CHAPTER 7
116
Selecting
2 Drag to draw a freehand selection border.
3 To draw a straight-edged selection border,
hold down Alt (Windows) or Option (Mac OS),
and click where segments should begin and end.
You can switch between freehand and straight-
edged segments.
4 To c lose the selection border, release the mouse
button and Alt key (Windows) or Option key
(Mac OS).
To use the polygonal lasso tool:
1 Select the polygonal lasso tool , and select
tool options in the options bar.
2 Click in the image to set the starting point.
3 Do one or more of the following:
• To draw a straight segment, position the pointer
where you want the first straight segment to
end, and click. Continue clicking to set
endpoints for subsequent segments.
• To draw a freehand segment, hold down
Alt (Windows) or Option (Mac OS), and drag.
When finished, release Alt or Option and the
mouse button.
• To erase recently drawn straight segments,
press the Delete key.
4 To close the selection border, do one of the
following:
• Position the pointer over the starting point
(a closed circle appears next to the pointer),
and click.
• If the pointer is not over the starting point,
double-click the pointer, or Ctrl-click
(Windows) or Command-click (Mac OS).
To use the magnetic lasso tool:
1 Select the magnetic lasso tool , and then
select tool options in the options bar:
• To specify the area of edge detection, enter a
pixel value between 1 and 40 for Width. The
magnetic lasso detects edges only within the
specified distance from the pointer.
To change the magnetic lasso cursor so that it
indicates the area of edge detection (the Width
value), press the Caps Lock key on the keyboard.
Change the cursor while the tool is selected but not
in use.
• To specify the lasso’s sensitivity to edges in the
image, enter a value between 1% and 100% for
Edge Contrast. A higher value detects only edges
that contrast sharply with their surroundings;
a lower value detects lower-contrast edges.
• To specify the rate at which the lasso sets
fastening points, enter a value between 0 and
100 for Frequency. A higher value anchors the
selection border in place more quickly.
On an image with well-defined edges, try higher
Width and Edge Contrast settings, and trace the
border roughly. On an image with softer edges, try
lower Width and Edge Contrast settings, and trace
the border more precisely.
• If you are working with a stylus tablet, select or
deselect the Pen Pressure option. When the
option is selected, an increase in stylus pressure
causes the width of the edge detection to
decrease.
2 Click in the image to set the first fastening
point. Fastening points anchor the selection
border in place.
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