diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7a11806..27716d6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -55,6 +55,9 @@ endif()
 
 if(CMAKE_CXX_COMPILER_ID STREQUAL GNU OR CMAKE_CXX_COMPILER_ID STREQUAL Clang)
     set(WARNING_FLAGS   "-Wall -Wextra -Wno-unused-parameter")
+    if(CMAKE_CXX_COMPILER_ID STREQUAL Clang)
+        set(WARNING_FLAGS "${WARNING_FLAGS} -Wfloat-conversion")
+    endif()
     set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS} ${WARNING_FLAGS}")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 ${WARNING_FLAGS}")
 endif()
diff --git a/src/glhelper.cpp b/src/glhelper.cpp
index 08564b7..e08aa07 100644
--- a/src/glhelper.cpp
+++ b/src/glhelper.cpp
@@ -713,7 +713,7 @@ double ssglStrWidth(const std::string &str, double h)
 {
     LoadVectorFont();
 
-    int width = 0;
+    double width = 0;
     for(char32_t codepoint : ReadUTF8(str)) {
         width += BuiltinVectorFont.GetGlyph(codepoint).advanceWidth;
     }
@@ -728,11 +728,11 @@ static Vector PixelAlign(Vector v) {
     return v;
 }
 
-static int DrawCharacter(const VectorFont::Glyph &glyph, Vector t, Vector o, Vector u, Vector v,
-                         double scale, ssglLineFn *fn, void *fndata, bool gridFit) {
-    int advanceWidth = glyph.advanceWidth;
+static double DrawCharacter(const VectorFont::Glyph &glyph, Vector t, Vector o, Vector u, Vector v,
+                            double scale, ssglLineFn *fn, void *fndata, bool gridFit) {
+    double advanceWidth = glyph.advanceWidth;
 
-    int actualWidth, offsetX;
+    double actualWidth, offsetX;
     if(gridFit) {
         o.x         += glyph.leftSideBearing;
         offsetX      = glyph.leftSideBearing;
diff --git a/src/mouse.cpp b/src/mouse.cpp
index d013d4e..a77e1e0 100644
--- a/src/mouse.cpp
+++ b/src/mouse.cpp
@@ -1294,7 +1294,7 @@ void GraphicsWindow::MouseLeftDoubleClick(double mx, double my) {
         hStyle hs = c->disp.style;
         if(hs.v == 0) hs.v = Style::CONSTRAINT;
         ShowGraphicsEditControl((int)p2.x, (int)p2.y,
-                                ssglStrFontSize(Style::TextHeight(hs)) * scale,
+                                (int)(ssglStrFontSize(Style::TextHeight(hs)) * scale),
                                 editMinWidthChar, editValue);
     }
 }
diff --git a/src/platform/gtkmain.cpp b/src/platform/gtkmain.cpp
index dd4cef3..97659f7 100644
--- a/src/platform/gtkmain.cpp
+++ b/src/platform/gtkmain.cpp
@@ -637,11 +637,11 @@ protected:
 
 private:
     int _w, _h;
-    void ij_to_xy(int i, int j, int &x, int &y) {
+    void ij_to_xy(double i, double j, int &x, int &y) {
         // Convert to xy (vs. ij) style coordinates,
         // with (0, 0) at center
-        x = i - _w / 2;
-        y = _h / 2 - j;
+        x = (int)i - _w / 2;
+        y = _h / 2 - (int)j;
     }
 };
 
@@ -1376,7 +1376,7 @@ protected:
     }
 
     virtual void on_scrollbar_value_changed() {
-        SS.TW.ScrollbarEvent(_scrollbar.get_adjustment()->get_value());
+        SS.TW.ScrollbarEvent((int)_scrollbar.get_adjustment()->get_value());
     }
 
     virtual void on_editing_done(Glib::ustring value) {
diff --git a/src/resource.cpp b/src/resource.cpp
index a271da9..808a7d5 100644
--- a/src/resource.cpp
+++ b/src/resource.cpp
@@ -88,7 +88,7 @@ static Pixmap ReadPNGIntoPixmap(png_struct *png_ptr, png_info *info_ptr) {
     Pixmap pixmap = {};
     pixmap.width    = png_get_image_width(png_ptr, info_ptr);
     pixmap.height   = png_get_image_height(png_ptr, info_ptr);
-    pixmap.hasAlpha = png_get_color_type(png_ptr, info_ptr) & PNG_COLOR_MASK_ALPHA;
+    pixmap.hasAlpha = (png_get_color_type(png_ptr, info_ptr) & PNG_COLOR_MASK_ALPHA) != 0;
 
     size_t stride = pixmap.width * pixmap.GetBytesPerPixel();
     if(stride % 4 != 0) stride += 4 - stride % 4;