                   ------------------------------
                   GNU Image Manipulation Program
                         2.10 Stable Branch
                   ------------------------------

This is the stable branch of GIMP. Unlike earlier stable branches,
we do allow some new features here, if they are not too invasive.
Otherwise, this branch is only for bug-fixes.

Overview of Changes from GIMP 2.10.8 to GIMP 2.10.10
===================================================

Core:

  - Add gimp-scratch allocator, a fast memory allocator (on the order of
    magnitude of alloca()), suitable for small (up to a few megabytes),
    short-lived (usually, bound to the current stack-frame) allocations.
    Unlike alloca(), gimp-scratch doesn't use the stack, and is therefore
    safer, and will also serve bigger requests, by falling-back to malloc().
  - In gimp_drawable_transform_buffer_affine(), avoid modifying the
    clipping mode when transforming layer masks, since this function
    is used (among other things) to transform layer masks together with
    their layer, in which case they should use the same clipping mode
    as the layer. This fixes a regression introduced by commit 2ae823ba,
    causing layer masks to be transformed with a mismatched clipping mode
    during layer transforms, leading to discrepencies between the
    transformed layer and the transformed mask.
  - Moved swap/cache and temporary files out the GIMP user config dir and
    added new config file substitutions ${gimp_cache_dir} and
    ${gimp_temp_dir}.
  - Pass the GEGL tile-cache size, swap path, and thread-count to plug-ins
    as part of their config, and have libgimp set the plug-in's GeglConfig
    accordingly upon initialization.
  - Layer groups are now rendered in bigger chunks rather than tile-by-tile
    (which used to pretty much eliminate multithreading for groups), which
    improves the rendering speed.
  - Make saving/exporting files more robust to errors. In particular if
    an error occurs during the process (be it a bug, a memory error, or
    anything else), GIMP won't overwrite anymore any existing file with
    incomplete contents, so that you won't end up with no valid files at
    all.
  - Fix a regression on support of various graphics tablet.
  - Remove the "Edit -> Fade..." feature: it makes GIMP use two buffers
    instead of one (east into system resources), it's broken in 2.10, and
    we can make the UX better for filters.
  - New generic canvas modifier 'Alt + middle click' allowing to pick
    layers by clicking on pixels. The available layers will be looped
    through (starting from the upper one) while Alt key is hold and the
    picked layer name will be temporarily displayed in the status bar.
  - When clearing a channel, do nothing if the channel is already empty;
    otherwise, align the cleared rectangle to the channel buffer's tile
    grid, so that all affected tiles are dropped, rather than zeroed.
    Furthermore, only update the affected region of the channel.
  - Brush and pattern saving logics has been moved to core code (instead
    of plug-in).
  - Clipboard brushes and pattern can now be duplicated.
  - Add an "Open as Image" button to the brushes dialog.
  - Parametric brushes are now 32-bit float to avoid posterization on
    large brushes.
    Note: raster brushes are still 8-bit and plug-ins only have access
    to 8-bit versions of high-precision brushes/patterns. New API will
    be required to handle high-precision data.

User interface:

  - Enabled HiDPI/Retina support for the GTK2/OSX build, fixes blurry icons. 
  - Add a tooltip to the "better compression" checkbox in save dialog to
    make it clearer it does not mean that the file size is necessarily
    smaller in every cases. In particular some best/worst case are
    possible when an algorithm less efficient in general may end up
    better on a particular image.
  - Add basic support for cursors with a scale factor of 2 for HiDPI
    (artwork to be updated).
  - Foreground and background color icons will now display out-of-gamut
    warning on indexed images for colors outside of the palette, as well
    as on grayscale images, for non-gray colors.
  - Pack color picker and hexadecimal entry on same line in Color dock.

