diff --git a/src/global.h b/src/global.h
index 8d3e8794..3e36627a 100644
--- a/src/global.h
+++ b/src/global.h
@@ -291,8 +291,7 @@ GFX2_GLOBAL int Pixel_width;
 GFX2_GLOBAL int Pixel_height;
 
 
-// -- Current image data
-
+/// Current image data
 GFX2_GLOBAL T_Document Main;
 
 /// Pointer to the pixel data of the main image
@@ -300,8 +299,7 @@ GFX2_GLOBAL byte *    Main_screen;
 /// Lookup table for XOR effects, pointing each color to the most different one
 GFX2_GLOBAL byte xor_lut[256];
 
-// -- Spare page data
-
+/// Spare page data
 GFX2_GLOBAL T_Document Spare;
 
 // -- Image backups
diff --git a/src/graph.c b/src/graph.c
index 075e7e64..6f13f93f 100644
--- a/src/graph.c
+++ b/src/graph.c
@@ -3502,18 +3502,32 @@ static void Pixel_in_screen_overlay_with_opt_preview(word x,word y,byte color,in
 
 Func_pixel_opt_preview Pixel_in_current_screen_with_opt_preview=Pixel_in_screen_direct_with_opt_preview;
 
+/**
+ * Put a pixel in the current layer of a "Document"
+ *
+ * @param doc pointer to either @ref Main or @ref Spare
+ * @param x x coordinate of the pixel to put
+ * @param y y coordinate of the pixel to put
+ * @param color the new color for the pixel
+ */
+void Pixel_in_document_current_layer(T_Document * doc, word x, word y, byte color)
+{
+  doc->backups->Pages->Image[doc->current_layer].Pixels[x + y*doc->image_width] = color;
+}
+
 void Pixel_in_spare(word x,word y, byte color)
 {
-  *((y)*Spare.image_width+(x)+Spare.backups->Pages->Image[Spare.current_layer].Pixels)=color;
+  Pixel_in_document_current_layer(&Spare, x, y, color);
 }
 
 void Pixel_in_current_layer(word x,word y, byte color)
 {
-  *((y)*Main.image_width+(x)+Main.backups->Pages->Image[Main.current_layer].Pixels)=color;
+  Pixel_in_document_current_layer(&Main, x, y, color);
 }
 
 byte Read_pixel_from_current_layer(word x,word y)
 {
+  // return Main.backups->Pages->Image[Main.current_layer].Pixels[x + y*Main.image_width];
   return *((y)*Main.image_width+(x)+Main.backups->Pages->Image[Main.current_layer].Pixels);
 }