Commit Graph

1120 Commits

Author SHA1 Message Date
Chun-wei Fan
ebadaaa3e0 GDK-Win32: Fix AeroSnap on HiDPI
Commit 1d0fad3 revealed that there were some assumptions made that were
actually to compensate for the bug fixed by that commit, so we need to
remove those assumptions as they would result in AerSnap to not work
properly on HiDPI screens.

Also re-do how we set the x and y positions of our GdkWindow, so that we
are more consistent across the board when we go between a GDK window
coordinate and a Windows API window cooredinate.

This would also simplify the code a bit.

https://bugzilla.gnome.org/show_bug.cgi?id=785999
2017-08-18 13:26:58 +08:00
Руслан Ижбулатов
f9df0fc94c GDK W32: Handle drivers that do not send WT_CSRCHANGE after WT_PROXIMITY
Some drivers don't do that (not sure whether that is the correct behaviour
or not). Remember each WT_PROXIMITY with LOWORD(lParam) != 0 that we get,
then look for a WT_CSRCHANGE. If WT_CSRCHANGE doesn't come, but a WT_PACKET
does, assume that this device is the one that sent WT_PROXIMITY.

Also include fallback code to ensure that WT_PACKETs for an enabled device
disable the system pointer, because WT_PROXIMITY handler might have
enabled it by mistake, since it's not possible to know which device left
the proximity (it might have been a disabled device).

https://bugzilla.gnome.org/show_bug.cgi?id=778328
2017-02-19 07:12:13 +00:00
Руслан Ижбулатов
1d0fad3d70 GDK W32: Apply HiDPI scale properly to monitors
Previously HiDPI scale was retrieved and applied too late in the initialization
process to affect monitor size and monitor workarea size, but the code that
initializes these sizes *did* try to use the scale, even though it was always
getting scale=1.

To fix this, move the too-late code into monitor enumeration routine.
This also fixes a probable semantic bug where width and height were divided
by scale, again.

Now monitor and workarea should be in application pixels (i.e. divided by scale),
as intended.

https://bugzilla.gnome.org/show_bug.cgi?id=778835
2017-02-19 07:00:17 +00:00
Руслан Ижбулатов
dca4f1e715 GDK W32: Different maximized window position for non-CSD windows
It seems that WM interprets the same MINMAXINFO contents differently
depending on which styles the window has. Play along.

https://bugzilla.gnome.org/show_bug.cgi?id=765161
2017-02-10 18:21:13 +00:00
Руслан Ижбулатов
4a5cd127ff GDK W32: Ensure that we use made-up monitors when there are none
Previously GDK only made up monitors when it initially found none. Now it
also makes up monitors when it initially finds some, but later fails to get
their informatin in a normal way and finally prunes them out, being left with
zero monitors.

Having zero-length monitor array is unexpected and causes a number
of critical warnings and some critical functionality (such as displaying
drop-down menus) fails in such cases.

Ideally, there might be such a way to interrogate W32 API that produces the
information about non-real (but active) monitors out of it so that it isn't
necessary for us to make stuff up. However, this code is already complicated,
and i am not prepared to dig W32 API to find a way to do this.

This fixes the issues people had when they accessed a Windows desktop via RDP.

https://bugzilla.gnome.org/show_bug.cgi?id=777527
2017-01-20 12:45:57 +00:00
Руслан Ижбулатов
a7ff95ce73 GDK W32: Fix idiotic gdk_win32_display_get_monitor() implementation
Replace the code borrowed from the X11 backend with the code borrowed from Wayland backend. Now GTK doesn't crash when the number of monitors is zero.
2017-01-20 09:08:41 +00:00
Руслан Ижбулатов
eece8a7dd2 GDK W32: Use keyboard hook to detect AeroSnap combinations better
Windows WM handles AeroSnap for normal windows on keydown. We did this
on keyup only because we do not get a keydown message, even if Windows WM
does nothing with a combination. However, in some specific cases it DOES
do something - and we have no way to detect that. Specifically, winkey+downarrow
causes maximized window to be restored by WM, and GDK fails to detect that. Then
GDK gets a keyup message, figures that winkey+downarrow was pressed and released,
and handles the combination - by minimizing the window.

To overcome this, install a low-level keyboard hook (high-level ones have
the same problem as normal message loop - they don't get messages when
Windows WM handles combinations) and use it to detect interesting key combinations
before Windows WM has a chance to block them from being processed.

