Add set_bottom option

spec/index.coffee

@@ -499,7 +499,48 @@ describe "sticky columns", ->
             expect(top cell).toBe 22
             expect(cell.is(".is_stuck")).toBe false
         ]
+
+    it "uses set_bottom", (done) ->
+      write_iframe("""
+        <div class="stick_header">
+          <div class="stick_cell header"></div>
+          <div class="stick_body"></div>
+        </div>
+        <script type="text/javascript">
+          var bar_height = 40
+          $(".stick_cell").stick_in_parent({offset_top: $(window).height() - bar_height, set_bottom: true, bar_height: bar_height})
+        </script>
+
+      """).then (f) ->
+        cell = f.find(".stick_cell")
+
+        # f.on "scroll", => console.warn f.scrollTop(), top cell
+
+        scroll_each f, done, [
+          at 5, =>
+            expect(cell.is(".is_stuck")).toBe true
+            expect(cell.css("bottom")).toBe "0px"
+
+          at 15, =>
+            expect(cell.is(".is_stuck")).toBe true
+            expect(cell.css("bottom")).toBe "0px"
+
+          at 40, =>
+            expect(cell.is(".is_stuck")).toBe true
+            expect(cell.css("bottom")).toBe "0px"
 
+          at 125, =>
+            expect(cell.is(".is_stuck")).toBe true
+            expect(cell.css("bottom")).toBe "0px"
+
+          at 15, =>
+            expect(cell.is(".is_stuck")).toBe true
+            expect(cell.css("bottom")).toBe "0px"
+
+          at 0, =>
+            expect(cell.is(".is_stuck")).toBe true
+            expect(cell.css("bottom")).toBe "0px"
+        ]
 
   describe "events", ->
     it "detects events when scrolling sticky header", (done) ->
@@ -719,4 +760,3 @@ scroll_each = (f, done, points) ->
       done()
 
   scroll_to_next()
-

sticky-kit.coffee

@@ -16,6 +16,8 @@ $.fn.stick_in_parent = (opts={}) ->
     offset_top
     spacer: manual_spacer
     bottoming: enable_bottoming
+    set_bottom
+    bar_height
   } = opts
 
   win_height = win.height()
@@ -92,7 +94,7 @@ $.fn.stick_in_parent = (opts={}) ->
 
           restore = true
 
-        top = elm.offset().top - (parseInt(elm.css("margin-top"), 10) or 0) - offset_top
+        top = if set_bottom then 0 else elm.offset().top - (parseInt(elm.css("margin-top"), 10) or 0) - offset_top
 
         height = elm.outerHeight true
 
@@ -114,6 +116,10 @@ $.fn.stick_in_parent = (opts={}) ->
       last_pos = undefined
       offset = offset_top
 
+      if set_bottom
+        win.resize ->
+          offset = offset_top =　win.height() - bar_height
+
       recalc_counter = recalc_every
 
       tick = ->
@@ -127,7 +133,7 @@ $.fn.stick_in_parent = (opts={}) ->
             recalc()
             recalced = true
 
-        if !recalced && doc_height != last_scroll_height
+        if !recalced && doc.height() != last_scroll_height
           recalc()
           recalced = true
 
@@ -265,5 +271,3 @@ $.fn.stick_in_parent = (opts={}) ->
 
     ) $ elm
   @
-
-