Optimize all those SettingsCore::paperColor().rgb() calls

Maybe the compiler can do it, but i can do it as well :D

core/utils.cpp

@@ -306,8 +306,8 @@ QSizeF Utils::realDpi(QWidget*)
 }
 #endif
 
-inline static bool isPaperColor( QRgb argb ) {
-    return ( argb & 0xFFFFFF ) == ( SettingsCore::paperColor().rgb() & 0xFFFFFF); // ignore alpha
+inline static bool isPaperColor( QRgb argb, QRgb paperColor ) {
+    return ( argb & 0xFFFFFF ) == ( paperColor & 0xFFFFFF); // ignore alpha
 }
 
 NormalizedRect Utils::imageBoundingBox( const QImage * image )
@@ -315,8 +315,9 @@ NormalizedRect Utils::imageBoundingBox( const QImage * image )
     if ( !image )
         return NormalizedRect();
 
-    int width = image->width();
-    int height = image->height();
+    const int width = image->width();
+    const int height = image->height();
+    const QRgb paperColor = SettingsCore::paperColor().rgb();
     int left, top, bottom, right, x, y;
 
 #ifdef BBOX_DEBUG
@@ -327,7 +328,7 @@ NormalizedRect Utils::imageBoundingBox( const QImage * image )
     // Scan pixels for top non-white
     for ( top = 0; top < height; ++top )
         for ( x = 0; x < width; ++x )
-            if ( !isPaperColor( image->pixel( x, top ) ) )
+            if ( !isPaperColor( image->pixel( x, top ), paperColor ) )
                 goto got_top;
     return NormalizedRect( 0, 0, 0, 0 ); // the image is blank
 got_top:
@@ -336,7 +337,7 @@ got_top:
     // Scan pixels for bottom non-white
     for ( bottom = height-1; bottom >= top; --bottom )
         for ( x = width-1; x >= 0; --x )
-            if ( !isPaperColor( image->pixel( x, bottom ) ) )
+            if ( !isPaperColor( image->pixel( x, bottom ), paperColor ) )
                 goto got_bottom;
     Q_ASSERT( 0 ); // image changed?!
 got_bottom:
@@ -349,10 +350,10 @@ got_bottom:
     for ( y = top; y <= bottom && ( left > 0 || right < width-1 ); ++y )
     {
         for ( x = 0; x < left; ++x )
-            if ( !isPaperColor( image->pixel( x, y ) ) )
+            if ( !isPaperColor( image->pixel( x, y ), paperColor ) )
                 left = x;
         for ( x = width-1; x > right+1; --x )
-            if ( !isPaperColor( image->pixel( x, y ) ) )
+            if ( !isPaperColor( image->pixel( x, y ), paperColor ) )
                 right = x;
     }