Incorrect center of zoom when pinching to zoom

[EpicWolverine]

When zooming with a mouse (Ctrl+Scroll wheel), the PDF is zoomed by using the position of the mouse pointer as the center of the zoom as expected. However, when pinching to zoom with a touchscreen, the center of zoom is in the upper left corner, not the midpoint between the fingers. This makes pinching to zoom confusing and frustrating to use.

[GitHubRulesOK]

@kjk duplicate of #953 but this may be better description ?

[GitHubRulesOK]

@kjk directly related to #439 where zoom using plus and minus is applied in similar fashion

[SumatraPeter]

Related forum topic: https://forum.sumatrapdfreader.org/t/pinch-to-zoom-and-pan-like-microsoft-edge/2784

[kjk]

Fixed by 485817e

[EpicWolverine]

Thank you!