3 files changed, 23 insertions, 1 deletions
diff --git a/src/cd.c b/src/cd.c
index b88cc1b..6435d0a 100644
--- a/src/cd.c
+++ b/src/cd.c
@@ -586,6 +586,20 @@ void cdCanvasClear(cdCanvas* canvas)
   canvas->cxClear(canvas->ctxcanvas);
 }
 
+int cdCanvasYAxisMode(cdCanvas* canvas, int invert)
+{
+  int old_invert_yaxis;
+  assert(canvas);
+  if (!_cdCheckCanvas(canvas)) return CD_ERROR;
+
+  if (invert == CD_QUERY)
+    return canvas->invert_yaxis;
+
+  old_invert_yaxis = canvas->invert_yaxis;
+  canvas->invert_yaxis = invert;
+  return old_invert_yaxis;
+}
+
 int cdCanvasUpdateYAxis(cdCanvas* canvas, int* y)
 {
   assert(canvas);
@@ -609,7 +623,7 @@ double cdfCanvasUpdateYAxis(cdCanvas* canvas, double* y)
   assert(y);
   if (!_cdCheckCanvas(canvas)) return CD_ERROR;
 
-  if(canvas->invert_yaxis)
+  if (canvas->invert_yaxis)
   {
     *y = _cdInvertYAxis(canvas, *y);
 
diff --git a/src/cd.def b/src/cd.def
index dd2f7ed..0aa2c35 100644
--- a/src/cd.def
+++ b/src/cd.def
@@ -297,6 +297,7 @@ EXPORTS
   cdCanvasInvertYAxis
   cdfCanvasUpdateYAxis
   cdfCanvasInvertYAxis
+  cdCanvasYAxisMode
   cdContextRegisterCallback
   cdCanvasBackground
   cdCanvasForeground
diff --git a/src/lua5/cdlua5_canvas.c b/src/lua5/cdlua5_canvas.c
index eeecc6d..7fb5402 100644
--- a/src/lua5/cdlua5_canvas.c
+++ b/src/lua5/cdlua5_canvas.c
@@ -273,6 +273,12 @@ static int cdlua5_updateyaxis(lua_State *L)
   return 1;
 }
 
+static int cdlua5_yaxismode(lua_State *L)
+{
+  lua_pushnumber(L, cdCanvasYAxisMode(cdlua_checkcanvas(L, 1), luaL_checkint(L, 2)));
+  return 1;
+}
+
 static int cdlua5_invertyaxis(lua_State *L)
 {
   lua_pushnumber(L, cdfCanvasInvertYAxis(cdlua_checkcanvas(L, 1), luaL_checknumber(L, 2)));
@@ -2192,6 +2198,7 @@ static const struct luaL_reg cdlib_canvas_meta[] = {
   /* Coordinate System */
   {"GetSize"       , cdlua5_getcanvassize},
   {"UpdateYAxis"   , cdlua5_updateyaxis},
+  {"YAxisMode"     , cdlua5_yaxismode},
   {"InvertYAxis"   , cdlua5_invertyaxis},
   {"MM2Pixel"      , cdlua5_mm2pixel},
   {"Pixel2MM"      , cdlua5_pixel2mm},