forked from AuroraMiddleware/gtk
408 lines
16 KiB
XML
408 lines
16 KiB
XML
<?xml version="1.0"?>
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<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
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"http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
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<!ENTITY % local.common.attrib "xmlns:xi CDATA #FIXED 'http://www.w3.org/2003/XInclude'">
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]>
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<chapter id="gtk-migrating-3-x-to-y">
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<title>Migrating from one GTK+ 3 release to another</title>
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<para>
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GTK+ 3 has seen considerable development over multiple stable releases.
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While we try to maintain compatibility as far as possible, some minor
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adjustments may be necessary when moving an application from one release
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of GTK+ 3 to the next.
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</para>
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<para>
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The following sections list noteworthy changes in GTK+ 3.x release that
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may or may not require applications to be updated.
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</para>
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<section>
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<title>Changes in GTK+ 3.2</title>
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<para>
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The accessible implementations for GTK+ widgets have been integrated
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into libgtk itself, and the gail module does not exist anymore. This
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change should not affect applications very much.
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</para>
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</section>
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<section>
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<title>Changes in GTK+ 3.4</title>
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<para>
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Scroll events have been separated from button events, and smooth
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scrolling has been added with a separate event mask. Widgets now
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need to have either GDK_SCROLL_MASK or GDK_SMOOTH_SCROLL_MASK in
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their event mask to receive scroll events. In addition, the
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GdkScrollDirection enumeration has gained a new member,
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GDK_SCROLL_SMOOTH, so switch statements will have to be amended
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to cover this case.
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</para>
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<para>
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GTK+ now uses <Primary> instead of <Control> in keyboard
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accelerators, for improved cross-platform handling. This should not
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affect applications, unless they parse or create these accelerator
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manually.
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</para>
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<para>
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The tacit assumption that the Alt key corresponds to the MOD1
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modifier under X11 is now a hard requirement.
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</para>
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<para>
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The beagle search backend for the file chooser has been dropped.
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Tracker is the only supported search backend on Linux now.
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</para>
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<para>
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GtkNotebook has been changed to destroy its action widgets when
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it gets destroyed itself. If your application is using action
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widgets in notebooks, you may have to adjust your code to take
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this into account.
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</para>
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<para>
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GtkApplication no longer uses the gtk_ mainloop wrappers, so
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it is no longer possible to use gtk_main_quit() to stop it.
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</para>
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<para>
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The -uninstalled variants of the pkg-config files have been dropped.
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</para>
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<para>
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Excessive dependencies have been culled from Requires: lines
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in .pc files. Dependent modules may have to declare dependencies
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that there were getting 'for free' in the past.
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</para>
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</section>
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<section>
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<title>Changes in GTK+ 3.6</title>
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<para>
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The accessibility bridge code that exports accessible objects
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on the bus is now used by default; atk-bridge has been converted
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into a library that GTK+ links against. To void the linking,
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pass --without-atk-bridge when configuring GTK+.
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</para>
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<para>
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GDK threading support has been deprecated. It is recommended to
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use g_idle_add(), g_main_context_invoke() and similar funtions
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to make all GTK+ calls from the main thread.
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</para>
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<para>
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GTK+ now follows the XDG Base Directory specification for
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user configuration and data files. In detail,
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<itemizedlist>
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<listitem>$XDG_CONFIG_HOME/gtk-3.0/custom-papers is the new location
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for $HOME/.gtk-custom-papers</listitem>
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<listitem>$XDG_CONFIG_HOME/gtk-3.0/bookmarks is the new location
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for $HOME/.gtk-bookmarks</listitem>
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<listitem>$XDG_DATA_HOME/themes is preferred over $HOME/.themes</listitem>
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<listitem>$XDG_DATA_HOME/icons is preferred over $HOME/.icons.</listitem>
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</itemizedlist>
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Existing files from the old location will still be read
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if the new location does not exist.
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</para>
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<para>
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$HOME/.gtk-3.0 is no longer in the default module load path.
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If you want to load modules from there, add it to the GTK_PATH
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environment variable.
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</para>
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</section>
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<section>
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<title>Changes in GTK+ 3.8</title>
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<para>
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GtkIconInfo has changed from being a boxed type to a GObject.
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This is technically an ABI change, but basically all existing code
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will keep working if its used as a boxed type, and it is not
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possible to instantiate GtkIconInfos outside GTK+, so this is
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not expected to be a big problem.
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</para>
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</section>
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<section>
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<title>Changes in GTK+ 3.10</title>
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<para>
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GDK has been changed to allow only a single screen per display.
