esir-item-icon-prep

name	esir-item-icon-prep
description	Use when ESIR item art needs to be turned into a transparent Factorio item icon strip, especially when source art has a baked light checkerboard or white background and must end up as a `128/64/32` mipmapped item icon under `exotic-space-industries-remembrance/graphics/items/`.

ESIR Item Icon Prep

Use this when a user drops source art for an ESIR item and wants it converted into a shippable Factorio icon.

The bundled helper:

• removes edge-connected light neutral backgrounds, including baked checkerboards
• preserves already-transparent sources
• fits the subject onto a 128x128 transparent canvas
• emits a horizontal 128/64/32 mip strip (224x128)
• follows the main-pack graphics convention: shipped icon filenames omit leading ei- even when the item prototype keeps an ei-* name

Workflow

1. Confirm the source art path and the destination item icon path.
2. If the destination file will be overwritten, write a backup into tmp/.
3. Run scripts/build_factorio_item_icon.py.
4. Inspect the generated 128x128 preview or the final strip with view_image.
5. If the item prototype uses the strip directly, keep:
   • icon_size = 128
   • icon_mipmaps = 3
6. If the item is already wired into a prototype, run the ESIR fast QC pass.

Command

Run from the repo root:

python .codex/skills/esir-item-icon-prep/scripts/build_factorio_item_icon.py `
  --source exotic-space-industries-remembrance/graphics/items/calcite-bed.png `
  --output exotic-space-industries-remembrance/graphics/items/calcite-bed.png `
  --backup tmp/calcite-bed-source-original.png `
  --preview tmp/calcite-bed-preview-128.png

Notes

• The helper is for source art, not an already-built 224x128 mip strip.
• Background removal keys off light, low-saturation pixels that are edge-connected to the canvas border, so bright highlights inside the subject are less likely to be eaten.
• The output strip is written into the main mod folder unless you point --output somewhere else.