What does GEGL graph do ?

rich2005 · **Joined:** Mar 04, 2011 **Posts:** 2425

GIMP Version: 2.10
Operating System: Windows
GIMP Experience: Intermediate Level

List any relevant plug-ins or scripts:
GEGL graph

I do not really want to disrupt the Learn GEGL thread so:

mackenzieh wrote

Quote:

I'm curious as to what this plugin does.

see: viewtopic.php?f=10&t=19463#p265540

The GEGL graph in Filters -> Generic lets the user run GEGL operations interactively. Those with a 'G' in the menus.

What is the advantage? Why not use the filters in the menus ?

The GEGL operations can be chained together and parameters adjusted without 'undoing' previous work.
A trivial example, posterize an image, followed by the very nice GEGL waterpixels then the illusion filter.
If I use a chain of operations like this.

Code: Select all

posterize 
    levels=4

waterpixels 
    size=32
    smoothness=1
    regularization=0

illusion
    division=8
    illusion-type=type1

I can adjust any of the values for any parameter (within the scope of the filter) in the GEGL graph and see the result. No need to undo anything to go back.

very quick example as an animation. https://i.imgur.com/XtP5rfk.mp4

racer-x · **Joined:** Apr 15, 2017 **Posts:** 1826

Interesting. I guess this will replace script making for many instances. Just make your own filter combinations and save the presets.

rich2005 · **Joined:** Mar 04, 2011 **Posts:** 2425

racer-x wrote:

Interesting. I guess this will replace script making for many instances. Just make your own filter combinations and save the presets.

Yes. Not impossible to script GEGL operations with Gimp 2.10 there are examples somewhere (but not easy). So you could make a collection of "boilerplate" text files for specific tasks.

or as you say, save as a preset. (a blank without all that commented text is a good start

)

The place for GEGL filters and syntax is https://gegl.org/operations/

cli345 · **Posted:** Mon Jun 28, 2021 10:52 am **(#4)**

Pleased with your intervention : very good introduction :tyspin

(I've added a link to here at start of my thread).

mackenzieh · **Posted:** Mon Jun 28, 2021 6:35 pm **(#5)**

It is interesting to see it in action. I'm glad you posted an example because I had no clue what the plugin did.

teapot · **Joined:** Dec 09, 2018 **Posts:** 644

Thank you for the explanation rich2005 as I was also wondering what was going on.

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1410

Try this

Code: Select all

noise-reduction iterations=6 
median-blur percentile=40 alpha-percentile=1

gaussian-blur #stays locked at 0.50 in default. Never changes.

emboss  type=bumpmap azimuth=30  elevation=40 depth=1                   

median-blur radius=4 percentile=900 alpha-percentile=90 high-precision=yes

opacity value=2

#repaste this to make more bevely

noise-reduction iterations=6 

median-blur percentile=40 alpha-percentile=1

gaussian-blur #stays locked at 0.50 in default. Never changes.

emboss  type=bumpmap azimuth=30  elevation=40 depth=1                   

median-blur radius=5 percentile=900 alpha-percentile=90 high-precision=yes

opacity value=2

#repaste this to make more bevely

#final effects

dropshadow radius=1 x=2 y=0.6 grow-radius=1  opacity=1.1

bloom threshold=-35

dropshadow x=7.3 y=7.3 grow-radius=1

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1410

I've been doing this for about a year. I have code designated for small, medium, large and very large text.

Code: Select all

gegl:rotate degrees=0  sampler=lohalo

gegl:color-overlay value=#00f525

gegl:dropshadow x=0.00  y=0.00 radius=0.00 grow-shape=circle grow-radius=7 opacity=1 color=#000000

gegl:dropshadow x=0.00  y=0 radius=0.00 grow-shape=circle grow-radius=5 opacity=1 color=#ffffff

gegl:dropshadow opacity=1.9 radius=1.6 x=-1.8 y=2.8

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1410

This is a specialty bevel with a custom image overlay from pattern monster.

Code: Select all

gegl:rotate degrees=0.0  sampler=lohalo

gegl:color-overlay value=#ffec00

median-blur percentile=50 alpha-percentile=2

gaussian-blur #stays locked at 0.50 in default. Never changes.

emboss  type=bumpmap azimuth=70  elevation=40 depth=3                   

median-blur radius=10 percentile=100 alpha-percentile=80 high-precision=yes

multiply aux=[gegl:layer src=PUT_YOUR_FILE_HERE.png] 
t
opacity value=2
gegl:gray

dropshadow opacity=0.5 x=4 y=2

dropshadow opacity=0.5 x=4 y=2

mahvin · **Joined:** Oct 06, 2010 **Posts:** 4050

Very nice results, Contrast. Thank you for sharing!

