gimp/NEWS

                   ------------------------------
                   GNU Image Manipulation Program
                         Development Branch
                   ------------------------------

This is the unstable branch of GIMP.


Overview of Changes from GIMP 2.99.6 to GIMP 2.99.8
===================================================

Core:

  - Selection display implementation now updated to more modern display
    server logics when drawing to display buffer. This fixes selection
    drawing in Wayland (and possibly in macOS Big Sur too, though this
    change is untested on this OS so far).
  - "Create a New Image" default action is "OK" so that hitting Enter in
    text/number fields is equivalent to clicking OK.
  - Paint tool core code can now receive multiple drawables as input
    though it is disabled by default, unless a tool calls
    gimp_paint_tool_enable_multi_paint() in its init() method. This is
    only used in source tools so far.
  - Clicking anywhere on toolbox empty space (dead areas between
    buttons) or on Wilber's drop area, as well as on the toolbox buttons
    themselves, actively focuses the canvas (similarly to the `Esc`
    shortcut).
  - Config folder migration for GIMP 3 with initial implementation.
  - Action "view-rotate-reset" renamed to "view-reset" (resets both
    flipping and rotate). New "view-rotate-reset" and "view-flip-rotate"
    for resetting rotation and flipping respectively.
  - New GimpEarlyRc class replacing GimpLangRc for very early config
    parsing (it used to be for language setting, now also for the
    pointer input API choice on Windows).

Tools:

  - Clone, Heal and Perspective clone now work on multiple selected
    layers. There are 2 new modes:
    * When cloning while multiple drawables are being selected, each
      drawable clones from itself to itself, i.e. every drawable is both
      its source and target.
    * When sourcing from multiple drawables then cloning into a single
      drawable, the source is the composited image. This is similar to
      "Sample Merged", except limited to a list of drawables.

User Interface:

  - Preferences now allows to select the input device API on Windows
    (Wintab or Windows Ink), as Windows Pointer Input Stack (Windows
    Ink) support was added recently in GTK3.
  - Layout of the Canvas Size dialog re-designed a bit more horizontally
    after the template selector feature made it too high.

API:

  - New gimp_display_present() function to present a specific display at
    the top of the image display stack.
  - New gimp_procedure_dialog_fill_expander() to create a GtkExpander in
    procedure dialogs.
  - All widgets within a same container in a GimpProcedureDialog are
    added to their own GtkSizeGroup.

Plug-ins:

  - PSD now supports bigger-than-4GiB files. File support was ported to
    GIO API with 64-bit offsets, hence allowing loading correctly very
    big files.
  - PSD now supports loading up to 99 channels (specs say that 56 is the
    max but some sample PSD files have more channels).
  - PSB file format is now supported for loading.
  - Scriptfu now handles GFile and GimpObjectArray types.
  - 16-bit SGI images now supported (until now, they were loaded as
    8-bit).
  - file-webp ported to GimpSaveProcedureDialog.
  - New JPEG XL plug-in (loading and exporting).

Translations:

  - New Vietnamese, Lithuanian and Portuguese translations for the
    installer.

Build:

  - Windows installer scripts updated to all supported languages.
  - New CI jobs for Windows native builds with MSYS2.
  - Several less critical CI jobs (32-bit cross-built Windows,
    meson/clang build, cppcheck static analysis) moved to a scheduled
    run for resource saving.
  - Windows installer now built as a CI job. The installer is not
    signed. The installer creation happens on tags for releases and at
    regular scheduled intervals for tests.
  - Improved tag handling in the CI for transparent release process.
  - New flatpak job (on scheduled interval) published on GNOME Nightly
    repository.
  - Windows installer and test flatpak (to download, no repository) can
    now be built by a merge request CI when the labels "5. Windows
    Installer" and/or "5. Flatpak package" are respectively set in the
    MR labels.
  - Scalable GIMP application icon is installed too.
  - Thumbnail icon feature was dropped: when images were opened, the
    application icon used to be a composition of the active image and
    the application icon (Wilber). This was confusing, hard to
    distinguish and working on less and less platforms because of recent
    OS and desktop rules.
  - Generate SHA* checksums for CI-generated Windows installers.
  - New `CODING_STYLE.md` document in repository for our coding style
    rules.
  - Configure: --enable-check-update now has an "auto" value.
    Meson: -Dcheck-update is now a yes|no|platform-default combo.
    The auto/platform-default value defaults to "yes" on Windows and
    macOS and "no" on other platforms.
  - GLib dependency's minimum required version bumped to 2.68.0.
  - GEGL minimum required version bumped to 0.4.32.
  - Flatpak nightly build now uses the new "fallback-x11" permission
    instead of "x11" to prevent unnecessary X11 access while in Wayland.


