[PATCH wayland-protocols v3 7/7] xdg-shell: Introduce xdg_positioner
Yong Bakos
junk at humanoriented.com
Sat May 28 13:22:53 UTC 2016
Hi Jonas and Mike,
On May 25, 2016, at 11:32 PM, Jonas Ådahl <jadahl at gmail.com> wrote:
>
> xdg_positioner is a method for declarative positioning of child surfaces
> (currently only xdg_popup surfaces). A client creates a description of a
> positioning logic using the xdg_positioner interface. The xdg_positioner
> object is then used when creating a xdg_popup for describing how the
> child surface should be positioned in relation to the parent surface.
>
> Signed-off-by: Jonas Ådahl <jadahl at gmail.com>
> Signed-off-by: Mike Blumenkrantz <zmike at samsung.com>
Whenever I see declarative positioning schemes, my warning bell goes off
because, from the perspective of a gui/app dev, resulting implementations
of constraint systems, etc can sometimes be a hassle. I'm not saying that
what's proposed here is bad, rather, I ask, "Was this based on an
existing system?" (Forgive me if that question is obvious / naive).
In other words, there's an opportunity to create a simple, flexible,
and anticipatable positioning mechanism here at the protocol level, so
it's important to Do It Really Well.
Acked-by: Yong Bakos <ybakos at humanoriented.com>
yong
> ---
>
> Changes since v2:
> - Grammar, typos and spelling fixes
> - Reordered enum values to be the same as already present similar enum
> - Added enum attribute to relevant requests
>
>
> unstable/xdg-shell/xdg-shell-unstable-v6.xml | 252 ++++++++++++++++++++++++++-
> 1 file changed, 249 insertions(+), 3 deletions(-)
>
> diff --git a/unstable/xdg-shell/xdg-shell-unstable-v6.xml b/unstable/xdg-shell/xdg-shell-unstable-v6.xml
> index 07cbbc9..1baafa7 100644
> --- a/unstable/xdg-shell/xdg-shell-unstable-v6.xml
> +++ b/unstable/xdg-shell/xdg-shell-unstable-v6.xml
> @@ -45,6 +45,8 @@
> summary="the client specified an invalid popup parent surface"/>
> <entry name="invalid_surface_state" value="4"
> summary="the client provided an invalid surface state"/>
> + <entry name="invalid_positioner" value="5"
> + summary="the client provided an invalid positioner"/>
> </enum>
>
> <request name="destroy" type="destructor">
> @@ -57,6 +59,15 @@
> </description>
> </request>
>
> + <request name="create_positioner">
> + <description summary="create a positioner object">
> + Create a positioner object. A positioner object is used to position
> + surfaces relative to some parent surface. See the interface description
> + and xdg_surface.get_popup for details.
> + </description>
> + <arg name="id" type="new_id" interface="zxdg_positioner_v6"/>
> + </request>
> +
> <request name="get_xdg_surface">
> <description summary="create a shell surface from a surface">
> This creates an xdg_surface for the given surface. While xdg_surface
> @@ -96,6 +107,225 @@
> </event>
> </interface>
>
> + <interface name="zxdg_positioner_v6" version="1">
> + <description summary="child surface positioner">
> + The xdg_positioner provides an interface for constructing positioning
> + rules used for positioning a child surface relative to a parent surface
> + in a certain way. It allows methods for defining a rule that will make
> + the child surface stay within the border of the visible area of the
> + screen, with different ways in which the child surface should change
> + its position, including sliding along an axis, or flipping around a
> + rectangle.
> +
> + See the various requests for details about possible rules.
> +
> + Semantically, an xdg_positioner is a collection of positioning rules. When
> + used for positioning a surface, for example when passed as an argument to
> + xdg_surface.get_popup, the compositor copies the rules that were set up at
> + the time of the request. Making any changes or destroying the object after
> + it was used has no effect on previous usages.
> +
> + For an xdg_positioner object to be considered complete, it must have a
> + non-zero size set by set_size, and a non-zero anchor rectangle set by
> + set_anchor_rect. Passing an incomplete xdg_positioner object when
> + positioning a surface raises an error.
> + </description>
> +
> + <enum name="error">
> + <entry name="invalid_input" value="0" summary="invalid input provided"/>
> + </enum>
> +
> + <request name="destroy" type="destructor">
> + <description summary="destroy the xdg_positioner object">
> + Notify the compositor that the xdg_positioner will no longer be used.
> + </description>
> + </request>
> +
> + <request name="set_size">
> + <description summary="set the size of the to-be positioned rectangle">
> + Set the size of the surface that is to be positioned with the positioner
> + object. The size is in surface-local coordinates and corresponds to the
> + window geometry. See xdg_surface.set_window_geometry.
