Quick Reference

Main image window

These keyboard and mouse operations are available when the main image window has the focus.

Mode control commands

About modes

Certain keystrokes invoke a mode—modes are usually indicated by the mode indicator: a small black rectangle with the mode name in one corner of the view. In a mode, there are usually some special key, cursor, and scroll bindings that override some of the default ones.

Modes additionally have a mode type which can be set to one of the following:

• held: mode is active while the activating key is held down

• oneshot: mode is released by initiating and finishing a cursor drag or when Esc is pressed, if no cursor drag is performed

• locked: mode is locked until the mode key is pressed again (or Esc)

By default, most modes are activated in “locked” type. The mode type is indicated in the brackets after the mode name in the mode indicator. The following keys are important for initiating a mode:

Commmand	Description
Space	Enter “meta” mode. Next keystroke will trigger a particular mode.
Esc	Exit any mode.

“meta” mode

Most modes are defined so that they are invoked from a special intermediate mode called “meta”. In that case a two-key sequence is required to enter the mode: pressing the key that invokes “meta” and then pressing the key that invokes the desired mode. The following table shows the modes that can be triggered from meta mode.

Commmand	Description
Space	Exit/Enter “meta” mode.
b	Enter draw mode (canvas must be enabled to draw).
q	Enter Pan mode.
w	Enter Zoom mode.
r	Enter Rotate mode.
t	Enter Contrast mode.
y	Enter CMap (color map) mode.
s	Enter Cuts mode.
d	Enter Color Distribution (“dist”) mode. See Dist mode.
n	Enter naxis (cube axis navigation) mode. See Naxis mode.
L	Toggle the normal lock to the current mode or any future modes.

Panning and zooming commands

Commmand	Description
scroll-wheel	Zoom in or out.
Shift + scroll-wheel	Zoom while keeping location under the cursor.
Ctrl + scroll-wheel	Pan in direction of scroll.
Digit (1234567890)	Zoom image to zoom steps 1, 2, …, 9, 10.
Shift + Digit	Zoom image to zoom steps -1, -2, …, -9, -10.
Backquote (`)	Zoom image to fit window and center it.
Minus, Underscore (-, _)	Zoom out.
Equals, Plus (=, +)	Zoom in.
Middle (scroll) button click	Set pan position (under cursor).
p	Set pan position (under cursor) for zooming.
Shift + left-click	Set pan position for zooming.
Shift + arrow key	Move pan position 1 pixel in that direction.
c	Set pan position to the center of the image.
Ctrl + left-drag	Proportional pan (press and drag left mouse button.
slash (/)	Set autocenter for new images to override.
question (?)	Toggle autocenter for images to on or off.
apostrophe (‘)	Set autozoom for new images to override.
double quote (“)	Toggle autozoom for new images to on or off.

Cut levels and colormap commands

Commmand	Description
a	Auto cut levels.
D	Reset color distribution algorithm to “linear”.
T	Restore the contrast (via colormap) to its original (unstretched, unshifted) state.
Y	Restore the color map to default (gray).
I	Invert the color map.
semicolon (;)	Set autocuts for new images to override.
colon (:)	Toggle autocuts for new images to on or off.

Transform commands

Commmand	Description
Left bracket ([)	Toggle flip image in X.
Left brace ({)	Reset to no flip of image in X.
Right bracket (])	Toggle flip image in Y.
Right brace (})	Reset to no flip image in Y.
Backslash (\)	Swap X and Y axes.
Vertical bar (|)	Reset to no swap of X and Y axes.
R	Restore rotation to 0 degrees and additionally undo any flip/swap transformations.
period (.)	Increment current rotation by 90 degrees.
comma (,)	Decrement current rotation by 90 degrees.
o	Orient image by transforms and rotation so that WCS indicates North=Up and East=Left.
O	Orient image by transforms and rotation so that WCS indicates North=Up and East=Right.

