modernize loops

15 files changed, 102 insertions, 105 deletions

diff --git a/src/display/cairo-utils.cpp b/src/display/cairo-utils.cpp
index 397d6d4b4..6dd343298 100644
--- a/src/display/cairo-utils.cpp
+++ b/src/display/cairo-utils.cpp
@@ -760,8 +760,8 @@ feed_curve_to_cairo(cairo_t *cr, Geom::Curve const &c, Geom::Affine const & tran
             Geom::Path sbasis_path = Geom::cubicbezierpath_from_sbasis(c.toSBasis(), 0.1);
 
             // recurse to convert the new path resulting from the sbasis to svgd
-            for (Geom::Path::iterator iter = sbasis_path.begin(); iter != sbasis_path.end(); ++iter) {
-                feed_curve_to_cairo(cr, *iter, trans, view, optimize_stroke);
+            for (const auto & iter : sbasis_path) {
+                feed_curve_to_cairo(cr, iter, trans, view, optimize_stroke);
             }
         }
     }
@@ -845,8 +845,8 @@ feed_pathvector_to_cairo (cairo_t *ct, Geom::PathVector const &pathv, Geom::Affi
     if (pathv.empty())
         return;
 
-    for(Geom::PathVector::const_iterator it = pathv.begin(); it != pathv.end(); ++it) {
-        feed_path_to_cairo(ct, *it, trans, area, optimize_stroke, stroke_width);
+    for(const auto & it : pathv) {
+        feed_path_to_cairo(ct, it, trans, area, optimize_stroke, stroke_width);
     }
 }
 
@@ -858,8 +858,8 @@ feed_pathvector_to_cairo (cairo_t *ct, Geom::PathVector const &pathv)
     if (pathv.empty())
         return;
 
-    for(Geom::PathVector::const_iterator it = pathv.begin(); it != pathv.end(); ++it) {
-        feed_path_to_cairo(ct, *it);
+    for(const auto & it : pathv) {
+        feed_path_to_cairo(ct, it);
     }
 }
 
diff --git a/src/display/canvas-arena.cpp b/src/display/canvas-arena.cpp
index fb20ccfe3..83693ea20 100644
--- a/src/display/canvas-arena.cpp
+++ b/src/display/canvas-arena.cpp
@@ -54,8 +54,8 @@ struct CachePrefObserver : public Inkscape::Preferences::Observer {
     {
         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
         std::vector<Inkscape::Preferences::Entry> v = prefs->getAllEntries(observed_path);
-        for (unsigned i=0; i<v.size(); ++i) {
-            notify(v[i]);
+        for (const auto & i : v) {
+            notify(i);
         }
         prefs->addObserver(*this);
     }
diff --git a/src/display/canvas-temporary-item-list.cpp b/src/display/canvas-temporary-item-list.cpp
index ad112cdbb..caa960969 100644
--- a/src/display/canvas-temporary-item-list.cpp
+++ b/src/display/canvas-temporary-item-list.cpp
@@ -26,8 +26,7 @@ TemporaryItemList::TemporaryItemList(SPDesktop *desktop)
 TemporaryItemList::~TemporaryItemList()
 {
     // delete all items in list so the timeouts are removed
-    for ( std::list<TemporaryItem*>::iterator it = itemlist.begin(); it != itemlist.end(); ++it ) {
-        TemporaryItem * tempitem = *it;
+    for (auto tempitem : itemlist) {
         delete tempitem;
     }
     itemlist.clear();
@@ -49,8 +48,8 @@ TemporaryItemList::delete_item( TemporaryItem * tempitem )
 {
     // check if the item is in the list, if so, delete it. (in other words, don't wait for the item to delete itself)
     bool in_list = false;
-    for ( std::list<TemporaryItem*>::iterator it = itemlist.begin(); it != itemlist.end(); ++it ) {
-        if ( *it == tempitem ) {
+    for (auto & it : itemlist) {
+        if ( it == tempitem ) {
             in_list = true;
             break;
         }
diff --git a/src/display/curve.cpp b/src/display/curve.cpp
index 3391864ae..331701f27 100644
--- a/src/display/curve.cpp
+++ b/src/display/curve.cpp
@@ -158,9 +158,9 @@ SPCurve::split() const
 {
     std::list<SPCurve *> l;
 
