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Metodo ImageAttributes.SetThreshold (Single, ColorAdjustType)

 

Imposta la soglia (intervallo di trasparenza) per una categoria specificata.

Spazio dei nomi:   System.Drawing.Imaging
Assembly:  System.Drawing (in System.Drawing.dll)

public void SetThreshold(
	float threshold,
	ColorAdjustType type
)

Parametri

threshold
Type: System.Single

Valore soglia compreso tra 0 e 1, usato come punto di interruzione per ordinare i colori che verranno mappati a un valore massimo o minimo.

type
Type: System.Drawing.Imaging.ColorAdjustType

Elemento dell'oggetto ColorAdjustType da cui viene specificata la categoria per la quale viene impostata la soglia di colore.

The threshold is a value from 0 through 1 that specifies a cutoff point for each color component. For example, suppose the threshold is set to 0.7, and suppose you are rendering a color whose red, green, and blue components are 230, 50, and 220, respectively. The red component (230) is greater than 0.7x255, so the red component will be changed to 255 (full intensity). The green component (50) is less than 0.7x255, so the green component will be changed to 0. The blue component (220) is greater than 0.7x255, so the blue component will be changed to 255.

An T:System.Drawing.Imaging.ImageAttributes object maintains color and grayscale settings for five adjustment categories: default, bitmap, brush, pen, and text. For example, you can specify a threshold for the default category, a threshold for the bitmap category, and still a different threshold for the pen category.

The default color-adjustment and grayscale-adjustment settings apply to all categories that do not have adjustment settings of their own. For example, if you never specify any adjustment settings for the pen category, the default settings apply to the pen category.

As soon as you specify a color-adjustment or grayscale-adjustment setting for a certain category, the default adjustment settings no longer apply to that category. For example, suppose you specify a collection of adjustment settings for the default category. If you set the threshold for the pen category by passing F:System.Drawing.Imaging.ColorAdjustType.Pen to the M:System.Drawing.Imaging.ImageAttributes.SetThreshold(System.Single,System.Drawing.Imaging.ColorAdjustType) method, none of the default adjustment settings will apply to pens.

For a code example, see the M:System.Drawing.Imaging.ImageAttributes.SetThreshold(System.Single) method.

.NET Framework
Disponibile da 1.1
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