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VOOZH | about |
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VOOZH | about |
| CanvasControl Class |
public sealed class CanvasControl : UserControl, IAnimationObject, IVisualElement, ICanvasResourceCreatorWithDpi, ICanvasResourceCreator
The CanvasControl type exposes the following members.
| Name | Description | |
|---|---|---|
| 👁 Public method | CanvasControl | Initializes a new instance of the CanvasControl class. |
| Name | Description | |
|---|---|---|
| 👁 Public property | ClearColor | The color that the control is cleared to before the Draw event is raised. |
| 👁 Public property | CustomDevice | Gets or sets an application-chosen device for this control. |
| 👁 Public property | Device | Gets the underlying device used by this control. |
| 👁 Public property | Dpi | Gets the current dots-per-inch (DPI) of this control. |
| 👁 Public property | DpiScale | Gets or sets a scaling factor applied to this control's Dpi. |
| 👁 Public property | ForceSoftwareRenderer | Gets or sets the whether the devices that this control creates will be forced to software rendering. |
| 👁 Public property | ReadyToDraw | Gets whether the control is in a state where it is ready to draw. |
| 👁 Public property | Size | Gets the current size of the control, in device independent pixels (DIPs). |
| 👁 Public property | UseSharedDevice | Gets or sets whether this control should create a new device each time, or use a device which may common between other controls. |
| Name | Description | |
|---|---|---|
| 👁 Public method | ConvertDipsToPixels | Converts units from device independent pixels (DIPs) to physical pixels based on the current DPI of this control. |
| 👁 Public method | ConvertPixelsToDips | Converts units from physical pixels to device independent pixels (DIPs) based on the current DPI of this control. |
| 👁 Public method | Invalidate | Indicates that the contents of the CanvasControl need to be redrawn.
Calling Invalidate results in the Draw event being raised shortly afterward. |
| 👁 Public method | RemoveFromVisualTree | Removes the control from the last FrameworkElement it was parented to. |
| Name | Description | |
|---|---|---|
| 👁 Public event | CreateResources | Hook this event to create any resources needed for your drawing. |
| 👁 Public event | Draw | This is where the magic happens! Hook this event to issue your immediate mode 2D drawing calls. |
To get started using Win2D, simply add a CanvasControl to your XAML tree, subscribe to its CanvasControl.Draw event, and use the methods of CanvasDrawEventArgs.DrawingSession to draw your immediate mode 2D graphics.
When using CanvasControl from managed code, care must be taken to avoid memory leaks due to reference count cycles. See Avoiding memory leaks for more information.
Starting with the "Blank App" XAML project template, edit MainPage.xaml and add the namespace and unloaded handler:
xmlns:canvas="using:Microsoft.Graphics.Canvas.UI.Xaml" Unloaded="Page_Unloaded"
Add a CanvasControl to the page:
<Grid> <canvas:CanvasControl x:Name="myWidget" CreateResources="myWidget_CreateResources" Draw="myWidget_Draw" ClearColor="CornFlowerBlue"/> </Grid>
Edit MainPage.xaml.cs, and add some drawing code:
public sealed partial class MainPage : Page { CanvasSolidColorBrush redBrush; public MainPage() { this.InitializeComponent(); } void myWidget_CreateResources(CanvasControl sender, CanvasCreateResourcesEventArgs args) { // Create any resources needed by the Draw event handler. // Asynchronous work can be tracked with TrackAsyncAction: args.TrackAsyncAction(myWidget_CreateResourcesAsync(sender).AsAsyncAction()); } async Task myWidget_CreateResourcesAsync(CanvasControl sender) { // Load bitmaps, create brushes, etc. bitmapTiger = await CanvasBitmap.LoadAsync(sender, "imageTiger.jpg"); } void myWidget_Draw(CanvasControl sender, CanvasDrawEventArgs args) { args.DrawingSession.DrawEllipse(155, 115, 80, 30, Colors.Black, 3); args.DrawingSession.DrawText("Hello, world!", 100, 100, Colors.Yellow); } void Page_Unloaded(object sender, RoutedEventArgs e) { this.myWidget.RemoveFromVisualTree(); this.myWidget = null; } }
