Customize Barcode Text and Captions in Python via .NET
This article describes how to work with text placed on barcode images. Aspose.BarCode for Python via .NET enables customizing various parameters of barcode text: visibility, font, spacings, text location, and wrapping modes.
Overview
Aspose.BarCode for Python via .NET 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 Python via .NET 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 in the example below.
Text Positioning
The position of a barcode text label can be modified by customizing two parameters: alignment and location. These parameters can be adjusted through location and alignment properties of class CodetextParameters.
Alignment
The alignment property is used to set the horizontal position of a text label in a barcode image: right-side, left-side, or center, as illustrated in the figures below. The default setting of barcode text alignment is Center.
| Text Alignment | Left | Center | Right |
|---|---|---|---|
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Location
The location property allows setting the vertical position of a text label, namely, placing it above or below bars, as shown in the figures below. The default setting is Below.
| Text Location | Above Barcode | Below Barcode |
|---|---|---|
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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 space property of class CodetextParameters. This property is not applicable to specific 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 Python via .NET provides font and font_mode properties of class CodetextParameters. The default font setting is Arial 5pt regular. This setting is ignored if the Auto mode is enabled using the font_mode property. This property is used to manage font size settings automatically. If it is called passing the Auto value, font size is determined automatically based on x_dimension 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 a text that is too long for a single row using the no_wrap property 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 no_wrap 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 to the barcode image itself, it is possible to call the two_d_display_text property of class CodetextParameters and pass new text to be placed. This is applicable to selected 2D type, including QR Code, Aztec Code, Data Matrix, MaxiCode, PDF417, and DotCode.
The sample barcode image shown below has been created using the two_d_display_text setting.
Caption
Aspose.BarCode for Python via .NET 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 simultaneously.
Caption Visibility
As stated above, additional text captions Caption_Above and Caption_Below are disabled by default. When required, top and bottom caption labels can be shown independently from each other or enabled simultaneously. The visible property of class CaptionParameters can be used to display one or two captions. Then, caption text can be inserted through the text property. If required, caption labels can replace main text in 1D barcodes by enabling the former and disabling the latter. The figures given below demonstrate how to caption positioning options.
| Caption Visibility | Above | Below |
|---|---|---|
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Text Positioning
The alignment property of class CaptionParameters allows modifying horizontal positions of caption labels in three directions: right, left, and center. The default position of captions is center. The 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 padding property of class CaptionParameters can be used to manage spacings for text captions. By default, the spacing 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 property 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 Python via .NET does not enable automatic font size settings 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 using the properties of class FontUnit. The default setting for caption font is Arial 8pt regular. The barcode image shown below explains different caption font settings.
NoWrap Mode for Caption
The no_wrap property of class CaptionParameters allows disabling text line breaks when a text string is too large to fit in one line. When this property is initiated using the True value, caption text is always displayed as a single line. Barcode images below show the difference between true and false settings.
| Caption Wrapping | no_wrap Is Set to False | no_wrap Is Set to True |
|---|---|---|
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