# Gui Widget Filtering Implementation

> Use when a GUI widget (e.g., isotopes display, compound list, or metabolite selector) should honor user preferences to show only a subset of available items, and the filtering logic must read from application preferences and apply it during widget rendering or refresh cycles.

- Skill: `holobiomicslab/gui-widget-filtering-implementation` (Agent Skill)
- Install (CLI): `npx skillmds@latest add holobiomicslab/gui-widget-filtering-implementation`
- Raw SKILL.md: https://api.skillmd.com/api/skills/holobiomicslab/gui-widget-filtering-implementation/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- License: CC-BY-4.0
- Author: HolobiomicsLab (https://skillmd.com/u/holobiomicslab)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/holobiomicslab/gui-widget-filtering-implementation

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# GUI widget filtering implementation

## Summary

Implement a preference-driven filter for GUI widgets that restricts display to user-selected items by reading application preferences and conditionally suppressing rendering of non-selected entities. This skill applies preference-selection logic to widget rendering loops in Qt-based applications.

## When to use

Use this skill when a GUI widget (e.g., isotopes display, compound list, or metabolite selector) should honor user preferences to show only a subset of available items, and the filtering logic must read from application preferences and apply it during widget rendering or refresh cycles.

## When NOT to use

- The filtering logic is already implemented in the widget or a parent container.
- The application uses a declarative UI framework (e.g., QML) rather than imperative C++ rendering loops, requiring different implementation strategies.
- Preferences are not yet defined or accessible in the codebase; preference schema must be designed first.

## Inputs

- Application preference file or store (containing selected item identifiers)
- Widget source code (Qt C++ files)
- Widget data source or model (list of all available items)

## Outputs

- Modified widget source code with preference-reading and rendering filter logic
- Compiled and relinked executable (via qmake/make)
- Widget display showing only selected items

## How to apply

Locate the widget's source code and its rendering loop (typically in the Maven GUI src/ directory tree). Identify where application preferences store the active/selected items (e.g., a preference key listing selected isotopes). Implement a filter that reads the active set from preferences before or during the widget's display rendering phase. For each item in the widget's data source, check membership in the active set; suppress rendering (skip or hide) any item not in that set. Recompile using qmake -r build.pro and make -j4, then manually test the widget to verify that visibility matches the preference selection. The rationale is that preference-driven filtering centralizes user intent in a single source of truth (application preferences) rather than distributing filter state across multiple UI elements.

## Related tools

- **git** (Clone the Maven repository and manage feature branches for the filtering implementation) — https://github.com/eugenemel/maven
- **qmake** (Generate build configuration from Qt project files before compilation)
- **make** (Compile and link the modified widget source code with parallel jobs)
- **Maven GUI** (Host application containing the widget to be filtered) — https://github.com/eugenemel/maven
- **Qt5** (GUI framework providing widget rendering, preference storage, and signal/slot mechanisms)

## Evaluation signals

- Widget rendering loop successfully reads application preferences without errors or undefined-reference exceptions.
- Manual testing confirms that only items present in the active preference set are visible in the widget; items not in the set are absent from display.
- Compilation completes with no errors using 'qmake -r build.pro && make -j4'.
- Preference changes (e.g., selecting/deselecting an isotope in preferences) cause the widget display to update on next refresh or application restart.
- Code review confirms that the filter logic is applied before or at the rendering stage, not after all items are already drawn.

## Limitations

- The article provides only a README with build instructions and retirement notice; no actual source code or preference-storage mechanism is documented, so the exact location and structure of preference keys must be discovered by code inspection.
- If preferences are not persisted across sessions or do not support the item identifiers used by the widget, the filter will fail silently or render all items.
- Performance implications are not discussed; if the data source is very large, reading preferences and filtering during every render cycle may cause lag.

## Evidence

- [other] How does the isotopes widget restrict its display to only those isotopes that have been selected in the application preferences?: "How does the isotopes widget restrict its display to only those isotopes that have been selected in the application preferences?"
- [other] Identify the preference-selection mechanism and the isotopes display rendering logic. 4. Implement a filter that reads the active isotopes from application preferences and applies it to the isotopes widget display loop, suppressing rendering of any isotope not in the selected set.: "Identify the preference-selection mechanism and the isotopes display rendering logic. 4. Implement a filter that reads the active isotopes from application preferences and applies it to the isotopes"
- [other] Recompile the project using qmake -r build.pro and make -j4 to verify no compilation errors.: "Recompile the project using qmake -r build.pro and make -j4 to verify no compilation errors."
- [other] Test the widget manually to confirm that isotope visibility now matches the preference selection.: "Test the widget manually to confirm that isotope visibility now matches the preference selection."
- [other] Locate the isotopes widget source code in the Maven GUI codebase (typically in the src/ directory tree).: "Locate the isotopes widget source code in the Maven GUI codebase (typically in the src/ directory tree)."