-    for (Geom::PathVector::const_iterator path_it = _pathv.begin(); path_it != _pathv.end(); ++path_it) {
+    for (const auto & path_it : _pathv) {
         Geom::PathVector newpathv;
-        newpathv.push_back(*path_it);
+        newpathv.push_back(path_it);
         SPCurve * newcurve = new SPCurve(newpathv);
         l.push_back(newcurve);
     }
@@ -327,8 +327,8 @@ SPCurve::is_closed() const
         return false;
     } 
     
-    for (Geom::PathVector::const_iterator it = _pathv.begin(); it != _pathv.end(); ++it) {
-        if ( ! it->closed() ) {
+    for (const auto & it : _pathv) {
+        if ( ! it.closed() ) {
             return false;
         }
     }
@@ -531,8 +531,8 @@ SPCurve::append(SPCurve const *curve2,
             _pathv.push_back( (*it) );
         }
     } else {
-        for (Geom::PathVector::const_iterator it = curve2->_pathv.begin(); it != curve2->_pathv.end(); ++it) {
-            _pathv.push_back( (*it) );
+        for (const auto & it : curve2->_pathv) {
+            _pathv.push_back( it );
         }
     }
 }
@@ -658,10 +658,10 @@ size_t
 SPCurve::nodes_in_path() const
 {
     size_t nr = 0;
-    for(Geom::PathVector::const_iterator it = _pathv.begin(); it != _pathv.end(); ++it) {
+    for(const auto & it : _pathv) {
         // if the path does not have any segments, it is a naked moveto,
         // and therefore any path has at least one valid node
-        size_t psize = std::max<size_t>(1, it->size_closed());
+        size_t psize = std::max<size_t>(1, it.size_closed());
         nr += psize;
     }
 
diff --git a/src/display/drawing-group.cpp b/src/display/drawing-group.cpp
index 3a2eeb018..0d6a2edfc 100644
--- a/src/display/drawing-group.cpp
+++ b/src/display/drawing-group.cpp
@@ -73,14 +73,14 @@ DrawingGroup::_updateItem(Geom::IntRect const &area, UpdateContext const &ctx, u
     if (_child_transform) {
         child_ctx.ctm = *_child_transform * ctx.ctm;
     }
-    for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-        i->update(area, child_ctx, flags, reset);
+    for (auto & i : _children) {
+        i.update(area, child_ctx, flags, reset);
     }
     if (beststate & STATE_BBOX) {
         _bbox = Geom::OptIntRect();
-        for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-            if (i->visible()) {
-                _bbox.unionWith(outline ? i->geometricBounds() : i->visualBounds());
+        for (auto & i : _children) {
+            if (i.visible()) {
+                _bbox.unionWith(outline ? i.geometricBounds() : i.visualBounds());
             }
         }
     }
@@ -92,23 +92,23 @@ DrawingGroup::_renderItem(DrawingContext &dc, Geom::IntRect const &area, unsigne
 {
     if (stop_at == nullptr) {
         // normal rendering
-        for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-            i->setAntialiasing(_antialias);
-            i->render(dc, area, flags, stop_at);
+        for (auto & i : _children) {
+            i.setAntialiasing(_antialias);
+            i.render(dc, area, flags, stop_at);
         }
     } else {
         // background rendering
-        for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-            if (&*i == stop_at) return RENDER_OK; // do not render the stop_at item at all
-            if (i->isAncestorOf(stop_at)) {
+        for (auto & i : _children) {
+            if (&i == stop_at) return RENDER_OK; // do not render the stop_at item at all
+            if (i.isAncestorOf(stop_at)) {
                 // render its ancestors without masks, opacity or filters
-                i->setAntialiasing(_antialias);
-                i->render(dc, area, flags | RENDER_FILTER_BACKGROUND, stop_at);
+                i.setAntialiasing(_antialias);
+                i.render(dc, area, flags | RENDER_FILTER_BACKGROUND, stop_at);
                 // stop further rendering
                 return RENDER_OK;
             } else {
-                i->setAntialiasing(_antialias);
-                i->render(dc, area, flags, stop_at);
+                i.setAntialiasing(_antialias);
+                i.render(dc, area, flags, stop_at);
             }
         }
     }
@@ -118,16 +118,16 @@ DrawingGroup::_renderItem(DrawingContext &dc, Geom::IntRect const &area, unsigne
 void
 DrawingGroup::_clipItem(DrawingContext &dc, Geom::IntRect const &area)
 {
-    for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-        i->clip(dc, area);
+    for (auto & i : _children) {
+        i.clip(dc, area);
     }
 }
 
