Introduce Header.{scrollToIfNeeded,getTopOf,getBottomOf}() and use them.

4chan X - now with proper bottom header support.

src/General/Header.coffee

@@ -247,12 +247,28 @@ Header =
     return unless /^p\d+$/.test(hash) and post = $.id hash
     return if (Get.postFromRoot post).isHidden
     Header.scrollTo post
-  scrollTo: (root) ->
+  scrollTo: (root, down, needed) ->
+    if down
+      x = Header.getBottomOf root
+      window.scrollBy 0, -x unless needed and x >= 0
+    else
+      x = Header.getTopOf root
+      window.scrollBy 0,  x unless needed and x >= 0
+  scrollToIfNeeded: (root, down) ->
+    Header.scrollTo root, down, true
+  getTopOf: (root) ->
     {top} = root.getBoundingClientRect()
     unless Conf['Bottom header']
       headRect = Header.toggle.getBoundingClientRect()
-      top -= headRect.top + headRect.height
-    window.scrollBy 0, top
+      top     -= headRect.top + headRect.height
+    top
+  getBottomOf: (root) ->
+    {clientHeight} = doc
+    bottom = clientHeight - root.getBoundingClientRect().bottom
+    if Conf['Bottom header']
+      headRect = Header.toggle.getBoundingClientRect()
+      bottom  -= clientHeight - headRect.bottom + headRect.height
+    bottom
 
   addShortcut: (el, index) ->
     shortcut = $.el 'span',

src/General/Index.coffee

@@ -50,7 +50,7 @@ Index =
       className: 'pagelist'
       hidden: true
       innerHTML: <%= importHTML('General/Index-pagelist') %>
-    Index.currentPage = Index.getCurrentPage()
+    @currentPage = @getCurrentPage()
     $.on window, 'popstate', @cb.popstate
     $.on @pagelist, 'click', @cb.pageNav
     $.asap (-> $('.pagelist', doc) or d.readyState isnt 'loading'), ->
@@ -81,7 +81,7 @@ Index =
       Index.pageNav +a.pathname.split('/')[2]
 
   scrollToIndex: ->
-    Header.scrollTo Index.root if Index.root.getBoundingClientRect().top < 0
+    Header.scrollToIfNeeded Index.root
 
   getCurrentPage: ->
     +window.location.pathname.split('/')[2]

src/Images/ImageExpand.coffee

@@ -45,7 +45,7 @@ ImageExpand =
           continue unless file and file.isImage and doc.contains post.nodes.root
           if ImageExpand.on and
             (!Conf['Expand spoilers'] and file.isSpoiler or
-            Conf['Expand from here'] and file.thumb.getBoundingClientRect().top < 0)
+            Conf['Expand from here'] and Header.getTopOf(file.thumb) < 0)
               continue
           $.queueTask func, post
       return
@@ -60,13 +60,10 @@ ImageExpand =
 
     # Scroll back to the thumbnail when contracting the image
     # to avoid being left miles away from the relevant post.
-    rect = post.nodes.root.getBoundingClientRect()
-    if rect.top < 0
-      y = rect.top
-      unless Conf['Bottom header']
-        headRect = Header.toggle.getBoundingClientRect()
-        y -= headRect.top + headRect.height
-    if rect.left < 0
+    top = Header.getTopOf post.nodes.root
+    if top < 0
+      y = top
+    if post.nodes.root.getBoundingClientRect().left < 0
       x = -window.scrollX
     window.scrollBy x, y if x or y
     ImageExpand.contract post
@@ -104,13 +101,12 @@ ImageExpand =
       $.addClass post.nodes.root, 'expanded-image'
       $.rmClass  post.file.thumb, 'expanding'
       return
-    prev = post.nodes.root.getBoundingClientRect()
+    {bottom} = post.nodes.root.getBoundingClientRect()
     $.queueTask ->
       $.addClass post.nodes.root, 'expanded-image'
       $.rmClass  post.file.thumb, 'expanding'
-      return unless prev.top + prev.height <= 0
-      curr = post.nodes.root.getBoundingClientRect()
-      window.scrollBy 0, curr.height - prev.height + curr.top - prev.top
+      return unless bottom <= 0
+      window.scrollBy 0, post.nodes.root.getBoundingClientRect().bottom - bottom
 
   error: ->
     post = Get.postFromNode @

src/Miscellaneous/Keybinds.coffee

@@ -183,43 +183,31 @@ Keybinds =
       location.href = url
 
   hl: (delta, thread) ->
+    postEl = $ '.reply.highlight', thread
+
     unless delta
-      if postEl = $ '.reply.highlight', thread
-        $.rmClass postEl, 'highlight'
+      $.rmClass postEl, 'highlight' if postEl
       return
-    if Conf['Bottom header']
-      topMargin = 0
-    else
-      headRect  = Header.toggle.getBoundingClientRect()
-      topMargin = headRect.top + headRect.height
-    if postEl = $ '.reply.highlight', thread
-      $.rmClass postEl, 'highlight'
-      rect = postEl.getBoundingClientRect()
-      if rect.bottom >= topMargin and rect.top <= doc.clientHeight # We're at least partially visible
+
+    if postEl
+      {height} = postEl.getBoundingClientRect()
+      if Header.getTopOf(postEl) >= -height and Header.getBottomOf(postEl) >= -height # We're at least partially visible
         root = postEl.parentNode
         axe = if delta is +1
           'following'
         else
           'preceding'
-        next = $.x "#{axe}-sibling::div[contains(@class,'replyContainer')][1]/child::div[contains(@class,'reply')]", root
-        unless next
-          @focus postEl
-          return
-        return unless g.VIEW is 'thread' or $.x('ancestor::div[parent::div[@class="board"]]', next) is thread
-        rect = next.getBoundingClientRect()
-        if rect.top < 0 or rect.bottom > doc.clientHeight
-          if delta is -1
-            window.scrollBy 0, rect.top - topMargin
-          else
-            next.scrollIntoView false
+        return unless next = $.x "#{axe}-sibling::div[contains(@class,'replyContainer')][1]/child::div[contains(@class,'reply')]", root
+        Header.scrollToIfNeeded next, delta is +1
         @focus next
+        $.rmClass postEl, 'highlight'
         return
+      $.rmClass postEl, 'highlight'
 
