diff --git a/src/Makefile b/src/Makefile
index 13466fff..448e5cab 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -391,7 +391,7 @@ endif
 .PHONY : all debug release clean depend zip version force install uninstall
 
 # This is the list of the objects we want to build. Dependancies are built by "make depend" automatically.
-OBJ = $(OBJDIR)/main.o $(OBJDIR)/init.o $(OBJDIR)/graph.o $(OBJDIR)/sdlscreen.o  $(OBJDIR)/misc.o $(OBJDIR)/special.o $(OBJDIR)/buttons.o $(OBJDIR)/palette.o $(OBJDIR)/help.o $(OBJDIR)/operatio.o $(OBJDIR)/pages.o $(OBJDIR)/loadsave.o $(OBJDIR)/readline.o $(OBJDIR)/engine.o $(OBJDIR)/filesel.o $(OBJDIR)/op_c.o $(OBJDIR)/readini.o $(OBJDIR)/saveini.o $(OBJDIR)/shade.o $(OBJDIR)/keyboard.o $(OBJDIR)/io.o $(OBJDIR)/version.o $(OBJDIR)/text.o $(OBJDIR)/SFont.o $(OBJDIR)/setup.o $(OBJDIR)/pxsimple.o $(OBJDIR)/pxtall.o $(OBJDIR)/pxwide.o $(OBJDIR)/pxdouble.o $(OBJDIR)/pxtriple.o $(OBJDIR)/pxtall2.o $(OBJDIR)/pxwide2.o $(OBJDIR)/pxquad.o $(OBJDIR)/windows.o $(OBJDIR)/brush.o $(OBJDIR)/realpath.o $(OBJDIR)/mountlist.o $(OBJDIR)/input.o $(OBJDIR)/hotkeys.o $(OBJDIR)/transform.o $(OBJDIR)/pversion.o $(OBJDIR)/factory.o $(PLATFORMOBJ) $(OBJDIR)/fileformats.o $(OBJDIR)/miscfileformats.o $(OBJDIR)/libraw2crtc.o $(OBJDIR)/brush_ops.o $(OBJDIR)/buttons_effects.o $(OBJDIR)/layers.o $(OBJDIR)/oldies.o 
+OBJ = $(OBJDIR)/main.o $(OBJDIR)/init.o $(OBJDIR)/graph.o $(OBJDIR)/sdlscreen.o  $(OBJDIR)/misc.o $(OBJDIR)/special.o $(OBJDIR)/buttons.o $(OBJDIR)/palette.o $(OBJDIR)/help.o $(OBJDIR)/operatio.o $(OBJDIR)/pages.o $(OBJDIR)/loadsave.o $(OBJDIR)/readline.o $(OBJDIR)/engine.o $(OBJDIR)/filesel.o $(OBJDIR)/op_c.o $(OBJDIR)/readini.o $(OBJDIR)/saveini.o $(OBJDIR)/shade.o $(OBJDIR)/keyboard.o $(OBJDIR)/io.o $(OBJDIR)/version.o $(OBJDIR)/text.o $(OBJDIR)/SFont.o $(OBJDIR)/setup.o $(OBJDIR)/pxsimple.o $(OBJDIR)/pxtall.o $(OBJDIR)/pxwide.o $(OBJDIR)/pxdouble.o $(OBJDIR)/pxtriple.o $(OBJDIR)/pxtall2.o $(OBJDIR)/pxwide2.o $(OBJDIR)/pxquad.o $(OBJDIR)/windows.o $(OBJDIR)/brush.o $(OBJDIR)/realpath.o $(OBJDIR)/mountlist.o $(OBJDIR)/input.o $(OBJDIR)/hotkeys.o $(OBJDIR)/transform.o $(OBJDIR)/pversion.o $(OBJDIR)/factory.o $(PLATFORMOBJ) $(OBJDIR)/fileformats.o $(OBJDIR)/miscfileformats.o $(OBJDIR)/libraw2crtc.o $(OBJDIR)/brush_ops.o $(OBJDIR)/buttons_effects.o $(OBJDIR)/layers.o $(OBJDIR)/oldies.o $(OBJDIR)/tiles.o 
 
