diff --git a/blitbuffer.c b/blitbuffer.c
index 2294b8d19..123b9cb55 100644
--- a/blitbuffer.c
+++ b/blitbuffer.c
@@ -423,6 +423,67 @@ static int invertRect(lua_State *L) {
 	return 0;
 }
 
+static int dimRect(lua_State *L) {
+	BlitBuffer *dst = (BlitBuffer*) luaL_checkudata(L, 1, "blitbuffer");
+	int x = luaL_checkint(L, 2);
+	int y = luaL_checkint(L, 3);
+	int w = luaL_checkint(L, 4);
+	int h = luaL_checkint(L, 5);
+	uint8_t *dstptr;
+
+	int cy, cx;
+	if(w <= 0 || h <= 0 || x >= dst->w || y >= dst->h) {
+		return 0;
+	}
+	if(x + w > dst->w) {
+		w = dst->w - x;
+	}
+	if(y + h > dst->h) {
+		h = dst->h - y;
+	}
+
+	if(x & 1) {
+		/* This will dimm the leftmost column
+		 * in the case when x is odd. After this,
+		 * x will become even. */
+		dstptr = (uint8_t*)(dst->data + 
+				y * dst->pitch + 
+				x / 2);
+		for(cy = 0; cy < h; cy++) {
+			int px = *dstptr & 0x0F;
+			*dstptr &= 0xF0 | px >> 1;
+			dstptr += dst->pitch;
+		}
+		x++;
+		w--;
+	}
+	dstptr = (uint8_t*)(dst->data + 
+			y * dst->pitch + 
+			x / 2);
+	for(cy = 0; cy < h; cy++) {
+		for(cx = 0; cx < w/2; cx++) {
+			*(dstptr+cx) =
+				*(dstptr+cx) >> 1 & 0xF0 |
+				*(dstptr+cx) & 0x0F >> 1;
+		}
+		dstptr += dst->pitch;
+	}
+	if(w & 1) {
+		/* This will dimm the rightmost column 
+		 * in the case when (w & 1) && !(x & 1) or
+		 * !(w & 1) && (x & 1). */
+		dstptr = (uint8_t*)(dst->data + 
+				y * dst->pitch + 
+				(x + w) / 2);
+		for(cy = 0; cy < h; cy++) {
+			int px = *dstptr & 0xF0;
+			*dstptr &= 0x0F | ( px >> 1 & 0xF0 );
+			dstptr += dst->pitch;
+		}
+	}
+	return 0;
+}
+
 static const struct luaL_Reg blitbuffer_func[] = {
 	{"new", newBlitBuffer},
 	{NULL, NULL}
@@ -436,6 +497,7 @@ static const struct luaL_Reg blitbuffer_meth[] = {
 	{"blitFullFrom", blitFullToBuffer},
 	{"paintRect", paintRect},
 	{"invertRect", invertRect},
+	{"dimRect", dimRect},
 	{"free", freeBlitBuffer},
 	{"__gc", freeBlitBuffer},
 	{NULL, NULL}
diff --git a/crereader.lua b/crereader.lua
index 4578edc19..a1f77deec 100644
--- a/crereader.lua
+++ b/crereader.lua
@@ -111,6 +111,14 @@ function CREReader:goto(pos, pos_type)
 
 	self.doc:drawCurrentPage(self.nulldc, fb.bb)
 
+	print("## self.show_overlap "..self.show_overlap)
+	if self.show_overlap < 0 then
+		fb.bb:dimRect(0,0, width, -self.show_overlap)
+	elseif self.show_overlap > 0 then
+		fb.bb:dimRect(0,height - self.show_overlap, width, self.show_overlap)
+	end
+	self.show_overlap = 0
+
 	if self.rcount == self.rcountmax then
 		print("full refresh")
 		self.rcount = 1
@@ -136,10 +144,12 @@ function CREReader:gotoTocEntry(entry)
 end
 
 function CREReader:nextView()
+	self.show_overlap = -self.pan_overlap_vertical
 	return self.pos + G_height - self.pan_overlap_vertical
 end
 
 function CREReader:prevView()
+	self.show_overlap = self.pan_overlap_vertical
 	return self.pos - G_height + self.pan_overlap_vertical
 end
 
diff --git a/test/tall.pdf b/test/tall.pdf
new file mode 100644
index 000000000..c58ebc3d8
Binary files /dev/null and b/test/tall.pdf differ
diff --git a/unireader.lua b/unireader.lua
index cf3868a41..b856f606d 100644
--- a/unireader.lua
+++ b/unireader.lua
@@ -54,6 +54,7 @@ UniReader = {
 	pan_y = 0,
 	pan_margin = 20, -- horizontal margin for two-column zoom
 	pan_overlap_vertical = 30,
+	show_overlap = 0,
 
 	-- the document:
 	doc = nil,
@@ -555,6 +556,14 @@ function UniReader:show(no)
 		"width:"..width..", height:"..height)
 	fb.bb:blitFrom(bb, dest_x, dest_y, offset_x, offset_y, width, height)
 
+	print("## self.show_overlap "..self.show_overlap)
+	if self.show_overlap < 0 then
+		fb.bb:dimRect(0,0, width, dest_y - self.show_overlap)
+	elseif self.show_overlap > 0 then
+		fb.bb:dimRect(0,dest_y + height - self.show_overlap, width, self.show_overlap)
+	end
+	self.show_overlap = 0
+
 	-- render highlights to page
 	if self.highlight[no] then
 		self:toggleTextHighLight(self.highlight[no])
@@ -671,6 +680,7 @@ function UniReader:nextView()
 			-- goto next view of current page
 			self.offset_y = self.offset_y - G_height
 							+ self.pan_overlap_vertical
+			self.show_overlap = -self.pan_overlap_vertical -- top < 0
 		end
 	else
 		-- not in fit to content width pan mode, just do a page turn
@@ -698,6 +708,7 @@ function UniReader:prevView()
 			-- goto previous view of current page
 			self.offset_y = self.offset_y + G_height
 							- self.pan_overlap_vertical
+			self.show_overlap = self.pan_overlap_vertical -- bottom > 0
 		end
 	else
 		-- not in fit to content width pan mode, just do a page turn
@@ -1186,8 +1197,8 @@ function UniReader:addAllCommands()
 					x = unireader.shift_x / 5
 					y = unireader.shift_y / 5
 				elseif unireader.pan_by_page then
-					x = G_width;
-					y = G_height - unireader.pan_overlap_vertical; -- overlap for lines which didn't fit
+					x = G_width
+					y = G_height - unireader.pan_overlap_vertical -- overlap for lines which didn't fit
 				else
 					x = unireader.shift_x
 					y = unireader.shift_y
@@ -1229,11 +1240,15 @@ function UniReader:addAllCommands()
 					unireader.offset_y = unireader.offset_y + y
 					if unireader.offset_y > 0 then
 						unireader.offset_y = 0
+					elseif unireader.pan_by_page then
+						unireader.show_overlap = unireader.pan_overlap_vertical -- bottom
 					end
 				elseif keydef.keycode == KEY_FW_DOWN then
 					unireader.offset_y = unireader.offset_y - y
 					if unireader.offset_y < unireader.min_offset_y then
 						unireader.offset_y = unireader.min_offset_y
+					elseif unireader.pan_by_page then
+						unireader.show_overlap = -unireader.pan_overlap_vertical -- top
 					end
 				elseif keydef.keycode == KEY_FW_PRESS then
 					if keydef.modifier==MOD_SHIFT then