Fix color buttons disappearing in windows when alpha is set (fix #10187)

nyalldawson · NathanW2 · commit da99331d8581 · 2014-06-12T20:56:17.000+10:00
diff --git a/src/gui/qgscolorbutton.cpp b/src/gui/qgscolorbutton.cpp
@@ -27,6 +27,25 @@
 #include <QClipboard>
 #include <QDrag>
 
+#ifdef Q_OS_WIN
+#include <windows.h>
+QString QgsColorButton::fullPath( const QString &path )
+{
+  TCHAR buf[MAX_PATH];
+  int len = GetLongPathName( path.toUtf8().constData(), buf, MAX_PATH );
+
+  if ( len == 0 || len > MAX_PATH )
+  {
+    QgsDebugMsg( QString( "GetLongPathName('%1') failed with %2: %3" )
+                 .arg( path ).arg( len ).arg( GetLastError() ) );
+    return path;
+  }
+
+  QString res = QString::fromUtf8( buf );
+  return res;
+}
+#endif
+
 /*!
   \class QgsColorButton
 
@@ -387,11 +406,15 @@ void QgsColorButton::setButtonBackground()
         mTempPNG.close();
       }
 
-      bkgrd = QString( " background-image: url(%1);" ).arg( mTempPNG.fileName() );
+      QString bgFileName = mTempPNG.fileName();
+#ifdef Q_OS_WIN
+      //on windows, mTempPNG will use a shortened path for the temporary folder name
+      //this does not work with stylesheets, resulting in the whole button disappearing (#10187)
+      bgFileName = fullPath( bgFileName );
+#endif
+      bkgrd = QString( " background-image: url(%1);" ).arg( bgFileName );
     }
 
-    //QgsDebugMsg( QString( "%1" ).arg( bkgrd ) );
-
     // TODO: get OS-style focus color and switch border to that color when button in focus
     setStyleSheet( QString( "QgsColorButton{"
                             " %1"
diff --git a/src/gui/qgscolorbutton.h b/src/gui/qgscolorbutton.h
@@ -191,6 +191,16 @@ class GUI_EXPORT QgsColorButton: public QPushButton
      */
     bool colorFromMimeData( const QMimeData *mimeData, QColor &resultColor );
 
+#ifdef Q_OS_WIN
+    /**
+     * Expands a shortened Windows path to its full path name.
+     * @returns full path name.
+     * @param path a (possibly) shortened Windows path
+     * @note added in 2.3
+     */
+    QString fullPath( const QString &path );
+#endif
+
   private slots:
     void onButtonClicked();
 