Once an interesting combination is detected, post a message to the window, which
will be handled in due order.

It should be noted that this code handles key repetitions in a very crude manner.

The downside is that AeroSnap will not work if hook installation function call fails.
Also, this is a global hook, and if the hook procedure does something wrong, bad things
can happen.

https://bugzilla.gnome.org/show_bug.cgi?id=776031
2017-01-10 12:54:43 +00:00
Руслан Ижбулатов
ca79296061 GDK W32: Handle CapsLock as part of the key shift level
Instead of using some kind of flawed logic about modifying a keypress result
when CapsLock is toggled, just add a CapsLock shift level (and all derived
shift levels, i.e. Shift+CapsLock and CapsLock+AltGr and Shift+CapsLock+AltGr)
and query Windows keyboard layout API about the result of keypresses involving
CapsLock.

Keysym table is going to be (roughly) twice as large now, but CapsLock'ed
keypresses will give correct results for some keyboard layouts (such as
Czech keyboard layout, which without this change produces lowercase letters
for CapsLock->[0,2,3,4...] instead of uppercase ones).

Keymap update time also increases accordingly.

https://bugzilla.gnome.org/show_bug.cgi?id=165385
2017-01-10 07:59:53 +00:00
Руслан Ижбулатов
125ef3539c GDK W32: Special handling for VK_PAUSE
Similar to VK_DIVIDE, this key can't be mapped to a scancode by
MapVirtualKeyEx(). Googling suggests that this is a known bug.

https://bugzilla.gnome.org/show_bug.cgi?id=769214
2017-01-09 15:15:52 +00:00
Руслан Ижбулатов
3326fba524 GDK W32: Change WM_SYSMENU style switch logic
Instead of checking for window state and giving it extra styles that
fit, just give it all styles that it is missing. It turned out that
otherwise it is impossible to, for example, restore a maximized window
via sysmenu. Also, be more flexible towards GDK/WM window state mismatches
and consider the window minimized/maximized if *either* GDK or WM thinks so.

https://bugzilla.gnome.org/show_bug.cgi?id=776485
2017-01-09 14:17:32 +00:00
Руслан Ижбулатов
51645b5851 GDK W32: Remove unneeded assertion
Just set check_for_dpi_awareness = TRUE and eventually it will be handled
correctly, even if setDpiAwareFunc() returns E_ACCESSDENIED or shcore functions
are NULL.

https://bugzilla.gnome.org/show_bug.cgi?id=777031
2017-01-09 10:00:22 +00:00
Руслан Ижбулатов
a1aee4602c GDK W32: Handle maximizing correctly for small primary monitors
When primary monitor is smaller than the actual monitor on which the
window is being maximized, the WM will do widnow size adjustments
that will completely screw the window size if we try to make it
smaller than 100% fullscreen (to account for taskbar size, for example).

Fix this by overriding maximized window size during WM_WINDOWPOSCHANGING.

https://bugzilla.gnome.org/show_bug.cgi?id=775808
2016-12-24 17:29:50 +00:00
Andrew Chadwick
0b129f3534 win32 event: check for NULL display or dev mgr
The recent Wintab testing revealed an interesting edge case: we cannot
for certain say that windowing system messages will not be received
while the default display and its device manager are still being set up.
We've ruled out the Wintab case now, but cannot rule out some future bit
of runtime DLL code doing stuff at this critical time.

This commit detects and avoids a potential null pointer dereference in
the message handling code while detecting grabs. Grabs don't really
exist yet, if the default display and/or its device manager are not yet
globally known.

https://bugzilla.gnome.org/show_bug.cgi?id=774379
2016-11-28 15:05:13 +00:00
Andrew Chadwick
66a08bf3a6 wintab: init only after the display is assigned
Only attempt to initialize Wintab after the display manager announces
that the first default display has been set. Fixes a segfault during
initialization of specific tablet drivers' wintab32.dlls. Add assertions
and verbose comments explaining this nonsense because this stuff is a
pain to have to keep fixing.

https://bugzilla.gnome.org/show_bug.cgi?id=774379
2016-11-22 12:52:00 +01:00
Andrew Chadwick
dd6a00bb31 wintab tilt: Check return location for validity
https://bugzilla.gnome.org/show_bug.cgi?id=774265
2016-11-22 12:17:32 +01:00
Andrew Chadwick
61a57465ea win32: Fix tilt from Wintab devices
Move the orientation sanity-checks into the packet decode func.
Rationale: the packet handling func may otherwise read beyond the end of
device->last_axis_data.