 DrawingItem *
 DrawingGroup::_pickItem(Geom::Point const &p, double delta, unsigned flags)
 {
-    for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-        DrawingItem *picked = i->pick(p, delta, flags);
+    for (auto & i : _children) {
+        DrawingItem *picked = i.pick(p, delta, flags);
         if (picked) {
             return _pick_children ? picked : this;
         }
diff --git a/src/display/drawing-item.cpp b/src/display/drawing-item.cpp
index d3729da94..6777be5cc 100644
--- a/src/display/drawing-item.cpp
+++ b/src/display/drawing-item.cpp
@@ -254,9 +254,9 @@ DrawingItem::clearChildren()
     // prevent children from referencing the parent during deletion
     // this way, children won't try to remove themselves from a list
     // from which they have already been removed by clear_and_dispose
-    for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-        i->_parent = NULL;
-        i->_child_type = CHILD_ORPHAN;
+    for (auto & i : _children) {
+        i._parent = NULL;
+        i._child_type = CHILD_ORPHAN;
     }
     _children.clear_and_dispose(DeleteDisposer());
     _markForUpdate(STATE_ALL, false);
@@ -418,8 +418,8 @@ void
 DrawingItem::setChildrenStyle(SPStyle* context_style)
 {
     _context_style = context_style;
-    for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-        i->setChildrenStyle( context_style );
+    for (auto & i : _children) {
+        i.setChildrenStyle( context_style );
     }
 }
 
@@ -1053,8 +1053,8 @@ DrawingItem::recursivePrintTree( unsigned level )
         std::cout << "  ";
     }
     std::cout << name() << std::endl;
-    for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-        i->recursivePrintTree( level+1 );
+    for (auto & i : _children) {
+        i.recursivePrintTree( level+1 );
     }
 }
 
@@ -1105,8 +1105,8 @@ DrawingItem::_invalidateFilterBackground(Geom::IntRect const &area)
         _cache->markDirty(area);
     }
 
-    for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-        i->_invalidateFilterBackground(area);
+    for (auto & i : _children) {
+        i._invalidateFilterBackground(area);
     }
 }
 
diff --git a/src/display/drawing-shape.cpp b/src/display/drawing-shape.cpp
index e1379a884..20544e1be 100644
--- a/src/display/drawing-shape.cpp
+++ b/src/display/drawing-shape.cpp
@@ -84,8 +84,8 @@ DrawingShape::_updateItem(Geom::IntRect const &area, UpdateContext const &ctx, u
     unsigned beststate = STATE_ALL;
 
