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Tools
The window containing the tool palette, as well as all other windows displayed
by Image can be freely moved around the screen. All the tools
work with images at any of the eight available levels of magnification.
One of the tools (the line selection tool) has three variations selected
using a pop-up menu.
Magnifying Glass - Click within the active image window
to zoom. Double-click on the magnifying glass icon to revert to 1:1 magnification.
Option-click (or use Undo) within the image to reduce magnification in
steps. Notice how the plus sign changes to a minus sign when you hold
the option key down. Eight magnification levels are available: 1:1, 2:1,
3:1, 4:1, 8:1, 16:1, 32:1 and 64:1.
Scrolling Tool (Grabber) - Allows you to scroll through
an image that is larger than its window. When using other tools (except
the text tool), you can temporarily switch to the grabber by holding down
the space bar.
Rectangular Selection Tool - Use this tool to specify
a rectangular subregion to be used by commands in the Edit, Process and
Analysis menus. The contents of a rectangular selection can be Saved,
Copied, Cleared, Filled, Duplicated, Scaled, Flipped, Rotated, Inverted,
filtered, or Measured. Hold down the shift key to constrain the selection
to be square. Double-click on this tool's icon to select the entire image.
As the rectangle is being drawn, its width and height are shown in the
Info window.
Oval Selection Tool - Creates elliptical subregions for
use by various commands in the Edit, Process and Analyze menus. Hold down
the shift key to constrain the selection to a perfect circle. As the ellipse
is being drawn, its width and height are shown in the Info window.
Polygonal Selection Tool - Creates polygon-shaped subregions
for use by various commands in the Edit, Process and Analyze menus. Click
in the small box at the starting point to end drawing. (Double-clicking
also terminates drawing.) Double-click on this tool's icon to bring up
the measurement options dialog box.
Freehand Selection Tool - Creates non-rectangular subregions
for use by various commands in the Edit, Process and Analysis menus. Double-click
on this tool's icon to bring up the Calibrate dialog box.
Image regions defined by the four outlining tools can be Copied, Filled,
Cleared, Inverted, Framed, filtered, or Measured. Immediately after using
the Fill command, you can change colors by clicking in the LUT window.
Similarly, after using Draw Boundary, you can change line widths by clicking
on the lines in the Tools window.
Selections can be edited by holding down the control key to add a new
selection to an existing selection or the option key to subtract a new
selection from the existing selection. When using the polygon or freehand
tools, you can also use the shift key to add to selections. Use the arrow
keys to "nudge" selections one pixel at a time.
Line Selection Tools - Use these tools to create straight,
freehand or segmented line selections. A pop-up menu (note the little
triangle) is used to select one of three line types. The pop-up menu is
accessed by clicking on the line selection tool's icon and holding the
mouse button down for at least 1/2 second. Once you have created a line
selection, you can measure its length using the Measure command, draw
it using the Fill command, generate a density profile plot using the Plot
Profile command, and outline the line (assuming line width is greater
than one) using the Draw Boundary command. With straight lines only, you
can dynamically vary the line width by clicking on the lines at the bottom
of the tool palette.
Freehand line selections are created in the same way as freehand region
selections, except they are not required to be closed. Segmented line
selections are created using a technique similar to the way polygon region
selections are made, using a double-click to terminate the line.
Line width is specified by clicking on the lines at the bottom of the
tool palette. Straight lines can be constrained to be either vertical
or horizontal by holding down the shift key. Line lengths recorded using
the Measure command are given in pixels unless Set Scale has been used
to perform spatial calibration. Type command-f (Fill) and command-1 (Measure)
to quickly draw and measure the length of a line selection. Use Show Results
to display the list of length measurements. Option-click with the text
tool to label lines with the measured length. Double-click on the line
selection tool to bring up the Set Scale dialog box.
Line selections can be moved in the same way as region of interest selections
by clicking inside the "marching ants" and dragging, although this has
to be done carefully for one pixel wide lines. Lines selections can also
be "nudged" a pixel at a time using the arrow keys. Straight line selections
have three "handles" (small black squares). The handles at either end
swing and stretch the line and the one in the center is used to move the
selection without changing its orientation.
Line selections can be edited in the same way as region selections by
holding down the control key to add a new selection or the option key
to subtract a new selection. Line selections, however, cannot be added
or subtracted from previous selections. Once they have been edited, line
selections revert to ordinary region of interest selections.
Pencil - Draws one pixel wide lines in the current foreground
color. Click in the LUT window, or option-click in the image, to change
the foreground color. Hold down the shift key to force pencil movements
to be either horizontal or vertical.
Eraser - Erases to the current background color. Click
in the LUT window, or option-click in the image, to change the background
color. The color of the eraser indicates the current background color.
The background color is used by the Cut, Clear and Photo Mode commands,
and as the background color for text. Hold down the shift key to force
eraser movements to be either horizontal or vertical. As a shortcut, you
can double-click on the eraser to erase the entire active image.
Paint Brush - Paints in the current foreground color.