Overview of Changes from GIMP 2.99.4 to GIMP 2.99.6
===================================================

Core:

  - Various fixes for Wayland support.
  - Canvas Size dialog now displays a template selector to simply
    resize the canvas to a known template. When the image's and
    template's pixel density don't match, a choice will be proposed to
    set the image's PPI to the template's one or to scale the template's
    pixel size with the image's pixel density.
  - Off-canvas guides are now allowed. Guides are not deleted anymore
    when dropped off-canvas, but when dropped off-viewport.
  - Pinch gesture is now possible on canvas for zooming in/out (works on
    Wayland, not on X11; untested yet on *BSD, macOS, Windows and
    others).
  - GimpAction core class now stores a reason for explaining being
    disabled. This can be used later for giving better hints on why some
    effects or plug-ins are not usable in some situations. We already
    had this feature, but by tweaking the action's tooltip, which
    prevented this to have proper styling on GUIs and disrupted action
    search (as the reason text was searched, hence may return actions it
    should not).
  - Copy|Cut-Paste could already operate on multiple layers, by merging
    the result into a single layer. It will still do this when a
    selection exists, yet will paste layers as-is otherwise. This makes
    an alternative way to move layers, which is sometimes easier than
    drag'n dropping (especially between separate images).

Tools:

  - Paint Select tool got various improvements:
    * apply a threshold on the image mask before triggering the
      automatic expansion to simplify mask handling in the gegl
      paint-select operation.
    * enable viewport-based local selection.
  - GEGL Operation tool is now moved into Filters > Generic menu because
    it behaves more like a generic filter conceptually. As other
    filters, the GEGL Operation action is now only active when there are
    opened images.

API:

  - The generate "Metadata" frame layout in a GimpSaveProcedureDialog
    has been improved to always show the same number of columns to avoid
    ugly layout with options on 3 columns, then 2 columns on the next
    line (for instance).
  - The "Reset" button in GimpProcedureDialog shows a down arrow to show
    this is actually a button menu.
  - "Save|Load Defaults" in GimpProcedureDialog are renamed as "Save
    Settings" and "Load Saved Settings". The term "defaults" was not
    very clear and could be confused with "factory defaults". Moreover
    tooltips were added and the "Load Defaults" button is now only
    sensitive if "Save Defaults" buttion has been hit at least once.
  - Annotations improved.
  - Drop g_object_notify() in favor of g_object_notify_by_pspec() in
    various implementations to avoid a slight performance hit because of
    a global lock.
  - New function gimp_parasite_get_data() replacing gimp_parasite_data()
    and gimp_parasite_data_size() in a GObject Introspection friendly
    way.
  - gimp_procedure_dialog_new() now allows a NULL title if a menu label
    was set on the GimpProcedure with gimp_procedure_set_menu_label().
  - gimp_progress_update() improved: do not update more than 20 times
    per second and do not warn on stderr when too many progression steps
    are outputted. Indeed we should not place the burden of deciding
    whether there are too much or not enough progression updates on
    plug-in developers. On the opposite, they should be encouraged to
    update the progression as often as possible while libgimp will
    handle the decision on whether it actually ignores the progression
    step or not. This makes easier plug-in development and good
    progression feedback of long process.
  - GimpInt16Array was removed: it was used neither by GIMP core nor any
    core plug-ins. If third-party plug-ins really need this type, they
    may easily reintroduce it through GimpUint8Array (array of bytes) or
    GimpInt32Array (using only a subrange).
  - New function gimp_image_take_selected_layers() similar to
    gimp_image_set_selected_layers() except that it takes a GList
    (instead of a C array) and it takes ownership of the list pointer.
  - New functions: gimp_procedure_set_sensitivity_mask() and
    gimp_procedure_get_sensitivity_mask() for plug-ins to advertize when
    a procedure should be sensitive (in particular relatively to
    multi-drawable selection).
  - GimpImageProcedure's run() functions now have an array of drawables
    as argument (instead of a single drawable), to be consistent with
    multi-drawable selection ability.
  - New gimp_plug_in_error_quark() as a generic GQuark/GError domain for
    plug-ins.
  - Several functions were renamed to be consistent with our naming
    scheme:
    * s/gimp_parasite_name/gimp_parasite_get_name/
    * s/gimp_parasite_flags/gimp_parasite_get_flags/
    * s/gimp_image_base_type/gimp_image_get_base_type/
    * s/gimp_image_width/gimp_image_get_width/
    * s/gimp_image_height/gimp_image_get_height/
    * s/gimp_drawable_bpp/gimp_drawable_get_bpp/
    * s/gimp_drawable_width/gimp_drawable_get_width/
    * s/gimp_drawable_height/gimp_drawable_get_height/
    * s/gimp_drawable_offsets/gimp_drawable_get_offsets/
  - gimp_parasite_data() and gimp_parasite_data_size() are replaced by
    gimp_parasite_get_data() which is introspection friendly.
  - libgimpconfig: GimpParasite can now be serialized. This is useful
    when using a GimpParasite procedure argument, whose random contents
    (possibly binary) can be stored across sessions.
  - Move public classes to G_DECLARE_DERIVABLE_TYPE and
    G_DECLARE_FINAL_TYPE in order not to expose useless variables to
    plug-in developers.
  - New function gimp_procedure_dialog_set_sensitive() sets
    GimpProcedureDialog's widget sensitive value or binding.
  - PDB procedure 'plug-in-autocrop-layer' multi-layer aware.
  - GimpProcedureDialog now handles GimpRGB arguments.

