Problem with coloring lines by hand

[slowtiger]

Sorry, this doesn't explain anything. I try again.

The question was not about transparency = same layer affected vs. stencil = other/several layers affected.

The question is why the stencil is calculated in a different way than the transparency. Surely it must be possible to add up transparency masks the same way as stencil masks, and surely it should be possible to use one layer's transparency mask on another layer as well? I just want to know the technical decision behind this.

[Peter Wassink]

Markus, let ME try again...
The thing ist gerade that they are NOT calculated in a different way!
i tried explaining it here

it is not a bug.
When recoloring on a layer that is itself in stencil mode, this will always happen.
The "artifacts" are caused by the anti aliased edges of the original drawing, the antialias pixels are partially transparent (thus the mask edge is partially transparent) and therefore when you apply color on the half transparent pixels the new color will only be applied with half opacity.
Therefore it results in a mix of both the new and old color. When the old color is darker, a dark halo will appear.

That is why if you want to perfectly recolor the layer itself you'll have to use the preserve transparency function.

What i didn't mention there is that they both already use the same alpha mask.

the difference is that they are displayed differently and this follows simply from the fact that in one case the result is ONE layer
and in the other case (Stencil) the result is one Two (or more) layers
see image:

[slowtiger]

Sorry, I don't follow that. There must be a technical difference since recoloring the same layer will yield different results when applying transparency preserve and stencil on itself.

[Elodie]

Sorry, I don't follow that. There must be a technical difference since recoloring the same layer will yield different results when applying transparency preserve and stencil on itself.

Yes, because you are not supposed to paint on a layer using stencil mode, but on a different one.

You modify lines' colors on current layer = use preserve alpha
You want to change line's color, but having the result on different layer = turn the original layer into a stencil, create a new layer and paint on this new layer. I also advise you to turn off the original layer.

Black lines = stencil mode / layer turn off
New layer is used to paint a new very of the line

stencil or preserver 001.png (69.58 KiB) Viewed 22050 times

I use the original line and I change its color, using preserve alpha channel.

stencil or preserver 002.png (63.79 KiB) Viewed 22050 times

Result is the same : all depend on the way you work.

Actually, I think we should propose an alert window when you try do draw on a layer turn into a stencil.

[Svengali]

Other differences between Stencils and alpha masking worth mentioning
1. Stencils have an invert mode which let you toggle between the source and everything but the source (from one layer but applied to all layers).
2. if stencil is toggled after you move to another layer, that layer becomes the stencil source (the stencil derived from the other layer is lost).
3. If you move to a layer where alpha mask is still active, you receive a warning at the time you invoke a stencil on the same layer since both affect where you can and cannot paint.
4. Each alpha masking derives from (and affects) its own layer only... also it remains in effect when you move to another layer.
5. Every layer can simultaneously have its own, active alpha mask which is layer specific not frame specific.

Layer Finder
Layer Finder Button/script identifies and displays all layers which have either alpha masking or stencil applied.
Layer Finder also includes a one-click option to clear all layer settings including ALL active, layer specific masks AND which ever layer's stencil might be active (whether normal or inverted).

George Control and Persistence for Stencil Display Settings
Someday hopefully we'll have a George command which will let you turn the Stencil visibility on/off and set the checkerboard color and transparent level for a specific layer. Now, with every session startup you must use the Display Settings panel to set visibility, color and degree of transparency %, EVERY SESSION. Hopefully, in the future, those Stencil settings will be persistent and remain from session to session like Layer Attentuation is about to be, please!

Sven

[Peter Wassink]

Sorry, I don't follow that. There must be a technical difference since recoloring the same layer will yield different results when applying transparency preserve and stencil on itself.

o.k. here is one last try to explain the difference:

Preserve transparency lets you replace the RGB value of ALL present pixels equally, no matter their transparency.
i think this is simple and clear.

Stencil gives a different result when you try to recolor on the layer itself.
This is not because the alpha mask of the stencil is different.
but its because you cannot replace the RGB value fully through a halftransparent mask.

o.k. lets try an example:
you want to paint a 50% transparent pixel from black to red
PreserveTransparency simply allows you to turn the RGB value of this pixel from black to red and because of the alpha channel, which is still at 50%, the pixel has become a 50% transparent red pixel (hurray!)
Stencil however is a different story, a bit more tricky to understand.
When you apply 100% red "paint" to the 50% black pixel, it won't turn into a 50% red pixel because the pixel is its own mask!
because of the stencil mask the red "paint" is blocked from reaching the 50% black pixel by its own 50% transparency, only 50% of the "red paint" comes through....

The half transparent pixels in the stencil mask prevent themselves to be recolored 100%
the more transparent a pixel is the less it can be recolored
that is why you see the effect mostly along the edges of lines, because of the anti alias these edges are transparent.

[Svengali]

o.k. here is one last try to explain the difference:

Well done Peter.

Sven

[Elodie]

o.k. here is one last try to explain the difference:

Well done Peter.

Sven

+1 !

[Sewie]

So if you would want to prevent these edges in stencil mode, is there a workaround for this?

[Peter Wassink]

So if you would want to prevent these edges in stencil mode, is there a workaround for this?

No.

To prevent edges, either work in preserve transparency mode
or apply in stencil mode on another layer.

Two reasonable alternatives i think.

[Sewie]

Thanks!

[drude]

Hello!

I am very fond of the preserve transparency mode in tvp10! i use it all the time. I am now working on a project where the current type of TVP we use is 9.5 - and now my problem is, that i don't know where that button is! - is this feature not part of TVP 9.5? And if it is, does anyone know where to find it?

Thanks!:)

[Svengali]

Not sure about 9.5, but a shortcut key assigned to Tools:Toggle Preserve Transparency works in 10.

Sven

[D.T. Nethery]

Hello!

I am very fond of the preserve transparency mode in tvp10! i use it all the time. I am now working on a project where the current type of TVP we use is 9.5 - and now my problem is, that i don't know where that button is! - is this feature not part of TVP 9.5? And if it is, does anyone know where to find it?

Thanks!:)

The location of the Preserve Transparency button in TVP 9.5 is at the top. See attached screen shot.

Preserve Transparency TVP 9.5.jpg (36.31 KiB) Viewed 21868 times

.

[drude]

THANK YOU! i completely forgot where it was, i was sure i had used it in 9.5 before - perfect! Now i remember!