BitmapPalette Classe

Definição

public ref class BitmapPalette sealed : System::Windows::Threading::DispatcherObject

public sealed class BitmapPalette : System.Windows.Threading.DispatcherObject

type BitmapPalette = class
    inherit DispatcherObject

Public NotInheritable Class BitmapPalette
Inherits DispatcherObject

Herança

Object

DispatcherObject

BitmapPalette

Exemplos

O exemplo seguinte demonstra como definir um custom BitmapPalette e aplicá-lo a um novo BitmapSource.

int width = 128;
int height = width;
int stride = width/8;
byte[] pixels = new byte[height*stride];

// Try creating a new image with a custom palette.
List<System.Windows.Media.Color> colors = new List<System.Windows.Media.Color>();
colors.Add(System.Windows.Media.Colors.Red);
colors.Add(System.Windows.Media.Colors.Blue);
colors.Add(System.Windows.Media.Colors.Green);
BitmapPalette myPalette = new BitmapPalette(colors);

// Creates a new empty image with the pre-defined palette

BitmapSource image = BitmapSource.Create(
    width,
    height,
    96,
    96,
    PixelFormats.Indexed1,
    myPalette, 
    pixels, 
    stride);

FileStream stream = new FileStream("empty.tif", FileMode.Create);
TiffBitmapEncoder encoder = new TiffBitmapEncoder();
TextBlock myTextBlock = new TextBlock();
myTextBlock.Text = "Codec Author is: " + encoder.CodecInfo.Author.ToString();
encoder.Frames.Add(BitmapFrame.Create(image));
MessageBox.Show(myPalette.Colors.Count.ToString());
encoder.Save(stream);

Dim width As Integer = 128
Dim height As Integer = width
Dim stride As Integer = CType(width / 8, Integer)
Dim pixels(height * stride) As Byte

' Try creating a new image with a custom palette.
Dim colors As New List(Of System.Windows.Media.Color)()
colors.Add(System.Windows.Media.Colors.Red)
colors.Add(System.Windows.Media.Colors.Blue)
colors.Add(System.Windows.Media.Colors.Green)
Dim myPalette As New BitmapPalette(colors)

' Creates a new empty image with the pre-defined palette
Dim image As BitmapSource = System.Windows.Media.Imaging.BitmapSource.Create(width, height, 96, 96, PixelFormats.Indexed1, myPalette, pixels, stride)
Dim stream As New FileStream("empty.tif", FileMode.Create)
Dim encoder As New TiffBitmapEncoder()
Dim myTextBlock As New TextBlock()
myTextBlock.Text = "Codec Author is: " + encoder.CodecInfo.Author.ToString()
encoder.Frames.Add(BitmapFrame.Create(image))
MessageBox.Show(myPalette.Colors.Count.ToString())
encoder.Save(stream)

O exemplo seguinte demonstra como recuperar a BitmapPalette de uma imagem.

// Get the palette from an image
BitmapImage image2 = new BitmapImage();
image2.BeginInit();
image2.UriSource = new Uri("tulipfarm.tif", UriKind.RelativeOrAbsolute);
image2.EndInit();
BitmapPalette myPalette3 = new BitmapPalette(image2, 256);

//Draw the third Image
Image myImage2 = new Image();
myImage2.Source = image2;
myImage2.Stretch = Stretch.None;
myImage2.Margin = new Thickness(20);

' Get the palette from an image
Dim image2 As New BitmapImage()
image2.BeginInit()
image2.UriSource = New Uri("tulipfarm.tif", UriKind.RelativeOrAbsolute)
image2.EndInit()
Dim myPalette3 As New BitmapPalette(image2, 256)

'Draw the third Image
Dim myImage2 As New Image()
myImage2.Source = image2
myImage2.Stretch = Stretch.None
myImage2.Margin = New Thickness(20)

Observações

Apenas os formatos de imagem Tagged Image File Format (TIFF) e Graphics Interchange Format (GIF) suportam paletas de imagem. No entanto, outros tipos de imagem podem ser usados para definir um BitmapPalette. Tentar definir a BitmapPalette para um formato bitmap não suportado não resulta numa exceção; a designação BitmapPalette é simplesmente ignorada.

Windows Presentation Foundation (WPF) suporta tanto paletas de cores personalizadas como paletas pré-definidas definidas pela classe BitmapPalettes.

Ver também

• BitmapPalettes