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
Canvas 8 Help: Selections and channels (1 of 32)                                                    Page #651