Set Barcode Text
This article describes how to work with text placed on barcode images. Aspose.BarCode for Node.js via Java enables customizing various parameters of barcode text: visibility, font, spacings, text location, and wrapping modes.
Overview
Aspose.BarCode for Node.js via Java allows developers to add human-readable text on barcode images in three different forms shown in the scheme below: main text label, top caption, and bottom caption. Any of these elements can be placed optionally or hidden.
Barcode Text
The main barcode text label contains short text information detached from bars by spacings. This text label can take six positions, as explained in the figure below: top center, top left, top right, bottom center, bottom left, or bottom right.
Text Visibility
Aspose.BarCode for Node.js via Java allows developers to visualize or hide barcode text. If there is no need to put human-readable text on a barcode image, barcode images can be generated without text labels, as shown below.
Text Positioning
The position of a barcode text label can be modified by customizing two parameters: alignment and location. These parameters can be set using setLocation and setAlignment methods of class CodetextParameters.
Location
The setLocation method allows setting the vertical position of a text label, namely, placing it above or below bars, as shown in figures below. The default setting is Below.
| Text Location | Above Barcode | Below Barcode |
|---|---|---|
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Alignment
The setAlignment method is used to set the horizontal position of a text label in a barcode image: right-side, left-side, or center, as illustrated in figures below. The default setting of barcode text alignment is CENTER.
| Text Alignment | Left | Center | Right |
|---|---|---|---|
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Spacing between Bars and Text Label
The default spacing (gap) between bars and a text label is equal to 2pt. It is possible to modify this spacing using the setSpace method of class CodetextParameters. This method is not applicable to several barcode types, including EAN-13, EAN-8, UPC-E, UPC-A, ISMN, ISBN, ISSN, and UpcaGs1DatabarCoupon.
Sample barcode images shown below have been created with various spacing settings (five and forty pixels).
| Text Spacing | Is Set to 5 Pixels | Is Set to 40 Pixels |
|---|---|---|
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Font Settings
To manage barcode text font, Aspose.BarCode for Node.js via Java provides setFont and setFontMode methods of class CodetextParameters. The default font setting is Arial 5pt regular. This setting is ignored if the Auto mode is enabled using the setFontMode method. This method is used to manage font size settings automatically. If it is called passing the Auto value, font size is determined automatically based on xDimension in such a way that the text label should take only one text line. FontMode.AUTO is recommended when AutoSizeMode.NEAREST or AutoSizeMode.INTERPOLATION settings are enabled. Alternatilvely, setting FontMode.MANUAL allows managing font size manually. Other font parameters, including font style, are set similarly in both Auto and Manual modes.
Barcode images shown below have been created with these two font modes.
| Font Setting Mode | Auto | Manual |
|---|---|---|
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NoWrap Mode for Text
It is possible to avoid line breaks in text that is too long for a single row using the setNoWrap method of class CodetextParameters. When the True setting is enabled, the text label is displayed in a single row regardless of the text length. The default setting is False. Barcode images shown below have been created with different NoWrap settings.
| Text Wrapping Mode | Wrap | No Wrap |
|---|---|---|
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Replacing Barcode Text in 2D Barcodes
To replace barcode text in 2D barcodes with some other text label with improved readability without modifications of the barcode image itself, it is possible to call the setTwoDDisplayText method of class CodetextParameters and pass new text to be placed. This is applicable to selected 2D types, including QR Code, Aztec, DataMatrix, MaxiCode, PDF417, and DotCode.
The sample barcode image shown below has been created using the TwoDDisplayText setting.
Caption
Aspose.BarCode for Node.js via Java allows developers to place additional text labels in a barcode image in form of captions above and below barcodes. As demonstrated in the figure below, such text captions have a parameter called Padding that allows modifying spacing size between captions and the nearest element (barcodes, main text label, or borders). Both text captions are disabled by default. If required, they can be shown by one or both simulteneously.
Caption Visibility
As stated above, additional text captions CaptionAbove and CaptionBelow are disabled by default. When required, top and bottom caption labels can be shown independently from each other or enabled simulteneously. The setVisible method of class CaptionParameters can be used to display one or two captions. Then, caption text can be inserted through the setText method. If required, caption labels can replace main text in 1D barcodes by enabling the former and disabling the latter. Figures given below demonstrate how caption positioning options.
| Caption Visibility | Above | Below |
|---|---|---|
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Text Positioning
The setAlignment method of class CaptionParameters allows modifying horizontal positions of caption labels in three directions: right, left, and center. The default position of captions is center. Figures shown below demonstrate barcode images with the top caption label with different alignment positions.
| Caption Alignment | Left | Center | Right |
|---|---|---|---|
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Caption Padding
The setPadding method of class CaptionParameters can be used to manage spacings for text captions. By default, the spacinng value is set to {5pt; 5pt; 0; 5pt} for the top caption and {0; 5pt; 5pt; 5pt} for the bottom one according to the standard Rectangle setting {Top, Left, Bottom, Right}. This method is inapplicable when captions are disabled. Barcode images shown below have been generated with different padding settings.
| Caption Padding | Is Set to 5 Pixels | Is Set to 40 Pixels |
|---|---|---|
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Caption Font
Aspose.BarCode for Node.js via Java does not enable automatic font size setting based on barcode size. Accordingly, caption font size requires manual setting. For top and bottom captions, various parameters, including font style and size can be set independently. Caption font can be customized through special methods of class FontUnit, setStyle and getSize. The default setting for caption font is Arial 8pt regular. The barcode image shown below explains different caption font settings.
let generator = new BarcodeGenerator(EncodeTypes.CODE_128);
generator.getParameters().getCaptionAbove().setText("CAPTION ABOOVE");
generator.getParameters().getCaptionAbove().setVisible(true);
generator.getParameters().getCaptionAbove().getFont().setStyle(FontStyle.ITALIC);
generator.getParameters().getCaptionAbove().getFont().getSize().setPoint(25);
NoWrap Mode for Caption
The setNoWrap method of class CaptionParameters allows disabling text line breaks when a text string is too large to fit in one line. When this method is called passing the True value, caption text is always displayed as a single line. Barcode images below show the difference between setNoWrap.TRUE and setNoWrap.FALSE settings.
| Caption Wrapping | Is Set to Wrap | Is Set to No Wrap |
|---|---|---|
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