Usability:

  - Attempting to transform locked layers or paint on them now results in
    blinking around the status bar (where the warning message is displayed)
    and around the toolbar where lock toggles are. The same applies to
    attempting to move a selection where there is none — GIMP will blink
    around the toolbar where the moving target (layer, selection, path)
    is chosen.
  - GIMP now allows selecting default export file type for new projects.
    The choice is limited to PNG, JPEG, WebP, PSD, ORA, TIFF, BMP.
  - Work around weird display of the item list in various drop down all
    over GIMP (all GIMP classes based off GtkComboBox), which had empty
    scrollable space at the top.
  - GimpSpinScale widget now has an optional feature to constrain the
    value to integer when dragging with a pointer (even if the scale
    allows for fractional numbers), set with new function
    gimp_spin_scale_set_constrain_drag().
    This is useful for settings where fractional numbers are technically
    possible, yet most common use case are with integers (such as pixel
    sizes, angles in degrees, etc.) so you want the easy interface to be
    constrained. Fractional numbers are still settable, for instance by
    keyboard edit; and arrow incrementation won't drop fraction parts.
    This is currently only activated for brush options in paint tools.

Tools:

  - In scale tool, scale around center even when using numeric input.
  - New algorithm in the Bucket Fill tool when selecting the affected
    area "Fill by line art detection", based off the G'Mic algorithm for
    "smart colorization": https://hal.archives-ouvertes.fr/hal-01891876
    In a few words, it identifies painted pixels (either based on
    grayscale or opacity values) and tries to close line arts to allow
    filling even with not perfectly closed zones; the second step of the
    algorithm will flood the colors under line art pixels to prevent
    "holes" in the filling.
    It is possible to control a max size (in pixels) for the flooding,
    as well as max length of closing segments and splines.
  - The Bucket Fill tool got new interaction allowing to hold the click
    and move the mouse to fill based on several seed zones (for "Fill
    by line art detection" as well as "Fill similar colors"). You can
    now cancel the fill in progress with right click as in other tools.
  - The Bucket Fill tool now allows color picking with ctrl-click, same
    as every painting tool. It will pick either the foreground or
    background color depending on the selected Fill Type. The ctrl-alt
    modifier combination is also possible to pick the non-Fill Type
    color.
  - In the Bucket Fill tool, the Alt modifier will now switch to
    "FG color fill" when "Pattern fill" was set (instead of doing
    nothing).
  - In the Unified Transform tool, default to preserving aspect ratio
    when scaling up or down.
  - In the Healing tool, "Sample merged" now also work for the target
    pixels, allowing to draw in empty layers.
  - Selection by color is now parallelized, hence improving speed of the
    Select by Color tool (and any other processing which may share this
    piece of code now or in the future).
  - Add "Constrain handles" and "Around center" options to the
    perspective-transform tool's GUI, which are similar to the
    corresponding options of the unified-transform tool.

Plug-ins:

  - file-pdf-save GUI now clearly indicates the order the layers will be
    used to make multi-page PDFs.
  - Add DDS loading/exporting plug-in originally developed by Shawn Kirst
    and Arne Reuter.
  - Rename the Guillotine plug-in to Slice Using Guides.
  - Add a new option saving a color profile when exporting PNG, JPEG, TIFF.
    Always save it when exporting to PSD.
  - Remove the "Advanced" expanders from the PNG and TIFF export dialogs.
  - Full rewrite of the Spyrogimp plug-in with much more options and
    better interaction.

Filters:

  - Add on-canvas GUI (simple lines) for circular, linear, and zoom motion
    blur.

Help:

  - Link to the bugtracker directly from the Help menu, also link to the
    wiki and the roadmap. Remove the link to currently disabled
    registry.gimp.org.

Installers:

  - Windows: proper fix for libthai to stop GIMP from crashing in the
    Thai locale. 

Translations:

  - Czech, Danish, French, Italian, Japanese, Marathi, Polish, Russian,
    Spanish, Swedish, Ukrainian.

Build:

  - Bumping GTK+ dependency to the micro update GTK+ 2.24.32 to handle
    several bugs on Windows (broken shortcuts on non-latin layouts and
    broken vector icons).

Overview of Changes from GIMP 2.10.6 to GIMP 2.10.8
===================================================

Core:

  - Use adaptive chunk size in GimpProjection when rendering the
    projection asynchronously, rather than using a fixed chunk size.
    This provides a better trade-off between throughput and
    responsiveness dynamically, based on how fast the processing is.
  - Add xyY color space to the color spaces for sampling colors.

