7.38. Llindar alfa

The Threshold Alpha command converts semi-transparent areas of the active layer into completely transparent or completely opaque areas, based on a threshold you set. It only works on layers which have an alpha channel. If the Lock alpha channel option is checked in the Layers dialog, the filter will have no effect.

7.38.1. Activació de l'ordre

  • You can access this command from the menubar through LayerTransparencyThreshold Alpha....

7.38.2. Descripció del quadre de diàleg

Figura 16.121. The «Threshold Alpha» filter options dialog

The «Threshold Alpha» filter options dialog

Presets, Input Type, Blending Options, Preview, Split view
[Nota] Nota

Aquestes opcions es descriuen a Secció 2, «Característiques comunes».


The threshold alpha value determines which values will become transparent or opaque. You can set the transparency value to be used by using the slider or by entering a value between 0 and 1 in the input box. All transparency values above this threshold will become opaque and all transparency values below or equal to this threshold will become completely transparent.

[Nota] Nota

Aquesta ordre no tornarà mai opacs els píxels completament transparents (valor alfa = 0).

Figura 16.122. Exemple de Llindar alfa

Exemple de Llindar alfa
Degradat de transparència 0-255.
Exemple de Llindar alfa
Estableix llindar a 50, 127, 210.