Eliminate clang warnings

-Wconstant-conversion
-Wenum-compare-switch
-Wpointer-bool-conversion
-Wundefined-bool-conversion
-Wunused-value

Excluding deprecation warnings and 3rdparty directory.

14 files changed, 60 insertions, 70 deletions

diff --git a/src/document.cpp b/src/document.cpp
index cba919cee..be0c556f0 100644
--- a/src/document.cpp
+++ b/src/document.cpp
@@ -1820,7 +1820,7 @@ void SPDocument::_importDefsNode(SPDocument *source, Inkscape::XML::Node *defs,
         if (src && SP_IS_GRADIENT(src)) {
             SPGradient *s_gr = SP_GRADIENT(src);
             for (auto& trg: getDefs()->children) {
-                if (&trg && (src != &trg) && SP_IS_GRADIENT(&trg)) {
+                if ((src != &trg) && SP_IS_GRADIENT(&trg)) {
                     SPGradient *t_gr = SP_GRADIENT(&trg);
                     if (t_gr && s_gr->isEquivalent(t_gr)) {
                          // Change object references to the existing equivalent gradient
@@ -1891,7 +1891,7 @@ void SPDocument::_importDefsNode(SPDocument *source, Inkscape::XML::Node *defs,
 
                 // Check that it really is a duplicate
                 for (auto& trg: getDefs()->children) {
-                    if(&trg && SP_IS_SYMBOL(&trg) && src != &trg ) {
+                    if (SP_IS_SYMBOL(&trg) && src != &trg) {
                         std::string id2 = trg.getRepr()->attribute("id");
 
                         if( !id.compare( id2 ) ) {
diff --git a/src/extension/internal/cairo-render-context.cpp b/src/extension/internal/cairo-render-context.cpp
index 4464742dd..60e83afef 100644
--- a/src/extension/internal/cairo-render-context.cpp
+++ b/src/extension/internal/cairo-render-context.cpp
@@ -932,6 +932,8 @@ CairoRenderContext::_setSurfaceMetadata(cairo_surface_t *surface)
             }
             break;
 #endif
+        default:
+            g_warning("unsupported target %d\n", _target);
     }
 }
 
diff --git a/src/extension/internal/emf-print.cpp b/src/extension/internal/emf-print.cpp
index 6d330f2ea..36f162ef9 100644
--- a/src/extension/internal/emf-print.cpp
+++ b/src/extension/internal/emf-print.cpp
@@ -1516,7 +1516,7 @@ bool PrintEmf::print_simple_shape(Geom::PathVector const &pathv, const Geom::Aff
 
             if (is_straight_curve(*cit)) {
                 lines++;
-            } else if (&*cit) {
+            } else if (dynamic_cast<Geom::CubicBezier const *>(&*cit)) {
                 curves++;
             }
         }
diff --git a/src/extension/internal/wmf-print.cpp b/src/extension/internal/wmf-print.cpp
index 6340bf0b6..79de51925 100644
--- a/src/extension/internal/wmf-print.cpp
+++ b/src/extension/internal/wmf-print.cpp
@@ -963,7 +963,7 @@ bool PrintWmf::print_simple_shape(Geom::PathVector const &pathv, const Geom::Aff
 
             if (is_straight_curve(*cit)) {
                 lines++;
-            } else if (&*cit) {
+            } else if (dynamic_cast<Geom::CubicBezier const *>(&*cit)) {
                 curves++;
             }
         }
diff --git a/src/file-update.cpp b/src/file-update.cpp
index 9ab83a7b9..d10a1c02d 100644
--- a/src/file-update.cpp
+++ b/src/file-update.cpp
@@ -319,20 +319,20 @@ void sp_file_convert_dpi(SPDocument *doc)
 