Plug-ins:

  - We dropped the dialog for the Freedesktop portal implementation of
    the screenshot plug-in. Basically the Freedesktop portal provides
    its own GUI with most options, so also showing ours is redundant.
    Just directly call the portal and wait for the image in return.
  - Color profile and comment is saved on each layer of a TIFF file to
    prevent any ambiguity as TIFF allows its layers to have different
    profiles.
  - On PNG import, create an ICC profile out of the gAMA and/or cHRM
    chunks, if any of them are present, if no color profile is set and
    if the sRGB chunk is not present. This happens for RGB images as
    well as grayscale images (creating respectively a RGB or grayscale
    color profile).
  - Improve PNG export in no-profile case with gAMA and cHRM chunks
    (additionally to the sRGB chunk) according to PNG spec
    recommendations. Moreover the "gamma" option has now been removed
    because we just have proper core support of this metadata through
    ICC profile creation now, which is just more powerful.
  - "gamma" option for PNG export was removed (from GUI and
    file-png-load PDB API) because it is now redundant as we have proper
    support for this metadata.
  - Various fixes and improvements to OpenRaster image support.
  - PDF export now has progression.
  - PSD import/export got multi-layer selection support.
  - Qbist:
    * make the applied pattern a bit more prominent by adding a
      label about the center pattern of the 9x9 grid (which is the
      selected one meant to be applied).
    * last used values now stored with the new API, hence surviving
      across sessions.
  - benchmark-foreground-extract.py moved to gimp-data-extras.
  - Various plug-ins now work with multiple selected drawables when
    relevant.

Devel docs:

  - Python 3 and Javascript API documentation are now generated inside
    the build directory devel-docs/g-ir-docs/html/ (not installed right
    now) if you configure the build with option --enable-g-ir-doc
    (alternative for the meson build: -Dg-ir-doc=true but the docs ends
    up incomplete so autotools build is advised, cf. #6362).

Translations:

  - New Hebrew translation for the installer.

Build:

  - Bumping minimum GEGL to version 0.4.30.


Overview of Changes from GIMP 2.99.2 to GIMP 2.99.4
===================================================

Core:

  - Action search now always show all actions, even inactive ones. In
    order not to clutter the results, inactive ones are shown after
    active results (following the same match quality level).
    Consequently the "Show unavailable actions" checkbox has been
    removed from the `Preferences > Help System` dialog.
  - Improve sample text logics for CJK fonts, showing different
    sample characters for Korean and Japanese, making detection
    at-a-glance of such fonts easier.
  - With "Ask what to do" color profile policy, profile conversion at
    image loading is not proposed anymore when the image's profile is
    the preferred profile set in Preferences for the current image type
    (currently it would only be discarded if the image's profile was the
    built-in profile, now GIMP accounts for both cases).
  - When file loading plug-ins are run, the file chooser dialog is now
    hidden until the plug-in returns.
  - GIMP tries to keep error dialogs above to raise awareness when they
    arrive (not discovered later under other dialogs).

User Interface:

