author Ryan C. Gordon
Mon, 21 Aug 2017 00:42:06 -0400
changeset 11334 749cb40916f2
parent 7635 c57071e3d636
permissions -rw-r--r--
x11: specify event mask for buttons when grabbing pointer (thanks, Stas!).

This fixes a strange corner case (notes appended below), and should be
safe to do anyhow.

Fixes Bugzilla #3674.

"I did more tests.
It appears the bug only happens if there is
another window on the screen that has "always
on top" property. For me it is xawtv - it is
always opened in a screen corner. Closing
xawtv or removing "always on top" property
from it makes the problem to go away.
Plus, it doesn't appear like the buttons are
not delivered at all. It appears that instead
the button presses are delivered on some mouse
positions, but not delivered when you move the
mouse to other part of the window... So this is
really weird and is likely somewhere deep in the
Maybe somehow it happens that the cursor is
actually above the xawtv window, but, because
my app uses grab, it is not visible there, and
in that case the events are not delivered to
my app?
But with my patch the button events are
always delivered flawlessly, it seems.

Hmm, and that indeed seems to explain my problem:
if the mask is set properly and my app uses
grab, then, even if the mouse is above some
other window, the events would still be delivered
to the grabbing app, which is what actually wanted
because my app uses relative mouse mode, so it
doesn't know the pointer can cross some other window
(my app draws the pointer itself).
So my current theory is that my patch only enforces
the mouse grab, which otherwise can be tricked by
some other window preventing the button events
delivery (but motion events are still delivered
via xinput2, which makes it all look very obscure)."
     2 Simple DirectMedia Layer CREDITS
     3 Thanks to everyone who made this possible, including:
     5 * Cliff Matthews, for giving me a reason to start this project. :)
     6  -- Executor rocks!  *grin*
     8 * Ryan Gordon for helping everybody out and keeping the dream alive. :)
    10 * Gabriel Jacobo for his work on the Android port and generally helping out all around.
    12 * Philipp Wiesemann for his attention to detail reviewing the entire SDL code base and proposes patches.
    14 * Andreas Schiffler for his dedication to unit tests, Visual Studio projects, and managing the Google Summer of Code.
    16 * Mike Sartain for incorporating SDL into Team Fortress 2 and cheering me on at Valve.
    18 * Alfred Reynolds for the game controller API and general (in)sanity
    20 * Jørgen Tjernø for numerous magical Mac OS X fixes.
    22 * Pierre-Loup Griffais for his deep knowledge of OpenGL drivers.
    24 * Julian Winter for the SDL 2.0 website.
    26 * Sheena Smith for many months of great work on the SDL wiki creating the API documentation and style guides.
    28 * Paul Hunkin for his port of SDL to Android during the Google Summer of Code 2010.
    30 * Eli Gottlieb for his work on shaped windows during the Google Summer of Code 2010.
    32 * Jim Grandpre for his work on multi-touch and gesture recognition during
    33   the Google Summer of Code 2010.
    35 * Edgar "bobbens" Simo for his force feedback API development during the
    36   Google Summer of Code 2008.
    38 * Aaron Wishnick for his work on audio resampling and pitch shifting during
    39   the Google Summer of Code 2008.
    41 * Holmes Futrell for his port of SDL to the iPhone and iPod Touch during the
    42   Google Summer of Code 2008.
    44 * Jon Atkins for SDL_image, SDL_mixer and SDL_net documentation.
    46 * Everybody at Loki Software, Inc. for their great contributions!
    48  And a big hand to everyone else who has contributed over the years.
    50 THANKS! :)
    52   -- Sam Lantinga			<>