KryptonColorDialog

Overview

The KryptonColorDialog class provides a Krypton-themed wrapper around the standard Windows color selection dialog. It inherits from System.Windows.Forms.ColorDialog and enhances it with Krypton styling, custom icons, titles, high-DPI support, and an optional alpha (transparency) slider for color selection with alpha channel support.

Class Hierarchy

System.Object
└── System.ComponentModel.Component
    └── System.Windows.Forms.CommonDialog
        └── System.Windows.Forms.ColorDialog
            └── Krypton.Toolkit.KryptonColorDialog

Constructor and Initialization

public KryptonColorDialog()

The constructor initializes all the enhanced components:

  • CommonDialogHandler: Manages Krypton theming and window behavior
  • Alpha Components: Creates alpha slider, label, and preview panel for transparency support
  • Timer: Handles real-time alpha value updates
  • Default Icon: Uses DialogImageResources.Colour_V10

Key Properties

Title Property

public string Title { get; set; }
  • Purpose: Sets the caption text shown in the dialog's title bar
  • Category: Appearance
  • Default Value: Empty string (uses system default)
  • Designer Visible: Yes

Usage Example:

var dialog = new KryptonColorDialog
{
    Title = "Choose Document Foreground Color"
};

Icon Property

public Icon Icon { get; set; }
  • Purpose: Sets a custom icon displayed in the dialog's title bar
  • Category: Appearance
  • Default Value: DialogImageResources.Colour_V10
  • Designer Visible: Yes

Usage Example:

var dialog = new KryptonColorDialog
{
    Icon = MyAppIcon  // Custom application icon
};

ShowIcon Property

[DefaultValue(false)]
public bool ShowIcon { get; set; }
  • Purpose: Controls whether the dialog displays an icon in the title bar
  • Category: Appearance
  • Default Value: false

Usage Example:

var dialog = new KryptonColorDialog
{
    ShowIcon = true,
    Icon = myCustomIcon
};

ShowAlphaSlider Property

[DefaultValue(false)]
public bool ShowAlphaSlider { get; set; }
  • Purpose: Enables the alpha (transparency) slider for selecting colors with alpha channel
  • Category: Behavior
  • Default Value: false
  • Side Effects: Automatically enables AllowFullOpen and FullOpen when set to true

Important Notes:

  • When enabled, forces the dialog into full-open mode
  • Adds a vertical alpha slider with real-time preview
  • Updates the Color property to include alpha values
  • Displays alpha values as tooltips and labels

Usage Example:

var dialog = new KryptonColorDialog
{
    ShowAlphaSlider = true,
    Color = Color.FromArgb(128, Color.Red)  // Semi-transparent red
};

Color Property (Enhanced)

public new Color Color { get; set; }
  • Purpose: Gets or sets the selected color, with alpha channel support when ShowAlphaSlider is enabled
  • Category: Data
  • Returns: Full color including alpha when alpha slider is active
  • Side Effects: Updates alpha slider value when color is set programmatically

Alpha-Aware Behavior:

dialog.ShowAlphaSlider = true;
dialog.Color = Color.FromArgb(180, Color.Blue);

// Later...
Color selectedColor = dialog.Color;  
// Returns: Color with alpha = 180

dialog.ShowAlphaSlider = false;
dialog.Color = Color.Red;
// Returns: Color with alpha = 255 (opaque)

Standard ColorDialog Properties

The dialog inherits all standard ColorDialog properties with full compatibility:

  • AllowFullOpen: Controls access to advanced color options
  • AnyColor: Allows selection of custom colors beyond palette
  • Color: The selected color (enhanced with alpha support)
  • CustomColors: Array of available custom colors
  • FullOpen: Whether advanced options panel is initially open
  • SolidColorOnly: Restricts selection to solid colors only

Display Behavior and Layout

Compact Mode (FullOpen = false)

  • Displays basic color palette
  • Customizable window title and icon
  • Optimized layout size (automatically calculated)
  • Alpha slider available if enabled

Full Open Mode (FullOpen = true)

  • Shows advanced color selection controls
  • RGB editing fields
  • Custom color definition area
  • Alpha slider integrated seamlessly (when enabled)

Alpha Slider Integration

When ShowAlphaSlider is enabled:

  • Vertical Slider: Positioned to right of RGB fields
  • Range: 0-255 (fully transparent to fully opaque)
  • Real-time Preview: Updates color preview panel
  • Tooltips: Shows current alpha value
  • Labels: Displays alpha value numerically

Advanced Features

Alpha Channel Management

public void SelectColorWithTransparency()
{
    var dialog = new KryptonColorDialog
    {
        ShowAlphaSlider = true,
        AllowFullOpen = true,  // Automatically set by ShowAlphaSlider
        Color = Color.FromArgb(200, Color.Green),
        Title = "Select With Transparency"
    };

    if (dialog.ShowDialog() == DialogResult.OK)
    {
        Color selectedColor = dialog.Color;
        int alpha = selectedColor.A;  // Alpha channel value
        Color baseColor = Color.FromArgb(red: 255, green: 128, blue: 64);
        // Use selectedColor.A as alpha value
    }
}

Theme Integration

The dialog automatically applies Krypton theming through:

  • CommonDialogHandler: Provides window management and styling
  • DPI Scaling: Automatic scaling for high-DPI displays
  • Palette Support: Respects global Krypton palette settings
  • Consistent Appearance: Matches other Krypton dialogs