  - GimpSpinScale widget improvements:
    * The widget will grab focus when starting to edit the entry, and
      in particular the current number will be fully selected (because
      often we want to just type down a completely different number
      accurately).
    * Also when giving focus to the entry with middle click (from
      anywhere inside the widget), the scale value doesn't change in the
      same time anymore.
    * Finally we can now target-click accurately the entry current value
      to edit the entry (again, without changing the value and selecting
      existing number fully) with the main button (usually left button).
      Even though middle click is simpler because we don't have to be
      accurate (we can middle-click anywhere in the spin scale widget),
      it is hardly discoverable, whereas clicking a number entry which
      is meant to be editable is the most common GUI interaction
      expectation.
    * To help feature discoverability, when hovering the widget, the
      cursor will change and show a "grab" cursor when a click would
      start an absolute edit (the cursor changes to "grabbing" when
      actually clicking and dragging the scale) or a "text" cursor when
      a click would focus the number entry. When Shift key is being
      hold, the cursor is the one for the relative edit, wherever the
      position over the widget. This should make discovering possible
      interactions with the widget a lot easier.
  - Various improvements in the Layers dockable (and similar tree view
    widgets):
    * The bigger thumbnail popup on long click (e.g. on a layer or mask
      thumbnail) does not pop out when any modifier is hold (such as
      Shift/Ctrl for multi-selection or any other modifier used for
      alternative actions).
    * Alternative actions which were available with modifier-clicks on
      layer or mask thumbnails have been moved to an Alt+ modifier when
      necessary, in order to not clash with multi-layer selection
      interaction. In particular:
      + Ctrl-click on a mask to enable/disable it now moved to
        Alt-Ctrl-click.
    * The Shift+click and Ctrl+click actions on a layer thumbnail to add
      and remove respectively a layer mask have been removed because the
      much older feature for "Alpha to Selection" already use all the
      Alt+ modifier combinations.
    * The alternative Alt+ actions now only operate on the clicked layer
      and not on the selection unlike the corresponding actions
      (available through buttons, actions and menus). Also they do not
      change the selection.  So you can Alt+click a layer for "Alpha to
      Selection", same as you can Alt+click a mask for showing it
      without triggering a selection change. This allows these
      alternative actions to not be redundant of the equivalent actions
      but complementary with a slightly different targeting behavior.
    * The various interactions with modifiers now catch the exact
      modifier combination they require, hence avoiding interaction
      cases running several actions (e.g. Alt-Ctrl on a layer thumbnail
      removes the clicked layer's alpha channel from the selection
      without modifying the selected layer while Ctrl only would modify
      the selection).

Tools:

  - New Paint Select tool in the playground. This is a tool prototype
    which would hopefully end up as a quick binary selection tool.
  - The new default dynamics is: "Pressure Size". This doesn't change
    anything for common input devices (mouses, touchpad) yet would allow
    tablet devices to directly show that pressure input is working on
    first use. Until now, people would have the impression that tablets
    are not working (even though GIMP 3 will have hotplug so it is
    actually working from scratch) just because "Dynamics Off" was the
    default.

Input Devices:

  - Various improvements to the Input Devices editor:
    * Do not show virtual devices and XTEST API (Linux/X11) device in
      the Input Devices editor as they are useless from a configuration
      standpoint.
    * Only show the axes returned by GDK instead of the whole
      list of possible axes, which made no sense.
    * Show better names for axes, as returned by GDK, for instance a X
      axis becomes often "Abs X" on a graphics tablet and "Rel X" on a
      mouse or other devices made to work relatively.
    * Don't show an empty list for devices with no axes, just don't show
      the list widget at all.
    * For each device, select by default the first axis with curve
      ability, if any, (i.e. the Pressure axis if the device has one) in
      order to make the dialog directly more useful and usable.
  - Default tool have been set on different device sources:
    * Pen devices (tablet styluses main input) now default to the
      paintbrush tool.
    * Eraser devices (tablet styluses back input) still defaults to
      eraser tool.
    * Touch screen (finger) defaults to Smudge tool.
    * All other devices defaults to paintbrush (this was already the
      case, but was broken for as long as I remember, now it should work
      properly).

API:

  - GimpFileEntry public variables were made private and a new function
    has been added: gimp_file_entry_get_entry().
  - New GimpScaleEntry and GimpColorScaleEntry widget classes and new
    relevant API for these objects, replacing the former functions
    creating various widgets and attaching them to a GtkGrid. This makes
    for easier to use and less constrained GUI functions (with a lot
    less arguments, as we try now to smartly generate appropriate
    defaults for many options; gimp_scale_entry_new() in particular went
    down from 17 arguments to 5), also better introspectability for
    bindings, and finally it will be useful for automatic dialog
    generation for plug-ins.
  - New GimpLabeled class and subclasses: GimpLabelSpin,
    GimpLabelIntWidget.
  - Several new functions for GimpProcedureDialog for automatic dialog
    generation based on input arguments. Though not mandatory, the
    various functions allow to organize better the widgets.
  - The GimpProcedureDialog class will now check that mnemonics are
    present on every option, and also that there is no duplicate
    mnemonics. It will print messages on stderr if any of these test
    fails (so that it won't bother users but developers and translators
    should be able to get feedback about missing/duplicate mnemonics).
  - GimpSaveProcedure now has generic metadata support (with an API so
    that an export procedure can declare whether it supports given
    metadata types or contents).
    Combined with a new subclass GimpSaveProcedureDialog (child of
    GimpProcedureDialog), this ensures that:
    * If a format supports a given metadata, they will always have an
      auxiliary argument with the same name across plug-ins.
    * The label and tooltips will also be always the same in the GUI.
    * Order of metadata widgets will also stay consistent.
    * The widgets will work the same (no more "Comment" text view
      missing in one plug-in but present in another, or with an entry
      here, and a text view there, and so on).
    * The metadata frame will show an "(edit)" link which will run the
      "plug-in-metadata-editor" plug-in. The eventual goal is to move
      some generic logics to the metadata editor (when it makes sense)
      and to raise awareness for metadata edition and viewing abilities.
      This is still a work-in-progress which requires much more
      improvements in said abilities.
  - New gimp_get_num_processors() function for plug-ins to be able to
    set their own multi-threading operations as configured in
    Preferences.

