About

Blazor components that render a fully featured HTML Color Picker control: an HSV Saturation/Brightness selection area, Hue and Alpha (opacity) sliders, editable HEX/RGB/HSL inputs, a known color name, a copy-to-clipboard button, a screen color picker (EyeDropper) and a predefined color palette. It comes in two flavours: an always-visible ColorPalette and a compact, click-triggered ColorPicker that hosts the palette inside a Popover. All components work with WebAssembly and Server hosted models. For code examples see usage.

You can try it out by using the demo app.

Features

• HSV Saturation/Brightness selection area with a draggable handle.
• Hue slider and optional Alpha (opacity) slider with ARGB output.
• Editable HEX, RGB(A) and HSL inputs, all kept in sync.
• Known color name field (e.g. RebeccaPurple) for named HTML colors.
• Copy to clipboard button for the current HEX value.
• Screen color picker (EyeDropper) button — rendered only when the browser supports the EyeDropper API.
• Predefined color palette of swatches, customizable via PaletteColors.
• Works with the standard System.Drawing.Color type and supports two-way binding with @bind-SelectedColor.
• Fully sizable areas (picker area, info area, slider height).
• ColorPicker adds a compact trigger button with a color preview, a Popover host, Apply support and open/close events.

Components

• ColorPalette: renders the full, always-visible color selector (HSV area, sliders, HEX/RGB/HSL info and palette).
• ColorPicker: renders a compact trigger button showing the selected color and opens a ColorPalette inside a Popover, with optional Apply-to-commit behavior.

Both components work with the System.Drawing.Color type. Add @using System.Drawing and (for the ToHtmlHex() / ToRgbString() helpers used in the examples) @using Majorsoft.Blazor.Components.Core.HtmlColors.

ColorPalette component (See: demo app)

The always-visible color selector. Pick a color in the HSV area, drag the Hue/Alpha sliders or type a HEX/RGB/HSL value; every change raises OnColorChanged and updates the two-way bound SelectedColor.

Properties

• SelectedColor: Color { get; set; } (default: Color.FromArgb(66, 135, 245))
  Currently selected System.Drawing.Color. Supports two-way binding with @bind-SelectedColor.
• HueAreaWidth: int { get; set; } (default: 300, min: 200)
  Width of the Saturation/Brightness selection area in pixels.
• HueAreaHeight: int { get; set; } (default: 250, min: 100)
  Height of the Saturation/Brightness selection area in pixels.
• InfoAreaWidth: int { get; set; } (default: 300, min: 200)
  Width of the info area (Hue/Alpha sliders, color info and predefined palette) in pixels.
• HueSliderHeight: int { get; set; } (default: 12)
  Height of the Hue and Alpha sliders in pixels.
• ShowInfoArea: bool { get; set; } (default: true)
  Shows or hides the HEX/RGB/HSL info and input area.
• ShowColorName: bool { get; set; } (default: true)
  Shows or hides the known color Name field. Requires ShowInfoArea.
• EnableAlpha: bool { get; set; } (default: false)
  Enables the Alpha (opacity) slider and ARGB output.
• ShowPalette: bool { get; set; } (default: true)
  Shows or hides the predefined color palette (swatches).
• ShowEyeDropper: bool { get; set; } (default: true)
  Shows or hides the screen color picker (EyeDropper) button. Only rendered when the browser supports the EyeDropper API.
• ShowCopyButton: bool { get; set; } (default: true)
  Shows or hides the 'copy to clipboard' button.
• PaletteColors: IEnumerable<Color>? { get; set; } (default: null)
  Predefined color swatches to show. When not set a default Material-style palette is used.
• Class: string? { get; set; } (default: null)
  Custom CSS class applied to the root element.
• Style: string? { get; set; } (default: null)
  Custom inline style applied to the root element.

Arbitrary HTML attributes e.g.: id="palette1" will be passed to the corresponding rendered root HTML element <div>.

