X Consortium Standard X Version 11, Release 6.4 KeithPackard MIT X Consortium
1989X Consortium Version 1.0 MIT X Consortium X Version 11, Release 6.4
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the ?Software?), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions: The above copyright notice and this
permission notice shall be included in all copies or substantial portions of
the Software. THE SOFTWARE IS PROVIDED ?AS IS?, WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO
EVENT SHALL THE X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE. Except as contained in this notice, the name of the X Consortium
shall not be used in advertising or otherwise to promote the sale, use or other
dealings in this Software without prior written authorization from the X
Consortium. This extension provides arbitrary window and border shapes within
the X11 protocol. The restriction of rectangular windows within the X protocol
is a significant limitation in the implementation of many styles of user
interface. For example, many transient windows would like to display a ?drop
shadow? to give the illusion of 3 dimensions. As another example, some user
interface style guides call for buttons with rounded corners; the full
simulation of a nonrectangular shape, particularly with respect to event
distribution and cursor shape, is not possible within the core X protocol. As a
final example, round clocks and nonrectangular icons are desirable visual
addition to the desktop. This extension provides mechanisms for changing the
visible shape of a window to an arbitrary, possibly disjoint, nonrectangular
form. The intent of the extension is to supplement the existing semantics, not
replace them. In particular, it is desirable for clients that are unaware of
the extension to still be able to cope reasonably with shaped windows. For
example, window managers should still be able to negotiate screen real estate
in rectangular pieces. Toward this end, any shape specified for a window is
clipped by the bounding rectangle for the window as specified by the window's
geometry in the core protocol. An expected convention would be that client
programs expand their shape to fill the area offered by the window manager. 
Each window (even with no shapes specified) is defined by two regions: the
bounding region and the clip region. The bounding region is the area of the
parent window that the window will occupy (including border). The clip region
is the subset of the bounding region that is available for subwindows and
graphics. The area between the bounding region and the clip region is defined
to be the border of the window. A nonshaped window will have a bounding region
that is a rectangle spanning the window, including its border; the clip region
will be a rectangle filling the inside dimensions (not including the border).
In this document, these areas are referred to as the default bounding region
and the default clip region. For a window with inside size of width by height
and border width bwidth, the default bounding and clip regions are the
rectangles (relative to the window origin): bounding.x = -bwidth bounding.y =
-bwidth bounding.width = width + 2 * bwidth bounding.height = height + 2 *
bwidth clip.x = 0 clip.y = 0 clip.width = width clip.height = height This
extension allows a client to modify either or both of the bounding or clip
regions by specifying new regions that combine with the default regions. These
new regions are called the client bounding region and the client clip region.
They are specified relative to the origin of the window and are always defined
by offsets relative to the window origin (that is, region adjustments are not
required when the window is moved). Three mechanisms for specifying regions are
provided: a list of rectangles, a bitmap, and an existing bounding or clip
region from a window. This is modeled on the specification of regions in
graphics contexts in the core protocol and allows a variety of different uses
of the extension. When using an existing window shape as an operand in
specifying a new shape, the client region is used, unless none has been set, in
which case the default region is used instead. The effective bounding region of
a window is defined to be the intersection of the client bounding region with
the default bounding region. Any portion of the client bounding region that is
not included in the default bounding region will not be included in the
effective bounding region on the screen. This means that window managers (or
other geometry managers) used to dealing with rectangular client windows will
be able to constrain the client to a rectangular area of the screen.
Construction of the effective bounding region is dynamic; the client bounding
region is not mutated to obtain the effective bounding region. If a client
bounding region is specified that extends beyond the current default bounding
region, and the window is later enlarged, the effective bounding region will be
enlarged to include more of the client bounding region. The effective clip
region of a window is defined to be the intersection of the client clip region
with both the default clip region and the client bounding region. Any portion
of the client clip region that is not included in both the default clip region
and the client bounding region will not be included in the effective clip
region on the screen. Construction of the effective clip region is dynamic; the
client clip region is not mutated to obtain the effective clip region. If a
client clip region is specified that extends beyond the current default clip
region and the window or its bounding region is later enlarged, the effective
clip region will be enlarged to include more of the client clip region if it is
included in the effective bounding region. The border of a window is defined to
be the difference between the effective bounding region and the effective clip
region. If this region is empty, no border is displayed. If this region is
nonempty, the border is filled using the border-tile or border-pixel of the
window as specified in the core protocol. Note that a window with a nonzero
border width will never be able to draw beyond the default clip region of the
window. Also note that a zero border width does not prevent a window from
having a border, since the clip shape can still be made smaller than the
bounding shape. All output to the window and visible regions of any subwindows
will be clipped to the effective clip region. The server must not retain window
contents beyond the effective bounding region with backing store. The window's
origin (for graphics operations, background tiling, and subwindow placement) is
not affected by the existence of a bounding region or clip region. Areas that
are inside the default bounding region but outside the effective bounding
region are not part of the window; these areas of the screen will be occupied
by other windows. Input events that occur within the default bounding region
but outside the effective bounding region will be delivered as if the window
was not occluding the event position. Events that occur in a nonrectangular
border of a window will be delivered to that window, just as for events that
occur in a normal rectangular border. An InputOnly window can have its bounding
region set, but it is a Match error to attempt to set a clip region on an
InputOnly window or to specify its clip region as a source to a request in this
extension. The server must accept changes to the clip region of a root window,
but the server is permitted to ignore requested changes to the bounding region
of a root window. If the server accepts bounding region changes, the contents
of the screen outside the bounding region are implementation dependent. The C
functions provide direct access to the protocol and add no additional
semantics. The include file for this extension is <X11/extensions/shape.h>. The
defined shape kinds are ShapeBounding and ShapeClip The defined region
operations are ShapeSet ShapeUnion ShapeIntersect ShapeSubtract and
ShapeInvert. Bool XShapeQueryExtension Display *display int *event_base int
*error_base XShapeQueryExtension returns True if the specified display supports
the SHAPE extension else False If the extension is supported, *event_base is
set to the event number for ShapeNotify events and *error_base would be set to
the error number for the first error for this extension. Because no errors are
defined for this version of the extension, the value returned here is not
defined (nor useful). Status XShapeQueryVersion Display *display int
*major_version int *minor_version If the extension is supported,
XShapeQueryVersion sets the major and minor version numbers of the extension
supported by the display and returns a nonzero value. Otherwise, the arguments
are not set and zero is returned. XShapeCombineRegion Display *display Window
dest int dest_kind int x_off int y_off int region int op REGION *region
XShapeCombineRegion converts the specified region into a list of rectangles and
calls XShapeCombineRectangles XShapeCombineRectangles Display *display Window
dest int dest_kind int x_off int y_off XRectangle *rectangles int n_rects int
op int ordering If the extension is supported, XShapeCombineRectangles performs
a ShapeRectangles operation; otherwise, the request is ignored.
