Added scroll bounds

Resolves #9
Resolves #6
Resolves #3

data/core/docview.lua

@@ -127,7 +127,7 @@ end
 
 
 function DocView:get_scrollable_size()
-  return self:get_line_height() * #self.doc.lines + style.padding.y * 2
+  return self:get_line_height() * (#self.doc.lines - 1) + self.size.y
 end
 
 

data/core/logview.lua

@@ -27,7 +27,6 @@ function LogView:update()
     self.yoffset = -(style.font:get_height() + style.padding.y)
   end
 
-  self.scroll.to.y = math.max(0, self.scroll.to.y)
   self:move_towards("yoffset", 0)
 
   LogView.super.update(self)

data/core/view.lua

@@ -45,13 +45,13 @@ end
 
 
 function View:get_scrollable_size()
-  return 0
+  return math.huge
 end
 
 
 function View:get_scrollbar_rect()
   local sz = self:get_scrollable_size()
-  if sz <= self.size.y then
+  if sz <= self.size.y or sz == math.huge then
     return 0, 0, 0, 0
   end
   local h = math.max(20, self.size.y * self.size.y / sz)
@@ -117,7 +117,14 @@ function View:get_content_offset()
 end
 
 
+function View:clamp_scroll_position()
+  local max = self:get_scrollable_size() - self.size.y
+  self.scroll.to.y = common.clamp(self.scroll.to.y, 0, max)
+end
+
+
 function View:update()
+  self:clamp_scroll_position()
   self:move_towards(self.scroll, "x", self.scroll.to.x, 0.3)
   self:move_towards(self.scroll, "y", self.scroll.to.y, 0.3)
 end