 SKIN_FILES = ../share/grafx2/skins/skin_classic.png ../share/grafx2/skins/skin_modern.png ../share/grafx2/skins/skin_DPaint.png ../share/grafx2/skins/font_Classic.png ../share/grafx2/skins/font_Fun.png ../share/grafx2/skins/font_Fairlight.png ../share/grafx2/skins/font_Melon.png ../share/grafx2/skins/font_DPaint.png ../share/grafx2/skins/skin_scenish.png ../share/grafx2/skins/font_Seen.png ../share/grafx2/skins/skin_Aurora.png
 
diff --git a/src/buttons_effects.c b/src/buttons_effects.c
index ed22df6f..2bf09ba3 100644
--- a/src/buttons_effects.c
+++ b/src/buttons_effects.c
@@ -193,6 +193,8 @@ void Button_Constraint_menu(void)
 void Button_Tilemap_mode(void)
 {
   Tilemap_mode=!Tilemap_mode;
+  if (Tilemap_mode)
+    Tilemap_create();
 }
 
 void Button_Tilemap_menu(void)
@@ -830,7 +832,9 @@ void Effects_off(void)
   Stencil_mode=0;
   Mask_mode=0;
   Sieve_mode=0;
-  Snap_mode=0;  
+  Snap_mode=0;
+  Constraint_mode=0;
+  Tilemap_mode=0;
 }
 
 
diff --git a/src/global.h b/src/global.h
index 191258cd..961722b6 100644
--- a/src/global.h
+++ b/src/global.h
@@ -348,6 +348,12 @@ GFX2_GLOBAL Uint32 Main_time_of_safety_backup;
 /// Letter prefix for the filenames of safety backups. a or b
 GFX2_GLOBAL byte Main_safety_backup_prefix;
 
+/// Tilemap for the main screen
+GFX2_GLOBAL T_Tile * Main_tilemap;
+
+GFX2_GLOBAL short Main_tilemap_width;
+GFX2_GLOBAL short Main_tilemap_height;
+
 // -- Spare page data
 
 /// Palette of the spare page
diff --git a/src/graph.c b/src/graph.c
index f4c024d1..682eb302 100644
--- a/src/graph.c
+++ b/src/graph.c
@@ -2748,11 +2748,7 @@ void Display_pixel(word x,word y,byte color)
     color=Effect_function(x,y,color);
     if (Tilemap_mode)
     {
-      int xx,yy;
-      for (yy=(y-Snap_offset_Y)%Snap_height+Snap_offset_Y;yy<Main_image_height;yy+=Snap_height)
-        for (xx=(x-Snap_offset_X)%Snap_width+Snap_offset_X;xx<Main_image_width;xx+=Snap_width)
-          Pixel_in_current_screen(xx,yy,color,yy>=Limit_top&&yy<=Limit_bottom&&xx>=Limit_left&&xx<=Limit_right);
-      Update_rect(0,0,0,0);
+      Tilemap_draw(x,y, color);
     }
     else
       Pixel_in_current_screen(x,y,color,1);
diff --git a/src/struct.h b/src/struct.h
index 25b2c2ea..4042ff00 100644
--- a/src/struct.h
+++ b/src/struct.h
@@ -543,4 +543,11 @@ typedef enum {
   MENUBAR_COUNT
 } T_Menubars;
 
+typedef struct
+{
+  int Previous_occurence;
+  int Next_occurence;
+  int First_occurence;
+} T_Tile;
+
 #endif
diff --git a/src/tiles.c b/src/tiles.c
index 32078abc..5049350e 100644
--- a/src/tiles.c
+++ b/src/tiles.c
@@ -2,7 +2,8 @@
 */
 /*  Grafx2 - The Ultimate 256-color bitmap paint program
 
