[Bf-compositor] [bug] filter an image after a transform node

[Bartek Skorupa (priv)]

The tools for transformations in compositor are tricky.
When you use "Transform" node or "Scale" node with "Relative" or "Absolute" option you'll never get canvas bigger then original dimensions of input image.
In fact you'll also not get smaller canvas when you scale the image down. outer parts of the image will be filled with black.
You can set scale to 2.0 let's say and the image will get scaled up and cropped. However this cropping is kind of not destructive.
Try this:
Scale the image up using "relative" option setting scale to 2.0
Then scale down the result to 0.5.
You'll get the original image back, although when looking at the result of first scale node - you see cropped image. Second scale node brings cropped pixels back.
The only way to get really scaled up image is to use "Scale" node and set it to "Render size". This way the canvas will get resized as well.
There is unfortunately no easy way to resize images.
I didn't yet find any whatsoever way to scale image up to different then render size dimensions.
There's nothing wrong with filer of blur nodes. The problems are cased by scaling that is far from being intuitive. A lot of tricks need to be performed to make it work.

Bartek Skorupa

www.bartekskorupa.com

On 26 kwi 2014, at 11:53, Francesco Paglia <f.paglia.80 at gmail.com> wrote:

> Hi everyone, 
> I don't know if its already a known bug or not.
> I noticed that if I add a filter node on an image picture  (in this case I used a sharpen but I could have added a blur as well) that has been scaled via a transform node it gets cropped to its original canvas.
> 
> https://lh3.googleusercontent.com/-Ofe6M4zczAU/U1t_TmuBMzI/AAAAAAAAJKE/Vj8V6Ni2D44/w1293-h808-no/sharpernerror.jpg
> 
> Step to reproduce:
> import an image (smaller than the render output to notice it)
> add a distort\transform node
> scale the image
> add a filter\blur or filter\filter node
> the image get cropped to the original canvas (at least it seems so)
> 
> this append with 2.70a as well as with the build I downloaded the 25th april hash 3b75d6c
> 
> 
> 
> -- 
> Francesco Paglia
> Vfx and Production Supervisor
> 
> mobile  +39 347.82.12.473
> e-mail   f.paglia.80 at gmail.com
> 
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