GEGL Edge Only Bevel (part of MISC BEVEL COLLECTION)

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1440

Hello, this is a thread about my progress on making a new GEGL plugin that bevels the edges of shapes only. This GEGL plugin does not yet exist because I don't know how to make it. Here is a preview of a script fu counterpart that does the desired outcome.

Attachment:

bevel_only_the _edge.png [ 262.14 KiB | Viewed 5522 times ]

Script fu uses the name "cone bevel" so maybe I'll call it that. In this thread I'll keep everyone updated on the progress of GEGL cone bevel's development.

so far I am trying to mimic this text style but keep failing.

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1440

I'm making progress. I managed to mimick the "cone bevel" in GEGL

The Bevel applies to edges but ignores the rest of the image.

Attachment:

progress.png [ 186.22 KiB | Viewed 5514 times ]

Syntax do to this. Requires invert transparency and custom bevel plugins found here
https://github.com/LinuxBeaver/GEGL-Cus ... l/releases
https://github.com/LinuxBeaver/GEGL-Cut ... t/releases

Code: Select all

id=1
gimp:layer-mode layer-mode=split  aux=[ ref=1

invert-transparency
median-blur radius=4 alpha-percentile=100
invert-transparency

 ]

id=inletter

median-blur radius=3 alpha-percentile=70
src-atop aux=[ ref=inletter custom-bevel depth=50 blendmode=Multiply gaus=2 box=2 elevation=40 size=0.3 opacity=9  opacity value=0.49 ]

If you apply this GEGL syntax on colored text (excludes grayscale/black and white) it will make a cone bevel effect entirely in GEGL.

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1440

Attachment:

gimps.png [ 479.25 KiB | Viewed 5513 times ]

More progress. Use Normal blend mode.

Code: Select all

id=1
gimp:layer-mode layer-mode=split  aux=[ ref=1

invert-transparency

median-blur radius=5 alpha-percentile=100

invert-transparency

 ]

id=inletter

median-blur radius=3 alpha-percentile=70
src-atop aux=[ ref=inletter  levels in-high=0.4 custom-bevel depth=50 blendmode=Multiply gaus=2 box=2 elevation=40 size=0.3 opacity=9  opacity value=0.90 ]

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1440

Code: Select all

id=n

over aux=[ ref=n
id=1
gimp:layer-mode layer-mode=split  aux=[ ref=1

invert-transparency

median-blur radius=5 alpha-percentile=100

invert-transparency

 ]

id=inletter

median-blur radius=3 alpha-percentile=70
src-atop aux=[ ref=inletter  levels in-high=0.4 custom-bevel depth=50 blendmode=Multiply gaus=2 box=2 elevation=40 size=0.3 opacity=9  opacity value=0.90 ]
 ]

This is the final syntax that will soon be translated into a plugin. This allows the cone bevel to work without the normal blend mode. Meaning it runs in default "replace".

My goal is to keep updating this thread to show every step involved in the process of making a GEGL plugin. I will even post incremental versions of the source code as it modifies to become more like this graph. Meaning I will upload incomplete .c files to show the development of a GEGL plugin. Stay tuned.

PixLab · **Posted:** Wed Oct 11, 2023 10:35 am **(#5)**

It Works also nicely on opaque surrounded by alpha :coolthup

Thanks a lot _contrast :tyspin

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1440

You are welcome PixLab.

---

This is the final graph.

Code: Select all

id=0 over aux=[ ref=0
id=1
median-blur radius=20 alpha-percentile=100
src-in aux=[ ref=1
id=2
gimp:layer-mode layer-mode=split  aux=[ ref=2

invert-transparency

median-blur radius=14 alpha-percentile=100
gaussian-blur

invert-transparency

 ]

id=3

median-blur radius=02 alpha-percentile=70
src-in aux=[ ref=3 levels out-low=0.01  gaussian-blur std-dev-x=2 std-dev-y=2 custom-bevel  depth=10 blendmode=Multiply gaus=1 box=1 elevation=90 size=0.3 opacity=2.1 opacity value=1.1   ]

 ]
nop
]
lb:edgesmooth
lb:threshold-alpha
median-blur radius=0

Below is how GEGL's .c file will understand the graph. None of this is defined or proper code for GEGL. This is just an example of how the nodes are connected in a .c file.

edgesmooth is my edge smooth plugin
ta2 is my threshold alpha 2 plugin
bevel is my custom bevel plugin
it (the letters "it") is my invert transparency plugin
normal is the normal blend mode
erase is the erase blend mode
src-in is a GEGL exclusive blend mode that is a fusion between replace and alpha lock. Gimp has no equal blend mode
nop and idref is (gegl:nop) for no operation; they functions as ref and id or grabbing content later on in a graph
median is a median blur.
gaus is a gaussian blur
If you see a 2 or 3 that means there is more then one of the same filter. Outside of ta2.

GEGL nodes connecting here
input, normal, edgesmooth, medianfix, ta2, output
(normal connects to nop)
idref1, median1, srcin1, nop,
idref2, erase, idref3, median3, srcin2,
(srcin connects to srcin2)
it, median2, gaus, it2,
(erase connects to it2)
idref3, levels, gaus2, bevel, opacity,
(srcin2 connects to opacity)

Once again, this is a rough draft on how GEGL's c file understands that syntax. Not proper .c code obviously. Once I edit the .c file template, something like this will be in the node area.

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1440

This plugin may end up being cancelled as an individual plugin and instead put inside "the exotic bevel collection" I will probably make nine variations of it. (small medium large) and with 3 different blend modes (3x3=9) as it will not have unique sliders.

Learn more about the up and coming "exotic bevel collection" mega GEGL plugin here.
viewtopic.php?f=4&t=20581

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1440

viewtopic.php?f=9&t=20591
You can download this mega plugin that includes 3 graphs in the drop down list of "outline edges only" bevel.

This has very little editable properties. This will soon be on Github

Attachment:

outline_edges_only.png [ 228.45 KiB | Viewed 5355 times ]

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