BitmapDataExtensionsAdjustContrast Method

Adjusts the contrast of the specified bitmapData.


Namespace: KGySoft.Drawing.Imaging
Assembly: KGySoft.Drawing.Core (in KGySoft.Drawing.Core.dll) Version: 7.0.0
public static void AdjustContrast(
	this IReadWriteBitmapData bitmapData,
	float contrast,
	IDitherer? ditherer = null,
	ColorChannels channels = ColorChannels.Rgb


bitmapData  IReadWriteBitmapData
The IReadWriteBitmapData to be transformed.
contrast  Single
A float value between -1 and 1, inclusive bounds. Positive values increase the contrast, while negative values decrease the it.
ditherer  IDitherer  (Optional)
An optional IDitherer instance to dither the result of the transformation if the transformed colors are not compatible with the PixelFormat of the specified bitmapData. This parameter is optional.
Default value: .
channels  ColorChannels  (Optional)
The ColorChannels, on which the adjustment has to be performed. This parameter is optional.
Default value: Rgb.

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).



This method adjusts the degree of parallelization automatically, blocks the caller, and does not support cancellation or reporting progress. Use the BeginAdjustContrast or AdjustContrastAsync (in .NET Framework 4.0 and above) methods for asynchronous call and to adjust parallelization, set up cancellation and for reporting progress.

This method calls the TransformColors method internally. See the Remarks section of the TransformColors method for more details.

If bitmapData has an indexed PixelFormat and ditherer is , then its palette entries are tried to be transformed instead of the actual pixels in the first place (if it is supported by bitmapData). To transform the colors of an indexed IBitmapData without changing the palette specify a non- ditherer. Transforming the palette is both faster and provides a better result.

The ditherer is ignored for KnownPixelFormats with more than 16 bits-per-pixel and for the Format16bppGrayScale format.


ArgumentNullExceptionbitmapData is .
ArgumentOutOfRangeExceptioncontrast is not between -1 and 1
channels is out of the defined flags.

See Also