Zooming and Panning

In terms of the parameters that define a view, zooming and panning affect the structure scale and the mid-point. These parameters may be adjusted explicitly via the Orientation Settings dialog box. More commonly, though, higher level operations may be used to zoom or pan.

Zoom Cursor Mode– When in the Zoom cursor mode:

• Dragging a rectangle in the window causes the image to be zoomed and panned to result in that rectangle filling the Window. Only when the aspect ratios of the rectangle and window are identical will this be exact; otherwise the scale is such that at least all of the rectangle remains visible.
• Click pans and zooms in. The image is panned to result in the point clicked on being at the mid-point of the view. The structure scale is multiplied by (zoom factor) where the zoom factor is a Graphics Preferences.
• Ctrl+Click pans and zooms out. The image is panned to result in the point clicked on being at the mid-point of the view. The structure scale is multiplied by (1 / zoom factor) where the zoom factor is a Graphics Preferences.
• Shft+Click pans. The image is panned to result in the point clicked on being at the mid-point of the view.

Dragging– When in the Rotate cursor mode:

• Ctrl+Drag up and down zooms in and out respectively. The sensitivity is governed by the zoom increment mouse sensitivity Graphics Preferences.
• Shft+Drag pans the image. The sensitivity is governed by the pan increment mouse sensitivity Graphics Preferences.

Intellimouse wheel– In any cursor mode:

• Rolling the mouse wheel forwards and backwards zooms in and out respectively. Each notch on the mouse wheel is equivalent to one Zoom In or Zoom Out command. If when rolling the mouse wheel the cursor is over the Graphic View then the zoom occurs pinned at the cursor position.
• Drag with the mouse wheel (or middle button) held down pans the image. The sensitivity is as for Shft+Drag, under Dragging above.
• Ctrl+Drag with the mouse wheel (or middle button) held down operates as Ctrl+Drag in the Rotate cursor mode.

Menu commands– The following commands (and their associated accelerator keys) are available from the “Graphics | Orientation” menu to allow zooming and panning.

• Zoom In (Ctrl+Up). Multiplies the structure scale by (zoom factor) where the zoom factor is a Graphics Preferences.
• Zoom Out (Ctrl+Dn). Multiplies the structure scale by (1 / zoom factor).
• Reset Pan (Shft+Home). Sets the mid-point to (0, 0, 0).
• Pan Right (Shft+Rt). Adjusts the mid-point to result in the picture shifting left by 1⁄16 of the picture width.
• Pan Left (Shft+Lft). Adjusts the mid-point to result in the picture shifting right by 1⁄16 of the picture width.
• Pan Up (Shft+Up). Adjusts the mid-point to result in the picture shifting down by 1⁄16 of the picture height.
• Pan Down (Shft+Down). Adjusts the mid-point to result in the picture shifting up by 1⁄16 of the picture height.

Note that scaling to fit effectively resets any zooming and panning.

Note also that these operations do not affect the object point so, for example, rotations that occur after a zoom or pan may not have the desired affect unless the object point is adjusted.