start implementing the mouse handler

Until now the hover actions were happening in surface coordinates sx/sy
but the mouse press action (done so far) was happening in viewport
coordinates vx/vy. Now it's consistent. Surface coordinates make more
sense since most data in memory uses them.

0006-on.mouse_press

@@ -3,11 +3,12 @@ on.mouse_press = function(x,y, mouse_button)
 		Cursor_node.show_cursor = nil
 		Cursor_node = nil
 	end
-	local node = to_text(x,y)
+	local sx, sy = sx(x), sy(y)
+	local node = to_node(sx,sy)
 	if node then
 		Cursor_node = node
 		edit.mouse_press(node.editor, x,y, mouse_button)
 	else
-		Pan = {x=Viewport.x+x/Viewport.zoom,y=Viewport.y+y/Viewport.zoom}
+		Pan = {x=sx,y=sy}
 	end
-end
+end

0007-to_text

@@ -1,11 +0,0 @@
-to_text = function(x,y)
-	for _,node in ipairs(Surface) do
-		if node.type == 'text' then
-			if x >= vx(node.x) and node.w and x < vx(node.x + node.w) then
-				if y >= vy(node.y) and node.h and y < vy(node.y + node.h) then
-					return node
-				end
-			end
-		end
-	end
-end

0036-on_move_bar

@@ -2,7 +2,7 @@ on_move_bar = function(sx,sy)
 	for _,node in ipairs(Nodes) do
 		if sx >= node.x-10 and sx < node.x-10+node.w/2 then
 			if sy >= node.y - 40 and sy < node.y-20 then
-				return true
+				return node
 			end
 		end
 	end

0037-on_resize

@@ -3,7 +3,7 @@ on_resize = function(sx,sy)
 		if sx >= node.x+node.w+20 and sx < node.x+node.w+24 then
 			local buffer_height = math.max(node.h, 3*node.editor.line_height)
 			if sy >= node.y and sy < node.y+buffer_height then
-				return true
+				return node
 			end
 		end
 	end

0038-to_node

@@ -0,0 +1,12 @@
+to_node = function(sx,sy)
+	for _,node in ipairs(Surface) do
+		if node.type == 'text' then
+			if sx >= node.x and sx < node.x + node.w then
+				local buffer_height = math.max(node.h, 3*node.editor.line_height)
+				if sy >= node.y and sy < node.y + buffer_height then
+					return node
+				end
+			end
+		end
+	end
+end