Plug-ins:

  - file-fli, file-tiff, file-jpeg and file-png updated to new dialog
    generation API. In the most complicated case (file-jpeg), this
    shaved 600 lines out of the plug-in code.
  - file-heif:
    - now uses gimp_get_num_processors() instead of
      g_get_num_processors() (allowing to bypass system thread info).
    - Realtime parameter is set for AOM encoder when Fast encoding
      speed is selected by user.
    - Ability to set pixel format (YUV444, RGB) is enabled
      for >= libheif 1.10 to avoid issues in older versions.
  - file-jp2 is now able to decode JPEG2000 files faster with
    multi-threading, using the thread number settings returned by
    gimp_get_num_processors().
  - Improved plug-in debugging helper infrastructure: GIMP_PLUGIN_DEBUG
    has a new `fatal-criticals` option and better defaults. Developer
    documentation got some rewriting and debugging code benefited from
    refactorization.
  - py-slice.py moved to gimp-data-extras.

Installer:

  - Various updates to adapt to the GIMP 2.99/3 build.
  - Lua made optional.

Devel docs:

  - Documentation to port GIMP 2.10 plug-ins to GIMP 3.0 has been
    started in `devel-docs/GIMP3-plug-in-porting-guide/`. It is also
    visible directly on out Gitlab instance with visual styling:
    https://gitlab.gnome.org/GNOME/gimp/-/tree/master/devel-docs/GIMP3-plug-in-porting-guide

Build:

  - Bumping minimum harfbuzz version to 1.0.5 for hb_ft_font_set_funcs().
  - Bumping minimum pango version to 1.44.0 for pango_font_has_char().
  - Bumping minimum GEGL to version 0.4.28.


Overview of Changes from GIMP 2.10.x to GIMP 2.99.2
===================================================

Core:

  - Improved "space invasion".
  - New extension format support (.gex a.k.a. GIMP Extension) which is
    an archive containing various supported data. So far, it can
    package: brushes, MyPaint brushes, dynamics, patterns, gradients,
    palettes, tool presets, plug-ins, splash images and themes.
  - New extension manager allowing to enable, disable or uninstall
    installed extensions, with a dialog available in `Edit > Manage
    Extensions`.
  - Multi selection of layers now possible. Various tools and features
    are now multi-selection aware.
  - XCF format bumped to version 14 with awareness of multiple layer
    selection.
  - All code is year-2038-safe with deprecated time API replaced.
  - "Alpha to Selection" various actions warn when the result selection
    is empty.
  - Color Profile Policy (import) now exposes a "Convert to Preferred
    Profile" (fourth) choice and the import dialog default "Convert"
    action will convert the image to the preferred profile (if any was
    set, otherwise it falls back to the built-in profile). Converting to
    the built-in profile will be still available as secondary action.
  - A new "Metadata Rotation Policy" is now exposed in the Preferences
    dialog, next to the "Color Profile Policy" (in page `Preferences >
    Image Import & Export`) with 3 options: "Ask what to do", "Discard
    metadata without rotating" and "Rotate the image then discard
    metadata".
    This policy used to be handled API-size, with a dialog generated by
    libgimpui gimp_image_metadata_load_finish(), and saved in a global
    parasite. The whole logics and GUI has been moved as core logics,
    similar to the "Color Profile Policy".

User Interface:

  - Whole interface ported to GTK+3:
    * Proper HiDPI support, which will follow the system's scale factor
      for all widgets. This is a core toolkit support, unlike the basic
      better-than-nothing hacks from GIMP 2.10.x.
    * GTK+3 CSS-like support. All themes for former versions are
      therefore not working anymore.
    * GTK+3 themes have the concept of "dark variant", so a same theme
      may propose both a light and a dark versions. Preference for dark
      variants can now be checked in `Preferences > Themes > Use dark
      theme variant if available` checkbox, allowing for instance to use
      your system theme in its light variant everywhere except in GIMP.
      This option is checked by default as graphics software are often
      preferred in dark modes.
    * Symbolic icon themes are now recolored automatically according to
      the theme colors (no theme and icon theme tweaking anymore to end
      up with dark on dark or light on light interfaces), except for
      color elements whose SVG style is marked as "!important".
    * Native Wayland support.
    * Various dialogs now use Client-Side decorations and modern GTK+
      widgets are being used when relevant (e.g. GtkSwitch which gives a
      better feeling of a general "ON/OFF state").
    * Progressive/smooth scroll actions (e.g. ctrl+scroll for zooming)
      are now possible.
  - Image display rendered faster with a render cache that keeps the
    result of scaling, color management, display filters and shell mask
    (for tools like fuzzy select).
  - Shift-click on layer GimpContainerTreeView (typically the Layers
    dockable) allows to expand/collapse all item groups but the clicked
    one.
  - Compact GimpSpinScale is now the only available version.
  - Scalable symbolic icons "switch-on", "switch-off" (from GTK
    repository) and "software-update-available" (from Adwaita
    repository) are now bundled with GIMP in a "hicolor" overlay so that
    they are available even if missing from the custom theme.