Also expand them to cope with my test Huion's weird reporting.

Also correct the azimuth angle to align with GDK's presentation.

Most importantly, fix annoying comment typo.

https://bugzilla.gnome.org/show_bug.cgi?id=774265
2016-11-22 11:22:16 +01:00
Andrew Chadwick
f40191ff19 wintab: fix skipping of odd-numbered devices
Fix a regression introduced in 4ce6d10601
which causes devices with an odd-numbered zero-based index in the list
to be passed over incorrectly. This might present as yet another "device
does not send pressure" bug for ~50% of devices out there.

This commit also closes off another potential segfault for wintab_devices
lists which have an odd length.

https://bugzilla.gnome.org/show_bug.cgi?id=774699
2016-11-21 19:12:41 +01:00
Chun-wei Fan
d3bdd384a1 gdkscreen-win32.c: Also define _WIN32_WINNT
As in the last commit on gdkdisplay-win32.c, we need to define that to be
0x0600 (Vista) or later so that the items needed in the Windows headers be
activated.

See: https://bugzilla.gnome.org/show_bug.cgi?id=768081#c62
2016-11-11 21:03:46 +08:00
Chun-wei Fan
27b68ff193 gdkdisplay-win32.c: Define _WIN32_WINNT
... to be for Vista (0x0600) or later.  This is so that the necessary
items in the Windows headers be activated so that the code will build
properly on mingw-w64, and we already require Vista or later for GTK+.

Thanks Ting-Wei Lan for pointing this out.

See: https://bugzilla.gnome.org/show_bug.cgi?id=768081#c62
2016-11-11 20:53:41 +08:00
Chun-wei Fan
4add92a431 GDK-Win32: Enable HiDPI support for Windows
This enables HiDPI support for GTK+ on Windows, so that the
fonts and window look better on HiDPI displays.  Notes for the current
work:

-The DPI awareness enabling can be disabled if and only if an application
 manifest is not embedded in the app to enable DPI awareness AND a user
 compatibility setting is not set to limit DPI awareness for the app, via
 the envvar GDK_WIN32_DISABLE_HIDPI.  The app manifest/user setting for
 DPI awareness will always win against the envvar, and so the HiDPI items
 will be always setup in such scenarios, unless DPI awareness is disabled.

-Both automatic detection for the scaling factor and setting the scale
 factor using the GDK_SCALE envvar are supported, where the envvar takes
 precedence, which will therefore disable automatic scaling when
 resolution changes.

-I am unable to test the wintab items because I don't have such devices
 around.

https://bugzilla.gnome.org/show_bug.cgi?id=768081
2016-11-07 15:38:02 +08:00
Chun-wei Fan
b67a1c7f39 GDK-Win32: Improve GL on Windows
Update the GDKGL implementation:

-Allow legacy contexts to be created.
-Use finer-grained attributes to ask for a pixel format when possible,
 which also adds support for anti-aliasing

In fact the changes here are required for GTKGL to work properly on
Windows for 4.x.

Note that creation of gles contexts are not done here, as the system does
not support such contexts directly on Windows, but only through means such
as ANGLE, which is a totally different issue here.

https://bugzilla.gnome.org/show_bug.cgi?id=773528
2016-10-28 16:07:02 +08:00
Jeremy Tan
b6ac1b4bbf GDK W32: Ignore autorepeated key presses on modifier keys
The X11 backend does not send autorepeated messages for modifier keys,
and doing so prevents motion compression from working.

https://bugzilla.gnome.org/show_bug.cgi?id=771568
2016-09-19 12:36:53 +00:00
Jeremy Tan
a5c8fedf47 GDK W32: Always process all available messages
The GLib main loop blocks on MsgWaitForMultipleObjectsEx to
determine if there are any incoming messages while also allowing
for background tasks to run. If all available messages are not
processed after MsgWaitForMultipleObjectsEx has signaled that
there are available, CPU usage will skyrocket.