> +
> + If a zero or negative size is set the invalid_input error is raised.
> + </description>
> + <arg name="width" type="int" summary="width of positioned rectangle"/>
> + <arg name="height" type="int" summary="height of positioned rectangle"/>
> + </request>
> +
> + <request name="set_anchor_rect">
> + <description summary="set the anchor rectangle within the parent surface">
> + Specify the anchor rectangle within the parent surface that the child
> + surface will be placed relative to. The rectangle is relative to the
> + window geometry as defined by xdg_surface.set_window_geometry of the
> + parent surface. The rectangle must be at least 1x1 large.
> +
> + When the xdg_positioner object is used to position a child surface, the
> + anchor rectangle may not extend outside the window geometry of the
> + positioned child's parent surface.
> +
> + If a zero or negative size is set the invalid_input error is raised.
> + </description>
> + <arg name="x" type="int" summary="x position of anchor rectangle"/>
> + <arg name="y" type="int" summary="y position of anchor rectangle"/>
> + <arg name="width" type="int" summary="width of anchor rectangle"/>
> + <arg name="height" type="int" summary="height of anchor rectangle"/>
> + </request>
> +
> + <enum name="anchor" bitfield="true">
> + <entry name="none" value="0"
> + summary="the center of the anchor rectangle"/>
> + <entry name="top" value="1"
> + summary="the top edge of the anchor rectangle"/>
> + <entry name="bottom" value="2"
> + summary="the bottom edge of the anchor rectangle"/>
> + <entry name="left" value="4"
> + summary="the left edge of the anchor rectangle"/>
> + <entry name="right" value="8"
> + summary="the right edge of the anchor rectangle"/>
> + </enum>
> +
> + <request name="set_anchor">
> + <description summary="set anchor rectangle anchor edges">
> + Set the anchor edges of the anchor rectangle. The anchor edges define
> + where on the anchor rectangle the child surface should be positioned
> + relative to. An anchor is a bit mask of up to two values of the anchor
> + enum.
> +
> + If two values on the same axis (for example left and right) are set the
> + invalid_input error is raised.
> +
> + If no anchor is set on any axis, the anchor position will be positioned
> + at the center of the anchor rectangle on the unset axis. The default
> + value is "none".
> + </description>
> + <arg name="anchor" type="uint" enum="anchor"
> + summary="bit mask of anchor edges"/>
> + </request>
> +
> + <enum name="gravity" bitfield="true">
> + <entry name="none" value="0"
> + summary="center over the anchor edge"/>
> + <entry name="top" value="1"
> + summary="position above the anchor edge"/>
> + <entry name="bottom" value="2"
> + summary="position below the anchor edge"/>
> + <entry name="left" value="4"
> + summary="position to the left of the anchor edge"/>
> + <entry name="right" value="8"
> + summary="position to the right of the anchor edge"/>
> + </enum>
> +
> + <request name="set_gravity">
> + <description summary="set child surface gravity">
> + The gravity defines in what direction a surface would be positioned,
> + relative to the anchor edges on the parent surface. A gravity is a
> + bit mask of up to two values of the gravity enum.
> +
> + If two values on the same axis (for example left and right) are set the
> + invalid_input error is raised.
> +
> + If no gravity is set on an axis, the gravity for that axis will be
> + equivalent to setting "none" for that axis, resulting in the child being
> + centered over the anchor edges on that axis.
> + </description>
> + <arg name="gravity" type="uint" enum="gravity"
> + summary="bit mask of gravity directions"/>
> + </request>
> +
> + <enum name="constrain_adjustment" bitfield="true">
> + <entry name="none" value="0">
> + <description summary="don't move the child surface when constrained">
> + Don't alter the surface position even if it is constrained on some
> + axis, for example partially outside the edge of a monitor.
> + </description>
> + </entry>
> + <entry name="slide_x" value="1">
> + <description summary="move along the x axis until unconstrained">
> + Slide the surface along the x axis until it is no longer constrained.
> +
> + First try to slide towards the direction of the gravity on the x axis
> + until either the edge in the opposite direction of the gravity is
> + unconstrained or the edge in the direction of the gravity is
> + constrained.
> +
> + Then try to slide towards the opposite direction of the gravity on the
> + x axis until either the edge in the direction of the gravity is
> + unconstrained or the edge in the opposite direction of the gravity is
> + constrained.
> + </description>
> + </entry>
> + <entry name="slide_y" value="2">
> + <description summary="move along the y axis until unconstrained">
> + Slide the surface along the y axis until it is no longer constrained.
> +
> + First try to slide towards the direction of the gravity on the y axis
> + until either the edge in the opposite direction of the gravity is
> + unconstrained or the edge in the direction of the gravity is
> + constrained.
