Gum Forms Default Visuals

Forms Default Visuals

What They Are

Default visuals are InteractiveGue subclasses that procedurally build a complete visual tree in their constructor — no Gum project file needed. Each one backs a specific Forms control (e.g., ButtonVisual backs Button). They live in MonoGameGum/Forms/DefaultVisuals/.

These are one implementation, not the structure. A control can be backed by any visual — a tool-authored component or a custom InteractiveGue subclass with a completely different tree — so structural features (a Window's Fill InnerPanelInstance, or sizing it to children via WindowVisual.MakeSizedToChildren()) live in the visual, never in the control. See the Visual/FrameworkElement split in gum-forms-controls.

Generation

All default visuals live under DefaultVisuals/V3/*Visual and use DefaultVisualsVersion.V3/.Newest — the only generation; the enum has a single member.

The Forms sprite-sheet icons are one of three icon pipelines in Gum (this one for the runtime; GumIcon/PathGeometry for tool WPF chrome; PNG ImageList for the tool tree view). For the umbrella overview and routing, see gum-icons.

Construction Pattern

Every *Visual constructor does four things in order:

1. Build child runtimes — NineSliceRuntime for background, TextRuntime for label, etc. Children are added via Children.Add().
2. Create a StateSaveCategory — Populated with StateSave objects for each interaction state (Enabled, Disabled, Highlighted, Pushed, Focused, etc.). States are applied by the Forms control via SetProperty.
3. Pull styling from Styling.ActiveStyle — Colors, texture coordinates, font config.
4. Attach the Forms control — FormsControlAsObject = new Button(this) (or whichever control type). This triggers ReactToVisualChanged on the Forms side.

Initialization — Two Paths

GumService.Initialize() always calls FormsUtilities.InitializeDefaults() first, which populates FrameworkElement.DefaultFormsTemplates with code-only default visuals.

If a .gumx project file is also passed to Initialize(), it then calls FormsUtilities.RegisterFromFileFormRuntimeDefaults(), which overrides the code-only defaults with project-defined Forms visuals (components with Forms behaviors). This is the path used when the Gum tool has authored the UI.

Code-only projects — call Initialize(DefaultVisualsVersion) with no project file. Controls get their visuals from the *Visual classes.

Project-based — call Initialize(gumProjectFile). The code-only defaults are registered first, then project components replace them via RegisterFromFileFormRuntimeDefaults().

Styling.cs

Centralized style constants consumed by default visuals:

• Colors — Primary, Danger, Warning, Success palettes
• NineSlice — Texture coordinate presets (Solid, Bordered, Outlined, etc.)
• Icons — Coordinates for 70+ icon sprites on the shared sprite sheet
• Text — Font configuration (Normal, Strong, Emphasis)
• Loads embedded UISpriteSheet.png by default via UseDefaults()

Styling.ActiveStyle is read at construction time only — set it before creating controls; existing controls don't retroactively restyle.

Every *Visual seeds BackgroundColor/ForegroundColor from Styling.ActiveStyle.Colors.*, but those setters don't paint — they call FormsControl?.UpdateState(), which re-runs the active state's StateSave.Apply lambda, which derives the real color via ColorExtensions.Adjust/.ToGrayscale() off the two base colors. Never set visual.Background.Color directly — the next state transition overwrites it. To override one state's look, clear and reassign its Apply lambda, then call UpdateState().

Named Children Convention

Forms controls locate children by name (e.g., "TextInstance", "FocusIndicator", "InnerPanel"). If a visual omits an expected named child, the Forms control silently skips it (or throws under FULL_DIAGNOSTICS). When building custom visuals, match the names the Forms control looks up in its ReactToVisualChanged.

Key Files

Cross-references

• Restyling these visuals as a distributable, palette-driven package: gum-theming.
• ColorExtensions.Adjust/.ToGrayscale() live alongside Styling in the same file.