Convert an Image to GDSII

Glyph can import a PNG or JPG as a reference bitmap, then trace its shapes into real polygons on a GDS layer. The bitmap itself never lands in the exported file — only the traced polygons do — so tracing is how a scanned mask, a screenshot, or hand-drawn art becomes fab-ready geometry.

Time: ~8 min

You'll need: a PNG, JPG, WEBP, BMP, or GIF image of the layout you want to reproduce, and Glyph open in a desktop browser.

Why trace an image into a layout?

GDSII has no raster primitive — every shape a mask writer can expose is a polygon, path, or reference. When your starting point is a photo of an existing die, a scanned drawing, or artwork from another tool that only exports images, tracing is the bridge: Glyph binarises or contours the pixels and turns the result into linear polygons you can edit, snap, boolean, and export like anything else you drew by hand.

Import your image

1. Bring the image into Glyph. Drag the file straight onto the Glyph window (a "Drop to open" overlay confirms it's accepted), or use File → Open… and pick the image instead of a .gds.
2. Set the scale. The import dialog asks for µm per pixel — pick a preset (0.1 / 0.5 / 1 / 5 / 10 µm/px) or type an exact value based on a known feature size in the source image. This scale is what turns pixel dimensions into real-world nanometres.
3. Confirm the drop position. The bitmap lands centered on the current viewport, on the active layer. It behaves like any other shape — select, move, rotate, scale, or mirror it with the Properties panel — but it's a tracing aid, not geometry.

Trace it to polygons

1. Select the bitmap, then open Edit → Trace bitmap….
2. Pick a mode:
   • Cutoff — one luminance threshold; pixels darker (or lighter, with Invert) become filled polygons. Best for clean black-on-white art.
   • Steps — N gray bands, each becoming a closed contour. Good for posterized or topo-style images.
   • Edges — a marching-squares contour on the image gradient, for line art where outlines matter more than fill.
   • Colors — median-cut clustering into N color bands, each its own polygon set. Use this to recover a multi-layer mask from a colored reference image.
3. Tune the shared knobs in the live preview: min area (drops speckle islands), RDP tolerance (fewer vertices vs. more faithful edges), oversample (smoother diagonals), and snap-to-grid. For Steps/Colors, toggle per-band layers if you want each band auto-split onto its own layer.
4. Click Apply. The traced polygons are added to the active cell as a new selection; the source bitmap is left in place so you can re-trace with different settings if the first pass isn't right.

Clean up and export

The bitmap you imported is excluded from .gds export — it's reference-only and never survives a real save. The polygons produced by Apply are ordinary shapes, so once you're happy with the trace, delete the bitmap (select it, press Delete) and save normally with File → Save as…, choosing the .gds extension. Only the traced geometry goes into the file.

What you built

A raster reference image converted into real, editable GDSII polygons — placed on the layer(s) you chose, cleaned of the source bitmap, and ready to export as a standard .gds file that any downstream tool can open.

Next steps

Traced geometry is layout the same as anything hand-drawn, so it flows into the same downstream process as every other Glyph design. See NANYTE's maskless lithography overview for how a traced layout like this one gets exposed. For the full reference on trace modes and knobs, read Bitmap import and Trace; for saving and export formats beyond .gds, see Open and save GDS files; or jump straight into the editor and try it on your own image.