     replies = $$ '.reply', thread
     replies.reverse() if delta is -1
     for reply in replies
-      rect = reply.getBoundingClientRect()
-      if delta is +1 and rect.top >= topMargin or delta is -1 and rect.bottom <= doc.clientHeight
+      if delta is +1 and Header.getTopOf(reply) > 0 or delta is -1 and Header.getBottomOf(reply) > 0
         @focus reply
         return
 

src/Miscellaneous/Nav.coffee

@@ -38,29 +38,24 @@ Nav =
     else
       Nav.scroll +1
 
-  getThread: (full) ->
-    if Conf['Bottom header']
-      topMargin = 0
-    else
-      headRect  = Header.toggle.getBoundingClientRect()
-      topMargin = headRect.top + headRect.height
-    threads = $$('.thread').filter (thread) ->
-      thread = Get.threadFromRoot thread
-      !(thread.isHidden and !thread.stub)
-    for thread, i in threads
-      rect = thread.getBoundingClientRect()
-      if rect.bottom > topMargin # not scrolled past
-        return if full then [threads, thread, i, rect, topMargin] else thread
+  getThread: ->
+    for threadRoot in $$ '.thread'
+      thread = Get.threadFromRoot threadRoot
+      continue if thread.isHidden and !thread.stub
+      if Header.getTopOf(threadRoot) >= -threadRoot.getBoundingClientRect().height # not scrolled past
+        return threadRoot
     return $ '.board'
 
   scroll: (delta) ->
-    [threads, thread, i, rect, topMargin] = Nav.getThread true
-    top = rect.top - topMargin
-
-    # unless we're not at the beginning of the current thread
-    # (and thus wanting to move to beginning)
-    # or we're above the first thread and don't want to skip it
-    if (delta is -1 and top > -5) or (delta is +1 and top < 5)
-      top = threads[i + delta]?.getBoundingClientRect().top - topMargin
-
-    window.scrollBy 0, top
+    thread = Nav.getThread()
+    axe = if delta is +1
+      'following'
+    else
+      'preceding'
+    if next = $.x "#{axe}-sibling::div[contains(@class,'thread')][1]", thread
+      # Unless we're not at the beginning of the current thread,
+      # and thus wanting to move to beginning,
+      # or we're above the first thread and don't want to skip it.
+      top = Header.getTopOf thread
+      thread = next if delta is +1 and top < 5 or delta is -1 and top > -5
+    Header.scrollTo thread

src/Monitoring/ThreadUpdater.coffee

@@ -246,8 +246,7 @@ ThreadUpdater =
     ThreadUpdater.lastPost = posts[count - 1].ID
     Main.callbackNodes Post, posts
 
-    scroll = Conf['Auto Scroll'] and ThreadUpdater.scrollBG() and
-      ThreadUpdater.root.getBoundingClientRect().bottom - doc.clientHeight < 25
+    scroll = Conf['Auto Scroll'] and ThreadUpdater.scrollBG() and Header.getBottomOf(ThreadUpdater.root) > -25
     $.add ThreadUpdater.root, nodes
     sendEvent()
     if scroll

src/Monitoring/Unread.coffee

@@ -42,18 +42,16 @@ Unread =
       while root = $.x 'preceding-sibling::div[contains(@class,"replyContainer")][1]', post.nodes.root
         break unless (post = Get.postFromRoot root).isHidden
       return unless root
-      onload = -> root.scrollIntoView false if checkPosition root
+      down = true
     else
       # Scroll to the last read post.
       posts  = Object.keys Unread.thread.posts
       {root} = Unread.thread.posts[posts[posts.length - 1]].nodes
-      onload = -> Header.scrollTo root if checkPosition root
-    checkPosition = (target) ->
-      # Scroll to the target unless we scrolled past it.
-      target.getBoundingClientRect().bottom > doc.clientHeight
     # Prevent the browser to scroll back to
     # the previous scroll location on page load.
-    $.on window, 'load', onload
+    $.on window, 'load', ->
+      # Scroll to the target unless we scrolled past it.
+      Header.scrollTo root, down if Header.getBottomOf(root) < 0
 
   sync: ->
     lastReadPost = Unread.db.get
@@ -102,7 +100,7 @@ Unread =
       body: post.info.comment
       icon: Favicon.logo
     notif.onclick = ->
-      Header.scrollTo post.nodes.root
+      Header.scrollToIfNeeded post.nodes.root, true
       window.focus()
     notif.onshow = ->
       setTimeout ->
@@ -132,9 +130,8 @@ Unread =
 
   read: (e) ->
     return if d.hidden or !Unread.posts.length
-    height = doc.clientHeight
     for post, i in Unread.posts
-      break if post.nodes.root.getBoundingClientRect().bottom > height # post is not completely read
+      break if Header.getBottomOf(post.nodes.root) <= 0 # post is not completely read
     return unless i
 
     Unread.lastReadPost = Unread.posts.splice(0, i)[i - 1].ID