Adds the ability to zoom into the preview when fixed scaling mode is
enabled.
(Edit by Jim: Also now saves zoom and scroll position)
Closesjp9000/obs-studio#917
Fixes bug 617 on mantis. Scaling the source manually in the viewport
wouldn't work properly when the source is flipped horizontally or
vertically.
Closesjp9000/obs-studio#751
As reboot pointed out, it's assumed that the intention of a locked
preview is to prevent editing the scene. Because scrolling the preview
does not have any interaction with the scene and its sources, you should
be able to still scroll around and look at different parts of your
preview while the preview is locked.
There is also a bugfix included: previously, if you were to
right click while space bar was held down, you would be stuck in
scroll mode until spacebar is pressed/released again. This gets around
it by forcing scroll mode to end when a right click is issued on the
preview.
Adds preview scaling to the right-click context menu for the preview
pane. This allows the ability to, for example, zoom the preview and
edit the preview 1:1 (canvas/base resolution). This was a missing
parity feature. Additionally, also allows scaling to the
"output/scaled" resolution the program is set to.
When the preview is in scale mode and is the focused widget, you can
hold space and drag with left click to change the zoomed position.
(Notes added by Jim)
Closesjp9000/obs-studio#687