Pan mode

Commmand	Description
left-drag	Pan proportionally to drag.
pan-gesture	Pan proportionally to gesture.
middle-click	Set pan position.
right-drag	Zoom in/out proportionally to L/R drag.
scroll-wheel	Zoom in or out.
pinch-gesture	Zoom in/out porportionally to gesture.
<Modifier> + arrow key	Pan in direction of arrow key. Adding Ctrl reduces amount, adding Shift reduces more.
p	Pan to position under cursor.
z	Save current scale (see below for use).
backquote (`)	Zoom to fit window and center.
r	Pan to cursor and zoom to saved scale level (or 1:1 if no scale level saved).
c	Set pan position to the center of the image.
slash (/)	Set autocenter for new images to override.
question (?)	Toggle autocenter for images to on or off.
apostrophe (‘)	Set autozoom for new images to override.
double quote (“)	Toggle autozoom for new images to on or off.

Zoom mode

Commmand	Description
scroll-wheel	Zoom in or out.
left-click	Set pan position, zoom in a step and warp cursor to pan position (if supported on backend).
right-click	Set pan position, zoom out a step and warp cursor to pan position (if supported on backend).
middle-drag	Pans freely over entire image in proportion to cursor position versus window.
p, z, backquote, r, c, arrow keys, pan and pinch gestures	(Same as for Pan mode.)

Dist mode

Commmand	Description
scroll-wheel	Select distribution from linear, log, etc.
b, up-arrow	Select prev distribution in list.
n, down-arrow	Select next distribution in list.
D	Reset color distribution algorithm to “linear”.

Cuts mode

Commmand	Description
left-drag	Interactive cut both low and high levels (vertical cuts low, horizontal cuts high).
Ctrl + left-drag	Interactive cut low level only (horizontal drag).
Ctrl + pan gesture	Change cut high level up/down.
Shift + left-drag	Interactive cut high level only (horizontal drag).
Shift + pan gesture	Change cut low level up/down.
scroll-wheel	Squeeze or stretch gap between cuts. Coarse (10%) adjustment in/out.
Ctrl + scroll-wheel	Squeeze or stretch gap between cuts. Fine (1%) adjustment in/out.
pinch gesture	Squeeze or stretch gap between cuts.
a, right-click	Do an auto level to restore cuts.
k	Set the high cut to the value under the cursor.
l	Set the low cut to the value under the cursor.
S	Set cuts to min/max values.
A	Set cuts to 0/255 values (for 8bpp RGB images).
b, up-arrow	Select prev auto cuts algorithm in list.
n, down-arrow	Select next auto cuts algorithm in list.
semicolon (;)	Set autocuts for new images to override.
colon (:)	Toggle autocuts for new images to on or off.

Contrast mode

Commmand	Description
left-drag	Interactive shift/stretch colormap (AKA contrast and bias). Left/Right controls shift, Up/Down controls stretch.
right-click	Restore the contrast (via colormap) to its original (unstretched, unshifted) state.
scroll-wheel	Increase/decrease contrast. (add Ctrl to adjust it more finely).
Shift + scroll-wheel	Increase/decrease brightness (bias). (add Ctrl to adjust it more finely).
Ctrl + pan gesture	Increase/decrease contrast.
Shift + pan gesture	Increase/decrease brightness (bias).
T	Restore the contrast (via colormap) to its original (unstretched, unshifted) state.

Rotate mode

Commmand	Description
left-drag	Drag around center of window to rotate image.
right-click	Restore rotation to 0 degrees (does not reset any flip/swap transformations).
R	Restore rotation to 0 degrees and additionally undo any flip/swap transformations.
Left bracket ([)	Toggle flip image in X.
Left brace ({)	Reset to no flip of image in X.
Right bracket (])	Toggle flip image in Y.
Right brace (})	Reset to no flip image in Y.
Backslash (\)	Swap X and Y axes.
Vertical bar (|)	Reset to no swap of X and Y axes.
period (.)	Increment current rotation by 90 degrees.
comma (,)	Decrement current rotation by 90 degrees.
o	Orient image by transforms and rotation so that WCS indicates North=Up and East=Left.
O	Orient image by transforms and rotation so that WCS indicates North=Up and East=Right.