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Only the X11 backend had multiple screens before, and multi-screen
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setups (not multi-monitor!) are very rare nowadays. If you really
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need multiple X screens, open them as separate displays.
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</para>
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<para>
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The behavior of GtkBox::expand has been changed to never propagate
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up. Previously, this was happening inconsistently. If you want the
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expand to propagate, use the GtkWidget h/v expand properties.
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If you experience sizing problems with widgets in ported code,
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carefully check the expand and fill flags of your boxes.
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</para>
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<para>
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GtkBin no longer provides default implementations for
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get_height_for_width, subclasses now have to provide their own
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implementation if they need height-for-width functionality.
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</para>
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<para>
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Widget state propagation has been changed. Historically, all of
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active, prelight, selected, insensitive, inconsistent and backdrop
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have been propagated to children. This has now been restricted
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to just the insensitive and backdrop states. This mostly affects
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theming.
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</para>
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<para>
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The way widget drawing happens has changed. Earlier versions handled
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one expose event per GdkWindow, each with a separate cairo_t. Now we
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only handle the expose event on the toplevel and reuse the same
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cairo_t (with the right translation and clipping) for the entire
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widget hierarchy, recursing down via the GtkWidget::draw signal.
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Having all rendering in the same call tree allows effects like
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opacity and offscreen rendering of entire widget sub-hierarchies.
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Generally this should not require any changes in widgets, but
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code looking at e.g. the current expose event may see different
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behavior than before.
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</para>
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<para>
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The Gtk+ scrolling implementation has changed. gdk_window_scroll()
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and gdk_window_move_region() no longer copy the region on the
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window, but rather invalidate the entire scrolled region. This is
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slightly slower, but allowed us to implement a offscreen surface
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scrolling method which better fits modern hardware. Most scrolling
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widgets in Gtk+ have been converted to use this model for scrolling,
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but external widgets implementing scrolling using GdkWindow may see
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some slowdown.
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</para>
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</section>
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<section>
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<title>Changes in GTK+ 3.12</title>
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<para>
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GtkWidget had a hack where if opacity is 0.999 we set up an opacity
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group when rendering the widget. This is no longer needed in 3.10,
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and GtkStack doesn't use it anymore. It has been removed in 3.12.
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GdStack is using it, so applications should be ported from GdStack
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to GtkStack in 3.12.
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</para>
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<para>
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GtkHeaderBar in 3.10 was not ordering its pack-end children in
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the right way. This has been fixed in 3.12. Applications which
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pack multiple widgets at the end of a headerbar will have to
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be updated.
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</para>
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<para>
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gtk_text_view_add_child_in_window has changed behaviour a bit.
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It now always positions the child in buffer coordinates, where
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it used to inconsistently scroll with the buffer but then go
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reposition to a window-relative position on redraw.
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</para>
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<para>
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A number of container widgets have been made more compliant with
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the uniform CSS rendering model by making them render backgrounds
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and borders. This may require some adjustments in applications that
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were making assumptions about containers never rendering backgrounds.
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</para>
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</section>
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<section>
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<title>Changes in GTK+ 3.14</title>
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<para>
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A new state, GTK_STATE_FLAG_CHECKED, has been added for checked states
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of radio and check buttons and menuitems. Applications that are using
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GTK+ styles without widgets will need adjustments.
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</para>
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<para>
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Adwaita is now the default theme on all platforms.
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</para>
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<para>
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The icon theme code has become a little pickier about sizes and is not
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automatically scaling icons beyond the limits defined in the icon theme
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unless explicitly asked to do so with GTK_ICON_LOOKUP_FORCE_SIZE.
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</para>
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<para>
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GTK+ now includes an interactive debugger which can be activated with
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the keyboard shortcuts Ctrl-Shift-d or Ctrl-Shift-i. If these shortcuts
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interfere with application keybindings, they can be disabled with the
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setting org.gtk.Settings.Debug.enable-inspector-keybinding.
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</para>
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<para>
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Most widgets have been ported to use the new gesture framework internally
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for event handling. Traditional event handlers in derived widgets are still
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being called.
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</para>
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<para>
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Using GTK+ under X11 without the X Render extension has been observed
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to be problematic. This combination is using code paths in cairo and
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graphics drivers which are rarely tested and likely buggy.
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</para>
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<para>
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GtkTextView is now using a pixel-cache internally, and is drawing
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a background underneath the text. This can cause problems for applications
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which assumed that they could draw things below and above the text
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by chaining up in the ::draw implementation of their GtkTextView subclass.
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As a short-term workaround, you can make the application apply a
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custom theme to the text view with a transparent background. For
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a proper fix, use the new ::draw_layer vfunc.