Tools:

  - In all selection tools, show error on attempt to
    subtract-from/intersect-with empty selection.
  - Fix text along path not working with vertical text.
  - Fix Text tool's frame position when undoing a move operation.
  - Streamline Text tool's drawing blocking/unblocking logic.
  - When moving a text layer using the text tool (through alt+drag),
    don't change the layer's box mode to "fixed", which is unnecessary,
    since the layer's size isn't affected.
  - Transform and deformation operations now maintain color for fully
    transparent pixels, making unerase and curves manipulation of alpha
    channel more reliable.
  - All transform tools now apply changes when you save or export/overwrite
    an image without pressing Enter first to confirm changes.
  - Heal, Dodge/Burn, Smudge, and Convolve tools now adjust the processed
    buffer and mask_buffer regions according to the changes made to the
    application region, as calculated by intersecting it with the
    drawable and mask extents. This fixes wrong application position
    when painting on a drawable whose origin is above/to the left of the
    image's origin, and there's a selection active.
  - New type of gradient interpolation called 'Step' for making multi-color
    hard-edge gradient fills.

Plug-ins:

  - Port all plug-ins to the new iterator API in GEGL.
  - Improve automatic detection of HEIC/HEIF files.
  - Improve RawTherapee discovery by looking up registry key (should
    become useful with RawTherapee 5.5 and more).

Usability and UI:

  - Compatibility information in the Save dialog is now more understandable.
    The minimum GIMP version for the XCF file is always written down when it
    is GIMP 2.8 or over. The list of features warranting the minimum version
    is now listed in an expander container rather than as tooltip, which
    makes it more discoverable. The warning on compression is now displayed
    as its own text under the checkbox and not as additional text to the
    minimum GIMP version label.
  - In all themes, fix the color of selected text, while editing a tree-view's
    item text (such as when renaming a layer), by overriding tree-view
    specific styling with the global text-entry style, for nested text entries
    inside tree-views. The text would previously use the same color as the
    selection background, making it unreadable.
  - Add option in the Windows menu to hide the image tab bar.

CLI:

  - New self-explanatory --enable-win32-debug-console CLI option

Debugging:

  - New GimpBacktrace API provides an interface for creating and
    traversing multi-threaded backtraces, as well as querying symbol
    information. Backends are available for Linux and Windows.
  - Performance log recording now available in the Dashboard dock.
    The log contains a series of samples of the dashboard variables,
    as well as the full program backtrace, when available. As such,
    it essentially acts as a built-in profiler, which allows us to
    correlate program execution with the information available
    through the Dashboard.
  - New performance-log-expand.py tool decodes a delta-encoded
    performance log by expanding the deltas, producing a log where
    each sample (and other relevant elements) contain complete
    information. The structure of expanded logs is identical to that
    of delta-encoded logs, the expanded log simply has no deltas.
  - New performance-log-resolve.py tool resolves symbol information
    in backtraces. The logs produced by GIMP only specify the program
    counter at each stack frame, providing an address-map to map
    program-counter addresses to actual symbols separately. This tool
    looks up each program-counter address in the address map,
    incorporating the relevant symbol information directly into the
    backtrace.
  - New performance-log-deduce.py tool that statistically deduces the
    correct thread states based on backtrace address frequency, fixing
    local inaccuracies.
  - New performance-log-viewer.py tool that is a viewer for GIMP
    performance logs, with a sample-selection area at the top and an
    information area at the bottom. The sample-selection area visualizes
    the sampled variables and markers using a simultaneous set of plots,
    and displays the currently selected samples. The information area
    shows global information stored in the log, as well as information
    specific to the currently selected samples, including variable listing
    and statistics, full backtrace, and profile/call-graph information.

Translations:

  - Updated translations: Danish, Dutch, Finnish, German, Hungarian,
    Italian, Marathi, Polish, Portuguese (Brazil), Russian, Spanish,
    Swedish, Ukrainian.


Overview of Changes from GIMP 2.10.4 to GIMP 2.10.6
===================================================

Core:

  - Render drawable previews asynchronously.
  - Merge the file view filter and file format lists in GimpFileDialog.
    The presence of 2 lists was very confusing.
  - DLL search priority is now updated before running a plug-in on
    Windows, depending on the executable bitness. This gets rid of one
    of the last remnant of DLL hell in GIMP, which was when running
    32-bit plug-ins from a 64-bit build of GIMP.