Devices:

  - Device hotplug supported (thanks to GTK+3). In particular:
    * you don't need to have your tablets and other devices plugged
      before you start GIMP anymore;
    * enabling your devices in the "Configure Input Devices" dialog is
      not needed anymore. Tablets will work out-of-the box;
    * you can safely unplug and replug the same or other input devices
      while GIMP is running.
  - "Input Devices" dialog improved:
    * "Save" and "Close" buttons replaced by "OK" (save and exit),
      "Cancel" (reset and exit) and "Reset" (reset to previous settings
      but keep the dialog open).
    * "Keys" list has been discontinued. The "key" concept is
      associated to "keyboard" devices (a tablet being a "pointing
      device" with buttons, not keys) so this list was actually useless
      and only confusing.

Plug-ins:

  - Major rewrite of the API (see below). So GIMP 2.10.x plug-ins and
    below must be ported to the new API.
  - Every introspected binding which we test comes with a "Goat
    Exercise", which is a demo plug-in popping a dialog and showing its
    own source code. It processes a simple "gegl:invert" operation on a
    drawable. All "Goat Exercises" must do the same thing in the same
    way, simply in their respective languages, as documentation/example
    code for a language binding.
  - The Goat Exercise plug-ins are themselves installed as a GIMP
    Extension, as a demo for extension creation.
  - Plug-ins must be installed in their own subdirectory in
    `$XDG_CONFIG_HOME/GIMP/2.99/plug-ins/`, thus preventing data mess
    (with plug-ins coming with data and installing it all in the root
    plug-ins/ directory) and DLL hell. The main plug-in executable must
    be named the same as the directory (possibly with an added
    extension).
    E.g.: `plug-ins/my-cool-plug-in/my-cool-plug-in.py`
  - HEIF export allows selecting color subsampling/pixel format (YUV444,
    YUV420, RGB) and encoder speed (Slow, Balanced, Fast).
    Lossless option delivers visually lossless output.
  - New "file-heif-av1-load" procedure separate from "file-heif-load"
    for AVIF only.
  - shadow_bevel.py, sphere.py, whirlpinch.py and clothify.py moved to
    gimp-data-extras.

API:

