Selection masks
In the Effects list, a symbol to the left of each effect name shows the
state the selection mask for the effect. You can click the symbol to
toggle the mask on (
) and off (
).
An active selection mask defines a selection for an effect. The selec-
tion will include objects, not empty space. The mask can preserve
transparent areas, such as empty space in a group object, and space
between text characters.
When the selection mask is on, the effect is based on the
selection area.
When the selection mask is off, the effect is based on the
entire bounding box area.
For example, if you apply the Add Noise command to a circle, the
selection includes only the circle, so the noise affects only the circle
if the mask is on. If the mask is off, the noise appears in the entire
bounding box area.
For a built-in effect, Canvas uses the best selection mask setting. For
third-party effects, you might need to change the mask setting for the
best results.
Blur effects usually require the selection mask to be off, so the blur
can extend beyond the outline of an object. Other effects look best
when they are based on a selection. For example, a flame effect will
cover an entire bounding box if the selection mask is off. If the mask
is on, flames will rise from just the objects or text characters in the
selection. This does not mean that flames cant rise above the selec-
tion, just that the effect will be based on the selection, not the entire
bounding box.
Mask off
Mask on
Noise applied to vector graphic