-    Copyright 2010 Adrien Destugues
+    Copyright 2011 Yves Rizoud
+    Copyright 2010-2011 Adrien Destugues
 
     Grafx2 is free software; you can redistribute it and/or
     modify it under the terms of the GNU General Public License
@@ -18,7 +19,12 @@
     along with Grafx2; if not, see <http://www.gnu.org/licenses/>
 */
 
-/// \file Handle tiles.
+#include "struct.h"
+#include "global.h"
+#include "graph.h"
+#include "sdlscreen.h"
+#include "tiles.h"
+
 
 /// Build the tile-area from the current picture 
 void build_tile_area()
@@ -28,7 +34,7 @@ void build_tile_area()
 
 	int* tileArea = malloc(tileAreaWidth*tileAreaHeight*sizeof(int));
 
-	word tile_x, tile_y, pixel_x, pixel_y;
+	word tile_x, tile_y;
 
 	// For each tile, we have to crawl up to the top of the picture and
 	// find the first identical tile
@@ -36,7 +42,7 @@ void build_tile_area()
 		for(tile_x = 0; tile_x < tileAreaHeight; tile_x++)
 		{
 			// So, this is the "for each tile"
-			word ctx, cty;
+			short ctx, cty;
 			// First we compare the tile with the others one in the same line at the left
 			for(ctx = tile_x - 1; ctx >= 0; ctx--)
 			if(compare_tiles(tile_x*Snap_width, tile_y*Snap_height, ctx*Snap_width, tile_y*Snap_height))
@@ -75,14 +81,15 @@ void build_tile_area()
 				tileArea[tile_y*tileAreaWidth+tile_x] = tile_y*tileAreaWidth+ctx;
 			}
 			
-found:
+      found:
+      ;
 		}
 }
 
 
 // Compare tiles
 // The parameters are in pixel-space.
-void compare_tiles(word x1, word y1, word x2, word y2)
+int compare_tiles(word x1, word y1, word x2, word y2)
 {
 	word pixel_x, pixel_y;
 	byte c1, c2;
@@ -90,14 +97,14 @@ void compare_tiles(word x1, word y1, word x2, word y2)
 	for (pixel_y = 0; pixel_y < Snap_width; pixel_y++)
 	for (pixel_x = 0; pixel_x < Snap_height; pixel_x++)
 	{
-		c1 = Main_screen + (y1+pixel_y) * Main_image_width + (x1+pixel_x);
-		c2 = Main_screen + (y2+pixel_y) * Main_image_width + (x2+pixel_x);
+		c1 = *(Main_screen + (y1+pixel_y) * Main_image_width + (x1+pixel_x));
+		c2 = *(Main_screen + (y2+pixel_y) * Main_image_width + (x2+pixel_x));
 		if (c1 != c2) return 0;
 	}
 