  - `GimpPDB` is now a class to represent the PDB communication channel
    with GIMP. It is a singleton which exist exactly once per running
    plug-in, hence it is not meant to be manually instantiated and can
    only be returned by gimp_get_pdb(). It is mostly used to look up
    procedures declared by other plug-ins or by GIMP core, check if a
    given procedure exist and run the procedures.
  - `GimpPlugIn` is a class which every plug-in should now subclass as a
    way to create their plug-in, and override at least the methods
    query_procedures() and create_procedure(). Two other methods
    (init_procedures() and quit()) can be optionally overridden.
    The new subclass must be declared to gimp by calling gimp_main() to
    make it available to the core (PDB procedure, menu items, etc.).
    A plug-in can obtain its own GimpPlugIn instance with
    gimp_get_plug_in(). This is a singleton object which belongs to
    libgimp.
  - Plug-In procedures are now represented by a class `GimpProcedure`.
    * The subclass `GimpFileProcedure` handles file-related procedures,
      and its own subclasses `GimpLoadProcedure` and `GimpSaveProcedure`
      handle load/export procedures (file format support).
    * The subclass `GimpThumbnailProcedure` for procedures run during
      the lifetime of the GIMP session each time a plug-in thumbnail
      procedure is called.
    * The subclass `GimpImageProcedure` handles `GimpImage`-related
      procedures, i.e. any procedure which want to work on the opened
      image (GIMP core will pass through the active image and selected
      drawables to the plug-in procedure).
    * Objects of the subclass `GimpPDBProcedure` are not meant to be
      created or freed by plug-ins, they represent any `GimpProcedure`
      and are returned by `gimp_pdb_lookup_procedure()` by looking it up
      by name on the singleton `GimpPDB` object.
  - `GimpProcedureConfig` is the base class to represent the arguments
    when running a `GimpProcedure`. It implements the `GimpConfig`
    interface and will provide proper management of saved settings
    (including the last used values) and generated GUI using
    prop_widgets to plug-ins. This is still a work-in-progress.
    Currently `GimpProcedure` run function is called with a
    `GimpValueArray` whose values can be transferred into a
    `GimpProcedureConfig` by calling `gimp_procedure_config_begin_run()`
    or `gimp_procedure_config_begin_export()`.
  - `GimpDisplay` is now a class of its own.
  - `GimpImage` is now a class to represent an opened image.
  - `GimpItem` is now a class to represent various `GimpImage` items.
    * `GimpVectors` subclass represents an image path.
    * `GimpDrawable` subclass represents drawable object but is a
      simili-abstract class as it won't be a finale object class, which
      can be so far either a:
      + `GimpLayer` represents image layers.
      + `GimpChannel` represents a `GimpImage` channel which is
         typically in GIMP a named channel which can be added into a
         `GimpImage` channel stack (the "Channels" dockable in the GUI)
         with `gimp_image_insert_channel()`. This class is not really
         used to represent a color space component though this is
         conceptually the same thing (so maybe some day) and named
         channel can actually be created from an image color component
         with `gimp_channel_new_from_component()`.
         Some other specific usages have their own subclasses:
        - `GimpLayerMask` subclass is used for a `GimpLayer` mask.
        - `GimpSelection` subclass is used for a `GimpImage` selection.
  - GimpImage, GimpItem and GimpDisplay (and their various subclasses)
    represent objects which can be passed through the PDB. They are
    managed by libgimp and should not be freed by plug-ins.
  - The PDB-passing classes still have IDs which can be obtained with
    gimp_image_get_id(), gimp_item_get_id() and gimp_display_get_id()
    respectively. Conversely you can get back the object with
    gimp_image_get_by_id(), gimp_item_get_by_id() and
    gimp_display_get_by_id().
    Specific variants exist to get back an item object from its ID, such
    as gimp_layer_get_by_id(), which do additional class verification
    (other than this, they are similar to gimp_item_get_by_id()).
    **NOTE**: since objects are managed by libgimp, you are ensured that
    a `*_get_by_id()` call returns you exactly the same object you had
    previously for a given object. Consequently you can do pointer
    comparison of objects to compare images, items or displays during a
    given run. This will work because objects are unique (these are not
    several object copies representing the same remote object).
  - Type validation function which used to work on IDs now work directly
    with object arguments while new function with added `*_id*` have
    been created to validate from an object ID instead, GIMP 2.10-style.
    To verify if an ID exist:
    * gimp_image_is_valid() / gimp_image_id_is_valid()
    * gimp_item_is_valid() / gimp_item_id_is_valid()
    * gimp_display_is_valid() / gimp_display_id_is_valid()
    To check if GimpItem are from specific subclasses:
    * gimp_item_is_drawable() / gimp_item_id_is_drawable()
    * gimp_item_is_layer() / gimp_item_id_is_layer()
    * gimp_item_is_text_layer() / gimp_item_id_is_text_layer()
    * gimp_item_is_channel() / gimp_item_id_is_channel()
    * gimp_item_is_layer_mask() / gimp_item_id_is_layer_mask()
    * gimp_item_is_selection() / gimp_item_id_is_selection()
    * gimp_item_is_vectors() / gimp_item_id_is_vectors()

    **NOTE**: since these are GObject classes, you can also use the
    GObject style macros such as GIMP_IS_LAYER(). Yet these macros do
    not do any ID verification (which is not a problem anyway in most
    cases as you got the object from API calls) and will not exist in
    bindings.

