Map Line Gradients

A mod for Slay the Spire 2 that replaces the plain-colored freehand map drawing lines with animated color gradients.

Features

• Built-in gradient presets
• Custom palette - define your own gradient using up to 10 hex color codes
• Live preview of the selected gradient in the mod settings UI
• Multiplayer support - each player's gradient preferences are synced across clients
• Random gradient - can be random each line drawn or the same pregenerated random gradient

Requirements

• Slay the Spire 2 (Early Access)
• BaseLib mod installed

Installation

1. Install BaseLib if you haven't already.
2. Copy the GradientLine/ folder (containing GradientLine.dll, GradientLine.pck, and GradientLine.json) into your StS2 mods directory.

Configuration

All settings are available in-game through the mod settings menu:

Setting	Default	Description
Gradient Type	Rainbow	Choose from: Rainbow, Fire, Ocean, Monochrome, Christmas, Spring, Random, or Custom
Animate	On	Whether the gradient shifts/animates as you draw
Randomize Start Offset	On	Whether each line starts with a random position in the gradient
Animation Speed	120	Controls how fast the gradient shifts while drawing (range: 30–200, higher = faster)

Custom Gradient Settings

(Only visible when Gradient Type is set to "Custom")

Setting	Default	Description
Custom Colors	(empty)	Up to 10 hex color codes, each prefixed with # (e.g. #FF0000#00FF00#0000FF)

Random Gradient Settings

(Only visible when Gradient Type is set to "Random")

Setting	Default	Description
Random Gradient Size	5	Number of color keyframes in the random gradient (range: 2–10)
Randomize Each Line	Off	Generate a new random gradient for every line drawn
Randomness	1.0	Controls color smoothness (range: 0.1–1.0). Lower values = smoother transitions between colors, higher values = more chaotic/vibrant
Reroll Random	(button)	Generate a new random gradient immediately

A live gradient preview strip updates in real time as you change settings.

Building from Source

Prerequisites

• .NET 9 SDK
• Godot 4.5.1 (the version bundled with StS2 / "Megadot") - needed only for exporting the .pck
• Slay the Spire 2 installed via Steam

The project auto-detects the Steam library location on Windows, Linux, and macOS. If it can't find the game, the build will error with a helpful message.

Build (DLL only)

dotnet build

This compiles the mod and copies GradientLine.dll, GradientLine.json, and required BaseLib files directly into the StS2 mods directory.

Publish (DLL + PCK)

dotnet publish

This additionally exports the Godot .pck asset bundle using Godot in headless mode.

Contributing New Gradient Presets

Adding a new built-in preset requires changes to two files:

1. Add the preset to GradientType enum in GradientUtil.cs

public enum GradientType : ushort
{
    Rainbow,
    Fire,
    // ...
    YourPreset, // add here (before Custom)
    Random,  
    Custom
}

2. Define color keyframes in GradientsPresets.cs

Making the last color identical to the first is recommended because a mismatch between the end and start colors creates a visible hard

3. Wire it up in BuildGradient

Add a case to the switch expression:

public static Gradient BuildGradient(float hueOffset)
{
    return Config.GradientType switch
    {
        // ...
        GradientType.Christmas => GradientsPresets.ChristmasColors,
        GradientType.Spring => GradientsPresets.SpringColors,
        GradientType.YourPreset => GradientsPresets.YourPresetColors,
        GradientType.Rainbow => null, // Handled differently
        GradientType.Custom => null,  // same
        _ => null
    };
}

TODO

• Make erasing better
• Allow gradient to repeat