     // update markers
-    for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-        i->update(area, ctx, flags, reset);
+    for (auto & i : _children) {
+        i.update(area, ctx, flags, reset);
     }
 
     if (!(flags & STATE_RENDER)) {
@@ -100,8 +100,8 @@ DrawingShape::_updateItem(Geom::IntRect const &area, UpdateContext const &ctx, u
                 }
             }
             if (beststate & STATE_BBOX) {
-                for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-                    _bbox.unionWith(i->geometricBounds());
+                for (auto & i : _children) {
+                    _bbox.unionWith(i.geometricBounds());
                 }
             }
         }
@@ -146,8 +146,8 @@ DrawingShape::_updateItem(Geom::IntRect const &area, UpdateContext const &ctx, u
     }
 
     if (beststate & STATE_BBOX) {
-        for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-            _bbox.unionWith(i->geometricBounds());
+        for (auto & i : _children) {
+            _bbox.unionWith(i.geometricBounds());
         }
     }
     return STATE_ALL;
@@ -206,8 +206,8 @@ void
 DrawingShape::_renderMarkers(DrawingContext &dc, Geom::IntRect const &area, unsigned flags, DrawingItem *stop_at)
 {
     // marker rendering
-    for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-        i->render(dc, area, flags, stop_at);
+    for (auto & i : _children) {
+        i.render(dc, area, flags, stop_at);
     }
 }
 
@@ -289,8 +289,8 @@ DrawingShape::_renderItem(DrawingContext &dc, Geom::IntRect const &area, unsigne
     }
 
     // Handle different paint orders
-    for (unsigned i = 0; i < NRStyle::PAINT_ORDER_LAYERS; ++i) {
-        switch (_nrstyle.paint_order_layer[i]) {
+    for (auto & i : _nrstyle.paint_order_layer) {
+        switch (i) {
             case NRStyle::PAINT_ORDER_FILL:
                 _renderFill(dc);
                 break;
@@ -412,8 +412,8 @@ DrawingShape::_pickItem(Geom::Point const &p, double delta, unsigned flags)
     }
 
     // if not picked on the shape itself, try its markers
-    for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-        DrawingItem *ret = i->pick(p, delta, flags & ~PICK_STICKY);
+    for (auto & i : _children) {
+        DrawingItem *ret = i.pick(p, delta, flags & ~PICK_STICKY);
         if (ret) {
             _last_pick = this;
             return this;
diff --git a/src/display/drawing-text.cpp b/src/display/drawing-text.cpp
index d809e8dcb..9d81d736d 100644
--- a/src/display/drawing-text.cpp
+++ b/src/display/drawing-text.cpp
@@ -446,8 +446,8 @@ unsigned DrawingText::_renderItem(DrawingContext &dc, Geom::IntRect const &/*are
         dc.setSource(rgba);
         dc.setTolerance(0.5); // low quality, but good enough for outline mode
 
-        for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-            DrawingGlyphs *g = dynamic_cast<DrawingGlyphs *>(&*i);
+        for (auto & i : _children) {
+            DrawingGlyphs *g = dynamic_cast<DrawingGlyphs *>(&i);
             if (!g) throw InvalidItemException();
 
             Inkscape::DrawingContext::Save save(dc);
@@ -512,9 +512,9 @@ unsigned DrawingText::_renderItem(DrawingContext &dc, Geom::IntRect const &/*are
             double leftmost  = DBL_MAX;
             bool   first_y   = true;
             double start_y   = 0.0;
-            for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
+            for (auto & i : _children) {
 
-                DrawingGlyphs *g = dynamic_cast<DrawingGlyphs *>(&*i);
+                DrawingGlyphs *g = dynamic_cast<DrawingGlyphs *>(&i);
                 if (!g) throw InvalidItemException();
 
                 if (!invset) {
@@ -576,8 +576,8 @@ unsigned DrawingText::_renderItem(DrawingContext &dc, Geom::IntRect const &/*are
         }
 
         // accumulate the path that represents the glyphs
-        for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-            DrawingGlyphs *g = dynamic_cast<DrawingGlyphs *>(&*i);
+        for (auto & i : _children) {
+            DrawingGlyphs *g = dynamic_cast<DrawingGlyphs *>(&i);
             if (!g) throw InvalidItemException();
 
