Chapter 4. Interactions

Table of Contents

4.1 Zoom/Move/Rotate (ZMR)
4.1.1 Central Point
4.2 Rubberband
4.2.1 Rubberband in YX Projection
4.2.2 Rubberband in φ/η Projection
4.3 Pick
4.4 Synchro Cursors
4.5 Fisheye
4.6 Clock
4.7 Skew
4.8 Scale

It is very important to understand how interactions work, so you may use the full power of each. There are two sets of interactions, the interactions that are sensible for all projections (global interactions) and the interactions which are only sensible for some specific projections (projection dependent interactions). As a consequence, each projection has a specific set of associated interactions represented by the set of tabs in the Control Window.

N.B.: See the detailed information about available projections in Chapter 5, Projections.

Global Interactions

Interactions that are available in all projections:

Projection Dependent Interactions

Interactions that perform operations which only make sense in specific projections:

Interaction Control

Interactions are selected and interaction parameters are modified via the interaction control (see 3.1.3 Interaction Control) of the Control Window.

Interaction Pop-up Menus

Many interactions have an associated pop-up menu that is invoked for a picture by right-clicking in the canvas pad. See 3.3.3 Interaction Menus.

4.1 Zoom/Move/Rotate (ZMR)

The ZMR interaction allows the user to perform zooming, moving and rotation of the picture content in a canvas pad (3.2.1 Canvas Pads). It is activated for the current canvas pad by clicking on the ZMR tab of the interaction control (3.1.3 Interaction Control) in the Control Window.

  • Zoom

    Zooming is always done with respect to a central point (4.1.1 Central Point) which the user can specify. The central point is represented by a small red circle superimposed on the picture.

    If you want to perform a zoom operation just drag a point of the picture inside or outside, increasing or decreasing its distance to the central point.

    See the Modifier Key Summary for the different types of zoom that can be applied.

  • Move

    You can move (pan) the picture by dragging a point of the picture while keeping the M key pressed.

  • Rotate

    Rotation is also done with respect to a central point (4.1.1 Central Point) which the user can specify. To obtain a rotation of the picture you drag a point of the picture around while keeping the R key pressed.

    Note that rotation is a projection dependent operation:

The ZMR Pop-up Menu

The ZMR pop-up menu can be accessed by right-clicking in a canvas window with ZMR applied. It contains the following utility operations:

  • To Center of Detector - Sets the central point (4.1.1 Central Point) to the geometrical center of the detector.

  • Center the Picture - Shifts the picture in such a way that the center of the detector coincides with the center of the canvas pad.

  • Unzoom Full - Restores the window to its initial zoomed state.

Modifier Key Summary

Table 4.1. Modifier key summary

Modifier KeyAction
NoneZoom with respect to the central point (horizontal zoom in the φ/ρ projection (5.5 φ/ρ Projection))
FFast Zoom with respect to the central point (horizontal zoom in the φ/ρ projection (5.5 φ/ρ Projection)); data are not updated during the zoom
HHorizontal Zoom with respect to the central point
VVertical Zoom with respect to the central point
MMove (panning)
RRotate (projection dependent)
CChange position of central point


4.1.1 Central Point

The central point is used by the ZMR interaction for zooming (all projections) and rotation (Y/X projection) in a canvas pad. It is represented as a small red circle superimposed on the picture.

By default the central point is in the center of the detector (0, 0, 0). There are different ways to change it's position:

  • By pressing the C key on the keyboard and the left mouse button to specify the new center position.

  • By selecting "To Center of Detector" in the ZMR Pop-up Menu to set the center back to it's initial position (center of the detector).