# Glow node¶

This documentation is for version 1.0 of Glow (fr.inria.Glow).

## Description¶

A glow effect based on the bloom filter node. The mask input limits the area where the glowing elements are. It does not cut off the shine produced by the glow.

For more interesting looks there are some additional features like stretch, rotation and postgrade.

Written by PostPollux

## Inputs¶

Input Description Optional
1   No

## Controls¶

Parameter / script name Type Default Function
Convert to Group / convertToGroup Button   Converts this node to a Group: the internal node-graph and the user parameters will become editable
Isolate Highlights / isolateHighlights Double 0.25
“Isolate Highlights” controls on which parts of the image the glow is applied.

high value -> only bright areas
Isolate Hue / isolateHue Boolean Off If checked, the picked hue will additionally limit the areas of the glow.
pick Hue / HSVTool1srcColor Color r: 0 g: 0 b: 0
Pick a color in the viewport to isolate it’s hue.

The glow will only be applied to those areas, if ‘Isolate Hue’ is checked.
GlowMap Preview / preview Boolean Off When checked, the output will be the glowmap. Use this as a preview to adjust the highlight and hue isolation.
Size / size Double 3 This will change the size of the glow.
Ratio / BloombloomRatio Double 2
Iterations / iterations Integer 7 Number of blur kernels of the bloom filter. The original implementation uses a value of 5. Higher values give a wider of heavier tail (the size of the largest blur kernel is 2**bloomCount*size). A count of 1 is just the original blur.
Filter / Bloomfilter Choice Quasi-Gaussian
Bluring filter. The quasi-Gaussian filter should be appropriate in most cases. The Gaussian filter is more isotropic (its impulse response has rotational symmetry), but slower.
Quadratic might also look a bit better, but it is slower, too.
Quasi-Gaussian (quasigaussian): Quasi-Gaussian filter (0-order recursive Deriche filter, faster) - IIR (infinite support / impulsional response).
Gaussian (gaussian): Gaussian filter (Van Vliet recursive Gaussian filter, more isotropic, slower) - IIR (infinite support / impulsional response).
Box (box): Box filter - FIR (finite support / impulsional response).
Triangle (triangle): Triangle/tent filter - FIR (finite support / impulsional response).
Quadratic (quadratic): Quadratic filter - FIR (finite support / impulsional response).
Stretch / stretch Double 0
Stretch the glow!

0 -> uniform proportions
1 -> blur only in one direction
Rotate / rotate Double 0 This will rotate your stretched glow. If “Stretch” is 0 it won’t have any effect.
Gain / PostGradeMasterGain Color r: 1 g: 1 b: 1 a: 1
Gamma / PostGradeMasterGamma Color r: 1 g: 1 b: 1 a: 1
Saturation / PostGradeMasterSaturation Color r: 1 g: 1 b: 1 a: 1
Screen / screen Boolean Off
If checked, the bloomed image will be screened on top of the input image. This helps to preserve the highlights in your image.

By default it is added on top of the imput image. (plus)
Add Input / addInput Boolean Off Add the input image to the bloomed one.
Glow Only / glowOnly Boolean Off
The output will only be the glow effect itself.

You can add it on top of your source with a plus-merge or a screen-merge, later.
expand RoD / expRoD Boolean Off
By default the Region of Definition (RoD) will be cropped to the input RoD.
Use this option, if you want the glow effect to be available even outside your input format, and thus being not cropped.
As the blur sizes of the bloom node can get very big, this may lead to a very big RoD! Especially, if you use a lot of iterations.
apply on alpha / alpha Boolean Off Controls if the glow is applied to the alpha channel, too.