             Inkscape::DrawingContext::Save save(dc);
@@ -678,8 +678,8 @@ void DrawingText::_clipItem(DrawingContext &dc, Geom::IntRect const &/*area*/)
         }
     }
 
-    for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
-        DrawingGlyphs *g = dynamic_cast<DrawingGlyphs *>(&*i);
+    for (auto & i : _children) {
+        DrawingGlyphs *g = dynamic_cast<DrawingGlyphs *>(&i);
         if (!g) {
             throw InvalidItemException();
         }
diff --git a/src/display/drawing.cpp b/src/display/drawing.cpp
index 3b41fc4c0..511de780a 100644
--- a/src/display/drawing.cpp
+++ b/src/display/drawing.cpp
@@ -146,10 +146,9 @@ void
 Drawing::setCacheLimit(Geom::OptIntRect const &r)
 {
     _cache_limit = r;
-    for (std::set<DrawingItem *>::iterator i = _cached_items.begin();
-         i != _cached_items.end(); ++i)
+    for (auto _cached_item : _cached_items)
     {
-        (*i)->_markForUpdate(DrawingItem::STATE_CACHE, false);
+        _cached_item->_markForUpdate(DrawingItem::STATE_CACHE, false);
     }
 }
 void
@@ -234,8 +233,8 @@ Drawing::_pickItemsForCaching()
     std::set_difference(_cached_items.begin(), _cached_items.end(),
                         to_cache.begin(), to_cache.end(),
                         std::inserter(to_uncache, to_uncache.end()));
-    for (std::set<DrawingItem*>::iterator j = to_uncache.begin(); j != to_uncache.end(); ++j) {
-        (*j)->setCached(false);
+    for (auto j : to_uncache) {
+        j->setCached(false);
     }
 }
 
diff --git a/src/display/nr-filter-gaussian.cpp b/src/display/nr-filter-gaussian.cpp
index 3a1e4a621..d1dd976bb 100644
--- a/src/display/nr-filter-gaussian.cpp
+++ b/src/display/nr-filter-gaussian.cpp
@@ -482,7 +482,7 @@ gaussian_pass_IIR(Geom::Dim2 d, double deviation, cairo_surface_t *src, cairo_su
 
     // Compute filter
     calcFilter(deviation, bf);
-    for(size_t i=0; i<N; i++) bf[i] = -bf[i];
+    for(double & i : bf) i = -i;
     b[0] = 1; // b[0] == alpha (scaling coefficient)
     for(size_t i=0; i<N; i++) {
         b[i+1] = bf[i];
diff --git a/src/display/nr-filter-merge.cpp b/src/display/nr-filter-merge.cpp
index fb2d6ba85..9ebfe4075 100644
--- a/src/display/nr-filter-merge.cpp
+++ b/src/display/nr-filter-merge.cpp
@@ -45,8 +45,8 @@ void FilterMerge::render_cairo(FilterSlot &slot)
     // output is RGBA if at least one input is RGBA
     bool rgba32 = false;
     cairo_surface_t *out = nullptr;
-    for (std::vector<int>::iterator i = _input_image.begin(); i != _input_image.end(); ++i) {
-        cairo_surface_t *in = slot.getcairo(*i);
+    for (int & i : _input_image) {
+        cairo_surface_t *in = slot.getcairo(i);
         if (cairo_surface_get_content(in) == CAIRO_CONTENT_COLOR_ALPHA) {
             out = ink_cairo_surface_create_identical(in);
             set_cairo_surface_ci( out, ci_fp );
@@ -60,8 +60,8 @@ void FilterMerge::render_cairo(FilterSlot &slot)
     }
     cairo_t *out_ct = cairo_create(out);
 
