By default, the AlphaFrom and AlphaTo properties are empty. While AlphaFrom property is empty, missing or invalid, 0 is used instead. While AlphaTo property is empty, missing or invalid, 254 is used instead. In other words, any pixel in the picture with the transparency-byte on 255 defines the clipping region ( by default, the opaque-pixels in the picture defines the clipping region. ). Use the AlphaFrom / AlphaTo to include semi-transparent pixels in the clipping region.  The picture being used as a clipping region must support transparency / alpha blending ( picture's attribute includes the PICTURE_TRANSPARENT ). For instance, you can use any PNG file with transparency. The DisplayAs property retrieves or sets a value that indicates the way how the graphic is arranged on the mask/clip.

For instance, having a picture like follows:

if we apply this picture as a clipping, we get something like ( includes pixels with alpha-blend byte on 255 only, opaque-pixels  ):

while if we change the AlphaTo field to 128 we can get something like ( includes pixels with alpha-blend byte between 129 and 255, opaque plus semi-transparent pixels to 128 ):

or if we change the AlphaFrom and Alpha fields to 255, we can get something like ( includes pixels with alpha-blend byte between 0 and 254, excludes the opaque pixels ):

or if we change the AlphaFrom to 128, and Alpha field to 255, we can get something like ( includes pixels with alpha-blend byte between 0 and 127, excludes the opaque pixels, and semi-transparent pixels to 128 ):

To define a picture clip region over the layer you can use any of the following properties:

• Name, Indicates the picture to be used as a mask/clip.
• DisplayAs, Retrieves or sets a value that indicates the way how the graphic is arranged on the mask/clip.
• AlphaFrom, Gets or sets a value that specifies the alpha-byte to start clipping the picture from.
• AlphaTo, Gets or sets a value that specifies the alpha-byte to end clipping the picture to.

To specify the position / size of the picture clip object you can use any of the following properties:

• Left, Specifies the left position / expression of the clip, relative to the layer.
• Top, Specifies the top position / expression of the clip, relative to the layer.
• Width, Specifies the width value / expression of the clip, relative to the layer.
• Height, Specifies the height value / expression of the clip, relative to the layer.

To move the clipping region you can use any of the following properties:

• OffsetX, Specifies the x-offset expression / value of the clip, relative to the layer.
• OffsetY, Specifies the y-offset expression / value of the clip, relative to the layer.

If none of these properties are calling no clipping is applied to layer.

The following screen shot shows properties of the clipping objects relative to the layer:

The InverseClip property inverses the current clipping region, so anything that was included in the clipping region will be excluded, and reverse.