BitmapDataExtensionsBeginDrawBeziers(IReadWriteBitmapData, Color32, IEnumerablePointF, DrawingOptions, AsyncConfig) Method

public static IAsyncResult BeginDrawBeziers(
	this IReadWriteBitmapData bitmapData,
	Color32 color,
	IEnumerable<PointF> points,
	DrawingOptions? drawingOptions = null,
	AsyncConfig? asyncConfig = null
)

<ExtensionAttribute>
Public Shared Function BeginDrawBeziers ( 
	bitmapData As IReadWriteBitmapData,
	color As Color32,
	points As IEnumerable(Of PointF),
	Optional drawingOptions As DrawingOptions = Nothing,
	Optional asyncConfig As AsyncConfig = Nothing
) As IAsyncResult

public:
[ExtensionAttribute]
static IAsyncResult^ BeginDrawBeziers(
	IReadWriteBitmapData^ bitmapData, 
	Color32 color, 
	IEnumerable<PointF>^ points, 
	DrawingOptions^ drawingOptions = nullptr, 
	AsyncConfig^ asyncConfig = nullptr
)

[<ExtensionAttribute>]
static member BeginDrawBeziers : 
        bitmapData : IReadWriteBitmapData * 
        color : Color32 * 
        points : IEnumerable<PointF> * 
        ?drawingOptions : DrawingOptions * 
        ?asyncConfig : AsyncConfig 
(* Defaults:
        let _drawingOptions = defaultArg drawingOptions null
        let _asyncConfig = defaultArg asyncConfig null
*)
-> IAsyncResult 

Parameters

bitmapData  IReadWriteBitmapData

The IReadWriteBitmapData instance to draw on.

color  Color32

The color of the curves to draw.

points  IEnumerablePointF

The points of the curves to draw.

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  AsyncConfig  (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

Usage Note

The allowed number of points in the points parameter is 0, 1, or a multiple of 3 plus 1.

When points has at least four items, the first four points define the first Bézier curve. Each additional three points define a new Bézier curve, where the last point of the previous curve is the starting point of the next curve.

This method draws cubic Bézier curves. A cubic Bézier curve is defined by four points: the starting point, two control points, and the end point. To draw quadratic Bézier curves, you can use the BeginDrawQuadraticCurves methods. In fact, those will transform the quadratic curves into cubic Bézier curve internally.

This method tries to use a shortcut to draw the curves directly, which is faster than creating a Path and adding the curves to it. A shortcut is possible when drawingOptions is and the specified color is opaque, or when FastThinLines is enabled in drawingOptions, and it specifies that no anti-aliasing and no alpha blending is required, the transformation is the identity matrix, and neither Quantizer nor Ditherer is specified.

When no shortcut can be used and the same Bézier curves are drawn repeatedly, creating a Path with PreferCaching enabled can provide a better performance.

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

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

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

If the curves are drawn by using a shortcut, then the operation is executed synchronously, it cannot be canceled, it is not parallelized, and there is no progress reporting, regardless of the asyncConfig parameter.

Reference