Filters:

  - New "Little Planet" (gegl:stereographic-projection) filter.
  - New "Long Shadow" (gegl:long-shadow) filter.

Tools:

  - Halt the Measure tool after straightening.
  - Add an "orientation" option to the measure tool, corresponding to
    the "orientation" property of GimpToolCompass (i.e., it controls the
    orientation against which the angle is measured, when not in 3-
    point mode.)  The orientation is "auto" by default, so that the
    angle is always <= 45 deg.  Note that the "orientation" option
    affects the tool's "straighten" function, so that the layer is
    rotated toward the current orientation.
  - Text layers can now represent vertical texts, with 4 variants:
    left-to-right and right-to-left lines, and forcing all characters to
    be upright or following Unicode's vertical orientation property.
    See also:
    * https://www.unicode.org/reports/tr50/
    * http://www.unicode.org/Public/UCD/latest/ucd/VerticalOrientation.txt

User Interface:

  - The Dashboard dockable dialog now has an "async" field to the
    dashboard's "misc" group, showing the number of async operations
    currently in the "running" state.
  - New Preferences option to enable/disable layer-group previews, since
    these can get quite time-expensive.

Translations:

  - New language: Marathi
  - 12 translations were updated: Brazilian Portuguese, Dutch, French,
    German, Greek, Italian, Latvian, Polish, Romanian, Slovenian,
    Spanish, Swedish.

Build:

  - Add --with-win32-32bit-dll-folder configuration option to override
    the folder where 32-bit versions of DLL will be installed (default:
    32/bin/).
  - Install all plug-ins in their own directories. Unlike on master,
    this is not mandatory to do so, but it would protect our core
    plug-ins against any DLL installed directly under plug-ins/ by
    third-party plug-ins (cf. Windows DLL hell).

Overview of Changes from GIMP 2.10.2 to GIMP 2.10.4
===================================================

Core:

  - Remove gimp_display_shell_draw_background() and all clipping hacks
    for drawing the canvas background. This optimizes away one entire
    step of drawing of image size, for each expose.
  - Font loading does not block startup anymore. Only consequence is
    that the Text tool may not be usable immediately if fonts are not
    fully loaded yet (and will output an appropriate error if you do
    so). All non-text related activities can be performed right away.
  - Change of the URL from bugzilla to gitlab where appropriate.
  - New tool option manager to better keep track of user context and
    paint options in a consistent manner.

User Interface:

  - The Dashboard dockable dialog now has a 'Memory' group that shows
    memory-usage information: the currently used memory size, the
    available physical memory size, and the total physical memory
    size.  It can also show the tile-cache size, for comparison
    against the other memory stats. Note that the upper-bound of the
    meter is the physical memory size, so the memory usage may be over
    100% when GIMP uses the swap.
  - The Dashboard dockable dialog now has "read" and "written" fields in
    the dashboard swap group, which report the total amount of data
    read-from/written-to the tile swap, respetively. Additionally, the
    swap busy indicator (used as the meter's LED) has been improved,
    so that it's active whenever data has been read-from/written-to
    the swap during the last sampling interval, rather than at the
    point of sampling.
  - Fonts can now be tagged. The user interface is the same as for
    brushes, patterns etc.
  - Some icons fixed: larger spacing between broken chains and
    gimp-tool-ellipse-select made symmetrical.

Usability:

  - When a plug-in cannot be applied to an image because of mismatch
    in image types (e.g. layer has no alpha or image is greyscale),
    GIMP now displays a message listing supported image types for this
    plug-in.

Tools:

  - The Measurement tool now has an "Auto straighten" option allowing
    to rotate the active drawable (layer, channel…) so that the
    measurement line is used as horizon. As other transform tools, the
    feature will work on linked drawables as well.
  - The Smudge tool now paints correctly on images with a color
    profile other than the GIMP's built-in one.

