How to Render Barcodes with Aspose.BarCode FOSS

Problem

After generating a barcode, you need to render it as an image file. Aspose.BarCode FOSS for Python renders barcodes to SVG and PNG formats via the to_svg() and to_png() methods on the Barcode object. The RenderOptions class controls visual properties such as scale, DPI, colors, quiet zone, and human-readable text display.

import aspose_barcode_foss as barcode
from aspose_barcode_foss import RenderOptions

bc = barcode.code128("RENDER-ME")
png = bc.to_png(options=RenderOptions(scale=2.0, dpi=300))

Prerequisites

Python 3.12 or later
pip package manager
aspose-barcode-foss installed via pip install aspose-barcode-foss

SVG Output

Call to_svg() to get the barcode as an SVG string. SVG output is vector-based and scales without quality loss.

import aspose_barcode_foss as barcode

bc = barcode.qr("https://example.com")
svg_string = bc.to_svg()

with open("barcode.svg", "w") as f:
    f.write(svg_string)

PNG Output

Call to_png() to get the barcode as PNG bytes. PNG output is rasterized at the specified scale and DPI.

import aspose_barcode_foss as barcode

bc = barcode.code128("PNG-OUTPUT")
png_bytes = bc.to_png()

with open("barcode.png", "wb") as f:
    f.write(png_bytes)

Controlling Scale and DPI

Use RenderOptions to set scale (a float multiplier for module size) and dpi (dots per inch for raster output). You can also set module_width and module_height directly for precise control over individual module dimensions.

from aspose_barcode_foss import RenderOptions

options = RenderOptions(
    scale=3.0,
    dpi=300,
    module_width=1.5,
    module_height=25.0,
)
png = bc.to_png(options=options)

Setting Colors

Set foreground_color and background_color as CSS color strings. Use transparent_background=True for PNG output with no background fill.

from aspose_barcode_foss import RenderOptions

options = RenderOptions(
    foreground_color="#003366",
    background_color="#FFFFFF",
)
svg = bc.to_svg(options=options)

# Transparent background for PNG
options_transparent = RenderOptions(
    foreground_color="#000000",
    transparent_background=True,
)
png = bc.to_png(options=options_transparent)

Quiet Zone

The quiet_zone property controls the whitespace margin around the barcode in module units. Barcode standards typically require a minimum quiet zone for reliable scanning.

from aspose_barcode_foss import RenderOptions

options = RenderOptions(quiet_zone=10.0)
svg = bc.to_svg(options=options)

Human-Readable Text

Set show_text=True to render human-readable text below the barcode. Control the font with font_family and font_size.

from aspose_barcode_foss import RenderOptions

options = RenderOptions(
    show_text=True,
    font_family="monospace",
    font_size=12.0,
)
svg = bc.to_svg(options=options)

RenderOptions Properties

Property	Type	Description
`scale`	`float`	Multiplier for module size
`dpi`	`int`	Dots per inch (raster output)
`module_width`	`float`	Width of one module
`module_height`	`float`	Height of one module
`quiet_zone`	`float`	Whitespace margin in module units
`foreground_color`	`str`	CSS color for bars/modules
`background_color`	`str`	CSS color for background
`transparent_background`	`bool`	Transparent PNG background
`show_text`	`bool`	Show human-readable text
`font_family`	`str`	Font for human-readable text
`font_size`	`float`	Font size for human-readable text

Known Limitations

The to_pdf() method and PdfRenderer class exist in the API but raise NotImplementedError. Use to_svg() or to_png() instead. SVG output can be embedded in PDF documents using external tools.