CHAPTER
33
SELECTIONS AND CHANNELS
Canvas gives you several ways to select pixels in an image. When
you select groups of pixels by area or color, you can use painting
tools, filters, and special effects to modify the selected pixels without
affecting the parts of the image that are not selected.
This chapter describes how to make selections in images, save selec-
tions in alpha channels, work with color and alpha channels, and cre-
ate channel masks, which can make parts of images transparent.
Selecting pixels in images
When a paint object is in edit mode, any filters, commands, and
painting tools that you apply can affect the entire image. When you
have selected pixels in the image, the effect of a tool, filter, or other
adjustment is confined to the selected pixels.
You can select areas in an image using painting tools or menu com-
mands. For example, you can make rectangular selections by drag-
ging the Marquee tool in an image, and you can use the Color Range
command to select groups of pixels based on color similarity.
Selection borders
The selected pixels in an image are referred to collectively as a selec-
tion. When you make a selection, Canvas surrounds the selected pix-
els with a moving dashed border. You can hide and display the
border without affecting the selection. To hide the border, choose
Image > Select > Hide Edges. To display the selection border, choose
Image > Select > Show Edges.
Deselecting an image selection
When you use a selection tool in normal mode, making a new selec-
tion replaces any existing selection in an image. To deselect pixels
without making a new selection, choose Image > Select > None. You
can also press Enter or Esc (Mac), or Esc (Windows) to deselect a
selection. If a selection is floating, pressing Esc once defloats the
selection; pressing Esc again deselects all pixels.
A dashed border outlines the
selected area in a photograph