Build:

  - Installer: set compatibility options to run Python plugins in
    HiDPI-aware mode.
  - Put back compatibility DLLs for really old plugins.
  - Install binary tool `gimp-test-clipboard` on the system to allow
    people to help us debug clipboard bugs.
  - --enable-bundled-mypaint-brushes renamed
    --enable-relocatable-bundle and also make WMF fonts looked up on
    the runtime prefix of GIMP (instead of the build-time path) when
    this build option was set.
  
Plug-ins:

  - gimptool-2.0 binary now accepts source files with non-standard
    extensions if it can try to guess appropriate language from the
    compiler being used. It will also properly quote arguments for
    shell usage.
  - Run explicitly Python 2 as Python plug-in interpreter to prevent
    breakage on systems where Python 3 is the default.
  - raw_input()'s argument in Python console is now optional, and
    input() support has been added.

File Formats:

  - The PSD loader now provides an option to load "merged",
    pre-composited version of the images that becomes available when a
    PSD file was saved with "Maximize Compatibility" option enabled in
    Photoshop. This is useful when loading PSD files that use features
    that GIMP doesn't currently support, and therefore can't render
    correctly, such as adjustment layers. When loading the merged
    image version, we avoid loading certain additional data from the
    file, such as channels, paths, and guides, while still loading
    metadata. This option is currently exposed as an additional file
    type ("Photoshop image (merged)"), which has to be explicitly
    selected from the file-type list when opening the image.
  - Embedding GIMP's built-in sRGB color profile to exported files is
    now optional. The default choice can be set in the Preferences
    dialog.

Translations:

  - Updated translations: Catalan, Czech, Danish, Dutch, Finnish,
    Greek, Hungarian, Italian, Latvian, Polish, Romanian, Russian,
    Spanish, Swedish, Ukrainian.


Overview of Changes from GIMP 2.10.0 to GIMP 2.10.2
===================================================

Core:

  - Discard fonts which fail to load and popup an info dialog to allow
    people debug their fonts.
  - New API to suppress updates in UI until plug-ins are done
    introducing changes.
  - New API to calculate histograms in separate threads, with possible further
    extension to handle similar cases elsewhere in GIMP.
  - Tool options are now properly saved and reloaded per-device at
    startup.

Plug-ins:

  - New plug-in for importing and exporting HEIF images.
  - Enable visibility of rasterized vector layer from PSD.
  - Single-window screenshots in Windows fixed to correctly snap a
    window even when it is partly off-screen or covered by another
    window or when display scaling is not set to 100%.

Filters:

  - New Spherize filter to wrap an image around a spherical cap
  - New Recursive Transform filter to create Droste effect.

Usability:

  - Warn users, when alpha-only painting has no effect. E.g. when target
    drawable doesn't have an alpha channel, or the alpha channel is locked.
  - Make the splash texts dynamic, so they are larger on larger splashes.
  - Mention pressing Enter to complete Foreground selection in the status bar.
  - Make sure that clicking outside any selection prevents Rectangle Select
    and Ellipse Select tools from creating empty selections.
  - Improve mouse wheel zooming behavior to keep the same point
    centered under the pointer even if the image is completely visible
    in the canvas.
  - Add "View -> Center Image in Window" (Shift+J) as a quick way to
    center the image at any zoom level.

Translations:

  - Updated translations: Catalan, Danish, Dutch, French, German, Greek,
    Hungarian, Icelandic, Italian, Latvian, Polish, Russian, Spanish,
    Swedish, Ukrainian.
  - New translation of Windows installer: Chinese (Taiwan)

Build:

  - Add a --with-bug-report-url configure option allowing packagers to
    set the address of their own bug tracker. This address will be the
    one opened by the debug dialog for reporting bugs.
  - Add a flatpak manifest for the gtk3-port branch.
  - Remove the possibility to disable script-fu.
  - Add a --with-icc-directory configure option to customize the color
    profile directory. By default, it is set to the common path
    /usr/share/color/icc.

Documentation:

  - Updating the description of the XCF format "devel-docs/xcf.txt", for
    third-party readers wishing to support GIMP 2.10 XCF files.
  - Add documentation skeletons for all enums in libgimpbase/, there is
    much room for improvement.
