There are a number of confusing things about Stencils and Preserve Alpha channel (per layer) - and their cross-influence that I find challenging (especially when they are controlled by GEORGE commands.)
For now, my confusion centers on the Stencil Icon
in the Menu Bar which can be directly toggled on and off: According to the documentation, Page 3-13, it's purpose is to enable or disable Stencils for one or more layers and for that it works. But there seems to be an anomaly in that the Menu Bar Stencil Icon
can be TOGGLED ON when NO MASKS ARE ENABLED FOR ANY LAYER, INVERTED OR NORMAL...
What does this mean? Shouldn't TVPaint turn the Stencil Icon
off AND disable it when NO Layer Mask icons are toggled on for any layer?
Another odd thing concerns how the Stencil Icon
relates to Selected Areas (marching ants). The Stencil Icon
is toggled on (automatically) when a shaped screen area is SELECTED... and for consistency, it toggles off (automatically) when that area is deleted. Interestingly, the Stencil Icon
in the Menu Bar can actually be used to toggle a selected screen area off and on (hiding and disabling, but not deleting, the selection).
Then, IF some layer has a Stencil defined but is currently off, and you try to select a screen area, the Stencil Icon
is activated (automatically) but this also activates any currently inactive stencil on the layer(s) where defined. That can be corrected by toggling the individual Layer stencil icons OFF, leaving the selected screen area still selected.
At best the Stencil Icon
and layer stencils in general can be disorienting. At worst, with stencils enabled on empty layers or on layers with drawings which are not visible, you can be mysteriously left unable to draw over parts of, or all of the screen.
BTW, the Stencil check box in the Display Panel can be helpful to reveal where and when the Stencil is actually on and off, simply by checking it.
Anyway, I guess my point is the visible status and the functionality of the Stencil Icon
in the Menu Bar can be confusing, ambiguous, counter-intuitive or downright wrong.
Finally there is GEORGE. There seems to be some internal inconsistency in how STENCILS function, depending on if they are controlled by clicking appropriate interface buttons or controlled by script commands such as tv_LayerStencil when used to query the status of a stencil layer or to set the mode and state for one or more layer's stencils.
I firmly believe the GEORGE scripting language is a HUGE asset to TVPaint, adding a rich dimension of artistic versatility to an already powerful software... but it can be frustrating trying to understand how some commands interact (or how the don't) and on occasion, trying to find work-arounds when things don't function as expected.