 	return 1;
 }
-
+/*
 /// Copy a tile pixeldata to all the identical ones
 // Call this after the end of an operation
 void update_tile(word pixel_x, word pixel_y)
@@ -112,3 +119,127 @@ void update_tile(word pixel_x, word pixel_y)
 		//do the copy of a block starting at (pixel_x, pixel_y)
 	}
 }
+*/
+
+/* Basic repeat-all
+void Tilemap_draw(word x, word y, byte color)
+{
+  int xx,yy;
+  for (yy=(y+Snap_height-Snap_offset_Y)%Snap_height+Snap_offset_Y;yy<Main_image_height;yy+=Snap_height)
+    for (xx=(x+Snap_width-Snap_offset_X)%Snap_width+Snap_offset_X;xx<Main_image_width;xx+=Snap_width)
+      Pixel_in_current_screen(xx,yy,color,yy>=Limit_top&&yy<=Limit_bottom&&xx>=Limit_left&&xx<=Limit_right);
+  Update_rect(0,0,0,0);
+}
+*/
+
+void Tilemap_draw(word x, word y, byte color)
+{
+  int tile, first_tile;
+  int rel_x, rel_y;
+  
+  if (x < Snap_offset_X
+   || y < Snap_offset_Y
+   || x >= Snap_offset_X + Main_tilemap_width*Snap_width
+   || y >= Snap_offset_Y + Main_tilemap_height*Snap_height)
+    return;
+  
+  tile = first_tile = TILE_FOR_COORDS(x,y);
+  rel_x = (x + Snap_offset_X + Snap_width) % Snap_width;
+  rel_y = (y + Snap_offset_Y + Snap_height) % Snap_height;
+  do
+  {
+    int xx,yy;
+    xx = (tile % Main_tilemap_width)*Snap_width+Snap_offset_X + rel_x;
+    yy = (tile / Main_tilemap_width)*Snap_height+Snap_offset_Y + rel_y;
+    Pixel_in_current_screen(xx,yy,color,yy>=Limit_top&&yy<=Limit_bottom&&xx>=Limit_left&&xx<=Limit_right);
+    tile = Main_tilemap[tile].Next_occurence;
+  } while (tile != first_tile);
+
+  Update_rect(0,0,0,0);
+}
+
+///
+int Tile_is_same(int t1, int t2)
+{
+  byte *bmp1,*bmp2;
+  int y;
+  
+  bmp1 = Main_screen+(TILE_Y(t1))*Main_image_width+(TILE_X(t1));
+  bmp2 = Main_screen+(TILE_Y(t2))*Main_image_width+(TILE_X(t2));
+  
+  for (y=0; y < Snap_height; y++)
+  {
+    if (memcmp(bmp1+y*Main_image_width, bmp2+y*Main_image_width, Snap_width))
+      return 0;
+  }
+  return 1;
+}
+
+/// Create or update a tilemap based on current screen pixels.
+void Tilemap_create(void)
+{
+  int width;
+  int height;
+  int tile;
+  T_Tile * tile_ptr;
+
+  width=(Main_image_width-Snap_offset_X)/Snap_width;
+  height=(Main_image_height-Snap_offset_Y)/Snap_height;
+  
+  if (width<1 || height<1 || width*height>1000000l
+   || (tile_ptr=(T_Tile *)malloc(width*height*sizeof(T_Tile))) == NULL)
+  {
+    if (Main_tilemap)
+    {
+      free(Main_tilemap);
+      Main_tilemap=NULL;
+    }
+    Main_tilemap_width=0;
+    Main_tilemap_height=0;
+    Tilemap_mode=0;
+    return;
+  }
+  Main_tilemap_width=width;
+  Main_tilemap_height=height;
+  Main_tilemap=tile_ptr;
+  
+  // Init array
+  for (tile=0; tile<width*height; tile++)
+  {
+    Main_tilemap[tile].Previous_occurence = tile;
+    Main_tilemap[tile].Next_occurence = tile;
+    //Main_tilemap[tile].First_occurence = 1;
+  }
+  
+  for (tile=1; tile<width*height; tile++)
+  {
+    int ref_tile=0;
+    while(1)
+    {
+      if (Main_tilemap[ref_tile].Previous_occurence<=ref_tile && Tile_is_same(ref_tile, tile))
+      {
+        // Insert at end
+        int last_tile=Main_tilemap[ref_tile].Previous_occurence;
+        Main_tilemap[tile].Previous_occurence=last_tile;
+        Main_tilemap[tile].Next_occurence=ref_tile;
+        //Main_tilemap[tile].First_occurence=0;
+        
+        Main_tilemap[ref_tile].Previous_occurence=tile;
+        Main_tilemap[last_tile].Next_occurence=tile;
+        
+        break;
+      }
+
+      ref_tile++;
+
+      if (ref_tile>=tile)
+      {
+        // New unique tile
+        //Main_tilemap[tile].First_occurence=1;
+        break;
+      }
+    }
+    
+  }
+  
+}
\ No newline at end of file