Delta Gerber

A Java library for parsing Gerber RS-274X and Excellon NC drill files with SVG rendering, realistic PCB visualization, and an interactive web viewer.

Try the online viewer at deltaproto.com — no install needed, runs in your browser.

Realistic PCB Rendering

Generate photorealistic top and bottom views of your PCB with proper layer stacking — FR4 substrate, copper with HASL/ENIG finish, semi-transparent soldermask, silkscreen, and drill holes with true SVG transparency.

Board Top	Board Bottom

All Layers	Realistic Top

Maven Dependency

<dependency>
    <groupId>com.deltaproto</groupId>
    <artifactId>delta-gerber</artifactId>
    <version>1.1.0</version>
</dependency>

Features

Gerber Parsing

• Full RS-274X support (.gbr, .ger, .gtl, .gbl, .gts, .gbs, .gto, .gbo, .gtp, .gbp, .gko, .gm, etc.)
• All standard apertures: circle (C), rectangle (R), obround (O), polygon (P)
• Aperture macros with primitives (circle, vector line, center line, outline, polygon, thermal)
• Region fills (G36/G37) with multiple contours
• Arc interpolation (G02/G03) with single and multi-quadrant modes
• Layer polarity (LPD/LPC) with true SVG mask-based transparency
• Step and Repeat (%SR%) for panelized boards
• Aperture transforms: rotation (LR), scaling (LS), mirroring (LM)
• Image polarity (%IP%) and offset (%OF%) recognition

Excellon Drill Parsing

• Standard Excellon NC drill format (.drl, .txt, .xln, .drd)
• Tool definitions with diameter
• Drill hits and routed slots (G85, M15/M16/M17 routing mode)
• Plated (PTH) and non-plated (NPTH) hole distinction
• Absolute and incremental coordinate modes (G90/G91)
• Metric and inch units with automatic format detection

CAD Tool Compatibility

• Altium Designer — Gerber X2 attributes, mechanical layer outlines (.GM, .GM1), format detection
• Cadence Allegro — Non-standard drill format with holesize comments, M00 tool separators, repeat codes (R02X...)
• EAGLE — Non-standard OC8/OCn octagon aperture type, combined FS+MO command blocks
• KiCad — Standard Gerber X2 output with file function attributes
• Legacy RS-274X — Deprecated G-codes (G54, G70/G71), deprecated extended commands (%IN, %LN, %AS, %MI, %SF, %IR%)
• UTF-8 BOM handling for files exported from Windows tools

SVG Rendering

• High-fidelity SVG output with native SVG elements (circles, arcs, paths)
• Polygonized mode for geometry processing
• Multi-layer composite rendering with configurable colors and opacity
• Realistic PCB rendering with physically accurate layer stacking:
  • FR4 substrate, copper (silver under mask / gold at exposed pads)
  • Semi-transparent soldermask with inverted mask for pad openings
  • Silkscreen nested inside soldermask (only visible where mask is present)
  • Drill holes punching through all layers as true SVG transparency

Web Viewer

• Interactive pan/zoom with mouse wheel and drag
• Three visualization modes: All Layers, Board Top, Board Bottom
• Layer type auto-detection from filename and content analysis
• Layer type dropdowns for manual override
• Select all/none checkbox with tri-state indicator
• Top/Bottom quick-filter buttons
• Hover-to-solo: preview individual layers by hovering
• Center-truncated filenames with instant tooltips
• Browser-side ZIP extraction and file persistence (IndexedDB)
• Recent project history with re-open support
• Stateless server architecture (browser owns the data)

Quick Start — Download and Run

Download the standalone JAR from the latest release and run:

java -jar delta-gerber-1.1.0-jar-with-dependencies.jar

Open http://localhost:938 and drop a Gerber ZIP file onto the viewer, or click "Try Example" to load the bundled Arduino Uno board.

Requires Java 17+. No other dependencies needed.

Build from Source

mvn clean package
java -jar target/delta-gerber-1.1.0-jar-with-dependencies.jar

Usage as Library

// Parse a Gerber file
GerberParser parser = new GerberParser();
GerberDocument doc = parser.parse(gerberContent);

// Render a single layer to SVG
SVGRenderer renderer = new SVGRenderer();
String svg = renderer.render(doc);

// Parse an Excellon drill file
ExcellonParser drillParser = new ExcellonParser();
DrillDocument drillDoc = drillParser.parse(excellonContent);

Multi-Layer Rendering

MultiLayerSVGRenderer renderer = new MultiLayerSVGRenderer();
List<MultiLayerSVGRenderer.Layer> layers = new ArrayList<>();
layers.add(new MultiLayerSVGRenderer.Layer("top-copper", copperDoc)
    .setColor("#e94560").setOpacity(0.85));
layers.add(new MultiLayerSVGRenderer.Layer("drill", drillDoc)
    .setColor("#00ffff"));

String svg = renderer.render(layers);

Realistic PCB Rendering

MultiLayerSVGRenderer renderer = new MultiLayerSVGRenderer();
List<MultiLayerSVGRenderer.Layer> layers = new ArrayList<>();

layers.add(new MultiLayerSVGRenderer.Layer("outline", outlineDoc)
    .setLayerType(LayerType.OUTLINE));
layers.add(new MultiLayerSVGRenderer.Layer("copper", copperDoc)
    .setLayerType(LayerType.COPPER_TOP));
layers.add(new MultiLayerSVGRenderer.Layer("mask", soldermaskDoc)
    .setLayerType(LayerType.SOLDERMASK_TOP));
layers.add(new MultiLayerSVGRenderer.Layer("silk", silkscreenDoc)
    .setLayerType(LayerType.SILKSCREEN_TOP));
layers.add(new MultiLayerSVGRenderer.Layer("drill", drillDoc)
    .setLayerType(LayerType.DRILL));

String realisticSvg = renderer.renderRealistic(layers);

Aperture Visual Test

The library includes a comprehensive visual test catalog with 127 test cases covering all aperture types, macros, regions, polarity, transforms, and legacy format support.

View Aperture Visual Test

Project Structure

• src/main/java/com/deltaproto/deltagerber/parser — Gerber and Excellon parsers
• src/main/java/com/deltaproto/deltagerber/lexer — Tokenizer for Gerber files
• src/main/java/com/deltaproto/deltagerber/model — Data model for Gerber/drill documents
• src/main/java/com/deltaproto/deltagerber/renderer/svg — SVG rendering engine
• src/main/java/com/deltaproto/deltagerber/web — Web viewer server
• src/main/resources/web — Web viewer HTML/CSS/JS
• testdata — Sample Gerber projects for testing

License

MIT