Masking Bitmap is similar process to cropping except the Bitmap object doesn't change the size. Instead the Bitmap transparency will be masked.
There are two types:
The masking Bitmap is a great way how to make an unwanted part of the Bitmap
You can make the mask object semitransparent so you will see through it.
1. Draw any object (we will cal it a mask) on the Bitmap. Make the
mask semitransparent so you can see the Bitmap behind it.
The Masking unlike the Crop keeps both objects and it doesn't alter the Bitmap.
You can reset the Masking by using Reset All from menu Bitmap or clicking at button
The same as a masking except the unwanted are is behind the mask object, not around it.
Use: Mask-From Object Inverted