Colors in Xamarin.Forms

The Color structure lets you specify colors as Red-Green-Blue (RGB) values, Hue-Saturation-Luminosity (HSL) values, Hue-Saturation-Value (HSV) values, or with a color name. An Alpha channel is also available to indicate transparency.

Color objects can be created with the Color constructors, which can be used to specify a gray shade, an RGB value, or an RGB value with transparency. In all cases, arguments are double values ranging from 0 to 1.

You can also use static methods to create Color objects:

• Color.FromRgb for double RGB values from 0 to 1.
• Color.FromRgb for integer RGB values from 0 to 255.
• Color.FromRgba for double RGB values with transparency.
• Color.FromRgba for integer RGB values with transparency.
• Color.FromHsla for double HSL values with transparency.
• Color.FromHsv for double HSV values from 0 to 1.
• Color.FromHsv for integer HSV values from 0 to 255.
• Color.FromHsva for double HSV values with transparency.
• Color.FromHsva for integer HSV values with transparency.
• Color.FromUint for a uint value calculated as (B + 256 * (G + 256 * (R + 256 * A))).
• Color.FromHex for a string format of hexadecimal digits in the form "#AARRGGBB" or "#RRGGBB" or "#ARGB" or "#RGB", where each letter corresponds to a hexadecimal digit for the alpha, red, green, and blue channels.

Once created, a Color object is immutable. The characteristics of the color can be obtained from the following properties:

• R, which represents the red channel of the color.
• G, which represents the green channel of the color.
• B, which represents the blue channel of the color.
• A, which represents the alpha channel of the color.
• Hue, which represents the hue channel of the color.
• Saturation, which represents the saturation channel of the color.
• Luminosity, which represents the luminosity channel of the color.

These properties are all double values ranging from 0 to 1.

Named colors

The Color structure also defines 240 public static read-only fields for common colors, such as AliceBlue.

Color.Accent

The Color.Accent value results in a platform-specific (and sometimes user-selectable) color that is visible on either a dark or light background.

Color.Default

The Color.Default value defines a Color with all channels set to -1, and is intended to enforce the platform's color scheme. Consequently, it has a different meaning in different contexts on different platforms. By default the platform color schemes are:

• iOS: dark text on a light background.
• Android: dark text on a light background.
• Windows: dark text on a light background.

Color.Transparent

The Color.Transparent value defines a Color with all channels set to zero.

Modify a color

Several instance methods allow modifying an existing color to create a new color:

• AddLuminosity returns a Color by modifying the luminosity by the supplied delta.
• MultiplyAlpha returns a Color by modifying the alpha, multiplying it by the supplied alpha value.
• ToHex returns a hexadecimal string representation of a Color.
• WithHue returns a Color, replacing the hue with the value supplied.
• WithLuminosity returns a Color, replacing the luminosity with the value supplied.
• WithSaturation returns a Color, replacing the saturation with the value supplied.

Implicit conversions

Implicit conversion between the Xamarin.Forms.Color and System.Drawing.Color types can be performed:

Xamarin.Forms.Color xfColor = Xamarin.Forms.Color.FromRgb(0, 72, 255);
System.Drawing.Color sdColor = System.Drawing.Color.FromArgb(38, 127, 0);

// Implicity convert from a Xamarin.Forms.Color to a System.Drawing.Color
System.Drawing.Color sdColor2 = xfColor;

// Implicitly convert from a System.Drawing.Color to a Xamarin.Forms.Color
Xamarin.Forms.Color xfColor2 = sdColor;

Examples

In XAML, colors are typically referenced using their named values, or with their Hex representations:

<Label Text="Sea color"
       TextColor="Aqua" />
<Label Text="RGB"
       TextColor="#00FF00" />
<Label Text="Alpha plus RGB"
       TextColor="#CC00FF00" />
<Label Text="Tiny RGB"
       TextColor="#0F0" />
<Label Text="Tiny Alpha plus RGB"
       TextColor="#C0F0" />

In C#, colors are typically referenced using their named values, or with their static methods:

Label red    = new Label { Text = "Red",    TextColor = Color.Red };
Label orange = new Label { Text = "Orange", TextColor = Color.FromHex("FF6A00") };
Label yellow = new Label { Text = "Yellow", TextColor = Color.FromHsla(0.167, 1.0, 0.5, 1.0) };
Label green  = new Label { Text = "Green",  TextColor = Color.FromRgb (38, 127, 0) };
Label blue   = new Label { Text = "Blue",   TextColor = Color.FromRgba(0, 38, 255, 255) };
Label indigo = new Label { Text = "Indigo", TextColor = Color.FromRgb (0, 72, 255) };
Label violet = new Label { Text = "Violet", TextColor = Color.FromHsla(0.82, 1, 0.25, 1) };

The following example uses the OnPlatform markup extension to selectively set the color of an ActivityIndicator:

<ActivityIndicator Color="{OnPlatform iOS=Black, Default=Default}"
                   IsRunning="True" />

The equivalent C# code is:

ActivityIndicator activityIndicator = new ActivityIndicator
{
    Color = Device.RuntimePlatform == Device.iOS ? Color.Black : Color.Default,
    IsRunning = true
};