CanvasVirtualImageSource Class

Provides a virtualized ImageSource that can be used with XAML controls.

Inheritance Hierarchy

SystemObject
Microsoft.Graphics.Canvas.UI.XamlCanvasVirtualImageSource

Namespace: Microsoft.Graphics.Canvas.UI.Xaml
Assembly: Microsoft.Graphics.Canvas (in Microsoft.Graphics.Canvas.dll) Version: 0.0.0.0

Syntax

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public sealed class CanvasVirtualImageSource : ICanvasResourceCreatorWithDpi, 
	ICanvasResourceCreator

The CanvasVirtualImageSource type exposes the following members.

Constructors

	Name	Description
	CanvasVirtualImageSource(ICanvasResourceCreatorWithDpi, Size)	Initializes a new instance of the CanvasVirtualImageSource class.
	CanvasVirtualImageSource(ICanvasResourceCreatorWithDpi, Single, Single)	Initializes a new instance of the CanvasVirtualImageSource class.
	CanvasVirtualImageSource(ICanvasResourceCreator, Single, Single, Single)	Initializes a new instance of the CanvasVirtualImageSource class.
	CanvasVirtualImageSource(ICanvasResourceCreator, Single, Single, Single, CanvasAlphaMode)	Initializes a new instance of the CanvasVirtualImageSource class.

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Properties

	Name	Description
	AlphaMode	Returns the alpha mode for this image source that was passed in to the constructor.
	Device	Gets the device used by this image source.
	Dpi	Gets the dots-per-inch (DPI) of this image source.
	Size	Gets the size of the image source, in device independent pixels (DIPs).
	SizeInPixels	Gets the size of the image source, in pixels.
	Source	Gets the VirtualSurfaceImageSource wrapped by this object.

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Methods

	Name	Description
	ConvertDipsToPixels	Converts units from device independent pixels (DIPs) to physical pixels based on the DPI of this image source.
	ConvertPixelsToDips	Converts units from physical pixels to device independent pixels (DIPs) based on the DPI of this image source.
	CreateDrawingSession	Returns a new drawing session for updating a region of the image source.
	Invalidate	Marks the entire image as needing to be redrawn.
	Invalidate(Rect)	Marks a region of the image as needing to be redrawn.
	RaiseRegionsInvalidatedIfAny	Raises RegionsInvalidated if there are any invalid regions.
	Recreate	Recreates the underlying image source associating it with a different CanvasDevice.
	Resize(Size)	Resizes the virtual image.
	Resize(Single, Single)	Resizes the virtual image.
	Resize(Single, Single, Single)	Resizes the virtual image and possibly changes the DPI.
	ResumeDrawingSession	Resumes a previously suspended drawing session.
	SuspendDrawingSession	Suspends a drawing session so that it may be resumed on another thread.

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Events

	Name	Description
	RegionsInvalidated	Occurs when a region of the image needs redrawing.

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Remarks

A CanvasVirtualImageSource can be sized much larger than the largest image that Win2D can render to. CanvasVirtualImageSource provides events to indicate when regions of the image need to be redrawn.

Examples

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var imageSource = new CanvasVirtualImageSource(canvasDevice, width, height, dpi);
imageControl.Source = imageSource.Source;
imageSource.RegionsInvalidated += ImageSource_RegionsInvalidated;

private void ImageSource_RegionsInvalidated(CanvasVirtualImageSource sender, CanvasRegionsInvalidatedEventArgs args)
{
    foreach (var region in args.InvalidatedRegions)
    {
        using (var ds = sender.CreateDrawingSession(clearColor, region))
        {
            // drawing commands
        }
    }
}

Reference

Microsoft.Graphics.Canvas.UI.Xaml Namespace