From my limited understanding (by inspection of profiling
under Visual Studio):
Key is pressed - MsgWaitForMultipleObjectsEx unblocks, and
sends message to GDK's event handler. Some event is now queued.

g_poll unblocks, calls the g_event_dispatch which finally
resolves to gdk_event_dispatch. This then calls
_gdk_win32_display_queue_events, but since a message is already
queued, it fails to call PeekMessage and returns immediately.

At the next iteration, g_poll again calls MsgWaitForMultipleObjectsEx
which queues yet another event and returns almost immediately, since
there are events available which haven't been processed by PeekMessage.

The dispatch function is then called and the process repeats.

https://bugzilla.gnome.org/show_bug.cgi?id=771568
2016-09-19 12:36:51 +00:00
Руслан Ижбулатов
0274b2c94e GDK W32: Set is_modifier field in GdkKeyEvent
This hardcodes Control, Alt and Shift as modifier keys.

https://bugzilla.gnome.org/show_bug.cgi?id=602773
2016-09-17 20:24:18 +00:00
Руслан Ижбулатов
b05ed13710 GDK W32: Remove obsolete assertions 2016-08-26 20:46:27 +00:00
Руслан Ижбулатов
09004b51a9 Update GTK+ Windows icon (now scles up to 256x256)
Also add the SVG file that was used to produce it (derived
from the old raster logo).

https://bugzilla.gnome.org/show_bug.cgi?id=768081
2016-08-19 23:55:19 -04:00
Руслан Ижбулатов
5e6c1928b4 W32: Prefer the deadkey combinations that the OS uses
Pick the W32 API for possible deadkey+<something> combinations
and prefer these to other sources of deadkey combos.
Specifically, if W32 API supports at least one combo for a particular
deadkey, only use that data and do not attempt to do other, unsupported
combinations, even if they make sense otherwise.
This is needed to, for example, correctly support US-International
keyboard layout, which produces a combined character for <' + a>
combo, but not for <' + s>, for example.

This is achieved by stashing all the deadkeys that we find in
an array, then doing extra loop through all virtual key codes and
trying to combine them with each of these deadkeys. Any combinations
that produce a single character are cached for later use.

In GTK Simple IM context, call a new GDK W32 function to do a lookup
on that cached combination table early on, among the "special cases"
(which are now partially obsolete).

A limitation of this code is that combinations with more than
one deadkey are not supported, except for combinations that consist
entirely of 2 known deadkeys. The upshot is that lookups should
be relatively fast, as deadkey array stays small and the combination
tree stays shallow.

Note that the use of ToUnicodeEx() seems suboptimal, as it should
be possible to just load a keyboard library (KBD*.DLL) manually
and obtain and use its key table directly. However, that is much more
complicated and would result in a significant rewrite of gdkkeys-win32.
The code from this commit, though hacky, is a direct addition to
existing code and should cover vast majority of the use-cases.

https://bugzilla.gnome.org/show_bug.cgi?id=569581
2016-08-04 16:37:19 +00:00
Руслан Ижбулатов
52c7e07948 GDK W32: Cache multiple keyboard layouts simultaneously
This changes the group/level semantic.
Previously W32 backend used "group 0/1" to denote "AltGr OFF/ON"
and "level 0/1" to denote "Shift is OFF/ON".
Now "group" means "keyboard layout" and there can be up to 255 groups,
while AltGr and Shift are combined into a single level enum that
takes values between 0 and 4.
Unlike X, W32 doesn't do effective group overriding, meaning that
it will never tell the caller that a different group was actually
used (even for universal keys, such as Enter), because key symbol
table is completely fabricated and there's no point in trying to
save a few of kilobytes of RAM by not duplicating universal key
records for all groups.

Also contains many whitespace changes (tab elimination, fixed
indentation) and cleanup (axed a few global variables, these are
now accessed via the default keymap).

https://bugzilla.gnome.org/show_bug.cgi?id=768722
2016-08-04 16:37:18 +00:00
Руслан Ижбулатов
2233566f48 GDK W32: Support UTF-16 surrogate pairs passed via VK_PACKET
This is, essentially, a piece of g_utf16_to_ucs4() built into GDK
W32 keyboard message processing.

