Re: Qt graphics zooming

[Rik]

On 03/03/2015 09:40 AM, John W. Eaton wrote:
> On 03/03/2015 12:16 PM, Rik wrote:
>> On 03/03/2015 09:00 AM, address@hidden wrote:
>>> Subject:
>>> Qt graphics zooming with Z+ Z-, and "save as" command
>>> From:
>>> Doug Stewart <address@hidden>
>>> Date:
>>> 03/03/2015 07:38 AM
>>>
>>> To:
>>> address@hidden
>>>
>>> List-Post:
>>> <mailto:address@hidden>
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>>> list
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>>>
>>>  hg tip
>>> changeset:   19893:67cb2f421255
>>>
>>> Qt graphics
>>> Ubuntu 14.04
>>>
>>> 1)    I tried out the Z+ and Z- buttons and found that they zoom
>>> relative to the center of the figure, but I expected them to zoom
>>> relative to where the mouse pointer was pointing.
>>> Was my expectation wrong?
>>
>> Were you zooming with the mouse wheel?
>>
>> By comparison, FLTK does zoom around the point where the mouse is. Can
>> someone verify what Matlab does in this regard?
>
> I checked in this change:
>
>   http://hg.savannah.gnu.org/hgweb/octave/rev/ac18e88ea1bf

This works well when using single mouse clicks.  I would add the same code to the canvasWheelEvent so that mouse wheel zoom is also based on the current location.

-- Canvas.cc:795 --
// FIXME: should we zoom about point for 2D plots?

ap.zoom (mode, factor);
-- End Code --

It looks like that may have been intended.

--Rik