#99 Centre map for next zoom level on mouse pointer

closed
nobody
5
2013-02-12
2012-07-22
Anonymous
No

If the zoom level of the map is changed, the center of the map stays the same. Therefor, the location on the map the user is interested in, is likely to leave the screen quickly and the user needs to move the map again to see his desired location.
It would be much more intuitive to keep the location below the position of the mouse were it is. This is the same behavior as seen on Google maps or in the KDE program marple for example.

Discussion

  • Rob Norris
    Rob Norris
    2012-08-03

    • summary: Centre map for next zoom levelon on mouse pointer --> Centre map for next zoom level on mouse pointer
     
  • Rob Norris
    Rob Norris
    2012-08-04

    • status: open --> open
     
  • Rob Norris
    Rob Norris
    2012-08-04

    Agreed, since clearly this is the point of interest the user wants to see and thus subsequent zoom requests keep focusing on that area without having to recenter the display.

    The modifiers of CTRL+SHIFT and mouse zoom retain keeping the center point in the center (which is in fact a reversal of the previous setting - unlikely to effect many users, as I didn't even know of this feature myself).

    Note the keyboard & menu zoom requests always maintain the center point.

    A preview release of the code to try out and for any comment is at:

    https://github.com/rnorris/viking/tree/StagingPatches

     
  • IMHO, the matter is the metaphor to reproduce:
    * desktop applications use the 4 and 5 buttons to scroll up/down and zoom in/out when Ctrl is added.
    * web slippy maps generally uses 4 and 5 buttons to directly zoom in/out (no need to handle Ctrl).

    I currently don't know what it is the better for a "desktop slippymap application".

     
  • Rob Norris
    Rob Norris
    2012-08-27

    IMHO mapping is more akin to viewing images than viewing other documents.

    Thus I expect the mouse wheel to control zoom in/out. Also see:

    https://live.gnome.org/UsabilityProject/HIG/ThreeZero/ImageZoomExamplePattern

    This issue here is that
    "When zooming with the mouse, make sure the fixed point of the transformation is at the mouse cursor, so the user can retain his point of focus on the zoomed image."

    However we can offer some alternate behaviours via keyboard modifiers - whether these are any good may be a matter of conjecture - especially if there is nothing comparable for reference/consistent behaviour.

     
  • Rob Norris
    Rob Norris
    2012-08-27

    Well:
    Gimp 2.8 uses Ctrl+Wheel to zoom the image. Wheel to scroll the image.
    Eog 3.4.2 uses Ctrl+Wheel to scroll the image. Wheel to zoom the image.
    JOSM 5267 uses Wheel to zoom in/out. Ctrl modifier doesn't seem to effect anything.
    Web: uses Wheel to zoom in/out. Ctrl modifier doesn't seem to effect anything.

    Viking - all versions - uses Eog/JOSM/Web behaviour (Wheel to zoom the image).

    Therefore I think the current behaviour is the most sensible policy, so no reason to change - the Ctrl modifier is a bonus behaviour.

     
  • Rob Norris
    Rob Norris
    2012-11-21

    • status: open --> open
     
  • Rob Norris
    Rob Norris
    2013-01-26

    • status: open --> pending
     
  • Rob Norris
    Rob Norris
    2013-02-12

    In Viking 1.4

     
  • Rob Norris
    Rob Norris
    2013-02-12

    • status: pending --> closed