From ca3f93e58a3cc3545b3d9fa5596eb7283ab3fc37 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Samuel=20R=C3=B8dal?= Date: Thu, 1 Mar 2012 18:06:29 +0100 Subject: [PATCH] Fixed Windows performance regression introduced by ac2818bef95f134. Only create a temporary DC if we're not on the main thread. Change-Id: Ia52cf7f44d8e55d537b0e520ee9d6b9633f4f3f3 --- src/gui/kernel/qwidget_win.cpp | 9 +++++++-- 1 files changed, 7 insertions(+), 2 deletions(-) diff --git a/src/gui/kernel/qwidget_win.cpp b/src/gui/kernel/qwidget_win.cpp index 1881a4a..49dbe9d 100644 --- a/src/gui/kernel/qwidget_win.cpp +++ b/src/gui/kernel/qwidget_win.cpp @@ -49,6 +49,7 @@ #include "qlayout.h" #include "qpainter.h" #include "qstack.h" +#include "qthread.h" #include "qt_windows.h" #include "qwidget.h" #include "qwidget_p.h" @@ -1636,6 +1637,8 @@ void QWidgetPrivate::scroll_sys(int dx, int dy, const QRect &r) } } +extern Q_GUI_EXPORT HDC qt_win_display_dc(); + int QWidget::metric(PaintDeviceMetric m) const { Q_D(const QWidget); @@ -1645,7 +1648,8 @@ int QWidget::metric(PaintDeviceMetric m) const } else if (m == PdmHeight) { val = data->crect.height(); } else { - HDC gdc = GetDC(0); + bool ownDC = QThread::currentThread() != qApp->thread(); + HDC gdc = ownDC ? GetDC(0) : qt_win_display_dc(); switch (m) { case PdmDpiX: case PdmPhysicalDpiX: @@ -1696,7 +1700,8 @@ int QWidget::metric(PaintDeviceMetric m) const val = 0; qWarning("QWidget::metric: Invalid metric command"); } - ReleaseDC(0, gdc); + if (ownDC) + ReleaseDC(0, gdc); } return val; } -- 1.7.1