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1410

yes and there is a lot more. I do not want to brag but I am a "GEGL Wizard" I want GEGL to put an end to the legacy engine.

Here is stained glass in GEGL

Code: Select all

#stained_glass
id=1

noise-spread amount-y=96 amount-x=46 seed=33
oilify mask-radius=1 exponent=3 intensities=115
noise-reduction iterations=2


gimp:layer-mode layer-mode=normal  opacity=0.40 aux=[ ref=1 gaussian-blur std-dev-x=2  std-dev-y=2  ] 
bloom threshold=80 

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1410

Code: Select all

gimp:desaturate
edge-neon amount=0.65

id=1

gimp:layer-mode layer-mode=hardlight  aux=[ ref=1 b gaussian-blur std-dev-y=5 std-dev-x=5   ]
gimp:layer-mode layer-mode=behind opacity=0.14  aux=[ ref=1 b gaussian-blur std-dev-y=33.00 std-dev-x=53.00 gaussian-blur std-dev-y=113.00 std-dev-x=66.00   ] 
gimp:layer-mode layer-mode=hardlight  aux=[ ref=1  ] 

id=2
gimp:layer-mode layer-mode=normal  aux=[ ref=2 color-to-alpha color=#000000 ] 
 color-to-alpha color=#000000 transparency-threshold=0.09
bloom radius=6
gaussian-blur std-dev-y=2.5 std-dev-x=2.5

median-blur neighborhood=diamond radius=2 high-precision=true alpha-percentile=1

id=3

gimp:layer-mode layer-mode=normal opacity=0.25  aux=[ ref=3 bloom limit-exposure=true ]

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1410

Gimp's blend modes control the color

Code: Select all

simplex-noise scale=20 iterations=1 seed=2949

lens-blur radius=0.52 highlight-factor=0.531 

softglow glow-radius=0.190 brightness=4.251 sharpness=0.503

median-blur radius=2. percentile=100 alpha-percentile=10 neighborhood=diamond

bloom threshold=77

lens-blur radius=0.50 highlight-factor=0.931

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1410

Another Bevel FIlter

Code: Select all

`gegl:rotate degrees=0 sampler=lohalo

gegl:color-overlay value=#00d8ff

median-blur percentile=40 alpha-percentile=2

gaussian-blur #stays locked at 0.50 in default. Never changes.

emboss type=bumpmap azimuth=35 elevation=40 depth=3

median-blur radius=10 percentile=080 alpha-percentile=60 high-precision=yes

opacity value=1.5

dropshadow x=2.6 y=2.6 opacity=1`

Code: Select all

noise-reduction iterations=6 
median-blur percentile=40 alpha-percentile=1

gaussian-blur #stays locked at 0.50 in default. Never changes.

emboss  type=bumpmap azimuth=30  elevation=40 depth=1                   

median-blur radius=4 percentile=900 alpha-percentile=90 high-precision=yes

opacity value=2

noise-reduction iterations=6 
median-blur percentile=40 alpha-percentile=1

gaussian-blur #stays locked at 0.50 in default. Never changes.

emboss  type=bumpmap azimuth=30  elevation=40 depth=1                   

median-blur radius=5 percentile=900 alpha-percentile=90 high-precision=yes

opacity value=2

dropshadow radius=2 x=2 y=2 grow-radius=1 

bloom threshold=-75

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1410

Code: Select all

noise-rgb 

gaussian-blur std-dev-y=1.3 std-dev-x=1.3
gray
sepia srgb=1 scale=2
saturation scale=1.2 colorspace=Native

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1410

Tas_mania · **Joined:** Nov 04, 2015 **Posts:** 1333

I tried the edge-desaturate-neon and got this result when changing Mode to 'Difference'.

I like the result but will be trying this on a video stream.

paynekj · **Posted:** Tue May 10, 2022 3:25 am **(#18)**

@contrast_
As you're a "GEGL Wizard" please tell me how to use gegl:contrast-curve without it crashing GIMP

Tas_mania · **Joined:** Nov 04, 2015 **Posts:** 1333

Wizard 101. You don't have to answer non-wizard questions. :lol

contrast_ · **Joined:** Oct 31, 2020 **Posts:** 1410

paynekj wrote:

@contrast_
As you're a "GEGL Wizard" please tell me how to use gegl:contrast-curve without it crashing GIMP

LOL, I don't use that filter in GEGL. It crashed for me too even when just typing an =. Something is wrong with it. My expertise is making layer effects in GEGL. I am trying to make a new GEGL filter that allows multiple strokes, a shadow, a bevel, and image file overlay. I will name it GEGL Effects and it will be able to make all sorts of stylish text in a GUI.

I can't figure out how currently. I need to better familiarize myself with GEGL's source code.

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