     // Check if potentially need viewbox or unit fix                                           
     switch (root->width.unit) {
-        case SP_CSS_UNIT_PC:
-        case SP_CSS_UNIT_PT:
-        case SP_CSS_UNIT_MM:
-        case SP_CSS_UNIT_CM:
-        case SP_CSS_UNIT_IN:
+        case SVGLength::PC:
+        case SVGLength::PT:
+        case SVGLength::MM:
+        case SVGLength::CM:
+        case SVGLength::INCH:
             need_fix_viewbox = true;
             break;
-        case SP_CSS_UNIT_NONE:
-        case SP_CSS_UNIT_PX:
+        case SVGLength::NONE:
+        case SVGLength::PX:
             need_fix_units = true;
             break;
-        case SP_CSS_UNIT_EM:
-        case SP_CSS_UNIT_EX:
-        case SP_CSS_UNIT_PERCENT:
+        case SVGLength::EM:
+        case SVGLength::EX:
+        case SVGLength::PERCENT:
             // OK                                                                              
             break;
         default:
@@ -340,20 +340,20 @@ void sp_file_convert_dpi(SPDocument *doc)
     }
 
     switch (root->height.unit) {
-        case SP_CSS_UNIT_PC:
-        case SP_CSS_UNIT_PT:
-        case SP_CSS_UNIT_MM:
-        case SP_CSS_UNIT_CM:
-        case SP_CSS_UNIT_IN:
+        case SVGLength::PC:
+        case SVGLength::PT:
+        case SVGLength::MM:
+        case SVGLength::CM:
+        case SVGLength::INCH:
             need_fix_viewbox = true;
             break;
-        case SP_CSS_UNIT_NONE:
-        case SP_CSS_UNIT_PX:
+        case SVGLength::NONE:
+        case SVGLength::PX:
             need_fix_units = true;
             break;
-        case SP_CSS_UNIT_EM:
-        case SP_CSS_UNIT_EX:
-        case SP_CSS_UNIT_PERCENT:
+        case SVGLength::EM:
+        case SVGLength::EX:
+        case SVGLength::PERCENT:
             // OK                                                                              
             break;
         default:
diff --git a/src/object/filters/sp-filter-primitive.cpp b/src/object/filters/sp-filter-primitive.cpp
index 8ed14ff3c..d896da571 100644
--- a/src/object/filters/sp-filter-primitive.cpp
+++ b/src/object/filters/sp-filter-primitive.cpp
@@ -170,7 +170,7 @@ Inkscape::XML::Node* SPFilterPrimitive::write(Inkscape::XML::Document *doc, Inks
 
 int SPFilterPrimitive::read_in(gchar const *name)
 {
-    if (!name || !this){
+    if (!name){
         return Inkscape::Filters::NR_FILTER_SLOT_NOT_SET;
     }
     // TODO: are these case sensitive or not? (assumed yes)
diff --git a/src/object/sp-paint-server.cpp b/src/object/sp-paint-server.cpp
index 286360efb..1ec4db841 100644
--- a/src/object/sp-paint-server.cpp
+++ b/src/object/sp-paint-server.cpp
@@ -38,9 +38,7 @@ SPPaintServer::~SPPaintServer() = default;
 
 bool SPPaintServer::isSwatch() const
 {
-    if( this ) // Protect against assumption that "vector" always exists.
-        return swatch;
-    return( false );
+    return swatch;
 }
 
