diff --git a/src/lib/sw_engine/tvgSwCommon.h b/src/lib/sw_engine/tvgSwCommon.h
index e06d3782..82a60237 100644
--- a/src/lib/sw_engine/tvgSwCommon.h
+++ b/src/lib/sw_engine/tvgSwCommon.h
@@ -75,13 +75,13 @@ struct SwPoint
         return (x != rhs.x || y != rhs.y);
     }
 
-    bool zero()
+    bool zero() const
     {
         if (x == 0 && y == 0) return true;
         else return false;
     }
 
-    bool small()
+    bool small() const
     {
         //2 is epsilon...
         if (abs(x) < 2 && abs(y) < 2) return true;
diff --git a/src/lib/sw_engine/tvgSwRenderer.cpp b/src/lib/sw_engine/tvgSwRenderer.cpp
index f5cab794..09b199be 100644
--- a/src/lib/sw_engine/tvgSwRenderer.cpp
+++ b/src/lib/sw_engine/tvgSwRenderer.cpp
@@ -40,7 +40,7 @@ struct SwTask : Task
     uint32_t opacity;
     SwBBox bbox = {{0, 0}, {0, 0}};       //Whole Rendering Region
 
-    void bounds(uint32_t* x, uint32_t* y, uint32_t* w, uint32_t* h)
+    void bounds(uint32_t* x, uint32_t* y, uint32_t* w, uint32_t* h) const
     {
         //Range over?
         auto xx = bbox.min.x > 0 ? bbox.min.x : 0;
diff --git a/src/lib/tvgPictureImpl.h b/src/lib/tvgPictureImpl.h
index d39809dd..e3b0c5d5 100644
--- a/src/lib/tvgPictureImpl.h
+++ b/src/lib/tvgPictureImpl.h
@@ -130,7 +130,7 @@ struct Picture::Impl
         return false;
     }
 
-    bool viewbox(float* x, float* y, float* w, float* h)
+    bool viewbox(float* x, float* y, float* w, float* h) const
     {
         if (!loader) return false;
         if (x) *x = loader->vx;
@@ -148,7 +148,7 @@ struct Picture::Impl
         return true;
     }
 
-    bool bounds(float* x, float* y, float* w, float* h)
+    bool bounds(float* x, float* y, float* w, float* h) const
     {
         if (!paint) return false;
         return paint->pImpl->bounds(x, y, w, h);
diff --git a/src/lib/tvgSceneImpl.h b/src/lib/tvgSceneImpl.h
index 5494565e..4745da75 100644
--- a/src/lib/tvgSceneImpl.h
+++ b/src/lib/tvgSceneImpl.h
@@ -81,7 +81,7 @@ struct Scene::Impl
         return true;
     }
 
-    bool bounds(RenderMethod& renderer, uint32_t* px, uint32_t* py, uint32_t* pw, uint32_t* ph)
+    bool bounds(RenderMethod& renderer, uint32_t* px, uint32_t* py, uint32_t* pw, uint32_t* ph) const
     {
         if (paints.count == 0) return false;
 
@@ -113,7 +113,7 @@ struct Scene::Impl
         return true;
     }
 
-    bool bounds(float* px, float* py, float* pw, float* ph)
+    bool bounds(float* px, float* py, float* pw, float* ph) const
     {
         if (paints.count == 0) return false;
 
diff --git a/src/lib/tvgShapeImpl.h b/src/lib/tvgShapeImpl.h
index 14f911e0..c50f9387 100644
--- a/src/lib/tvgShapeImpl.h
+++ b/src/lib/tvgShapeImpl.h
@@ -168,7 +168,7 @@ struct ShapePath
         cmds[cmdCnt++] = PathCommand::Close;
     }
 
-    bool bounds(float* x, float* y, float* w, float* h)
+    bool bounds(float* x, float* y, float* w, float* h) const
     {
         if (ptsCnt == 0) return false;