diff --git a/ddresc_visu/draw.py b/ddresc_visu/draw.py
index 4f4fb9e..d2d33b2 100644
--- a/ddresc_visu/draw.py
+++ b/ddresc_visu/draw.py
@@ -14,7 +14,8 @@ colors = {
 
 BORDERCOLOR = (64,64,64)
 
-W = 1920
+W = 1920 // 2 - 2
+W = 1920 - 2
 H = 1040
 CELLSIZE = 8
 CELLBORDER = 0
@@ -45,22 +46,26 @@ class Visualisation:
 
 		self.mapfile = MapFile(fn, **kwargs)
 		self.mapfile.load()
-
-	def draw(self):
-		self.disp.fill((0,0,0)) # Dark theme :-)
-
+		self.squares = None
+	
+	def gen_squares(self):
+		self.squares = []
 		sz = self.mapfile.size
 		sqsz = max(sz / CELLS, 4096)
-		print(f"INFO: Each square represents {sqsz} bytes")
 		for cid in range(CELLS):
 			start = cid * sqsz
 			end = (cid + 1) * sqsz
 			hist = self.mapfile.get_hist(start, end)
 			symb = get_symb(hist)
 			color = colors[symb]
+			self.squares.append(color)
 
-			line = cid // COLUMNS
-			col = cid % COLUMNS
+	def draw(self):
+		self.disp.fill((0,0,0)) # Dark theme :-)
+		if self.squares is None: self.gen_squares()
+		for cell, color in enumerate(self.squares):
+			line = cell // COLUMNS
+			col = cell % COLUMNS
 			pos = (line, col)
 
 			rect = pygame.Rect(col * CELLOFFSET + CELLBORDER, line * CELLOFFSET + CELLBORDER, CELLSIZE+2*CELLBORDER, CELLSIZE+2*CELLBORDER)
@@ -71,18 +76,22 @@ class Visualisation:
 
 	def reload(self):
 		self.mapfile.load()
+		self.squares = None
 		self.draw()
 	
 	def run(self, *, refresh=2):
-		pygame.time.set_timer(pygame.USEREVENT, refresh * 1000)
+#		pygame.time.set_timer(pygame.USEREVENT, refresh * 1000)
 		pygame.event.set_blocked(None)
-		pygame.event.set_allowed([pygame.USEREVENT, pygame.VIDEORESIZE, pygame.VIDEOEXPOSE, pygame.QUIT, pygame.KEYDOWN])
+#		pygame.event.set_allowed([pygame.USEREVENT, pygame.VIDEORESIZE, pygame.VIDEOEXPOSE, pygame.QUIT, pygame.KEYDOWN])
+		pygame.event.set_allowed([pygame.VIDEORESIZE, pygame.VIDEOEXPOSE, pygame.QUIT, pygame.KEYDOWN])
 		self.draw()
 		while True:
 			ev = pygame.event.wait()
 			if ev.type == pygame.QUIT or ev.type == pygame.KEYDOWN and ev.key == pygame.K_q:
 				return
-			if ev.type in [pygame.VIDEOEXPOSE, pygame.VIDEORESIZE, pygame.USEREVENT]:
+			if ev.type in [pygame.VIDEOEXPOSE, pygame.VIDEORESIZE]:
+				self.draw()
+			if ev.type == pygame.KEYDOWN and ev.key == pygame.K_r:
 				self.reload()
 
 
diff --git a/test.py b/test.py
index 0909bf2..3b99369 100755
--- a/test.py
+++ b/test.py
@@ -30,6 +30,4 @@ args = ap.parse_args()
 
 visu = v.Visualisation(args.file, start=args.start, end=args.end)
 
-
-
 visu.run(refresh=35)