> +
> + Then try to slide towards the opposite direction of the gravity on the
> + y axis until either the edge in the direction of the gravity is
> + unconstrained or the edge in the opposite direction of the gravity is
> + constrained.
> + </description>
> + </entry>
> + <entry name="flip_x" value="4">
> + <description summary="invert the anchor and gravity on the x axis">
> + Invert the anchor and gravity on the x axis if the surface is
> + constrained on the x axis. For example, if the left edge of the
> + surface is constrained, the gravity is 'left' and the anchor is
> + 'left', change the gravity to 'right' and the anchor to 'right'. If
> + the resulting position after inverting ends up also being constrained,
> + the behaviour is undefined.
> + </description>
> + </entry>
> + <entry name="flip_y" value="8">
> + <description summary="invert the anchor and gravity on the y axis">
> + Invert the anchor and gravity on the y axis if the surface is
> + constrained on the y axis. For example, if the bottom edge of the
> + surface is constrained, the gravity is 'bottom' and the anchor is
> + 'bottom', change the gravity to 'top' and the anchor to 'top'. If
> + the resulting position after inverting ends up also being constrained,
> + the behaviour is undefined.
> + </description>
> + </entry>
> + </enum>
> +
> + <request name="set_constrain_adjustment">
> + <description summary="set the adjustment to be done when constrained">
> + Specify how the window should be positioned if the originally intended
> + position caused the surface to be constrained, meaning at least
> + partially outside positioning boundaries set by the compositor. The
> + adjustment is set by constructing a bitmask with one bit per axis set
> + describing the adjustment to be made when the surface is constrained on
> + that axis. If no bit for one axis is set, the compositor will assume
> + that the child surface should not change its position on that axis when
> + constrained. The default adjustment is none.
> + </description>
> + <arg name="constrain_adjustment" type="uint"
> + summary="bit mask of constrain adjustments"/>
> + </request>
> +
> + <request name="set_offset">
> + <description summary="set surface position offset">
> + Specify the surface position offset relative to the position of the
> + anchor on the anchor rectangle and the anchor on the surface. For
> + example if the anchor of the anchor rectangle is at (x, y), the surface
> + has the gravity bottom|right, and the offset is (ox, oy), the calculated
> + surface position will be (x + ox, y + oy). The offset position of the
> + surface is the one used for constraint testing. See
> + set_constrain_adjustment.
> +
> + An example use case is placing a popup menu on top of a user interface
> + element, while aligning the user interface element of the parent surface
> + with some user interface element placed somewhere in the popup surface.
> + </description>
> + <arg name="x" type="int" summary="surface position x offset"/>
> + <arg name="y" type="int" summary="surface position y offset"/>
> + </request>
> + </interface>
> +
> <interface name="zxdg_surface_v6" version="1">
> <description summary="desktop user interface surface base interface">
> An interface that may be implemented by a wl_surface, for
> @@ -163,8 +393,7 @@
> </description>
> <arg name="id" type="new_id" interface="zxdg_popup_v6"/>
> <arg name="parent" type="object" interface="zxdg_surface_v6"/>
> - <arg name="x" type="int"/>
> - <arg name="y" type="int"/>
> + <arg name="positioner" type="object" interface="zxdg_positioner_v6"/>
> </request>
>
> <request name="set_window_geometry">
> @@ -724,7 +953,7 @@
> button press, key press, or touch down event. The serial number of the
> event should be passed as 'serial'.
>
> - The parent of a grabbing popup must either be a xdg_toplevel surface or
> + The parent of a grabbing popup must either be an xdg_toplevel surface or
> another xdg_popup with an explicit grab. If the parent is another
> xdg_popup it means that the popups are nested, with this popup now being
> the topmost popup.
> @@ -759,6 +988,23 @@
> <arg name="serial" type="uint" summary="the serial of the user event"/>
> </request>
>
> + <event name="configure">
> + <description summary="configure the popup surface">
> + This event asks the popup surface to configure itself given the
> + configuration. It is not sent by itself but is as a latched state prior
> + to the xdg_surface.configure event. See xdg_surface.configure for
> + details.
> +
> + The x and y arguments represent the position the popup was placed at
> + given the xdg_positioner rule, relative to the upper left corner of the
> + window geometry of the parent surface.
> + </description>
> + <arg name="x" type="int"
> + summary="x position relative to parent surface window geometry"/>
> + <arg name="y" type="int"
> + summary="y position relative to parent surface window geometry"/>
> + </event>
> +
> <event name="popup_done">
> <description summary="popup interaction is done">
> The popup_done event is sent out when a popup is dismissed by the
> --
> 2.5.5
>
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