-    for (std::vector<int>::iterator i = _input_image.begin(); i != _input_image.end(); ++i) {
-        cairo_surface_t *in = slot.getcairo(*i);
+    for (int & i : _input_image) {
+        cairo_surface_t *in = slot.getcairo(i);
 
         set_cairo_surface_ci( in, ci_fp );
         cairo_set_source_surface(out_ct, in, 0, 0);
@@ -86,8 +86,7 @@ double FilterMerge::complexity(Geom::Affine const &)
 
 bool FilterMerge::uses_background()
 {
-    for (unsigned int i = 0; i < _input_image.size(); ++i) {
-        int input = _input_image[i];
+    for (int input : _input_image) {
         if (input == NR_FILTER_BACKGROUNDIMAGE || input == NR_FILTER_BACKGROUNDALPHA) {
             return true;
         }
diff --git a/src/display/nr-filter-slot.cpp b/src/display/nr-filter-slot.cpp
index 91a55639f..4d9dc239d 100644
--- a/src/display/nr-filter-slot.cpp
+++ b/src/display/nr-filter-slot.cpp
@@ -59,8 +59,8 @@ FilterSlot::FilterSlot(DrawingItem *item, DrawingContext *bgdc,
 
 FilterSlot::~FilterSlot()
 {
-    for (SlotMap::iterator i = _slots.begin(); i != _slots.end(); ++i) {
-        cairo_surface_destroy(i->second);
+    for (auto & _slot : _slots) {
+        cairo_surface_destroy(_slot.second);
     }
 }
 
diff --git a/src/display/nr-filter-turbulence.cpp b/src/display/nr-filter-turbulence.cpp
index e1b6fbfd3..91a71abcd 100644
--- a/src/display/nr-filter-turbulence.cpp
+++ b/src/display/nr-filter-turbulence.cpp
@@ -128,8 +128,8 @@ public:
         double y = p[Geom::Y] * _baseFreq[Geom::Y];
         double ratio = 1.0;
 
-        for (int k = 0; k < 4; ++k)
-            pixel[k] = 0.0;
+        for (double & k : pixel)
+            k = 0.0;
 
         for(int octave = 0; octave < _octaves; ++octave)
         {
diff --git a/src/display/nr-filter.cpp b/src/display/nr-filter.cpp
index c6bbf3b81..eec7c1aa6 100644
--- a/src/display/nr-filter.cpp
+++ b/src/display/nr-filter.cpp
@@ -145,8 +145,8 @@ int Filter::render(Inkscape::DrawingItem const *item, DrawingContext &graphic, D
 
     units.set_paraller(false);
     Geom::Affine pbtrans = units.get_matrix_display2pb();
-    for (unsigned i = 0 ; i < _primitive.size() ; i++) {
-        if (!_primitive[i]->can_handle_affine(pbtrans)) {
+    for (auto & i : _primitive) {
+        if (!i->can_handle_affine(pbtrans)) {
             units.set_paraller(true);
             break;
         }
@@ -157,8 +157,8 @@ int Filter::render(Inkscape::DrawingItem const *item, DrawingContext &graphic, D
     slot.set_blurquality(blurquality);
     slot.set_device_scale(graphic.surface()->device_scale());
 
-    for (unsigned i = 0 ; i < _primitive.size() ; i++) {
-        _primitive[i]->render_cairo(slot);
+    for (auto & i : _primitive) {
+        i->render_cairo(slot);
     }
 
     Geom::Point origin = graphic.targetLogicalBounds().min();
@@ -185,8 +185,8 @@ void Filter::set_primitive_units(SPFilterUnits unit) {
 }
 
 void Filter::area_enlarge(Geom::IntRect &bbox, Inkscape::DrawingItem const *item) const {
-    for (unsigned i = 0 ; i < _primitive.size() ; i++) {
-        if (_primitive[i]) _primitive[i]->area_enlarge(bbox, item->ctm());
+    for (auto i : _primitive) {
+        if (i) i->area_enlarge(bbox, item->ctm());
     }
 