Custom Icon Workflow

public class ColorSelectionService
{
    private static readonly Icon AppIcon = LoadApplicationIcon();

    public Color ShowColorDialog(string title, Color defaultColor, bool withAlpha = false)
    {
        using var dialog = new KryptonColorDialog
        {
            Title = title,
            Icon = AppIcon,
            ShowIcon = true,
            ShowAlphaSlider = withAlpha,
            Color = defaultColor
        };

        return dialog.ShowDialog() == DialogResult.OK ? dialog.Color : defaultColor;
    }

    public Color SelectTextColor() => ShowColorDialog("Text Color", Color.Black, false);
    public Color SelectBackgroundColor() => ShowColorDialog("Background", Color.White, true);
}

Performance Considerations

  • Lazy Alpha Components: Alpha slider created only when needed
  • Timer Management: Alpha update timer disabled when not in use
  • Memory Cleanup: Proper disposal patterns for embedded controls
  • DPI Handling: Automatic scaling prevents layout issues

Usage Patterns

Basic Color Selection

private Color GetUserColorChoice()
{
    var dialog = new KryptonColorDialog
    {
        Title = "Choose Primary Color"
    };

    return dialog.ShowDialog() == DialogResult.OK ? dialog.Color : Color.Black;
}

Advanced Color Selection with Alpha

private void ConfigureButtonBackground()
{
    var dialog = new KryptonColorDialog
    {
        Title = "Button Background (support transparency)",
        ShowAlphaSlider = true,
        AllowFullOpen = true,
        AnyColor = true
    };

    if (dialog.ShowDialog() == DialogResult.OK)
    {
        myButton.BackColor = dialog.Color;
        // Color includes alpha: rgba(red, green, blue, alpha)
    }
}

Theme-Aware Color Selection

public class ThemedColorSelector
{
    public Color ShowDialog(IPalette palette, string title)
    {
        var dialog = new KryptonColorDialog
        {
            Title = title,
            Icon = palette.GetThemedIcon()  // Assuming palette provides themed icons
        };

        return dialog.ShowDialog() == DialogResult.OK ? dialog.Color : Color.Empty;
    }
}

Design-Time Integration

Visual Studio Designer

  • Toolbox Integration: Available with custom bitmap representation
  • Property Window: All properties properly categorized and exposed
  • Icon Selection: Type editor for icon selection
  • Serialization: Design-time settings saved to designer files

Property Categories

  • Data: Core color selection properties (Color, CustomColors)
  • Behavior: Control behavior (ShowAlphaSlider, AllowFullOpen)
  • Appearance: Visual customization (Title, Icon, ShowIcon)

Common Issues and Solutions

Alpha Slider Not Appearing

Issue: Alpha slider not visible despite enabling ShowAlphaSlider
Solution: Ensure AllowFullOpen or FullOpen is enabled (automatically handled)

Custom Colors Not Persisting

Issue: Custom colors lost between dialog instances
Solution: Store CustomColors array and restore between uses:

private static int[] _savedCustomColors = new int[16];

var dialog = new KryptonColorDialog
{
    CustomColors = _savedCustomColors  // Restore previous custom colors
};

if (dialog.ShowDialog() == DialogResult.OK)
{
    _savedCustomColors = dialog.CustomColors;  // Save current state
}

DPI Scaling Issues

Issue: Dialog appears incorrectly scaled on high-DPI displays
Solution: Automatic handling by CommonDialogHandler, no additional code needed

Performance with Alpha Animations

Issue: Dialog slows down with continuous alpha slider updates
Solution: Timer-based updates are optimized; alpha slider provides immediate feedback

Migration from Standard ColorDialog

Direct Replacement

// Old code
using ColorDialog = System.Windows.Forms.ColorDialog;
var dialog = new ColorDialog();

// New code  
var dialog = new KryptonColorDialog();

Enhanced Features

// Standard ColorDialog (limited)
var standardDialog = new ColorDialog();

// KryptonColorDialog (enhanced)
var kryptonDialog = new KryptonColorDialog
{
    Title = "Enhanced Color Selection",
    Icon = applicationIcon,
    ShowIcon = true,
    ShowAlphaSlider = true  // Alpha channel support!
};

Real-World Integration Examples

Color Palette Editor

public class PaletteEditor : Form
{
    public PaletteEditor()
    {
        InitializeComponent();
    }

    private void EditColor(Control targetControl)
    {
        var dialog = new KryptonColorDialog
        {
            Title = $"Edit {targetControl.Name} Color",
            ShowAlphaSlider = SupportsTransparency(targetControl),
            Color = targetControl.BackColor,
            AllowFullOpen = true,
            AnyColor = true
        };

        if (dialog.ShowDialog() == DialogResult.OK)
        {
            targetControl.BackColor = dialog.Color;
            targetControl.Invalidate(); // Refresh display
        }
    }

    private static bool SupportsTransparency(Control control) => 
        control.SupportsTransparency() || control is Panel;
}

Multi-Step Color Workflow

public class DocumentStyler
{
    public DocumentStyle ConfigureStyling()
    {
        var style = new DocumentStyle();

        // Step 1: Main text color
        var textDialog = new KryptonColorDialog
        {
            Title = "Step 1: Main Text Color",
            Color = Color.Black
        };
        if (textDialog.ShowDialog() == DialogResult.OK)
            style.TextColor = textDialog.Color;

        // Step 2: Background with transparency option
        var bgDialog = new KryptonColorDialog
        {
            Title = "Step 2: Background Color",
            ShowAlphaSlider = true,
            Color = Color.FromArgb(240, Color.White) // Semi-transparent white
        };
        if (bgDialog.ShowDialog() == DialogResult.OK)
            style.BackgroundColor = bgDialog.Color;

        // Step 3: Accent color
        var accentDialog = new KryptonColorDialog
        {
            Title = "Step 3: Accent Color",
            ShowIcon = true,
            Icon = SystemIcons.Information,
            Color = Color.Blue
        };
        if (accentDialog.ShowDialog() == DialogResult.OK)
            style.AccentColor = accentDialog.Color;

        return style;
    }
}