 
diff --git a/src/ui/dialog/grid-arrange-tab.cpp b/src/ui/dialog/grid-arrange-tab.cpp
index edfdf2838..ea425a1f1 100644
--- a/src/ui/dialog/grid-arrange-tab.cpp
+++ b/src/ui/dialog/grid-arrange-tab.cpp
@@ -563,7 +563,7 @@ void GridArrangeTab::updateSelection()
 GridArrangeTab::GridArrangeTab(ArrangeDialog *parent)
     : Parent(parent),
       XPadding(_("X:"), _("Horizontal spacing between columns."), UNIT_TYPE_LINEAR, "", "object-columns", &PaddingUnitMenu),
-      YPadding(_("Y:"), _("Vertical spacing between rows."), XPadding, "", "object-rows", &PaddingUnitMenu),
+      YPadding(_("Y:"), _("Vertical spacing between rows."), XPadding, "", "object-rows"),
       PaddingTable(Gtk::manage(new Gtk::Grid()))
 {
      // bool used by spin button callbacks to stop loops where they change each other.
diff --git a/src/ui/dialog/input.cpp b/src/ui/dialog/input.cpp
index 29cb57286..438914d6f 100644
--- a/src/ui/dialog/input.cpp
+++ b/src/ui/dialog/input.cpp
@@ -856,20 +856,20 @@ void InputDialogImpl::setupTree( Glib::RefPtr<Gtk::TreeStore> store, Gtk::TreeIt
                 deviceRow[getCols().device] = dev;
                 deviceRow[getCols().mode] = dev->getMode();
                 switch ( dev->getSource() ) {
-                    case GDK_SOURCE_MOUSE:
+                    case Gdk::SOURCE_MOUSE:
                         deviceRow[getCols().thumbnail] = getPix(PIX_CORE);
                         break;
-                    case GDK_SOURCE_PEN:
+                    case Gdk::SOURCE_PEN:
                         if (deviceRow[getCols().description] == _("pad")) {
                             deviceRow[getCols().thumbnail] = getPix(PIX_SIDEBUTTONS);
                         } else {
                             deviceRow[getCols().thumbnail] = getPix(PIX_TIP);
                         }
                         break;
-                    case GDK_SOURCE_CURSOR:
+                    case Gdk::SOURCE_CURSOR:
                         deviceRow[getCols().thumbnail] = getPix(PIX_MOUSE);
                         break;
-                    case GDK_SOURCE_ERASER:
+                    case Gdk::SOURCE_ERASER:
                         deviceRow[getCols().thumbnail] = getPix(PIX_ERASER);
                         break;
                     default:
@@ -1759,10 +1759,11 @@ bool InputDialogImpl::eventSnoop(GdkEvent* event)
             /// \fixme GTK3 added new GDK_SOURCEs that should be handled here!
             case GDK_SOURCE_KEYBOARD:
             case GDK_SOURCE_TOUCHSCREEN:
-            case GDK_SOURCE_TOUCHPAD: {
+            case GDK_SOURCE_TOUCHPAD:
+            case GDK_SOURCE_TRACKPOINT:
+            case GDK_SOURCE_TABLET_PAD:
                  g_warning("InputDialogImpl::eventSnoop : unhandled GDK_SOURCE type!");
                  break;
-            }
         }
 
         updateTestButtons(key, hotButton);
diff --git a/src/ui/dialog/styledialog.cpp b/src/ui/dialog/styledialog.cpp
index 884da2df2..7dfe2d7e8 100644
--- a/src/ui/dialog/styledialog.cpp
+++ b/src/ui/dialog/styledialog.cpp
@@ -1082,7 +1082,7 @@ void StyleDialog::_writeStyleElement(Glib::RefPtr<Gtk::TreeStore> store, Glib::u
 
         std::string pos = std::to_string(selectorpos);
         std::string selectormatch = "(";
-        for (selectorpos; selectorpos > 1; selectorpos--) {
+        for (; selectorpos > 1; selectorpos--) {
             selectormatch = selectormatch + "[^}]*?}";
         }
         selectormatch = selectormatch + ")([^}]*?})((.|\n)*)";
diff --git a/src/ui/previewable.h b/src/ui/previewable.h
index 6c611a668..c25f2dbb6 100644
--- a/src/ui/previewable.h
+++ b/src/ui/previewable.h
@@ -32,11 +32,6 @@ enum PreviewStyle {
     PREVIEW_STYLE_PREVIEW_BLURB
 };
 
-enum ViewType {
-    VIEW_TYPE_LIST = 0,
-    VIEW_TYPE_GRID
-};
-
 
 class Previewable
 {
diff --git a/src/ui/previewholder.cpp b/src/ui/previewholder.cpp
index 1787665f2..28fcc5c6b 100644
--- a/src/ui/previewholder.cpp
+++ b/src/ui/previewholder.cpp
@@ -137,7 +137,7 @@ void PreviewHolder::addPreview( Previewable* preview )
         int i = items.size() - 1;
 