https://bugzilla.gnome.org/show_bug.cgi?id=769126
2016-07-28 15:55:11 +00:00
Matthias Clasen
82fd72a477 Opt in to structured logging
Define G_LOG_USE_STRUCTURED, so that all our g_debug, g_warning,
etc calls directly use structured logging and provide source information.
2016-07-22 23:13:20 -04:00
Руслан Ижбулатов
bd86715ed3 GDK W32: Fix dragging AeroSnap application
The original patch for commit b420c53773
was applied incorrectly, doing the actual snapping in the wrong place.
Move the code.
2016-06-05 09:00:40 +00:00
Matthias Clasen
0f476590fb Make gdk_event_get_pointer_emulated public
There is not strong reason to keep the getter private.
At the same time, strip _-prefixes from a few other GdkEvent
APIs. Update all callers.
2016-05-10 15:16:45 -04:00
Chun-wei Fan
e24530d03b gdk/win32/gdkmonitor-win32.c: Fix build on non-GCC
WINBOOL is MinGW-specific, so change it to BOOL, which is universally
available.

Also, Visua Studio is more picky on where __stdcall (WINAPI) is placed, so
fix that to be in-sync with what is done in the other sources.
2016-05-09 13:14:01 +08:00
Руслан Ижбулатов
026cb53875 win32: Port to new monitor api 2016-04-27 23:18:16 -04:00
Jonas Ådahl
1a4f000f3b gdk/dnd: Don't use default display when getting cursor
Always associate a drag context with a GdkDisplay and use that when
getting a cursor for a given action.

If we don't do this, dragging on a window that doesn't use the default
display will make us use cursors from the wrong display.

https://bugzilla.gnome.org/show_bug.cgi?id=765565
2016-04-26 23:03:24 +08:00
Frediano Ziglio
cf14fea5a8 Save scancode inside GdkEventPrivate
Windows save in hardware_keycode an information which is not so low
level and some application require the hardware scancode.
As Windows provides this information save it in GdkEventPrivate
and provide a function to get this information.
For no Windows system the function return the hardware_keycode instead.

Signed-off-by: Frediano Ziglio <fziglio@redhat.com>

https://bugzilla.gnome.org/show_bug.cgi?id=765259
2016-04-21 22:35:47 -04:00
Jeremy Tan
8ebb6969cb GDK W32: Fix positioning of reparented window
MoveWindow should not be used over the pre-existing move/resize
functions, which already correctly position a window with respect
to its parent, while also taking into account the size of window
decorations.

https://bugzilla.gnome.org/show_bug.cgi?id=765100
2016-04-15 13:21:11 +00:00
Jeremy Tan
260d521dd7 GDK W32: Fix bounding rect calculation on window creation The bounding rect specifies the top left and bottom right corners - the bottom right corner must account for the current window position.
https://bugzilla.gnome.org/show_bug.cgi?id=764996
2016-04-13 14:15:36 +00:00
Руслан Ижбулатов
c2aa7d0749 GDK W32: Deduplicate reparenting
gdk_window_reparent() already changes children list for old and new parent.
Doing so twice results in a circular reference in the list, which can hang
the application later, for example in gtk_window_show().

https://bugzilla.gnome.org/show_bug.cgi?id=764845
2016-04-12 12:56:11 +00:00
Ignacio Casal Quinteiro
a3bff7d41e win32: rollback change and use _gdk_display
This makes usage of _gdk_display again when creating a window.
This is needed because there is a window created when the display
is being initialized, so it becomes a chicken and egg problem.
For now we roll back this to fix the wintab crash but we might
want to fix this again in the future by improving the wintab
initialization.

https://bugzilla.gnome.org/show_bug.cgi?id=764664
2016-04-11 22:25:41 +02:00
Ignacio Casal Quinteiro
c9add3161f win32: add missing empty lines 2016-04-11 22:25:41 +02:00
Руслан Ижбулатов
adff59843b GDK W32: Don't move windows into top-left corner on style change
This fixes a bug that was introduced by db1b24233e.
The reason why 0:0 coordinates were passed was that SWP_NOREPOSITION was
misinterpreted as SWP_NOMOVE. That is not the case - SWP_NOREPOSITION
prevents owner Z-order change, not the window position change.
2016-04-06 10:22:15 +00:00
Руслан Ижбулатов
bde5281ae8 GDK W32: Use a dumb window class for decorative windows
Currently only one kind of decorative window is in use - the shape
indicator that is shown when snapping windows to the edge of the screen.

When normal toplevel class is used, its window procedure expects certain
motions from GDK (passing user data to CreateWindowEx(), registering
handle in a hash map etc), and might crash if that is not done.

