# Re: [Gimp-developer] Unified transform tool

```On 04/17/2011 08:31 AM, Michael Grosberg wrote:
> Ofnuts<ofnuts<at>  laposte.net>  writes:
>
>> Symmetry mode is not well defined... In your drawing, you drag on
>> top-right and the top-left follows (vertical axis), but it could as well
>> have been the bottom-right (horizontal axis), and even the bottom-left
>> (radial).
> As I did mention, it was not a complete spec. The points you raise are valid,
> but they are already treated well in the original spec, and I only wanted to
> present the differences.
>
> In distort mode, Symmetry is applied to the larger distort delta of the two
> axes, i.e. if you distort a corner point 20 px to the right and 10px to the
> top, the symmetry will be horizontal.
>
>> IMHO, your proposal, like the original one, doesn't address a very
>> frequent use of these transforms, which is to match the transformed
>> object with an existing one.
> Actually, the original spec DOES mention that scale from center is toggled
> by the CTRL key. Moving the center point lets you scale from any given point.
>
Assuming we are both talking about
<http://gui.gimp.org/index.php/Transformation_tool_specification>, this
is not how I read it... there is the rotation axis, and the centre, that
is defined as "the point where the two diagonals through the corner
points cross".```
```
The spec for the rotation does specify that the rotation axis can be
dragged (that part would have been moved outside of the rotation
transform it were usable with other transforms)

The spec for the scaling, when using the "from centre" constraint, says
"translate the opposite side by the same distance" which implies that
the centre is equidistant to both sides and thus is still the centre
defined above. An arbitrary fixed point would have implied the use of
"proportional" somewhere in the spec.

I may be wrong.

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