Custom images

A mod can ship its own command buttons and unit portraits instead of reusing the game's. Draw in any program, save a PNG and convert it with a tool. You need Node.js.

Example to copy: examples/ability-example (the "Respiro" button).

Convert a PNG

node tools/convert-image.js <entrada.png> <salida.bmp> --type button
node tools/convert-image.js <entrada.png> <salida.bmp> --type icon

boton: a command's button (button="..." of a <cmd>). In the game it's 153 x 51: three 51 x 51 frames (normal, mouse-over and disabled). You supply a 51 x 51 PNG and the tool makes the other two frames (a lighter one and a gray one). If you already have all three, a 153 x 51 PNG is used as is. Any other size is scaled without distortion.
icon: a unit's portrait (icon="...") or its training queue portrait (queueicon="..."). It's 65 x 76. A PNG of any size works: it's scaled without distortion, and transparent areas become the pure green the game treats as transparent.

With --background #RRGGBB you pick the color that fills a button's transparent areas (by default, a dark brown like the game's buttons).

The PNG must be 8 bits per channel and non-interlaced, which is the norm when saving from any program. If it isn't, the tool says so.

Where the file goes

With the same path the game uses, inside the mod folder. The rule for buttons is gameres/cmdbar/<whatever button= says>:

What	In the XML	File in your mod
A command's button	`button="Actions/Respiro.bmp"`	`gameres/cmdbar/Actions/Respiro.bmp`
An upgrade's button	`button="research/Mejora.bmp"`	`gameres/cmdbar/research/Mejora.bmp`
A unit's portrait	`<properties icon="gameres/icons/MiUnidad.bmp"/>`	`gameres/icons/MiUnidad.bmp`
Queue portrait	`queueicon="gameres/icons/MiUnidad.bmp"`	`gameres/icons/MiUnidad.bmp`

The game's commands also use the upgrades, skills, states and specials folders inside cmdbar. They work the same way.

Case doesn't matter in paths. If the game can't find an image, the button shows as a plain blue square.

If it doesn't show

Set LogFiles=1 in [Debug] of imperivm-mod.ini. The log notes every file the game opens and flags the ones that don't exist (VFS: opens … -> does not exist), so you can see the exact name it asks for.

What you can't do

Help images (help/...), the info bar images of each civilization and menu backgrounds have no converter.
Unit and building models and animations (.rle and .ent.xml) are a different matter: see Custom graphics.