Fix:core: cancel drawing on resize request (#1142)

* Fix:core: cancel drawing on resize request

This commit causes navit to cancel async drawing in case of resize
request. Drawing is started again after that. this should effectively
cause a redraw on subsequent calls to resize. Some graphics like qt5
call resize for both dimension changes if the wigdet get's resized.

* Fix:graphics:qt5 Clear pixmap on resize

To remove ugly artefacts after resizing the widget until navit completes
to redraw the screen the widgets pixmap is cleared.

2 files changed, 2 insertions, 12 deletions

diff --git a/navit/graphics/qt5/QNavitQuick.cpp b/navit/graphics/qt5/QNavitQuick.cpp
index dcd0d2aa5..966072852 100644
--- a/navit/graphics/qt5/QNavitQuick.cpp
+++ b/navit/graphics/qt5/QNavitQuick.cpp
@@ -181,12 +181,7 @@ void QNavitQuick::geometryChanged(const QRectF& newGeometry, const QRectF& oldGe
     if (graphics_priv->pixmap == NULL) {
         graphics_priv->pixmap = new QPixmap(width(), height());
     }
-    painter = new QPainter(graphics_priv->pixmap);
-    if (painter != NULL) {
-        QBrush brush;
-        painter->fillRect(0, 0, width(), height(), brush);
-        delete painter;
-    }
+    graphics_priv->pixmap->fill(Qt::transparent);
     dbg(lvl_debug, "size %fx%f", width(), height());
     dbg(lvl_debug, "pixmap %p %dx%d", graphics_priv->pixmap, graphics_priv->pixmap->width(),
         graphics_priv->pixmap->height());
diff --git a/navit/graphics/qt5/QNavitWidget.cpp b/navit/graphics/qt5/QNavitWidget.cpp
index 869d5f2ec..43c04d87f 100644
--- a/navit/graphics/qt5/QNavitWidget.cpp
+++ b/navit/graphics/qt5/QNavitWidget.cpp
@@ -105,12 +105,7 @@ void QNavitWidget::resizeEvent(QResizeEvent* event) {
     if (graphics_priv->pixmap == NULL) {
         graphics_priv->pixmap = new QPixmap(size());
     }
-    painter = new QPainter(graphics_priv->pixmap);
-    if (painter != NULL) {
-        QBrush brush;
-        painter->fillRect(0, 0, width(), height(), brush);
-        delete painter;
-    }
+    graphics_priv->pixmap->fill(Qt::transparent);
     dbg(lvl_debug, "size %dx%d", width(), height());
     dbg(lvl_debug, "pixmap %p %dx%d", graphics_priv->pixmap, graphics_priv->pixmap->width(),
         graphics_priv->pixmap->height());