backing store

diff --git a/src/frontends/qt4/GuiWorkArea.cpp b/src/frontends/qt4/GuiWorkArea.cpp
index 7955731ad36ed06432efa1a5df93e56f8ff81840..5c0ae40e2233c8281c4c626d39f9bb9d29823c4c 100644 (file)
--- a/src/frontends/qt4/GuiWorkArea.cpp
+++ b/src/frontends/qt4/GuiWorkArea.cpp
@@ -235,13 +235,27 @@ SyntheticMouseEvent::SyntheticMouseEvent()
 
 
 GuiWorkArea::Private::Private(GuiWorkArea * parent)
-: p(parent), buffer_view_(0), lyx_view_(0),
-  caret_(0), caret_visible_(false),
-  need_resize_(false), preedit_lines_(1),
-  last_pixel_ratio_(1.0),
-  completer_(new GuiCompleter(p, p)), dialog_mode_(false), shell_escape_(false),
-  read_only_(false), clean_(true), externally_modified_(false)
-{
+: p(parent), buffer_view_(0), lyx_view_(0), caret_(0),
+  caret_visible_(false), need_resize_(false), preedit_lines_(1),
+  last_pixel_ratio_(1.0), completer_(new GuiCompleter(p, p)),
+  dialog_mode_(false), shell_escape_(false), read_only_(false),
+  clean_(true), externally_modified_(false)
+{
+/* Qt on macOS and Wayland does not respect the
+ * Qt::WA_OpaquePaintEvent attribute and resets the widget backing
+ * store at each update. Therefore, we use our own backing store in
+ * these two cases. */
+#if QT_VERSION >= 0x050000
+       use_backingstore_ = guiApp->platformName() == "cocoa"
+                           || guiApp->platformName() == "wayland";
+#else
+#  ifdef Q_OS_MAC
+       use_backingstore_ = true;
+#  else
+       use_backingstore_ = false;
+#  endif
+#endif
+
        int const time = QApplication::cursorFlashTime() / 2;
        if (time > 0) {
                caret_timeout_.setInterval(time);
@@ -1261,6 +1275,41 @@ void GuiWorkArea::Private::paintPreeditText(GuiPainter & pain)
 }
 
 
+void GuiWorkArea::Private::resetScreen()
+{
+       if (use_backingstore_) {
+               int const pr = p->pixelRatio();
+               screen_ = QImage(static_cast<int>(pr * p->viewport()->width()),
+                                static_cast<int>(pr * p->viewport()->height()),
+                                QImage::Format_ARGB32_Premultiplied);
+#  if QT_VERSION >= 0x050000
+               screen_.setDevicePixelRatio(pr);
+#  endif
+       }
+}
+
+
+QPaintDevice * GuiWorkArea::Private::screenDevice()
+{
+       if (use_backingstore_)
+               return &screen_;
+       else
+               return p->viewport();
+}
+
+
+void GuiWorkArea::Private::updateScreen(QRectF const & rc)
+{
+       if (use_backingstore_) {
+               QPainter qpain(p->viewport());
+               double const pr = p->pixelRatio();
+               QRectF const rcs = QRectF(rc.x() * pr, rc.y() * pr,
+                                         rc.width() * pr, rc.height() * pr);
+               qpain.drawImage(rc, screen_, rcs);
+       }
+}
+
+
 void GuiWorkArea::paintEvent(QPaintEvent * ev)
 {
        // Do not trigger the painting machinery if we are not ready (see

diff --git a/src/frontends/qt4/GuiWorkArea_Private.h b/src/frontends/qt4/GuiWorkArea_Private.h
index 83012fa99f10123329936de2a27f254a7387d87e..6342eaba4ac153fc7b1bf6201453ba39f5bd140b 100644 (file)
--- a/src/frontends/qt4/GuiWorkArea_Private.h
+++ b/src/frontends/qt4/GuiWorkArea_Private.h
@@ -20,14 +20,6 @@
 #include <QMouseEvent>
 #include <QTimer>
 
-#ifdef Q_OS_MAC
-/* Qt on macOS does not respect the Qt::WA_OpaquePaintEvent attribute
- * and resets the widget backing store at each update. Therefore, we
- * use our own backing store in this case */
-#define LYX_BACKINGSTORE 1
-#include <QPainter>
-#endif
-
 namespace lyx {
 
 class Buffer;
@@ -107,37 +99,12 @@ struct GuiWorkArea::Private
 
        void paintPreeditText(GuiPainter & pain);
 
-       void resetScreen() {
-#ifdef LYX_BACKINGSTORE
-               int const pr = p->pixelRatio();
-               screen_ = QImage(static_cast<int>(pr * p->viewport()->width()),
-                                static_cast<int>(pr * p->viewport()->height()),
-                                QImage::Format_ARGB32_Premultiplied);
-#  if QT_VERSION >= 0x050000
-               screen_.setDevicePixelRatio(pr);
-#  endif
-#endif
-       }
-
-       QPaintDevice * screenDevice() {
-#ifdef LYX_BACKINGSTORE
-               return &screen_;
-#else
-               return p->viewport();
-#endif
-       }
-
-#ifdef LYX_BACKINGSTORE
-       void updateScreen(QRectF const & rc) {
-               QPainter qpain(p->viewport());
-               double const pr = p->pixelRatio();
-               QRectF const rcs = QRectF(rc.x() * pr, rc.y() * pr,
-                                         rc.width() * pr, rc.height() * pr);
-               qpain.drawImage(rc, screen_, rcs);
-       }
-#else
-       void updateScreen(QRectF const & ) {}
-#endif
+       /// Prepare screen for next painting
+       void resetScreen();
+       /// Where painting takes place
+       QPaintDevice * screenDevice();
+       /// Put backingstore to screen if necessary
+       void updateScreen(QRectF const & rc);
 
        ///
        GuiWorkArea * p;
@@ -146,10 +113,11 @@ struct GuiWorkArea::Private
        ///
        GuiView * lyx_view_;
 
-#ifdef LYX_BACKINGSTORE
+       /// Do we need an intermediate image when painting (for now macOS and Wayland)
+       bool use_backingstore_;
        ///
        QImage screen_;
-#endif
+
        ///
        CaretWidget * caret_;
        /// is the caret currently displayed