Tài liệu Working with Selections

Working with Selections

Learning how to select areas of an


image is of primary importance when


working with Adobe® Photoshop® —


you must first select what you want to


affect. Once you’ve made a selection,


only the area within a selection can be


edited; areas outside the selection are


protected from change. In this lesson, you’ll learn how to do the following:


ã Use the marquee, lasso, and magic wand tools to select parts of an image in various ways.


ã Reposition a selection marquee.


ã Deselect a selection.


ã Move and duplicate a selection.


ã Constrain the movement of a selection.


ã Adjust a selection with the arrow keys.


ã Add to and subtract from selections.


ã Rotate, scale, and transform a selection.


ã Combine selection tools.


ã Crop an image.


Tool overview


In Adobe Photoshop, you can make selections based on size, shape, and color using four basic sets
of tools—the marquee, lasso, magic wand, and pen tools. In addition, you can use a fifth tool, the
move tool, to reposition the selections you create.


Note: In this lesson, you will use just the marquee, lasso, magic wand, and move tools; for more infor-
mation on the pen tools, see Chapter 7, “Selecting,” in the Adobe Photoshop User Guide.


A B


C D


A. Marquee Tool B. Move Tool
C. Lasso Tool D. Magic Wand Tool


The marquee and lasso tool icons contain hidden tools, which you can select by holding down the
mouse button on the toolbox icon and dragging to the desired tool in the pop-up menu.


The rectangular marquee tool ( ) lets you select a rectangular area in an image. The elliptical
marquee tool ( ) lets you select elliptical areas. The single row and single column marquee tools ( )
( ) let you select a 1-pixel-high row and 1-pixel-wide column. You can also use the crop tool ( ) to
crop an image.


The lasso tool ( ) lets you make a freehand selection around an area. Thepolygon lasso tool ( ) lets
you make a straight-line selection around an area. The magnetic lasso tool ( ) lets you draw a
freehand border that snaps to the edges of an area.


The magic wand tool ( ) lets you select parts of an image based on the similarity in color of adjacent
pixels. This tool is useful for selecting odd-shaped areas without having to trace a complex outline
using the lasso tool.