Events

• SelectedColorChanged: EventCallback<Color> delegate
  Callback for two-way binding. Invoked with the new Color when the selection changes. Used by @bind-SelectedColor.
• OnColorChanged: EventCallback<Color> delegate
  Notification callback invoked with the new Color when the selection changes.

ColorPicker component (See: demo app)

A compact trigger button that shows a color preview (and optional HEX text) and opens a ColorPalette inside a Popover. By default every change is committed immediately while the Popover stays open; set RequireApply to only commit when the Apply button is clicked. Most ColorPalette options are forwarded to the inner palette.

Properties

• SelectedColor: Color { get; set; } (default: Color.FromArgb(66, 135, 245))
  Currently selected (committed) System.Drawing.Color. Supports two-way binding with @bind-SelectedColor.
• RequireApply: bool { get; set; } (default: false)
  When true the selected color is only committed (and the Popover closed) after the Apply button is clicked. When false every change is committed immediately and the Popover stays open.
• ApplyButtonText: string { get; set; } (default: "Apply")
  Text shown on the Apply button. Only used when RequireApply is true.
• HeaderText: string { get; set; } (default: "Pick a color")
  Header text shown on the color selector Popover.
• Position: TooltipPositions { get; set; } (default: TooltipPositions.Top)
  Position of the Popover relative to the trigger button. Values: { Top, Right, Bottom, Left }.
• CloseOnOutsideClick: bool { get; set; } (default: true)
  When true the Popover closes when the user clicks outside of it.
• Disabled: bool { get; set; } (default: false)
  When true the picker is disabled and cannot be opened.
• ShowHex: bool { get; set; } (default: true)
  Shows or hides the HEX value text next to the color preview on the trigger button.
• PreviewSize: int { get; set; } (default: 28)
  Size (width and height) of the color preview square on the trigger button, in pixels.
• IsOpen: bool { get; set; } (default: false)
  Gets or sets whether the color selector Popover is open. Supports two-way binding with @bind-IsOpen. Set to true to open it, false to close it.

The following properties are forwarded to the inner ColorPalette and behave exactly as documented above: EnableAlpha (default: false), ShowInfoArea (default: true), ShowColorName (default: true), ShowPalette (default: true), ShowEyeDropper (default: true), ShowCopyButton (default: true), HueAreaWidth (default: 300), HueAreaHeight (default: 250), InfoAreaWidth (default: 300), HueSliderHeight (default: 12) and PaletteColors (default: null). Class and Style are applied to the root (trigger) container element.

Arbitrary HTML attributes e.g.: id="picker1" will be passed to the corresponding rendered root HTML element.

Events

• SelectedColorChanged: EventCallback<Color> delegate
  Callback for two-way binding. Invoked with the committed Color (on Apply when RequireApply is true, otherwise on every change). Used by @bind-SelectedColor.
• OnColorSelected: EventCallback<Color> delegate
  Notification callback invoked with the committed Color (on Apply when RequireApply is true, otherwise on every change).
• OnColorChanged: EventCallback<Color> delegate
  Notification callback invoked with the live Color on every change inside the palette, even before it is applied.
• OnOpen: EventCallback delegate
  Callback function called when the color selector Popover is opening.
• OnClose: EventCallback delegate
  Callback function called when the color selector Popover is closing.
• IsOpenChanged: EventCallback<bool> delegate
  Callback for two-way binding. Invoked with the new open/closed state whenever the Popover opens or closes. Used by @bind-IsOpen.

Configuration

Installation

Majorsoft.Blazor.Components.ColorPicker is available on NuGet.

dotnet add package Majorsoft.Blazor.Components.ColorPicker

Use the --version option to specify a preview version to install.

Usage

Add using statement to your Blazor <component/page>.razor file. Or globally reference it into _Imports.razor file.

@using Majorsoft.Blazor.Components.ColorPicker

Dependences

Majorsoft.Blazor.Components.ColorPicker package depends on other Majorsoft Nuget packages:

• Majorsoft.Blazor.Components.Common.JsInterop which handles JS Interop for the drag handle (global mouse events), the copy-to-clipboard button and the Popover outside-click detection.
• Majorsoft.Blazor.Components.Tooltips which provides the Popover used by the ColorPicker.