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</para>
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</section>
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<section>
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<title>Changes in GTK+ 3.16</title>
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<para>
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GTK+ now includes an OpenGL rendering widget. To support GL on various
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platforms, GTK+ uses libepoxy.
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</para>
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<para>
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GTK+ no longer uses gtk-update-icon-cache during its build. The
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--enable-gtk2-dependency configure option has been removed.
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</para>
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<para>
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The introspection annotations for the x and y parameters of
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GtkMenuPositionFunc have been corrected from 'out' to 'inout'.
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If you are using such a function from language-bindings, this
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may require adjustments.
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</para>
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<para>
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The lookup order for actions that are activated via keyboard
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accelerators has been changed to start at the currently focused
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widget. If your application is making use fo nested action groups
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via gtk_widget_insert_action_group, you may want to check that
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this change does not upset your accelerators.
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</para>
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<para>
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The GtkScrollable interface has gained a new vfunc, get_border,
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that is used to position overshoot and undershoot indications that
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are drawn over the content by GtkScrolledWindow. Unless your scrollable
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has non-scrolling parts similar to treeview headers, there is no need
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to implement this vfunc.
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</para>
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<para>
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The GtkSearchEntry widget has gained a number of new signals that
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are emitted when certain key sequences are seen. In particular, it
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now handles the Escape key and emits ::stop-search. Applications that
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expect to handle Escape themselves will need to be updated.
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</para>
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</section>
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<section>
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<title>Changes in GTK+ 3.18</title>
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<para>
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The GtkListBox model support that was introduced in 3.16 has been
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changed to no longer call gtk_widget_show_all on rows created by
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the create_widget_func. You need to manage the visibility of child
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widgets yourself in your create_widget_func.
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</para>
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<para>
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The alpha component of foreground colors that are applied to
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GtkCellRendererText is no longer ignored. If you don't want your
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text to be translucent, use opaque colors.
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</para>
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</section>
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<section>
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<title>Changes in GTK+ 3.20</title>
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<para>
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The way theming works in GTK+ has been reworked fundamentally, to
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implement many more CSS features and make themes more expressive.
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As a result, custom CSS that is shipped with applications and third-party
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themes will need adjustments. Widgets now use element names much more
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than style classes; type names are no longer used in style matching.
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Every widget now documents the element names it has and the style classes
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it uses. The GTK+ inspector can also help with finding this information.
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</para>
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<para>
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GTK+ now uses internal subobjects (also known as gadgets) for allocating
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and drawing widget parts. Applications that subclass GTK+ widgets may see
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warnings if they override the size_allocate vfunc and don't chain up.
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The proper way to subclass is to chain up in size_allocate. If you do not
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want to do that for some reason, you have to override the draw vfunc as
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well.
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</para>
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<para>
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Several fixes for window sizing and window placement with client-side
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decorations may affect applications that are saving and restoring window
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sizes. The recommended best practice for this which is known to work with
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client-side and server-side decorations and with older and newer versions
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of GTK+ is to use gtk_window_get_size() to save window sizes and
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gtk_window_set_default_size() to restore it.
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See https://wiki.gnome.org/HowDoI/SaveWindowState for a detailed example.
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</para>
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<para>
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Geometry handling in GtkWindow has been removed. If you are using the
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functions gtk_window_resize_to_geometry, gtk_window_set_default_geometry,
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gtk_window_parse_geometry or gtk_window_set_geometry_hints, you may need
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to make some changes to your code.
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</para>
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<para>
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GtkDrawingArea used to implicitly render the theme background before
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calling the ::draw handler. This is no longer the case. If you rely
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on having a theme-provided background, call gtk_render_background()
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from your ::draw handler.
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</para>
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<para>
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The GtkFileChooser interface prerequisite changed from GtkWidget
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to GObject, allowing non-widget implementations of this interface.
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This is a minor change in ABI, as applications are no longer guaranteed
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that a GtkFileChooser also supports all GtkWidget methods. However, all
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previously existing implementations still derive from GtkWidget, so no
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existing code should break.
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</para>
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<para>
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The way in which GtkLevelBar determines the offset to apply was a bit
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inconsistent in the past; this has been fixed. Applications that are using
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custom offsets should double-check that their levels look as expected.
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</para>
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</section>
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<section>
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<title>Changes in GTK+ 3.22</title>
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<para>
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The CSS parser has gotten a bit more selective in what it accepts as
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valid values for the font: shorthand. Following the CSS specification,
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at least a size and a family name are required now. If you want to
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change an individual facet of the font, like the weight, use the
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individual CSS properties: font-weight, font-size, font-family, etc.
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</para>
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</section>
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</chapter>
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