Convert CGM to OTB

Understanding CGM and OTB file formats

CGM (Computer Graphics Metafile) is a standardized file format used for 2D vector graphics, raster graphics, and text. It is widely used in technical illustration, engineering, and aviation industries due to its platform-independent nature and ability to store complex graphics in a compact form.

OTB (Over The Air Bitmap) is a bitmap image format primarily used for sending simple monochrome images, such as logos or icons, to mobile phones via SMS or MMS. OTB files are compact and optimized for low-resolution displays, making them suitable for early mobile devices.

How to convert CGM to OTB

Converting a CGM file to OTB format involves transforming a vector-based image into a monochrome bitmap suitable for mobile devices. This process typically requires two steps: first, converting the CGM file to a common raster format (such as PNG or BMP), and then converting that raster image to OTB.

Recommended software for CGM to OTB conversion

There is no direct, mainstream software that supports CGM to OTB conversion in a single step. However, you can use the following workflow:

1. Convert CGM to PNG or BMP: Use Inkscape (free and open-source) to open your CGM file and export it as a PNG or BMP. Go to File → Export PNG Image or File → Save As and select BMP.
2. Convert PNG/BMP to OTB: Use ImageMagick (a powerful command-line tool) to convert the raster image to OTB format. The command is:
   convert input.png output.otb

Both Inkscape and ImageMagick are available for Windows, macOS, and Linux.

Key considerations

• Image quality: OTB supports only monochrome images, so complex CGM graphics may lose detail during conversion.
• Resolution: OTB files are optimized for small, low-resolution screens. Resize your image accordingly before conversion.
• Batch conversion: ImageMagick supports batch processing, making it efficient for converting multiple files.

Summary

To convert CGM to OTB, first export the CGM as a raster image using Inkscape, then use ImageMagick to convert the raster file to OTB. This two-step process ensures compatibility and preserves as much image quality as possible within the limitations of the OTB format.