 /*
@@ -279,9 +279,9 @@ Geom::OptRect Filter::filter_effect_area(Geom::OptRect const &bbox)
 double Filter::complexity(Geom::Affine const &ctm)
 {
     double factor = 1.0;
-    for (unsigned i = 0 ; i < _primitive.size() ; i++) {
-        if (_primitive[i]) {
-            double f = _primitive[i]->complexity(ctm);
+    for (auto & i : _primitive) {
+        if (i) {
+            double f = i->complexity(ctm);
             factor += (f - 1.0);
         }
     }
@@ -290,8 +290,8 @@ double Filter::complexity(Geom::Affine const &ctm)
 
 bool Filter::uses_background()
 {
-    for (unsigned i = 0 ; i < _primitive.size() ; i++) {
-        if (_primitive[i] && _primitive[i]->uses_background()) {
+    for (auto & i : _primitive) {
+        if (i && i->uses_background()) {
             return true;
         }
     }
@@ -374,8 +374,8 @@ FilterPrimitive *Filter::get_primitive(int handle) {
 
 void Filter::clear_primitives()
 {
-    for (unsigned i = 0 ; i < _primitive.size() ; i++) {
-        delete _primitive[i];
+    for (auto & i : _primitive) {
+        delete i;
     }
     _primitive.clear();
 }
diff --git a/src/display/sp-canvas.cpp b/src/display/sp-canvas.cpp
index 331528654..e7ac1ab9b 100644
--- a/src/display/sp-canvas.cpp
+++ b/src/display/sp-canvas.cpp
@@ -827,8 +827,8 @@ void SPCanvasGroup::update(SPCanvasItem *item, Geom::Affine const &affine, unsig
     SPCanvasGroup *group = SP_CANVAS_GROUP(item);
     Geom::OptRect bounds;
 
-    for (auto it = group->items.begin(); it != group->items.end(); ++it) {
-        SPCanvasItem *i = &(*it);
+    for (auto & item : group->items) {
+        SPCanvasItem *i = &item;
 
         sp_canvas_item_invoke_update (i, affine, flags);
 
@@ -863,8 +863,8 @@ double SPCanvasGroup::point(SPCanvasItem *item, Geom::Point p, SPCanvasItem **ac
     *actual_item = nullptr;
 
     double dist = 0.0;
-    for (auto it = group->items.begin(); it != group->items.end(); ++it) {
-        SPCanvasItem *child = &(*it);
+    for (auto & it : group->items) {
+        SPCanvasItem *child = &it;
 
         if ((child->x1 <= x2) && (child->y1 <= y2) && (child->x2 >= x1) && (child->y2 >= y1)) {
             SPCanvasItem *point_item = nullptr; // cater for incomplete item implementations
@@ -897,8 +897,8 @@ void SPCanvasGroup::render(SPCanvasItem *item, SPCanvasBuf *buf)
 {
     SPCanvasGroup *group = SP_CANVAS_GROUP(item);
 
-    for (auto it = group->items.begin(); it != group->items.end(); ++it) {
-        SPCanvasItem *child = &(*it);
+    for (auto & item : group->items) {
+        SPCanvasItem *child = &item;
         if (child->visible) {
             if ((child->x1 < buf->rect.right()) &&
                 (child->y1 < buf->rect.bottom()) &&
@@ -916,8 +916,8 @@ void SPCanvasGroup::viewboxChanged(SPCanvasItem *item, Geom::IntRect const &new_
 {
     SPCanvasGroup *group = SP_CANVAS_GROUP(item);
 
-    for (auto it = group->items.begin(); it != group->items.end(); ++it) {
-        SPCanvasItem *child = &(*it);
+    for (auto & item : group->items) {
+        SPCanvasItem *child = &item;
         if (child->visible) {
             if (SP_CANVAS_ITEM_GET_CLASS(child)->viewbox_changed) {
                 SP_CANVAS_ITEM_GET_CLASS(child)->viewbox_changed(child, new_area);