FormatConvertedBitmap.BeginInit Method

Reference

Definition

Namespace:: System.Windows.Media.Imaging

Assembly:: PresentationCore.dll

Important

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Signals the start of the FormatConvertedBitmap initialization.

public:
 virtual void BeginInit();

public void BeginInit ();

abstract member BeginInit : unit -> unit
override this.BeginInit : unit -> unit

Public Sub BeginInit ()

Implements

BeginInit()

Exceptions

InvalidOperationException

The FormatConvertedBitmap is currently being initialized. BeginInit() has already been called.

-or-

The FormatConvertedBitmap has already been initialized.

Examples

The following example demonstrates how to initialize a FormatConvertedBitmap with a set of properties by using the BeginInit and EndInit methods.

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace SDKSample
{
    public partial class FormatConvertedBitmapExample : Page
    {
        public FormatConvertedBitmapExample()
        {

            ///// Create a BitmapImage and set it's DecodePixelWidth to 200. Use  /////
            ///// this BitmapImage as a source for other BitmapSource objects.    /////

            BitmapImage myBitmapImage = new BitmapImage();

            // BitmapSource objects like BitmapImage can only have their properties
            // changed within a BeginInit/EndInit block.
            myBitmapImage.BeginInit();
            myBitmapImage.UriSource = new Uri(@"sampleImages/WaterLilies.jpg",UriKind.Relative);

            // To save significant application memory, set the DecodePixelWidth or  
            // DecodePixelHeight of the BitmapImage value of the image source to the desired 
            // height or width of the rendered image. If you don't do this, the application will 
            // cache the image as though it were rendered as its normal size rather then just 
            // the size that is displayed.
            // Note: In order to preserve aspect ratio, set DecodePixelWidth
            // or DecodePixelHeight but not both.
            myBitmapImage.DecodePixelWidth = 200;
            myBitmapImage.EndInit();

            ////////// Convert the BitmapSource to a new format ////////////
            // Use the BitmapImage created above as the source for a new BitmapSource object
            // which is set to a gray scale format using the FormatConvertedBitmap BitmapSource.                                               
            // Note: New BitmapSource does not cache. It is always pulled when required.

            FormatConvertedBitmap newFormatedBitmapSource = new FormatConvertedBitmap();

            // BitmapSource objects like FormatConvertedBitmap can only have their properties
            // changed within a BeginInit/EndInit block.
            newFormatedBitmapSource.BeginInit();

            // Use the BitmapSource object defined above as the source for this new 
            // BitmapSource (chain the BitmapSource objects together).
            newFormatedBitmapSource.Source = myBitmapImage;

            // Set the new format to Gray32Float (grayscale).
            newFormatedBitmapSource.DestinationFormat = PixelFormats.Gray32Float;
            newFormatedBitmapSource.EndInit();

            // Create Image Element
            Image myImage = new Image();
            myImage.Width = 200;
            //set image source
            myImage.Source = newFormatedBitmapSource;

            // Add Image to the UI
            StackPanel myStackPanel = new StackPanel();
            myStackPanel.Children.Add(myImage);
            this.Content = myStackPanel;
        }
    }
}

Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Media
Imports System.Windows.Media.Imaging

Namespace SDKSample

    Class FormatConvertedBitmapExample
        Inherits Page

        Public Sub New()

            '/// Create a BitmapImage and set it's DecodePixelWidth to 200. Use  /////
            '/// this BitmapImage as a source for other BitmapSource objects.    /////
            Dim myBitmapImage As New BitmapImage()

            ' BitmapSource objects like BitmapImage can only have their properties
            ' changed within a BeginInit/EndInit block.
            myBitmapImage.BeginInit()
            myBitmapImage.UriSource = New Uri("sampleImages/WaterLilies.jpg", UriKind.Relative)

            ' To save significant application memory, set the DecodePixelWidth or  
            ' DecodePixelHeight of the BitmapImage value of the image source to the desired 
            ' height or width of the rendered image. If you don't do this, the application will 
            ' cache the image as though it were rendered as its normal size rather then just 
            ' the size that is displayed.
            ' Note: In order to preserve aspect ratio, set DecodePixelWidth
            ' or DecodePixelHeight but not both.
            myBitmapImage.DecodePixelWidth = 200
            myBitmapImage.EndInit()

            '//////// Convert the BitmapSource to a new format ////////////
            ' Use the BitmapImage created above as the source for a new BitmapSource object
            ' which is set to a gray scale format using the FormatConvertedBitmap BitmapSource.                                               
            ' Note: New BitmapSource does not cache. It is always pulled when required.
            Dim newFormatedBitmapSource As New FormatConvertedBitmap()

            ' BitmapSource objects like FormatConvertedBitmap can only have their properties
            ' changed within a BeginInit/EndInit block.
            newFormatedBitmapSource.BeginInit()

            ' Use the BitmapSource object defined above as the source for this new 
            ' BitmapSource (chain the BitmapSource objects together).
            newFormatedBitmapSource.Source = myBitmapImage

            ' Set the new format to Gray32Float (grayscale).
            newFormatedBitmapSource.DestinationFormat = PixelFormats.Gray32Float
            newFormatedBitmapSource.EndInit()

            ' Create Image Element
            Dim myImage As New Image()
            myImage.Width = 200
            'set image source
            myImage.Source = newFormatedBitmapSource

            ' Add Image to the UI
            Dim myStackPanel As New StackPanel()
            myStackPanel.Children.Add(myImage)
            Me.Content = myStackPanel

        End Sub
    End Class
End Namespace 'ImagingSnippetGallery

Remarks

Property initialization must be done between BeginInit and EndInit calls. After the FormatConvertedBitmap has been initialized, property changes are ignored.

Applies to

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