Edge Expander

[MJW]

This plugin may be more interesting than useful (and interesting may be a matter of opinion). It's in the Effects>Object menu.
 
Plugin: EdgeExpander.zip
 
Quoting from the Help menu:
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Edge Expander expands object edges to include the pixels within a given distance of the original edge pixels. The edge consists of the pixels above an opacity threshold which border pixels below the threshold. Each expanded edge pixel is set to the color of the nearest edge pixel. The transparency depends on the distance from the edge.
The controls are:
Use Full Distance Range: When checked, the distance range extends to the full window. The Maximum Distance control will be disabled.
Maximum Distance: Specifies the pixel distance the edge will be expanded.
Fade Rate: Specifies the rate at which the pixels become transparent as they approach the Maximum Distance. Setting the rate to zero disables fading. Setting the rate to one produces a linear fade. The transparency of expanded edge pixels is determined by the Fade Rate and the transparency of the nearest edge pixel, unless the Make Pixels Above Threshold Opaque option is enabled.
Opacity Threshold: Specifies the minimum alpha for object pixels. Pixels whose alphas are below this value are background pixels and are either part of the expanded edge if within the Maximum Distance, or become transparent.
Make Pixels Above Threshold Opaque: When checked, pixels whose alphas are above the Opacity Threshold become fully opaque.
Only Expand Edges Inside Selection: When checked, edges ouside the current selection are ignored and will not expand into the selction.
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The user interface:

 
Here is a simple example using an image from toe_head2001:

Original image:

Image with the edges expanded with full range and zero fade rate:

 
The plugin uses the fast NearestPixel transform discussed in the Fast algorithm for finding the minimum distances to a set thread.

 

It's a Visual Studio project consisting of the main project and two support files.

Main project: EdgeExpander.zip

Support files: DistanceTransformAndHelp.zip

 

Though the plugin was mostly written as an experiment, I can think of a few possible uses for it, including softening edges for antialiasing and as a sort of more flexible Crystallize effect, which I'll explain in a follow-up comment.

Edited January 21, 2016 by MJW

[toe_head2001]

Nice, you did all the work of adapting the algorithm for my needs.

 

A fast algorithm indeed.

[Eli]

Thanks MJW, I can make image outlines now. I am going to have fun!

 

[Red ochre]

[Seerose]

Thank you very much MJW!  

 

 

[Seerose]

 

 

Red ochre! Sorry!    Tomorrow... 

 

[Red ochre]

[Seerose]

 Red ochre! For you. 

[Eli]

Edge Expander can be used to remove thin scratches from photos:

 

1. Erase the scratches with the Eraser Tool.

2. Duplicate the layer.

3. Use the Edge Expander on the lower layer.

Edited February 21, 2016 by Eli

[ReMake]

Very original using of the effect.

[Seerose]

 

 

Dear Eli! Thank you so much. This is a very good method.   

Edited February 26, 2016 by Seerose

[Eli]

Guess : What is hidden in this image? Use Edge Expander if you can not see it. 

Spoiler

It's a toucan!

 

[MJW]

Very interesting, Eli!

 

In my initial comment I said:

Quote

Though the plugin was mostly written as an experiment, I can think of a few possible uses for it, including softening edges for antialiasing and as a sort of more flexible Crystallize effect, which I'll explain in a follow-up comment.

 

I never did post a follow-up comment, but that's the type of thing I had in mind. The effect is much like Crystallize, except the distribution of the centers (and therefore the distribution and size of the cells) can be modified.

 

[DuggleB]

IS it possible to use this feature to match the "expand image" feature in Micrographix's Picture Publisher 10 where you can "add" some additional blank cells to an image

I want to add / paste an image alongside an existing image so the final result is as if the two were stuck with selotape

Edited December 4, 2016 by DuggleB

[MJW]

To answer the question, I'd need to see examples of what you're talking about.

[DuggleB]

It's OK, I worked out that the Expand Canvas "sort of" does what I want, the nice thing about the Micrographix solution was that you could expand all 4 edges by differing amounts, whereas the Paint.Net solution old extends the Right & bottom edge

[Ego Eram Reputo]

Not so. Anchor the existing image to the center and the canvas will be enlarged around all four sides.

[FKasa]

Great plugin and what the community does with it looks exciting!

 

I was looking for something which, after an hour of searching and playing with your plugin, I learned is called 'blur fill'.

 

You plugin does something similar. From the posts, I can see how the alpha fade is useful in cases the result will be placed on top of another layer.

In cases like mine, with single images, I think it would be great to be have the option to blur fade. Maybe with checkboxes  allowing to even select both fade blur & alpha.

[Vagabondi]

Accidentally found out how much better a fire text can look with with effect. Thank you @MJW!