Fix:graphics_qt5:Dont't clear overlays on move

This commit keeps the internal pixmap of an overlay intact if resize is
called for the overlay, but the actual size was not changed. This keeps
icons and so on intact as they are not repainted after resize.

1 files changed, 13 insertions, 6 deletions

diff --git a/navit/graphics/qt5/graphics_qt5.cpp b/navit/graphics/qt5/graphics_qt5.cpp
index c23a4f60f..c71b951a5 100644
--- a/navit/graphics/qt5/graphics_qt5.cpp
+++ b/navit/graphics/qt5/graphics_qt5.cpp
@@ -304,7 +304,11 @@ static struct graphics_image_priv* image_new(struct graphics_priv* gr, struct gr
     }
     QString key(path);
     QString renderer_key(key);
-    QString extension = key.right(key.lastIndexOf("."));
+    int index = key.lastIndexOf(".");
+    QString extension;
+    if(index > 0) {
+        extension = key.right(index);
+    }
     QFile imagefile(key);
     if (!imagefile.exists()) {
         /* file doesn't exit. Either navit wants us to guess file name by
@@ -348,7 +352,7 @@ static struct graphics_image_priv* image_new(struct graphics_priv* gr, struct gr
     }
 
     /* check if we got image */
-    if (image_priv->pixmap->isNull()) {
+    if ((image_priv->pixmap == NULL) || (image_priv->pixmap->isNull())) {
         g_free(image_priv);
         return NULL;
     } else {
@@ -771,15 +775,18 @@ static void overlay_disable(struct graphics_priv* gr, int disable) {
 }
 
 static void overlay_resize(struct graphics_priv* gr, struct point* p, int w, int h, int wraparound) {
-    //        dbg(lvl_debug,"enter");
+    //        dbg(lvl_debug,"enter %d %d %d %d %d", p->x, p->y, w, h, wraparound);
     gr->x = p->x;
     gr->y = p->y;
     if (gr->painter != NULL) {
         delete (gr->painter);
     }
-    delete (gr->pixmap);
-    gr->pixmap = new QPixmap(w, h);
-    gr->pixmap->fill(Qt::transparent);
+    /* replacing the pixmap clears the content. Only neccesary if size actually changes */
+    if((gr->pixmap->height() != h) || (gr->pixmap->width() != w)) {
+        delete (gr->pixmap);
+        gr->pixmap = new QPixmap(w, h);
+        gr->pixmap->fill(Qt::transparent);
+    }
     if (gr->painter != NULL)
         gr->painter = new QPainter(gr->pixmap);
 }