Re: [Gimp-developer] Border artifact from using nohalo to scale a layer with an alpha channel

[Øyvind Kolås <pippin gimp org>]

In general it is better to open new bug-reports, rather than re-open
old ones seeming similar - long threads of possibly different problems
discussed in comments makes it hard to follow progress of an issue.
This issue seems like it might already have a bug though bug #698468.

/pippin

On Tue, Feb 23, 2016 at 12:12 AM, Elle Stone
<ellestone ninedegreesbelow com> wrote:
> The following three bugs are closed, but there still seems to be a related?
> new? bug with nohalo scaling (and probably lohalo, but not with cubic or
> linear):
>
> https://bugzilla.gnome.org/show_bug.cgi?id=634901
> Bug 634901 - Resizing an image with alphachannel creates 1 pixel border down
> and right
>
> https://bugzilla.gnome.org/show_bug.cgi?id=698601
> Bug 698601 - scaling up without alpha adds several-pixel gradient border
>
> https://bugzilla.gnome.org/show_bug.cgi?id=734378
> Bug 734378 - Image manipulation (scale,rotate) may cause vertical image
> artefacts
>
> Scaling up or down using nohalo produces a partially transparent border
> around the layer if the layer has an alpha channel. This is a long-standing
> issue that still obtains (at least scaling down has produced the edge
> artifact for a long time, bug 698601 describes the opposite situtation for
> scaling up).
>
> I only just discovered that removing the alpha channel at least sometimes
> allows to scale a layer without creating the edge artifacts. So I'm not sure
> if removing the alpha channel always allows to scale without creating edge
> artifacts.
>
> This bug was confirmed using babl/GEGL/GIMP updated today.
>
> Should I file a new bug report? or maybe instead open one of the old bug
> reports?
>
> Elle
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