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Window/Unix: fix SFML issue #1228, getPosition() returns incorrect results on Linux depending on the used WM,

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as well as not returning values that are in-sync with what was given to setPosition(x, y).
This commit is contained in:
Luca Longinotti 2017-08-21 17:38:06 +02:00 committed by Lukas Dürrenberger
parent 93a2e9502d
commit 58b7c2c48a
1 changed files with 145 additions and 6 deletions
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151
src/SFML/Window/Unix/WindowImplX11.cpp
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@ -66,6 +66,8 @@ namespace
sf::Mutex allWindowsMutex;
sf::String windowManagerName;
sf::String wmAbsPosGood[] = { "Enlightenment", "FVWM", "i3" };
static const unsigned long eventMask = FocusChangeMask | ButtonPressMask |
ButtonReleaseMask | ButtonMotionMask |
PointerMotionMask | KeyPressMask |
@ -260,6 +262,90 @@ namespace
return true;
}
// Get the parent window.
::Window getParentWindow(::Display* disp, ::Window win)
{
::Window root, parent;
::Window* children = NULL;
unsigned int numChildren;
XQueryTree(disp, win, &root, &parent, &children, &numChildren);
// Children information is not used, so must be freed.
if (children != NULL)
XFree(children);
return parent;
}
// Get the Frame Extents from EWMH WMs that support it.
bool getEWMHFrameExtents(::Display* disp, ::Window win,
long& xFrameExtent, long& yFrameExtent)
{
if (!ewmhSupported())
return false;
Atom frameExtents = sf::priv::getAtom("_NET_FRAME_EXTENTS", true);
if (frameExtents == None)
return false;
bool gotFrameExtents = false;
Atom actualType;
int actualFormat;
unsigned long numItems;
unsigned long numBytesLeft;
unsigned char* data = NULL;
int result = XGetWindowProperty(disp,
win,
frameExtents,
0,
4,
False,
XA_CARDINAL,
&actualType,
&actualFormat,
&numItems,
&numBytesLeft,
&data);
if ((result == Success) && (actualType == XA_CARDINAL) &&
(actualFormat == 32) && (numItems == 4) && (numBytesLeft == 0) &&
(data != NULL))
{
gotFrameExtents = true;
long* extents = (long*) data;
xFrameExtent = extents[0]; // Left.
yFrameExtent = extents[2]; // Top.
}
// Always free data.
if (data != NULL)
XFree(data);
return gotFrameExtents;
}
// Check if the current WM is in the list of good WMs that provide
// a correct absolute position for the window when queried.
bool isWMAbsolutePositionGood()
{
// This can only work with EWMH, to get the name.
if (!ewmhSupported())
return false;
for (size_t i = 0; i < (sizeof(wmAbsPosGood) / sizeof(wmAbsPosGood[0])); i++)
{
if (wmAbsPosGood[i] == windowManagerName)
return true;
}
return false;
}
sf::Keyboard::Key keysymToSF(KeySym symbol)
{
switch (symbol)
@ -676,14 +762,67 @@ void WindowImplX11::processEvents()
////////////////////////////////////////////////////////////
Vector2i WindowImplX11::getPosition() const
{
::Window root, child;
int localX, localY, x, y;
unsigned int width, height, border, depth;
// Get absolute position of our window relative to root window. This
// takes into account all information that X11 has, including X11
// border widths and any decorations. It corresponds to where the
// window actually is, but not necessarily to where we told it to
// go using setPosition() and XMoveWindow(). To have the two match
// as expected, we may have to subtract decorations and borders.
::Window child;
int xAbsRelToRoot, yAbsRelToRoot;
XGetGeometry(m_display, m_window, &root, &localX, &localY, &width, &height, &border, &depth);
XTranslateCoordinates(m_display, m_window, root, localX, localY, &x, &y, &child);
XTranslateCoordinates(m_display, m_window, DefaultRootWindow(m_display),
0, 0, &xAbsRelToRoot, &yAbsRelToRoot, &child);
return Vector2i(x, y);
// CASE 1: some rare WMs actually put the window exactly where we tell
// it to, even with decorations and such, which get shifted back.
// In these rare cases, we can use the absolute value directly.
if (isWMAbsolutePositionGood())
return Vector2i(xAbsRelToRoot, yAbsRelToRoot);
// CASE 2: most modern WMs support EWMH and can define _NET_FRAME_EXTENTS
// with the exact frame size to subtract, so if present, we prefer it and
// query it first. According to spec, this already includes any borders.
long xFrameExtent, yFrameExtent;
if (getEWMHFrameExtents(m_display, m_window, xFrameExtent, yFrameExtent))
{
// Get final X/Y coordinates: subtract EWMH frame extents from
// absolute window position.
return Vector2i((xAbsRelToRoot - xFrameExtent), (yAbsRelToRoot - yFrameExtent));
}
// CASE 3: EWMH frame extents were not available, use geometry.
// We climb back up to the window before the root and use its
// geometry information to extract X/Y position. This because
// re-parenting WMs may re-parent the window multiple times, so
// we'd have to climb up to the furthest ancestor and sum the
// relative differences and borders anyway; and doing that to
// subtract those values from the absolute coordinates of the
// window is equivalent to going up the tree and asking the
// furthest ancestor what it's relative distance to the root is.
// So we use that approach because it's simpler.
// This approach assumes that any window between the root and
// our window is part of decorations/borders in some way. This
// seems to hold true for most reasonable WM implementations.
::Window ancestor = m_window;
::Window root = DefaultRootWindow(m_display);
while (getParentWindow(m_display, ancestor) != root)
{
// Next window up (parent window).
ancestor = getParentWindow(m_display, ancestor);
}
// Get final X/Y coordinates: take the relative position to
// the root of the furthest ancestor window.
int xRelToRoot, yRelToRoot;
unsigned int width, height, borderWidth, depth;
XGetGeometry(m_display, ancestor, &root, &xRelToRoot, &yRelToRoot,
&width, &height, &borderWidth, &depth);
return Vector2i(xRelToRoot, yRelToRoot);
}