To create a channel mask by rendering
Canvas can create a channel mask when you render a vector, group,
paint, or text object. To create the mask, choose the Mask and Trans-
parency options in the Render dialog box. Canvas will create a chan-
nel mask that makes blank areas around and inside the objects
transparent.
When you make a new paint object by pasting a non-rectangular
selection copied from an image, Canvas makes a channel mask to
hide white pixels surrounding the selection.
Preserving transparency in images
You can select the Preserve Visibility checkbox in the Channels pal-
ette to preserve transparency when you paint or apply filters to an
image. The Preserve Visibility checkbox is available when you edit a
paint object that has a visibility mask. A paint object has a visibility
mask if it was created with a transparent background, or if you
applied a visibility mask with the Add Visibility Mask command.
If a paint object has an opaque background, the Preserve Visibility
checkbox is dimmed and cant be selected.
To preserve transparency while editing an image
When a paint object is in edit mode, select Preserve Visibility in the
Channels palette. When the option is selected, you can paint and edit
the image without affecting clear areas or reducing the transparency
of partially transparent pixels.
Channel mask from
alpha channel
Vignette
Original