ReadWriteBitmapDataExtensionsDrawTextAsync(IReadWriteBitmapData, Color32, GlyphRun, PointF, DrawingOptions, TaskConfig) Method

Draws a text represented by a GlyphRun instance asynchronously, filling the characters with a solid brush of the specified color.

Definition

Namespace: KGySoft.Drawing.Wpf
Assembly: KGySoft.Drawing.Wpf (in KGySoft.Drawing.Wpf.dll) Version: 10.0.0-rc.1

public static Task<bool> DrawTextAsync(
	this IReadWriteBitmapData bitmapData,
	Color32 color,
	GlyphRun text,
	PointF offset,
	DrawingOptions? drawingOptions = null,
	TaskConfig? asyncConfig = null
)

<ExtensionAttribute>
Public Shared Function DrawTextAsync ( 
	bitmapData As IReadWriteBitmapData,
	color As Color32,
	text As GlyphRun,
	offset As PointF,
	Optional drawingOptions As DrawingOptions = Nothing,
	Optional asyncConfig As TaskConfig = Nothing
) As Task(Of Boolean)

C++

public:
[ExtensionAttribute]
static Task<bool>^ DrawTextAsync(
	IReadWriteBitmapData^ bitmapData, 
	Color32 color, 
	GlyphRun^ text, 
	PointF offset, 
	DrawingOptions^ drawingOptions = nullptr, 
	TaskConfig^ asyncConfig = nullptr
)

[<ExtensionAttribute>]
static member DrawTextAsync : 
        bitmapData : IReadWriteBitmapData * 
        color : Color32 * 
        text : GlyphRun * 
        offset : PointF * 
        ?drawingOptions : DrawingOptions * 
        ?asyncConfig : TaskConfig 
(* Defaults:
        let _drawingOptions = defaultArg drawingOptions null
        let _asyncConfig = defaultArg asyncConfig null
*)
-> Task<bool>

Parameters

bitmapData IReadWriteBitmapData: The IReadWriteBitmapData instance to draw on.
color Color32: The color of the solid brush to draw the text with.
text GlyphRun: A GlyphRun instance representing the text to draw.
offset PointF: The offset to be applied to the BaselineOrigin of text.
drawingOptions DrawingOptions (Optional): A DrawingOptions instance that specifies the drawing options to use. If , then the default options are used. This parameter is optional.
Default value: .
asyncConfig TaskConfig (Optional): The configuration of the asynchronous operation such as parallelization, cancellation, reporting progress, etc. When Progress is set in this parameter, then this library always passes a DrawingOperation instance to the generic methods of the IAsyncProgress interface. This parameter is optional.
Default value: .

Return Value

TaskBoolean
A task that represents the asynchronous operation. Its result is , if the operation completed successfully, or , if the operation has been canceled and the ThrowIfCanceled property in asyncConfig parameter was .

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IReadWriteBitmapData. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

Remarks

This method fills the characters of the text. To draw the outline of a text, you can use the DrawTextOutlineAsync methods.

Tip

To draw a text with both filled and outlined characters, instead of calling DrawTextAsync and DrawTextOutlineAsync consecutively, you can achieve a better performance by creating a Path once, and then calling the FillPathAsync and DrawPathAsync methods. You can convert the specified text to a Path by obtaining a Geometry instance by calling the GlyphRun.BuildGeometry method, and then using the ToPath extension method. If you draw the text without antialiasing, it is recommended to set the FastThinLines to in drawingOptions so the outline correctly aligns to the filled area.

When AntiAliasing is set in drawingOptions and you use non-monochromatic colors, it is recommended to specify Linear color space when you obtain the IReadWriteBitmapData instance, especially for small fonts; otherwise, the quality of the drawn text can be poor if alpha colors are blended in the sRGB color space. See more details at the Examples section of the WorkingColorSpace enumeration.

In .NET Framework 4.0 and above you can use also the DrawTextAsync methods.

To finish the operation and to get the exception that occurred during the operation you have to call the EndDrawText method.

This method is not a blocking call even if the MaxDegreeOfParallelism property of the asyncConfig parameter is 1.

Exceptions

ArgumentNullException	bitmapData or text is .
OverflowException	The coordinates (after a possible transformation specified in drawingOptions) are outside the bounds of an int value.
TaskCanceledException	The operation has been canceled and the ThrowIfCanceled property in asyncConfig was . This exception is thrown when the result is awaited.