Could you please implement the xBRZ filter? It is produces slightly more refined outputs and would be very helpful.

Lena.png: 512x512

Filter -> Render -> Pixel Art Scalers

-> GIMP

Result: 400x400

Originally posted by @nightmaredream in #2 (comment)

About "seamless" processing...

And about "pixels stuck to sides" on semi-transparent images...

I'll show you an example of side stuck upscale pixels.

The left mushroom thing's topmost part is squared, that's because the upscale process bounces to borders...

It would be difficult to difference different jobs, so separating seamless batch from no-repeat batch would allow to do, in one batch, save borders.. And in the other batch... Emulate seamlessness with copies of the tiles in every directions and then reduce back to original size.

But yeah, for the moment, a tolerance slider... Then making every tolerated pixels fully opaque!

Seamlessness examples

While it's still a very nice result, seamlessness is broken.

Another example: (Very good, but broken seamlessness)

Hi, when i upscale any image, any mode, that has an alpha channel and transparency in it, it makes a contour line of glitched colors from pink to white and so on. I really need a solid line, and i'm batch doing files so i can't just go around and remove these contour lines one by one, it's a skull-scratching issue. Pixel art should Never have glitched contour lines, ever. I can't understand why this plugins isn't pre-fixed about that. IT'S obvious that upscaled sprites needs solid edges.

Batch-jobbing with Gimp is already a hassle (Using tinytask, doing eveything manually, automated, it's time-expensive)... Adding supplementary tasks such as "create layer mask, posterize mask, go filter, generic, erode, then saving, for every files with an alpha channel, consumes a lot of time... hence, your plugin should do solid edges.

Hi @bbbbbr .

See stbiscalenx: Stb Image Scale Near X.

This method is very similar to ScaleX. This method does not add new colors, only uses those that already exist. Replacing equal with near makes color selection more flexible, allowing pixel scaling techniques to be applied even to full-color images. I use this to scale scanned material containing a lot of glyphs and contours.

origin	x2	x3

See:

• https://github.com/ImageProcessing-ElectronicPublications/photoquick-plugins/tree/master/src/transform/pixart-scaler
• https://github.com/ImageProcessing-ElectronicPublications/photoquick-examples/tree/main/plugins/transform/upscale

❓ It may be worth replacing this awkward and inconvenient function reference with a wrapper of the form:

void scalers_select(uint32_t * sp, uint32_t * dp, int Xres, int Yres, int factor, int numalg){...}

Not?

Maybe?:

    // Attach the label and combo to the table and show them all
    gtk_table_attach_defaults (GTK_TABLE (settings_table), settings_scaler_label, 0, 1, 0, 1); // Left side of table
    gtk_table_attach_defaults (GTK_TABLE (settings_table), settings_scaler_combo, 1, 2, 0, 1); // Left side of table

    gtk_table_attach_defaults (GTK_TABLE (settings_table), settings_semi_transparency_checkbutton, 0, 1, 1, 2); // Left side of table
    gtk_table_attach_defaults (GTK_TABLE (settings_table), settings_semi_transparency_spinbutton, 1, 2, 1, 2); // Left side of table

    gtk_table_attach_defaults (GTK_TABLE (settings_table), settings_hidden_colors_checkbutton, 0, 1, 2, 3);     // Left side of table
    gtk_table_attach_defaults (GTK_TABLE (settings_table), settings_hidden_colors_spinbutton, 1, 2, 2, 3);     // Left side of table

Hi, I'm trying to batch a large number of images with your plugin in BIMP and I'm having some issues. I can't seem to control the resolution or much of anything really. These are the options I see:

The end result of the image also results in 3/4ths of the image being cut out, leaving only the upper left corner:

if you could please advise, I have a very large amount of images to process and I would greatly appreciate the help

Apparently, macports is also an option, but I use homebrew and i didn't want to mix the two package managers.

Luckily, @ryan-robeson set up a tap which includes libgimp (for https://github.com/bootchk/resynthesizer), and installing it allowed make to work. https://gist.github.com/ryan-robeson/5841f712ff23c910bbbfac793c16bfad#3---install-dependencies

And the default directory to install the plugin is ~/Library/Application\ Support/GIMP/2.10/plug-ins

And it works!

I can submit a simple PR to update the readme.

First error message is:

The second is the same
the third is:

Fourth is:

And then it closes. It is not telling me where it is looking, or lets me try somewhere else

The migration to GTK3 will likely break the plugin. Deprecated GTK and libgimp function calls will need to be replaced.

No action will be taken until after the GIMP 3 release. This is just a placeholder for now.

Also see:

• bootchk/resynthesizer#59
• https://wiki.gimp.org/wiki/Roadmap#GIMP_3.0

Thank you very much for doing this, bbbbbr. It should have been in main GIMP for decades.

On my devuan ceres linux, building with libgtk2.0-dev Version: 2.24.33-2 fails with:

gcc -c src/filter_dialog.c -o obj/filter_dialog.o -pthread -I/usr/local/include/libpng17 -I/usr/include/gtk-2.0 -I/usr/lib/aarch64-linux-gnu/gtk-2.0/include -I/usr/include/pango-1.0 -I/usr/include/atk-1.0 -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng16 -I/usr/include/aarch64-linux-gnu -I/usr/include/pango-1.0 -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/fribidi -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/harfbuzz -I/usr/include/glib-2.0 -I/usr/lib/aarch64-linux-gnu/glib-2.0/include -I/usr/include/uuid -I/usr/include/freetype2 -pthread -I/usr/local/include/libpng17 -I/usr/include/gimp-2.0 -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng16 -I/usr/include/aarch64-linux-gnu -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/uuid -I/usr/include/freetype2 -I/usr/include/gegl-0.4 -I/usr/include/gio-unix-2.0 -I/usr/include/json-glib-1.0 -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/glib-2.0 -I/usr/lib/aarch64-linux-gnu/glib-2.0/include -I/usr/include/babl-0.1
In file included from /usr/include/gtk-2.0/gdk/gdkevents.h:34,
                 from /usr/include/gtk-2.0/gdk/gdkdisplay.h:32,
                 from /usr/include/gtk-2.0/gdk/gdkscreen.h:33,
                 from /usr/include/gtk-2.0/gdk/gdkapplaunchcontext.h:31,
                 from /usr/include/gtk-2.0/gdk/gdk.h:32,
                 from /usr/include/gtk-2.0/gtk/gtk.h:32,
                 from /usr/include/gimp-2.0/libgimp/gimpui.h:22,
                 from src/filter_dialog.c:19:
/usr/include/gtk-2.0/gdk/gdkcolor.h:74:3: warning: parameter names (without types) in function declaration
   74 |   gint      GSEAL (size);
      |   ^~~~
/usr/include/gtk-2.0/gdk/gdkcolor.h:74:13: error: field ‘GSEAL’ declared as a function
   74 |   gint      GSEAL (size);

The only possibly relevant discussion to GSEAL which I have found (with the now almost completely broken-for-FOSS web search engines) is here.
https://stackoverflow.com/questions/15569756/how-do-i-get-access-to-gsealed-values-from-gtk-widget-modify-gtkwidgets.
[Not able to insert a link because the new github owners have broken the comment editor for my browser.]