Convert CGM to PNG — Free Online Converter
Convert Computer Graphics Metafile (.cgm) to Portable Network Graphics (.png) online for free. Fast, secure image conversion with no watermarks or reg...
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How to Convert
Upload your .cgm file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .png file when it's ready.
About CGM to PNG Conversion
CGM (Computer Graphics Metafile) is an ISO-standardized vector graphics format (ISO 8632) used primarily in technical documentation, engineering drawings, and aviation standards. CGM is the mandated illustration format in ATA iSpec 2200 (aviation maintenance manuals), NATO STANAG 4602 (military technical publications), and S1000D (international defense documentation). These industries produce millions of CGM files for aircraft maintenance, defense systems, and industrial equipment documentation.
PNG (Portable Network Graphics) is the universal lossless raster format supported by every device and application. Converting CGM to PNG makes specialized technical illustrations viewable outside their native CGM viewers, enabling embedding in web-based documentation, PowerPoint presentations, and standard document formats.
Why Convert CGM to PNG?
CGM files require specialized viewer software (IsoDraw, CGM Viewer, Micrografx) that most people do not have. When technical illustrations need to be shared with stakeholders, included in presentations, or published on web-based documentation portals, PNG provides universal accessibility. Engineers can view CGM in their specialized tools, but everyone else needs PNG.
Web-based technical documentation systems increasingly replace PDF-based manuals. Interactive electronic technical manuals (IETMs) and component maintenance manuals (CMMs) published as web applications need illustrations in web-compatible formats. Converting CGM to PNG enables these illustrations to display in browsers without plugin dependencies.
Common Use Cases
- Convert aviation CGM illustrations for embedding in web-based electronic technical manuals
- Export CGM engineering drawings as PNG for inclusion in PowerPoint technical presentations
- Convert CGM military technical illustrations for web-based S1000D documentation viewers
- Produce PNG versions of CGM diagrams for email distribution to stakeholders without CGM viewers
- Convert CGM technical drawings for embedding in Word reports and compliance documentation
How It Works
LibreOffice imports the CGM file using its metafile parser, which reads the CGM binary or clear-text encoding to extract vector elements: polylines, polygons, text, circles, arcs, and fill areas. The vector content is rasterized at the specified resolution with anti-aliasing applied to edges. The PNG output uses 24-bit RGB color with optional 8-bit alpha transparency. Default resolution is 150 DPI for screen display; 300 DPI is available for print-quality output. CGM's coordinate system is mapped to pixel dimensions with aspect ratio preservation.
Quality & Performance
Line work, shapes, text labels, and fill patterns from the CGM are accurately rasterized in the PNG. Anti-aliasing produces smooth edges on diagonal lines and curves. Text is rendered with the specified font or a substitute if the original font is unavailable. The main consideration is resolution selection — technical drawings with fine detail need higher DPI for readable line work and text. CGM files using custom hatch patterns or device-specific rendering may show minor differences from the original CGM viewer output.
Device Compatibility
| Device | CGM | PNG |
|---|---|---|
| Windows PC | Partial | Native |
| macOS | Partial | Native |
| iPhone/iPad | Partial | Native |
| Android | Partial | Native |
| Linux | Partial | Native |
| Web Browser | No | Native |
Tips for Best Results
- 1Use 300 DPI for technical illustrations that contain fine line work and small text labels
- 2For web-based technical documentation, PNG provides the broadest browser compatibility
- 3If you need scalable technical illustrations, convert to SVG instead of PNG
- 4Verify text rendering after conversion — original CGM fonts may be substituted with system fonts
- 5For large CGM files with many elements, the PNG file size at 300 DPI can be substantial — optimize for your target use
CGM-to-PNG conversion makes specialized technical illustrations from aviation, defense, and engineering industries accessible in the universal PNG image format for web publishing, presentations, and document embedding.