[LyX/master] Shut up compiler warning

[Georg Baum]

commit 1586f79499ec817fbb036a37b02a19777220820c
Author: Georg Baum <b...@lyx.org>
Date:   Thu May 14 10:48:50 2015 +0200

    Shut up compiler warning
    
    We know that ceil() returns an integer, although the type is double.

diff --git a/src/frontends/qt4/GuiImage.cpp b/src/frontends/qt4/GuiImage.cpp
index 7e3307f..f8e5261 100644
--- a/src/frontends/qt4/GuiImage.cpp
+++ b/src/frontends/qt4/GuiImage.cpp
@@ -65,9 +65,9 @@ QImage const & GuiImage::image() const
 unsigned int GuiImage::width() const
 {
 #if QT_VERSION >= 0x050000
-       return is_transformed_ ?
-               ceil(transformed_.width() / transformed_.devicePixelRatio()) :
-               ceil(original_.width() / original_.devicePixelRatio());
+       return static_cast<unsigned int>(ceil(is_transformed_ ?
+               (transformed_.width() / transformed_.devicePixelRatio()) :
+               (original_.width() / original_.devicePixelRatio())));
 #else
        return is_transformed_ ? transformed_.width() : original_.width();
 #endif
@@ -77,9 +77,9 @@ unsigned int GuiImage::width() const
 unsigned int GuiImage::height() const
 {
 #if QT_VERSION >= 0x050000
-       return is_transformed_ ?
-               ceil(transformed_.height() / transformed_.devicePixelRatio()) :
-               ceil(original_.height() / original_.devicePixelRatio());
+       return static_cast<unsigned int>(ceil(is_transformed_ ?
+               (transformed_.height() / transformed_.devicePixelRatio()) :
+               (original_.height() / original_.devicePixelRatio())));
 #else
        return is_transformed_ ? transformed_.height() : original_.height();
 #endif