path: root/src/plugins/platforms/windows/qwindowsintegration.cpp
diff options
authorRomain Pokrzywka <>2018-08-22 22:43:29 -0500
committerRomain Pokrzywka <>2018-09-14 15:41:28 +0000
commit5728a9d8a7f8b64099cf369d9d307a00b5fce29c (patch)
treea7d1580ae766d438846dd262a753e0b65e4263e5 /src/plugins/platforms/windows/qwindowsintegration.cpp
parenta62bab95d3adfcd6aab1f32d41750f0c1a5adfe3 (diff)
Windows QPA: Dispatch skipped touch/pen events if compression is off
If the hardware produces events faster than the app can consume between two updates, Windows automatically coalesces them into a single message with the latest touch/pen pointer state and coordinates, effectively compressing those events. But the pointer API also supports querying and retrieving the skipped individual touch and pen frames. There are cases where keeping all the events generated by the hardware is desired, especially for pen events where having the most sampled points available is critical to precisely rendering curves. Qt already defines application attributes to control event compression for general high frequency events and for tablet events in particular. Use them on Windows also to control whether to retrieve skipped frames. [ChangeLog][Windows] The application attributes AA_CompressTabletEvents and AA_CompressHighFrequencyEvents are now supported on Windows 8 and above for touch/pen input, with the same defaults as on X11 (compress touch events, don't compress tablet events) Task-number: QTBUG-44964 Task-number: QTBUG-60437 Change-Id: I1b11a043e2d71ee502895971fafb3a46306a89d8 Reviewed-by: Andre de la Rocha <> Reviewed-by: Friedemann Kleint <>
Diffstat (limited to 'src/plugins/platforms/windows/qwindowsintegration.cpp')
1 files changed, 3 insertions, 1 deletions
diff --git a/src/plugins/platforms/windows/qwindowsintegration.cpp b/src/plugins/platforms/windows/qwindowsintegration.cpp
index 0694435427..7d621126b9 100644
--- a/src/plugins/platforms/windows/qwindowsintegration.cpp
+++ b/src/plugins/platforms/windows/qwindowsintegration.cpp
@@ -236,7 +236,9 @@ QWindowsIntegrationPrivate::QWindowsIntegrationPrivate(const QStringList &paramL
m_options = parseOptions(paramList, &tabletAbsoluteRange, &dpiAwareness);
- if (!m_context.initPointer(m_options)) {
+ if (m_context.initPointer(m_options)) {
+ QCoreApplication::setAttribute(Qt::AA_CompressHighFrequencyEvents);
+ } else {
if (tabletAbsoluteRange >= 0)