         switch(_view) {
-            case VIEW_TYPE_LIST:
+            case UI::Widget::VIEW_TYPE_LIST:
                 {
                     Gtk::Widget* label = Gtk::manage(preview->getPreview(UI::Widget::PREVIEW_STYLE_BLURB,
                                                                          UI::Widget::VIEW_TYPE_LIST,
@@ -156,7 +156,7 @@ void PreviewHolder::addPreview( Previewable* preview )
                 }
 
                 break;
-            case VIEW_TYPE_GRID:
+            case UI::Widget::VIEW_TYPE_GRID:
                 {
                     Gtk::Widget* item = Gtk::manage(items[i]->getPreview(UI::Widget::PREVIEW_STYLE_PREVIEW,
                                                                          UI::Widget::VIEW_TYPE_GRID,
@@ -367,7 +367,7 @@ void PreviewHolder::rebuildUI()
     }
 
     switch (_view) {
-        case VIEW_TYPE_LIST:
+        case UI::Widget::VIEW_TYPE_LIST:
         {
             _insides->set_column_spacing(8);
 
@@ -388,7 +388,7 @@ void PreviewHolder::rebuildUI()
         }
         break;
 
-        case VIEW_TYPE_GRID:
+        case UI::Widget::VIEW_TYPE_GRID:
         {
             int col = 0;
             int row = 0;
diff --git a/src/ui/tool/node.cpp b/src/ui/tool/node.cpp
index e1b63370c..addc0759c 100644
--- a/src/ui/tool/node.cpp
+++ b/src/ui/tool/node.cpp
@@ -264,26 +264,23 @@ void Handle::setDirection(Geom::Point const &dir)
     setRelativePos(unitdir * length());
 }
 
+/**
+ * See also: Node::node_type_to_localized_string(NodeType type)
+ */
 char const *Handle::handle_type_to_localized_string(NodeType type)
 {
-    char const *s = "";
-
     switch(type) {
     case NODE_CUSP:
-        s = _("Corner node handle");
-        break;
+        return _("Corner node handle");
     case NODE_SMOOTH:
-        s = _("Smooth node handle");
-        break;
+        return _("Smooth node handle");
     case NODE_SYMMETRIC:
-        s = _("Symmetric node handle");
-        break;
+        return _("Symmetric node handle");
     case NODE_AUTO:
-        s = _("Auto-smooth node handle");
-        break;
+        return _("Auto-smooth node handle");
+    default:
+        return "";
     }
-
-    return (s);
 }
 
 bool Handle::_eventHandler(Inkscape::UI::Tools::ToolBase *event_context, GdkEvent *event)
@@ -1627,26 +1624,23 @@ Glib::ustring Node::_getDragTip(GdkEventMotion */*event*/) const
     return ret;
 }
 
+/**
+ * See also: Handle::handle_type_to_localized_string(NodeType type)
+ */
 char const *Node::node_type_to_localized_string(NodeType type)
 {
-    char const *s = "";
-
     switch (type) {
     case NODE_CUSP:
-        s = _("Corner node");
-        break;
+        return _("Corner node");
     case NODE_SMOOTH:
-        s = _("Smooth node");
-        break;
+        return _("Smooth node");
     case NODE_SYMMETRIC:
-        s = _("Symmetric node");
-        break;
+        return _("Symmetric node");
     case NODE_AUTO:
-        s = _("Auto-smooth node");
-        break;
+        return _("Auto-smooth node");
+    default:
+        return "";
     }
-
-    return (s);
 }
 
 bool Node::_is_line_segment(Node *first, Node *second)
diff --git a/src/ui/widget/color-scales.cpp b/src/ui/widget/color-scales.cpp
index 03d5767a9..a93ab2a16 100644
--- a/src/ui/widget/color-scales.cpp
+++ b/src/ui/widget/color-scales.cpp
@@ -707,7 +707,7 @@ static const gchar *sp_color_scales_hue_map()
             *p++ = SP_COLOR_F_TO_U(rgb[0]);
             *p++ = SP_COLOR_F_TO_U(rgb[1]);
             *p++ = SP_COLOR_F_TO_U(rgb[2]);
-            *p++ = 255;
+            *p++ = 0xFF;
         }
     }