Hold down the shift key to force brush movements to be either horizontal
or vertical. Click in the LUT window, or option-click in the image, to
change the foreground color. The color of the brush indicates the current
foreground color. Double-click on the brush to change its size.
LUT Tool - Click and drag in the LUT window with this
tool to dynamically modify the current color look-up table. Hold the option
key down to rotate all 256 entries in the LUT. The LUT tool is also used
to manipulate the density slice when density slicing is enabled. As a
shortcut, you can double-click on this tool to enable/disable density
slicing.
Spray Can Tool - Draws random pixels in the current
foreground color. Double-click on the tool to change the brush diameter.
Line Drawing Tool
Draws straight lines using the current foreground color and line width.
The line width is specified by clicking on the lines at the bottom of
the tool palette. Lines can be constrained to be either vertical or horizontal
by holding down the shift key.
Automatic Outlining Tool (Wand)
Traces the edge of a binary, density sliced, or thresholded
object, and, optionally, measures and/or numbers it, producing a selection
outline in the process. To outline an object, either click inside near
the right edge, or outside to the left of the object. To visualize what's
happening, imagine a turtle that starts moving to the right from where
you click looking for a binary edge. Once it finds an edge, it follows
it in a counter clock-wise direction until it returns to the starting
point.
Selections created with the wand tool are added to any existing selection
if either the shift or control keys are held down and subtracted from
any existing selection if the option key is held down.
You can specify that the objects be automatically measured by checking
Wand Auto-Measure in the Analyze/Options dialog box. In addition,
objects will be numbered if Label Particles is checked in
the Analyze Particles dialog box. The numbers correspond to measurement
numbers. Use Undo to remove the most recent label, along with the corresponding
measurement.
Density Profile Tool
Creates a straight line selection and uses it to generate a density profile
plot. Pixel averaging is done if the current line width is greater than
one. Change the line width by clicking on the lines at the bottom of the
Tools window. The line selection can be constrained to horizontal or vertical
be holding down the shift key. Use the Draw Boundary command (command-B)
to draw a reference line in the current foreground color. To highlight
the pixels used to generate the profile plot, hold down the mouse button
and drag in the Plot window. The Plot window, unlike the Histogram window,
can be resized.
Plots can be copied to the Clipboard and then pasted into an image window.
In addition to the plot, the Copy command also copies the plot data values
as a single column of numbers. These numbers can then be pasted into analysis
and plotting programs, such as Excel and KaleidaGraph. Profile plot data
values can also be exported to a text file using the Export command.
Various aspects of the plots produced by the profile plotting tool can
be altered using the Profile Plot Options dialog box. As a shortcut, you
can bring up this dialog box by double-clicking on the density profile
tool.
Paint Bucket
Flood fills, using the current foreground color, the area with
the same color as the point you click on. Note that the "hot spot" is
at the end of the paint coming from the bucket.
Text Tool
Adds text to images using a typeface and style chosen from the
Font, Size and Style sub-menus in the Options menu. Various attributes,
such as typeface, size and color, can be changed after the text has been
entered. Once you choose another tool, however, or type return, the text
becomes part of the image's bitmap.
Hold down the option key to get the text tool to automatically type in
the most recent length, angle, or area measurement. Clicking repeatedly
with the option key down enters multiple readings, starting with the most
recent one.
Eyedropper - Sets the foreground color by "picking up"
colors from the image or from the LUT window. Option-click to change the
background color. If you are using pseudocolor, double-clicking on a color
in the LUT window causes the Color Picker dialog box to be displayed,
allowing you to modify that color. In density slicing mode, double-clicking
in the LUT window allows you to change the density slice color. Note that,
when using this tool, pixel values are displayed in the Info window as
RGB components.
Angle Tool - Measures the angle formed by two lines drawn
through a point. The angle is displayed interactively in the Info window
as the lines are drawn. Use Show Results to display the complete list
of angle measurements. The angle tool creates a line selection that can
be used to draw the angle using the Draw Boundary command. The value of
the angle can be permanently displayed in the image by option-clicking
with the text tool.
Cross Hair Tool - Counts objects and records their X-Y
coordinates, leaving markers so objects are not counted twice. The markers
are drawn in the current foreground color and their size is related to
the current line width. Holding down various modifier keys alters the
behavior of the cross hair tool. Use the option key to label using the
current measurement count. Use the control key to display X-Y coordinates.
Use the shift key to decrement the count and leave a marker in the background
color. Use the Font, Size and Style sub-menus in the Options menu to vary
typeface, size, etc. Use Show Results to display the list of X-Y coordinates.
The cross hair tool alters the image pixel data. To avoid this, duplicate
the image and work on a copy.
Line Width - Allows you to vary the line width used
by the line selection tool, the line drawing tool, the profile plotting
tool, or the Draw Boundary command. The lines are 1, 2, 3, 4, 6, or 8
pixels wide. Line widths greater than eight can be specified in the Profile
Plot Options dialog box.
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