    **IMPORTANT**: using IDs is mostly for internal usage and actually
    there are very few reasons to ever need to get an object ID from a
    plug-in. Usually you should rather just work only with the unique
    object pointers returned by the API.
  - The whole API has been updated to use objects instead of object IDs
    when relevant. For instance all existing libgimp functions from 2.10
    which were called on an image ID are now called on a GimpImage
    object instead.
  - All file paths procedure parameters are now handled by GIO's `GFile`
    which simplify various file handling issues (path formats, encoding,
    etc.) and brings new features (remote access, secure protocol
    support, etc.). We also got rid of the "filename" vs "raw_filename"
    differentiation in parameters. Hence all libgimp* functions with
    these parameters have been updated as well.
  - gimp_image_metadata_load_finish() is now fully GUI/GTK-code free.
    The first consequence is that it is not in libgimpui anymore, but in
    libgimp, as it should. The second consequence is that the boolean
    `interactive` argument has been removed. Now all image rotation
    logics (the part which needed a GUI) has been moved into core and
    will be automatically run when normally loading images from GIMP's
    interface, similarly as to how color profiles was already handled.
  - 2 new libgimp functions: gimp_image_policy_rotate() and
    gimp_image_policy_color_profile() are now available to explicitly
    call the Preferences-set policy on an image. This may result in a
    dialog being presented to the user if `interactive` is TRUE and
    settings is "Ask what to do".
    It is unnecessary to call these functions when developing a new
    GimpLoadProcedure because the core will automatically do the right
    thing and call these on normal image loading workflow.
    Instead if a plug-in calls such GimpLoadProcedure through the PDB,
    no such functions will be run automatically. It is up to the plug-in
    to decide what to do (no conversion, mandatory conversion, or using
    user settings, possibly with a dialog to decide, hence calling these
    functions explicitly).
  - New function gimp_export_comment() to query the user settings (as
    set in Preferences) on whether or not a file plug-in should export
    the image's comment.
  - Several functions which are returning C-array of objects with a size
    output argument now also have a GList counterpart (not as
    replacement, but as additional API):
    * gimp_get_images() -> gimp_list_images()
    * gimp_image_get_layers() -> gimp_image_list_layers()
    * gimp_image_get_selected_layers() -> gimp_image_list_selected_layers()
    * gimp_image_get_channels() -> gimp_image_list_channels()
    * gimp_image_get_vectors() -> gimp_image_list_vectors()
    * gimp_item_get_children() -> gimp_item_list_children()
  - New function gimp_vectors_stroke_reverse() to reverse a specified
    stroke in a given GimpVectors.
  - In GIMP 2.10, functions gimp_drawable_preview_get_drawable() and
    gimp_zoom_preview_get_drawable() got deprecated in favor of
    respectively gimp_drawable_preview_get_drawable_id() and
    gimp_zoom_preview_get_drawable_id(). The original names have been
    reinstated and now returns a GimpDrawable object, whereas the newer
    functions got removed.
    Similarly gimp_zoom_preview_new_from_drawable_id() and
    gimp_drawable_preview_new_from_drawable_id() are replaced by
    respectively gimp_zoom_preview_new_from_drawable() and
    gimp_drawable_preview_new_from_drawable().
  - Deprecated functions in GIMP 2.10.x have been removed. To get a list
    of these function, this file should hopefully map most of them to a
    replacement equivalent:
    devel-docs/GIMP3-plug-in-porting-guide/removed_functions.md
  - gimp_spin_button_new() had some weird compatibility macro to expand
    to a newer or older signature depending on the number of arguments.
    Now only the newer signature with 3 arguments is available.
  - Properties removed from custom widgets:
    * GimpAspectPreview, GimpDrawablePreview and GimpZoomPreview had a
      deprecated "drawable" property in favor of "drawable-id" property.
      The "drawable" property got reinstated (and the "drawable-id"
      removed) and obviously now stores a GimpDrawable object rather
      than an integer.
    * The property "stock-id" was removed from GimpHintBox and
      GimpCellRendererToggle. Use "icon-name" instead.
  - Note: there are likely more API changes, unfortunately we haven't
    kept the NEWS file up-to-start from scratch. The best is to look at
    the API generated documentation.
  - The full API is GObject Introspected into 2 modules: Gimp and
    GimpUi. This means plug-ins can be written in various non-C
    languages. So far the following languages have been tested and work
    well: Python 3, Lua, Javascript and Vala.
    (Note: Python 2 is also working, but considering that this language
    is end-of-life since 2020, we don't really care).
  - All pygimp specific Python API does not exist anymore. Python will
    use the same API as C plug-ins, introspected through GObject
    Introspection.

Documentation:

  - `devel-docs/xcf.txt` updated to handle XCF 14.

Build:

  - New meson build system. Still deemed "experimental" for the time
    being. Packagers are recommended to continue using the autotools
    build system in order to avoid build system-specific bugs.
  - Continuous integration in Gitlab with:
    - an autotools build with GCC on a Debian/testing runner
    - an autotools distcheck build on a Debian/testing runner
    - a meson build with GCC on a Debian/testing runner
    - a meson build with Clang on a Debian/testing runner
    - a meson cross-build with Mingw-w64 for Windows 32-bit
    - a meson cross-build with Mingw-w64 for Windows 64-bit
    - static code analysis with cppcheck
    - a source tarball distribution job (tar.bz2 and tar.xz)
    - a ready-to-run Windows 64-bit test archive
    - a ready-to-run Windows 32-bit test archive

Known blocker issues:

  - GTK+3 port is functional but not complete as some deprecated APIs
    are still being used.
  - Space invasion is still a work-in-progress.
  - Plug-ins API update is still a work-in-progress.
  - GIMP extensions are still a work-in-progress.
  - Multiple layer selection is still work-in-progress. Some issues are
    expected, and possibly even some crashes in code paths which were
    not updated yet.
  - No custom theme yet, in particular we want a neutral gray theme with
    light/dark variants, and a middle-gray theme too.
  - We probably want to revive a "Small" theme as well with smaller
    icons (useful on smaller displays, or mid-high density displays or
    simply depending on tastes).
  - Various blocking bugs happen on Wayland only.