XShapeCombineMask Display *display int dest int dest_kind int x_off int y_off
Pixmap src int op If the extension is supported, XShapeCombineMask performs a
ShapeMask operation; otherwise, the request is ignored. XShapeCombineShape
Display *display Window dest int dest_kind int x_off int y_off Window src int
src_kind int op If the extension is supported, XShapeCombineShape performs a
ShapeCombine operation; otherwise, the request is ignored. XShapeOffsetShape
display dest dest_kind x_off y_off If the extension is supported,
XShapeOffsetShape performs a ShapeOffset operation; otherwise, the request is
ignored. Status XShapeQueryExtents Display *display Window window Bool
*bounding_shaped int *x_bounding int *y_bounding unsigned int *w_bounding
unsigned int *h_bounding Bool *clip_shaped int *x_clip int *y_clip unsigned int
*w_clip unsigned int *h_clip If the extension is supported, XShapeQueryExtents
sets x_bounding, y_bounding, w_bounding, h_bounding to the extents of the
bounding shape and sets x_clip, y_clip, w_clip, h_clip to the extents of the
clip shape. For unspecified client regions, the extents of the corresponding
default region are used. If the extension is supported, a nonzero value is
returned; otherwise, zero is returned. XShapeSelectInput Display *display
Window window unsigned long mask To make this extension more compatible with
other interfaces, although only one event type can be selected via the
extension, XShapeSelectInput provides a general mechanism similar to the
standard Xlib binding for window events. A mask value has been defined,
ShapeNotifyMask that is the only valid bit in mask that may be specified. The
structure for this event is defined as follows: typedef struct { int type; /*
of event */ unsigned long serial; /* # of last request processed by server */
Bool send_event; /* true if this came frome a SendEvent request */ Display
*display; /* Display the event was read from */ Window window; /* window of
event */ int kind; /* ShapeBounding or ShapeClip */ int x, y; /* extents of new
region */ unsigned width, height; Time time; /* server timestamp when region
changed */ Bool shaped; /* true if the region exists */ } XShapeEvent; unsigned
long XShapeInputSelected Display *display Window window XShapeInputSelected
returns the current input mask for extension events on the specified window;
the value returned if ShapeNotify is selected for is ShapeNotifyMask otherwise,
it returns zero. If the extension is not supported, it returns zero. XRectangle
*XShapeGetRectangles Display *display Window window int kind int *count int
*ordering If the extension is not supported, XShapeGetRectangles returns NULL.
Otherwise, it returns a list of rectangles that describe the region specified
by kind. bounding region The area of the parent window that this window will
occupy. This area is divided into two parts: the border and the interior. clip
region The interior of the window, as a subset of the bounding region. This
region describes the area that will be painted with the window background when
the window is cleared, will contain all graphics output to the window, and will
clip any subwindows. default bounding region The rectangular area, as described
by the core protocol window size, that covers the interior of the window and
its border. default clip region The rectangular area, as described by the core
protocol window size, that covers the interior of the window and excludes the
border. client bounding region The region associated with a window that is
directly modified via this extension when specified by ShapeBounding This
region is used in conjunction with the default bounding region to produce the
effective bounding region. client clip region The region associated with a
window that is directly modified via this extension when specified by ShapeClip
This region is used in conjunction with the default clip region and the client
bounding region to produce the effective clip region. effective bounding region
The actual shape of the window on the screen, including border and interior
(but excluding the effects of overlapping windows). When a window has a client
bounding region, the effective bounding region is the intersection of the
default bounding region and the client bounding region. Otherwise, the
effective bounding region is the same as the default bounding region. effective
clip region The actual shape of the interior of the window on the screen
(excluding the effects of overlapping windows). When a window has a client clip
region or a client bounding region, the effective clip region is the
intersection of the default clip region, the client clip region (if any) and
the client bounding region (if any). Otherwise, the effective clip region is
the same as the default clip region.