Cmap mode

Commmand	Description
scroll	Select color map.
left-drag	Rotate color map.
right-click	Unrotate color map.
b, up-arrow	Select prev color map in list.
n, down-arrow	Select next color map in list.
I	Toggle invert color map.
r	Restore color map to unrotated, uninverted state.
Ctrl + scroll	Select intensity map.
j, left-arrow	Select prev intensity map in list.
k, right-arrow	Select next intensity map in list.
i	Restore intensity map to “ramp”.
c	Toggle a color bar overlay on the image.
Y	Restore the color map to default (‘gray’).

Naxis mode

Note

Naxis mode can be used when viewing data that has more than 2 dimensions (e.g., data cubes).

Commmand	Description
scroll	Select previous or next slice of current axis.
Ctrl + scroll	Select previous or next axis as current axis.
left drag	select slice as a function of percentage of cursor/window width.
up-arrow	Select prev axis as current axis.
down-arrow	Select next axis as current axis.

Plot mode

Plot mode is only valid when the viewer is used with a PlotAide object to display a graph.

Commmand	Description
scroll	Zoom the X axis. (Sets autoaxis_x to off, if it was on)
Ctrl + scroll	Zoom the Y axis. (Sets autoaxis_y to off)
x	Toggle autoaxis_x between on and off.
p	Toggle autoaxis_x between pan and off.
y	Toggle autoaxis_y between on and off.
v	Toggle autoaxis_y between vis and off.

The graph can be flipped in X or Y and the axes swapped, using the keystroke commands found in the transform section above (Transform commands).

To understand the role of the autoaxis_x and autoaxis_y settings, please see the chapter on plots (Plots).

Autozoom setting

The “autozoom” setting can be set to one of the following: “on”, “override”, “once” or “off”. This affects the behavior of the viewer when changing to a new image (when done in the typical way) as follows:

• on: the image will be scaled to fit the window

• override: like on, except that once the zoom/scale is changed by the user manually it turns the setting to off

• once: like on, except that the setting is turned to off after the first image

• off: an image scaled to the current viewer setting

(In the Reference Viewer, this is set under the “Zoom New” setting in the channel preferences.)

Autocenter setting

The “autocenter” setting can be set to one of the following: “on”, “override”, “once” or “off”. This affects the behavior of the viewer when changing to a new image (when done in the typical way) as follows:

• on: the pan position will be set to the center of the image

• override: like on, except that once the pan position is changed by the user manually it turns the setting to off

• once: like on, except that the setting is turned to off after the first image

• off: the pan position is taken from the current viewer setting

(In the Reference Viewer, this is set under the “Center New” setting in the channel preferences.)

Autocuts setting

The “autocuts” setting can be set to one of following: “on”, “override”, “once” or “off”. This affects the behavior of the viewer when changing to a new image (when done in the typical way) as follows:

• on: the cut levels for the image will be calculated and set according to the autocuts algorithm setting

• override: like on, except that once the cut levels are changed by the user manually it turns the setting to off

• once: like on, except that the setting is turned to off after the first image

• off: the cut levels are applied from the current viewer setting

(In the ref:Reference Viewer, this is set under the “Cut New” setting in the channel preferences.)

Reference Viewer Only

Commmand	Description
H	Raise Header tab (if Header plugin has been started).
Z	Raise Zoom tab (if Zoom plugin has been started).
D	Raise Dialogs tab.
C	Raise Contents tab.
less than (<)	Toggle collapse left pane.
greater than (>)	Toggle collapse right pane.
f	Toggle full screen.
F	Panoramic full screen.
h	Pop up a quick help tab for the current mode.
m	Maximize window.
J	Cycle workspace type (tabs/mdi/stack/grid). Note that “mdi” type is not supported on all platforms.
k	Add a channel with a generic name.
Left, Right (arrow keys)	Previous/Next channel.
Up, Down (arrow keys)	Previous/Next image in channel.

Note

If there are one or more plugins active, additional mouse or keyboard bindings may be present. In general, the left mouse button is used to select, pick or move, and the right mouse button is used to draw a shape for the operation.

On the Mac, Ctrl + mouse button can also be used to draw or right-click. You can also invoke draw mode as described above in the section on modes.