Register services

Both components rely on the JS Interop extensions (global mouse events, clipboard and outside-click handling), so register them once during application startup.

In case of WebAssembly project register services in your Program.cs file:

using Majorsoft.Blazor.Components.Common.JsInterop;
...
public static async Task Main(string[] args)
{
	var builder = WebAssemblyHostBuilder.CreateDefault(args);

	//Register dependencies
	builder.Services.AddJsInteropExtensions();
}

In case of Server hosted project register services in your Startup.cs file:

using Majorsoft.Blazor.Components.Common.JsInterop;
...

public void ConfigureServices(IServiceCollection services)
{
	//Register dependencies
	services.AddJsInteropExtensions();
}

ColorPalette usage

Following code example shows how to use the ColorPalette component with all features enabled and two-way binding via @bind-SelectedColor.

@using System.Drawing
@using Majorsoft.Blazor.Components.Core.HtmlColors

<ColorPalette @bind-SelectedColor="_selectedColor"
			  ShowInfoArea="true"
			  ShowColorName="true"
			  EnableAlpha="true"
			  ShowPalette="true"
			  ShowEyeDropper="true"
			  ShowCopyButton="true"
			  HueAreaWidth="320"
			  HueAreaHeight="250"
			  InfoAreaWidth="320"
			  HueSliderHeight="12"
			  OnColorChanged="@OnColorChanged" />

<p>
	Selected color:
	<span style="display:inline-block; width:24px; height:24px; vertical-align:middle; border:1px solid #ccc; background:@_selectedColor.ToHtmlHex();"></span>
	<strong>@_selectedColor.ToHtmlHex()</strong> (@_selectedColor.ToRgbString())
</p>

@code {
	private Color _selectedColor = Color.FromArgb(66, 135, 245);

	private void OnColorChanged(Color color)
	{
		//Write your event handling code here...
	}
}

You can also supply your own palette swatches through PaletteColors:

<ColorPalette @bind-SelectedColor="_selectedColor"
			  PaletteColors="_swatches" />

@code {
	private Color _selectedColor = Color.Red;
	private readonly Color[] _swatches = new[]
	{
		Color.Red, Color.Green, Color.Blue, Color.Orange, Color.Purple, Color.Black, Color.White,
	};
}

ColorPicker usage

Following code example shows how to use the compact ColorPicker component. With RequireApply the color is only committed when the Apply button is clicked; otherwise it is committed on every change while the Popover stays open.

@using System.Drawing
@using Majorsoft.Blazor.Components.Core.HtmlColors

<ColorPicker @bind-SelectedColor="_color"
			 RequireApply="true"
			 ApplyButtonText="Apply"
			 HeaderText="Pick a color"
			 Position="@TooltipPositions.Bottom"
			 CloseOnOutsideClick="true"
			 ShowHex="true"
			 PreviewSize="28"
			 EnableAlpha="false"
			 OnColorSelected="@OnColorSelected"
			 OnColorChanged="@OnColorChanged"
			 OnOpen="@OnOpen"
			 OnClose="@OnClose" />

<p>
	Selected color:
	<span style="display:inline-block; width:24px; height:24px; vertical-align:middle; border:1px solid #ccc; background:@_color.ToHtmlHex();"></span>
	<strong>@_color.ToHtmlHex()</strong>
</p>

@code {
	private Color _color = Color.FromArgb(66, 135, 245);

	//Committed value (on Apply, or on every change when RequireApply is false)
	private void OnColorSelected(Color color)
	{
		//Write your event handling code here...
	}

	//Live value on every change, even before it is applied
	private void OnColorChanged(Color color)
	{
		//Write your event handling code here...
	}

	private void OnOpen()
	{
		//Write your event handling code here...
	}
	private void OnClose()
	{
		//Write your event handling code here...
	}
}