UI & Preview Extensions

This chapter introduces Lertaro.PluginSdk interfaces for extending the main sidebar, adding custom table columns, providing dynamic Quick Panel tabs, crafting QuickLook file previewers, extracting thumbnails, and building WPF themes and i18n localization packs.

1. Sidebar Filter Provider ISidebarFilterProvider

Injects custom category filter trees into the left sidebar of the Full Search window:

namespace Lertaro.PluginSdk;

public interface ISidebarFilterProvider : IPluginComponent
{
    IEnumerable<SidebarFilterGroup> GetFilterGroups();
}

public sealed class SidebarFilterGroup
{
    public required string GroupName { get; init; }
    public required IReadOnlyList<SidebarFilterItem> FilterItems { get; init; }
}

public sealed class SidebarFilterItem
{
    public required string Id { get; init; }
    public required string DisplayName { get; init; }
    public ImageSource? Icon { get; init; }
    public required Func<ISearchResult, bool> FilterFunc { get; init; } // Match predicate
}

SidebarFilterGroup.Id is an optional stable group identifier. The host can use recognised identifiers such as Type to apply built-in behaviour; leave it empty when the group is entirely plugin-defined.

2. Custom Table Column Provider IResultColumnProvider

Appends custom data columns to the "Details" table view of the Full Search window (e.g. displaying media duration, lines of code, or Git branches):

public interface IResultColumnProvider : IPluginComponent
{
    string ColumnId { get; }
    string HeaderText { get; }
    double DefaultWidth => 120;
    double MinWidth => 40;
    bool IsVisibleByDefault => false;
    string? GetCellText(ISearchResult result);
    int Compare(ISearchResult a, ISearchResult b) => 0; // Header click sort comparer
}

3. Quick Panel Tab Provider IQuickPanelTabProvider

Contributes dynamic workspace tabs to the Quick Panel under the Quick Search bar:

public interface IQuickPanelTabProvider : IPluginComponent
{
    string TabId { get; }
    string Title { get; }
    string? IconPath => null;
    Task<IReadOnlyList<ISearchResult>> GetItemsAsync(CancellationToken token);

    // Drag-and-drop acceptance logic
    bool CanHandleDragOver(IDataObject data) => false;
    Task HandleDropAsync(IDataObject data, CancellationToken token) => Task.CompletedTask;

    // Drag-to-reorder support
    bool SupportsReorder => false;
    Task SaveOrderAsync(IReadOnlyList<ISearchResult> orderedItems) => Task.CompletedTask;

    // Custom tab action context
    DynamicActionContext CreateActionContext() => DynamicActionContext.Default;
}

4. File Previews & Thumbnails

Custom File Preview Provider IFilePreviewProvider

Renders interactive previews inside the QuickLook window (triggered via Space):

public interface IFilePreviewProvider : IPluginComponent
{
    bool CanPreview(string filePath);
    int Priority => 0;                  // Priority when multiple providers match
    FrameworkElement CreatePreviewControl(string filePath);
}

Preview Lifecycle & Reuse Contracts

When your returned WPF FrameworkElement implements the following optional contracts, the host optimizes the preview lifecycle:

• IPreviewSessionAware: Implements void OnPreviewClosed(), triggered when the preview window closes or navigates to an incompatible file, ensuring safe disposal of media players, WebView2 instances, or file streams.
• IReusablePreview: Implements void UpdatePreview(string filePath). When navigating continuously between similar files via arrow keys, the host updates content in-place without destroying and recreating the control, eliminating UI flicker.

Custom Thumbnail Provider IThumbnailProvider

Extracts high-resolution thumbnails for proprietary formats without native Shell thumbnail handlers (e.g. .blend, .psd, .dwg):

public interface IThumbnailProvider : IPluginComponent
{
    bool CanProvide(string filePath);
    Task<ImageSource?> GetThumbnailAsync(string filePath, int targetSize, CancellationToken token);
}

5. Themes & Localization

Theme Provider IThemeProvider

Contributes custom color palettes and WPF Resource Dictionaries to Lertaro:

public interface IThemeProvider : IPluginComponent
{
    string ThemeId { get; }
    string DisplayName { get; }
    ResourceDictionary GetResourceDictionary(bool isDark);
}

Localization Provider ITranslationProvider

Supplies localized translation dictionaries dynamically:

public interface ITranslationProvider : IPluginComponent
{
    IReadOnlyDictionary<string, string> GetTranslations(string cultureName);
}