...

src/calibre/ebooks/oeb/display/cfi.coffee

@@ -4,6 +4,7 @@
 ###
  Copyright 2011, Kovid Goyal <kovid@kovidgoyal.net>
  Released under the GPLv3 License
+ Based on code originally written by Peter Sorotkin (epubcfi.js)
 ###
 #
 log = (error) ->
@@ -271,6 +272,67 @@ class CanonicalFragmentIdentifier
         this.encode(doc, target, offset, tail)
     # }}}
 
+    point: (cfi, doc=window?.document) -> # {{{
+        r = this.decode(cfi, doc)
+        if not r
+            return null
+    node = r.node
+    ndoc = node.ownerDocument
+    if not ndoc
+        log("CFI node has no owner document: #{ cfi } #{ node }")
+        return null
+
+    nwin = ndoc.defaultView
+    x = null
+    y = null
+
+    if typeof(r.offset) == "number"
+        # Character offset
+        range = ndoc.createRange()
+        if r.forward
+            try_list = [{start:0, end:0, a:0.5}, {start:0, end:1, a:1}, {start:-1, end:0, a:0}]
+        else
+            try_list = [{start:0, end:0, a:0.5}, {start:-1, end:0, a:0}, {start:0, end:1, a:1}]
+        k = 0
+        a = null
+        rects = null
+        node_len = node.nodeValue.length
+        until rects or rects.length or k >= try_list.length
+            t = try_list[k++]
+            start_offset = r.offset + t.start
+            end_offset = r.offset + t.end
+            a = t.a
+            if start_offset < 0 or end_offset >= node_len
+                continue
+            range.setStart(node, start_offset)
+            range.setEnd(node, end_offset)
+            rects = range.getClientRects()
+
+        if not rects or not rects.length
+            log("Could not find caret position: rects: #{ rects } offset: #{ r.offset }")
+            return null
+
+        rect = rects[0]
+        x = (a*rect.left + (1-a)*rect.right)
+        y = (rect.top + rect.bottom)/2
+    else
+        x = node.offsetLeft - nwin.scrollX
+        y = node.offsetTop - nwin.scrollY
+        if typeof(r.x) == "number" and node.offsetWidth
+            x += (r.x*node.offsetWidth)/100
+            y += (r.y*node.offsetHeight)/100
+
+    until ndoc == doc
+        node = nwin.frameElement
+        ndoc = node.ownerDocument
+        nwin = ndoc.defaultView
+        x += node.offsetLeft - nwin.scrollX
+        y += node.offsetTop - nwin.scrollY
+
+    {x:x, y:y, node:r.node, time:r.time}
+
+    # }}}
+
 if window?
     window.cfi = new CanonicalFragmentIdentifier()
 else if process?