BitmapDataExtensionsDrawQuadraticCurvesAsync(IReadWriteBitmapData, Color32, IEnumerablePointF, DrawingOptions, TaskConfig) Method

Draws a series of one-pixel wide quadratic Bézier curves with the specified color asynchronously.

Definition

Namespace: KGySoft.Drawing.Shapes
Assembly: KGySoft.Drawing.Core (in KGySoft.Drawing.Core.dll) Version: 10.0.0-rc.1
C#
public static Task<bool> DrawQuadraticCurvesAsync(
	this IReadWriteBitmapData bitmapData,
	Color32 color,
	IEnumerable<PointF> points,
	DrawingOptions? drawingOptions = null,
	TaskConfig? asyncConfig = null
)

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  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

In the points parameter 0 or odd number of points are expected.

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

This method draws quadratic Bézier curves. A quadratic Bézier curve is defined by three points: the starting point, the control point, and the end point. To draw cubic Bézier curves, you can use the DrawBeziersAsync methods. In fact, this method transforms the quadratic curves into cubic Bézier curves 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 curves are drawn repeatedly, creating a Path with PreferCaching enabled can provide a better performance.

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.

Exceptions

ArgumentNullExceptionbitmapData or points is .
ArgumentExceptionThe number of points is not zero, or an odd number.
OverflowExceptionThe coordinates (after a possible transformation specified in drawingOptions) are outside the bounds of an int value.
TaskCanceledExceptionThe operation has been canceled and the ThrowIfCanceled property in asyncConfig was . This exception is thrown when the result is awaited.

See Also