or not the quiet zones will be represented) anticlockwise. You can use the LeadingQuietZone, TrailingQuietZone, TopQuietZone, and BottomQuietZone properties to specify the size of these quiet zones in modules. And use the ShowQuietZone property to specify whether to represent these quiet zones. See diagram (the SpaceColor property is set to clSilver in order to accentuate the quiet zones):

  

  For the 2D component TBarcode2D_CCA, TBarcode2D_CCB, or TBarcode2D_CCC, if its Linear property is set, the 2D symbol and the linear symbol are assembled to generate an EAN.UCC composite barcode symbol, and they will be rotated as an entirety. See diagram (the SpaceColor property is set to clSilver in order to accentuate the quiet zones):

  

  The parameter defaults to -1 if the Angle is not provided, and the barcode symbol will be rotated based on the value of the Orientation property:

  • boLeftRight: 0 degrees
  • boRightLeft: 180 degrees
  • boTopBottom: 270 degrees
  • boBottomTop: 90 degrees

  If you want to use the -1 degrees, the 359 degrees can be used instead.

• HDPI: Integer, Specifies the horizontal resolution of canvas in logical DPI. It's the number of logical dots or pixels per inch. It defaults to 0 if the HDPI is not provided, and the physical horizontal resolution obtained from the Canvas parameter will be used. So if you use the MM_TEXT map mode, you can specify it to 0. If you use the MM_ISOTROPIC or MM_ANISOTROPIC map mode, and the horizontal units or scaling is changed, the parameter is required in order to represent the correct barcode symbol when the symbol is rotated.

• VDPI: Integer, Specifies the vertical resolution of canvas in logical DPI. It's the number of logical dots or pixels per inch. It defaults to 0 if the VDPI is not provided, and the physical vertical resolution obtained from the Canvas parameter will be used. So if you use the MM_TEXT map mode, you can specify it to 0. If you use the MM_ISOTROPIC or MM_ANISOTROPIC map mode, and the vertical units or scaling is changed, the parameter is required in order to represent the correct barcode symbol when the symbol is rotated.

Return:

• If the method succeeds, the return value is zero.

• If the length of barcode text specified by the Barcode or Data (only for Delphi/C++ Builder 2009 or later) property is invalid, the return valus is -1 or -65537. Corresponding to the OnInvalidLength or OnInvalidDataLength (only for Delphi/C++ Builder 2009 or later) event will occur.

  For the TBarcode2D_CCA, TBarcode2D_CCB, and TBarcode2D_CCC barcode components, if the Linear property is set, the 2D symbol and the linear symbol are assembled to generate an EAN.UCC composite barcode symbol. If the length of barcode text of the 2D symbol is invalid, the return valus is -1. If the length of barcode text of the linear symbol is invalid, the return valus is -65537.

  For other barcode components, if the length of barcode text is invalid, the return valus is -1.

• If there is any invalid character in the the barcode text specified by the Barcode or Data (only for Delphi/C++ Builder 2009 or later) property, the return value is greater than zero. In general, it's the position index of first invalid character, the index 1 denotes that the first character is invalid character. Corresponding to the OnInvalidChar or OnInvalidDataChar (only for Delphi/C++ Builder 2009 or later) event will occur.

  For the TBarcode2D_CCA, TBarcode2D_CCB, and TBarcode2D_CCC barcode components, if the Linear property is set, the 2D symbol and the linear symbol are assembled to generate an EAN.UCC composite barcode symbol. If the invalid character is in the 2D symbol, the 17th bit of the return value is set to 0 (the return value is the position index of first invalid character, the index 1 denotes that the first character is invalid character). If the invalid character is in the linear symbol, the 17th bit of the return value is set to 1 (the difference between the return value and 65536 is the position index of first invalid character. For example, the return value 65537 denotes that the first character is invalid character).

  For other barcode components, if there is any invalid character in the the barcode text, the return value is the position index of first invalid character, the index 1 denotes that the first character is invalid character.

Note:

The method uses GetDeviceCaps function to retrieves device-specific information for the specified device. When using Printer.Canvas as the target cvanvas, it will fail if a default printer is not set in Windows. Please ensure that a default printer is specified in Windows:

Set default printer for current application:

uses Winapi.Printers;

procedure SetAppPrinter(const PrinterName: string);

var

Idx: Integer;

begin

Idx := Printer.Printers.IndexOf(PrinterName);

if Idx <> -1 then

Printer.PrinterIndex := Idx

else

ShowMessage('Printer not found!');

end;

Set the global default printer.

uses Winapi.WinSpool;

procedure SetWindowsDefaultPrinter(const PrinterName: string);

begin

if SetDefaultPrinter(PChar(PrinterName)) then

SendMessage(HWND_BROADCAST, WM_SETTINGCHANGE, 0, 0)

else

RaiseLastOSError;

end;

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