Dumb window doesn't require anything, it can just be.

https://bugzilla.gnome.org/show_bug.cgi?id=763013
2016-03-30 09:04:46 +00:00
Руслан Ижбулатов
cfbb8c5252 GDK W32: Add/subtract shadow when (un)snapping
Now halfleft/halfright/fullup snaps do hug screen edges as intended.

Documents AeroSnap behaviour when snapped windows are drag-resized
(currently this implementation handles this in a very simplistic way).

Don't believe GTK when it tells us that window shadow is 0, preserve
previous values (but do remember that GTK wants no shadow, in case
we need that).

Fixes a couple of bugs in unsnapping (check offset against the half
of the window; don't put pointer in the middle of the window vertically
if it still fits in the top half).

https://bugzilla.gnome.org/show_bug.cgi?id=763013
2016-03-30 09:04:37 +00:00
Руслан Ижбулатов
f853283d7b GDK W32: Add/subtract shadow when drag-resizing
Implements gdk_win32_window_set_shadow_width().
Uses shadow width/height to adjust max tracking size, allowing
windows to be drag-resized to cover the whole desktop.

Also uses SM_C*VIRTUALSCREEN instead of SM_C*MAXTRACK.

https://bugzilla.gnome.org/show_bug.cgi?id=763013
2016-03-30 09:03:56 +00:00
Руслан Ижбулатов
b0131616b2 GDK W32: Draw snap indicators for AeroSnap
Indicator is a bare layered click-through native window,
painted completely by GDK, including animation.

This commit also isolates some of the more spam-ish debug logging
under ifdef.

This commit also changes the system metric used for maximal window
height for the snapping purposes. Turns out, SM_CYMAXTRACK is way
too large, use SM_CYVIRTUALSCREEN instead.

https://bugzilla.gnome.org/show_bug.cgi?id=763013
2016-03-30 09:03:41 +00:00
Руслан Ижбулатов
b420c53773 GDK W32: Add drag-to-snap feature to AeroSnap
This implements the part of AeroSnap that snaps windows when you
drag them (while moving or resizing) to the edge of the screen.

It also fixes drag behaviour for snapped and maximized windows
(if such windows are dragged, first they must be unmaximized/unsnapped).

Note that this code does not take into account the shadow width, and
because of that the under-pointer-position-preserving window moves
might not look as such for maximized windows, which lack the shadow
when maximized, but do have the shadow when unmaximized.

This commit also doesn't cover some corner-cases the same way AeroSnap does.

Also, the snapping indicator (which is supposed to be a window shape that
shows where the window will be if the drag op is stopped at its current
point) is not being drawn, all routines responsible for its creation,
moving and drawing are stubs.

https://bugzilla.gnome.org/show_bug.cgi?id=763013
2016-03-30 09:00:07 +00:00
Руслан Ижбулатов
2ea96cf946 GDK W32: Improve AeroSnap - don't resize windows that fit
This is what AeroSnap does. If a window is being unsnapped on
a new monitor, check if the work area is large enough for the
window to fit in its normal size. If the window fits, just
reposition it so that the ratio of
left-window-edge-to-screen-edge / right-window-edge-to-screen-edge
remains the same, without scaling the window.

https://bugzilla.gnome.org/show_bug.cgi?id=763013
2016-03-30 09:00:02 +00:00
Руслан Ижбулатов
0ce217cf94 GDK W32: Re-implement AeroSnap for CSD windows
It works exactly like AeroSnap.
Except for shift+win+left/right, which is left for AeroSnap
to handle (AeroSnap takes action before we get the message,
so there's no way for us to override it).
The only thing that doesn't work is shift+win+left/right on
a maximized window, for reasons unknown at the moment.

This only implements winkey+stuff behaviour of AeroSnap,
not the drag-to-the-edge-and-something-funny-happens one.

https://bugzilla.gnome.org/show_bug.cgi?id=763013
2016-03-30 08:59:56 +00:00
Руслан Ижбулатов
77eebbda5c GDK W32: Erase hidden layered windows before showing them
If a layered window was hidden and is made visible, erase its
contents before showing it. GDK will schedule a redraw, but until
then we generally don't want to show old contents.

https://bugzilla.gnome.org/show_bug.cgi?id=763783
2016-03-29 14:30:19 +00:00