ErrorDiffusionDithererConfigureProcessingDirection Method

Gets a new ErrorDiffusionDitherer instance that has the specified processing direction.

Definition

Namespace: KGySoft.Drawing.Imaging
Assembly: KGySoft.Drawing.Core (in KGySoft.Drawing.Core.dll) Version: 9.1.1

C#

public ErrorDiffusionDitherer ConfigureProcessingDirection(
	bool serpentine
)

VB

Public Function ConfigureProcessingDirection ( 
	serpentine As Boolean
) As ErrorDiffusionDitherer

C++

public:
ErrorDiffusionDitherer^ ConfigureProcessingDirection(
	bool serpentine
)

F#

member ConfigureProcessingDirection : 
        serpentine : bool -> ErrorDiffusionDitherer

Parameters

serpentine Boolean: to process odd lines right-to-left and even lines left-to-right; to process all lines left-to-right.

Return Value

ErrorDiffusionDitherer
A new ErrorDiffusionDitherer instance that has the specified processing direction.

Remarks

Note

This method always returns a new ErrorDiffusionDitherer instance instead of changing the processing direction of the original one. This is required for the static properties so they can return a cached instance.

A typical artifact of error diffusion dithering is a ripple effect, which often appears in homogeneous areas of the dithered image. This is due to the fact that most filters propagate quantization errors mostly to right and down, whereas pixels are processed left-to-right in each line while lines are scanned top-down (raster processing). The ripple effect can be reduced if every second line is processed in the opposite direction (serpentine processing).

Examples

The following table demonstrates the effect of different processing directions:

Original image	Quantized image
Original test image "Cameraman"	Quantizing with black and white palette and Floyd-Steinberg dithering, using raster processing. The ripple effect is clearly visible on the coat. Quantizing with black and white palette and Floyd-Steinberg dithering, using serpentine processing. The ripple effect is gone.

The following example demonstrates how to specify the processing direction for a predefined filter:

C#

// getting a predefined ditherer with serpentine processing:
IDitherer ditherer = ErrorDiffusionDitherer.FloydSteinberg.ConfigureProcessingDirection(serpentine: true);