RGBA palette in pyanatomist

[guillaume]

Hello,

I would like to build a custom palette in pyanatomist that would include a transparency component (RGBA).

I have been playing with RGB palette following the nice tutorial http://brainvisa.info/pyanatomist/sphin ... orial.html, but I do not find examples for RGBA, is there any tuto or example for that anywhere?

Thanks for your help!
gui

[guillaume]

Maybe I found the solution, but please confirm:

in http://brainvisa.info/anatomist-4.6/dev ... mands.html
I see the color_mode parameter that can be set to "RGB" or "RGBA"
I tried to set in my code:
colors = []
colors.extend([128,128,0,0])
colors.extend([128,128,0,255])
customPalette.setColors(colors=colors, color_mode='RGBA')

and I can see the changes... now I'm playing with the transparency to really understand how it works

[riviere]

Hi Guillaume,

Yes normally you are right, except that... there is a bug. The transparency status of the palette is not updated when calling customPalette.setColors(...).
I'm fixing this.
In the meantime, you can call manually, after setColors():

Code: Select all

customPalette.update()

Note also that depending on the texturing mode applied to the displayed object, transparency may not be used. See the texturing parameters on the object in Anatomist GUI. On a volume for instance the default mode is "decal", which does not render transparently. Use "replace" or "geometric" instead. You can setup this mode in a script using the TexturingParams command.

[guillaume]

Hi Denis,

almost everything works.
The only remaining difficulty is with texturing mode.
I tried with TexturingParams without success.

I manage to do it manually (through the Anatomist GUI) by setting the 'mapping mode' in the 'fusion 2D control' panel of the fused object to 'Linear / A if B is not opaque'.

To do it in python, I tried to set it using the two possible commands:
a.execute("Fusion2DParams", object=fus, mode="linear_A_if_B_transparent")
and
a.execute("TexturingParams", object=fus, mode="linear_A_if_B_transparent")

but it didn't work.

I also tried mode="linear_A_if_B_not_opaque" which did not work neither.

Thanks for your help!
gui

[riviere]

Hi Guillaume,
I guess what is missing is an extra parameter "texture_index=1" in the TexturingParams command: actually a Fusion2D has 2 textures, and the mixing mode you want to apply here is when merging the 2nd texture (index 1) with the previous one, thus the merging textue index is 1.
I see also that there is an update issue there. You may need to add 2 lines until I fix it:

Code: Select all

fusion.setChanged()
fusion.notifyObservers()

(this should be done automatically but it does not seem to be currently)
Denis

[guillaume]

Yessssssssss it finally works!

I used the texture_index, and also fixed one mistake:
I was using object=fus which is not correct and should be replaced by objects=[fus].

So at the end, the following works fine:

Code: Select all

            customPalette=a.createPalette("maPalette")
            customPalette.setColors(colors=colors, color_mode='RGBA')
            customPalette.update()
            a.setObjectPalette(avol1, customPalette)
            fus=a.fusionObjects([ aT1vol, avol1 ], 'Fusion2DMethod')
            a.execute("TexturingParams", objects=[fus], mode="linear_A_if_B_transparent", texture_index=1, rate=0)
            fus.setChanged()
            fus.notifyObservers()

Thank you Denis!
gui

[riviere]

Right
By the way I fixed the update bug in anatomist sources (bug_fix branch, version 4.6.1).
Denis