Content providers are meant to be immutable, apart from very special
cases, but in those cases they need to emit
gdk_content_provider_content_changed().
Having a constructor that just uses a get_func invites abuse of this
by not making developers aware of those requirments.
In fact, all users in GTK failed to do this.
Instead, code should use the GtkDragSource::prepare signal to create
content providers when needed.
The same problem exists with gdk_content_provider_new_with_formats(),
but this commit doesn't touch that.
In Vala and JS at least, gtk_widget_get_css_name() and
gtk_widget_class_get_css_name() are resolved to
GtkWidget.get_css_name().
To avoid this problem, we rename the class version.
Otherwise the compositor gets all confused when it's trying to make
drag happen but we know it's not going to happen.
After all, we exchange data behind its back, we just need to keep it
informed.
1. GdkDrop does deserialization, so add the deserialize formats
2. If the drop is local, we can copy straight from the drag, so we can
also copy all its formats. This fixes cases where the backend would
drop formats it doesn't support.
Accessors like these are weird to have and we can add widgets to the
content area via gtk_container_add() as well as add widgets to the
action area via gtk_info_bar_add_action_widget().
Some systems (notably macOS) will not allow enumeration of an extension that has been promoted to core OpenGL for context in use. This change assumes that GL_ARB_timer_query is available on OpenGL 3.3+.
I could not find definitive information on whether GL_ARB_debug_output or GL_KHR_debug have been added to core. Other extensions in use were addressed by https://gitlab.gnome.org/GNOME/gtk/merge_requests/1422 .
For a given OpenGL context, macOS in particular does not support enumeration / detection of OpenGL features that have been promoted to core OpenGL functionality. It is possible other drivers are the same. This change assumes support for GL_ARB_texture_non_power_of_two with OpenGL 2.0+, GL_ARB_texture_rectangle with OpenGL 3.1+ and GL_EXT_framebuffer_blit with OpenGL 3.0+. I failed to find definitive information on whether GL_GREMEDY_frame_terminator has been promoted to OpenGL core, or whether GL_ANGLE_framebuffer_blit or GL_EXT_unpack_subimage have been promoted to core in OpenGL ES. This change results in a significant GtkGLArea performance boost on macOS.
Closes#2428
