ONOS-6391: writing API readme's for the following modules:
- dialog
- event
- filter
- force

Change-Id: I38208b1eb0fccfe5300361cd3605b2ea1befe5a1
diff --git a/web/gui/src/main/webapp/_doc/view/topo/README.dialog.md b/web/gui/src/main/webapp/_doc/view/topo/README.dialog.md
index 9089999..33f8d5e 100644
--- a/web/gui/src/main/webapp/_doc/view/topo/README.dialog.md
+++ b/web/gui/src/main/webapp/_doc/view/topo/README.dialog.md
@@ -5,5 +5,16 @@
 ### Function Descriptions
+* Opens the topology view dialog box
+* Closes the topology view dialog box
+* `cls`: CSS class to assign (optional)
+* Creates a (detached) _div_ element
+* If `cls` is defined, it is applied as a CSS class
+  to the _div_
+* Returns a D3 selection of that _div_
diff --git a/web/gui/src/main/webapp/_doc/view/topo/README.event.md b/web/gui/src/main/webapp/_doc/view/topo/README.event.md
index 0894c09..9c3a1ea 100644
--- a/web/gui/src/main/webapp/_doc/view/topo/README.event.md
+++ b/web/gui/src/main/webapp/_doc/view/topo/README.event.md
@@ -5,5 +5,12 @@
 ### Function Descriptions
+* Binds the topology view event handlers to the web socket service
+* Initiates topology view by sending "start" event to server
+* Deactivates topology view by sending "stop" event to server
diff --git a/web/gui/src/main/webapp/_doc/view/topo/README.filter.md b/web/gui/src/main/webapp/_doc/view/topo/README.filter.md
index 4cc4466..eb9b47e 100644
--- a/web/gui/src/main/webapp/_doc/view/topo/README.filter.md
+++ b/web/gui/src/main/webapp/_doc/view/topo/README.filter.md
@@ -5,5 +5,21 @@
 ### Function Descriptions
+* `api`: reverse linkage to topoForce module
+  * `node()`: reference to D3 node selection
+  * `link()`: reference to D3 link selection
+* Initializes this module with a function API to other modules
+* Increments filter mode index and re-renders nodes and links
+  to highlight those in the newly selected layer
+* Returns the currently selected "layer"
+  * (`all`, `pkt`, or `opt`)
+`inLayer(d, layer)`
+* `d`: model data (link, host, device)
+* `layer`: layer id (e.g. `pkt`)
+* Returns true if the given element is "in" the specified layer
diff --git a/web/gui/src/main/webapp/_doc/view/topo/README.force.md b/web/gui/src/main/webapp/_doc/view/topo/README.force.md
index b13b914..bbdfc45 100644
--- a/web/gui/src/main/webapp/_doc/view/topo/README.force.md
+++ b/web/gui/src/main/webapp/_doc/view/topo/README.force.md
@@ -5,5 +5,111 @@
 ### Function Descriptions
+`initForce(svg, forceG, uplink, dim, opts)`
+* `svg`: D3 selection of _svg_ element for force layout rendering
+* `forceG`: D3 selection of force layout _SVG_ group element
+* `uplink`: API uplink to main _topo.js_ module
+  * `showNoDevs(b)` - show or hide _no connected devices_ message
+  * `projection()` - return ref to map projection object
+  * `zoomLayer()` - return ref to zoom layer element
+  * `zoomer()` - return ref to zoomer object
+  * `opacifyMap(b)` - show or hide map layer
+  * `topoStartDone()` - callback invoked after topo data
+     has been received from server
+* `dim`: initial dimensions of _SVG_ ... `[w, h]`
+* `opts`: options object
+  * can be used to override default settings
+  * _gravity_, _friction_, _charge_, _linkDistance_, _linkStrength_
+* `dim`: new dimensions ... `[w, h]`
+* Sets new dimensions of force layout
+* Frees up all resources, cancels timers, cleans up DOM
+* Delegates to _topoD3.js_ function of same name
+* `x`: boolean (optional)
+* If `x` is not defined, toggles host visibility
+* If `x` is defined, sets or clears host visibility
+* `x`: boolean (optional)
+* If `x` is not defined, toggles port labels visibility
+* If `x` is defined, sets or clears port labels visibility
+* `x`: boolean (optional)
+* If `x` is not defined, toggles offline devices visibility
+* If `x` is defined, sets or clears offline devices visibility
+* Increments the device label mode and re-renders device labels
+* will _unpin_ a node over which the mouse currently hovers
+* `masterId`: ONOS instance identifier (e.g. IP address)
+* If `masterId` is defined, will render the display to highlight
+  those devices mastered by the given cluster member
+* If `masterId` is not defined, restores the display
+* Will briefly highlight links for which there is only a single backing link
+* Also writes a summary of bad links to the console
+* `scale`: the scale to use
+* Rescales the nodes and links (and labels) based on the input parameter
+* Resets all nodes (hosts, devices) to the configured positions
+* `data`: add-device event payload
+* Adds a device to the model (and renders it)
+* `data`: update-device event payload
+* Updates information for a device (re-rendering it)
+* `data`: remove-device event payload
+* Removes a device from the model (and animates its removal)
+* `data`: add-host event payload
+* Adds a host to the model (and renders it if hosts visible)
+* `data`: update-host event payload
+* Updates information for a host (re-rendering it)
+* `data`: move-host event payload
+* Updates information for a host to move it to a new location
+  (re-rendering it if hosts visible)
+* `data`: remove-host event payload
+* Removes host from the model (and animates removal if hosts visible)
+* `data`: add-link event payload
+* Adds a link to the model (and renders it)
+* `data`: update-link event payload
+* Updates information for a link (re-rendering it)
+* `data`: remove-link event payload
+* Removes link from model (and animates removal)
+* Callback invoked once the server signals that all topology data
+  has been transferred