diff --git a/src/Brush.py b/src/Brush.py
index 9b22859..7c95d7a 100644
--- a/src/Brush.py
+++ b/src/Brush.py
@@ -85,30 +85,48 @@ def LayerApplied(self):
 
     # ----- for test -----
     def DrawLine(self, x0, y0, x1, y1):
+        # print('draw', (x0, y0), (x1, y1))
+        dx = x1 - x0
+        dy = y1 - y0
+        ab = 1 if dy > 0 else -1
+        if dx == 0:
+            for y in range(y0, y1 + ab, ab):
+                self.pencil.OnMouseDown((x0, y), self._layer)
+            return
         if x0 > x1:
             x0, x1 = x1, x0
             y0, y1 = y1, y0
-        print(' ')
-        print((x0, y0), (x1, y1))
-        dx = x1 - x0
-        dy = y1 - y0 - 1
+            dy = -dy
+            ab = -ab
+        # print(' ')
+        # print((x0, y0), (x1, y1))
         slope = abs(dy / dx)
-        print(dx, dy)
-        print(slope)
-        ab = 1 if dy > 0 else -1
+        # print(dx, dy)
+        # print(slope)
         error = 0
-        y = y0
-        for x in range(x0, x1 + 1):
-            print('x:', x)
-            self.pencil.OnMouseDown((x, y), self._layer)
-            print((x, y))
-            error += slope
-            while error >= 0.5:
-                error -= 1
+        if slope < 1:
+            y = y0
+            for x in range(x0, x1 + 1):
+                # print((x, y), error)
                 self.pencil.OnMouseDown((x, y), self._layer)
-                print((x, y))
-                if y != y1:
+                error += slope
+                if error > 0.5:
+                    error -= 1
+                    self.pencil.OnMouseDown((x, y), self._layer)
+                    # print((x, y), error)
                     y += ab
+        else:
+            slope = 1 / slope
+            x = x0
+            for y in range(y0, y1 + ab, ab):
+                self.pencil.OnMouseDown((x, y), self._layer)
+                # print((x, y), error)
+                error += slope
+                if error > 0.5:
+                    error -= 1
+                    # print((x, y), error)
+                    self.pencil.OnMouseDown((x, y), self._layer)
+                    x += 1
             # if error > 0.5:
             #     for _ in [0] * int(error - 0.5):
             #         self.pencil.OnMouseDown((x, y), self._layer)
diff --git a/src/Section.py b/src/Section.py
index 7eb89ba..c33e4a1 100644
--- a/src/Section.py
+++ b/src/Section.py
@@ -80,8 +80,6 @@ class CanvasSection(Section):
     maxMagnification = 25
     bgColor = (60, 63, 65)
     canvasOutlineWidth = 2
-    # ----- for test -----
-    first = None
 
     def SetupCanvas(self, w, h):
         self.sprite = Sprite.Empty(w, h)
@@ -178,19 +176,11 @@ def PositionToPixel(self, x, y) -> (int, int, bool):
     def OnMouseDown(self, button, x, y):
         if button == 1:
             pass
-            _localX, _localY = self.LocalPosition((x, y))
-            _pixelX, _pixelY, _valid = self.PositionToPixel(_localX, _localY)
+            # _localX, _localY = self.LocalPosition((x, y))
+            # _pixelX, _pixelY, _valid = self.PositionToPixel(_localX, _localY)
             # if _valid:
             #     Brush.OnMouseDown((_pixelX, _pixelY))
             #     self.Changed()
-
-            # ----- for test -----
-            if _valid:
-                if self.first is None:
-                    self.first = (_pixelX, _pixelY)
-                else:
-                    Brush.DrawLine(*self.first, _pixelX, _pixelY)
-                    self.first = None
         elif button == 4:
             self.Magnify(1, self.LocalPosition((x, y)))
         elif button == 5:
@@ -198,10 +188,13 @@ def OnMouseDown(self, button, x, y):
 
     def OnMouseDrag(self, button, x, y, _x, _y):
         if button == 1:
-            _localX, _localY = self.LocalPosition((x, y))
-            _pixelX, _pixelY, _valid = self.PositionToPixel(_localX, _localY)
-            if _valid:
-                Brush.OnMouseDown((_pixelX, _pixelY))
+            _pixelX, _pixelY, _valid = self.PositionToPixel(*self.LocalPosition((x, y)))
+            _prePixelX, _prePixelY, _preValid = self.PositionToPixel(*self.LocalPosition((_x, _y)))
+            if _valid and _preValid:
+                if abs(_prePixelX - _pixelX) > 1 or abs(_prePixelY - _pixelY) > 1:
+                    Brush.DrawLine(_prePixelX, _prePixelY, _pixelX, _pixelY)
+                else:
+                    Brush.OnMouseDown((_pixelX, _pixelY))
                 self.Changed()
         elif button == 2:
             self.MoveCanvas(x - _x, y - _y)
diff --git a/src/Window.py b/src/Window.py
index e8cb42a..b39b2bb 100644
--- a/src/Window.py
+++ b/src/Window.py
@@ -61,9 +61,9 @@ def MainLoop(self):
 
             self.clock.tick(self.fps)
 
-            # cnt += 1
-            # if cnt % 200 == 0:
-            #     print(self.clock.get_fps())
+            cnt += 1
+            if cnt % 200 == 0:
+                print(self.clock.get_fps())
 
     def GetMouseSection(self):
         if CanvasSection.IsClicked((self.mouseX, self.mouseY)):