Specs: markdown cleanup

sky/specs/ui.md

 UI Events
 =========
 
 Scope
 -----
 
 The following input devices are supported by sky:
  - fingers on multitouch screens
  - mice, including mouse wheels
  - styluses on screens
@@ skipping 74 matching lines @@
 until the corresponding pointer-up event (even if the buttons change).
 At the time of a pointer-up event, if there is another pointer that is
 already down and is of the same kind, and that has either no buttons
 or only its primary button active, then that becomes the new primary
 pointer.
 
 
 These events all bubble and their data is an object with the following
 fields:
 
-      pointer: an integer assigned to this touch or pointer when it
-               enters the system, never reused, increasing
-               monotonically every time a new value is assigned,
-               starting from 1 (if the system gets a new tap every
-               microsecond, this will cause a problem after 285 years)
+       pointer: an integer assigned to this touch or pointer when it
+                enters the system, never reused, increasing
+                monotonically every time a new value is assigned,
+                starting from 1 (if the system gets a new tap every
+                microsecond, this will cause a problem after 285
+                years)
 
-         kind: one of 'touch', 'mouse', 'stylus', 'inverted-stylus'
+          kind: one of 'touch', 'mouse', 'stylus', 'inverted-stylus'
 
-            x: x-position relative to the top-left corner of the
-               surface of the node on which the event was fired
+             x: x-position relative to the top-left corner of the
+                surface of the node on which the event was fired
 
-            y: y-position relative to the top-left corner of the
-               surface of the node on which the event was fired
+             y: y-position relative to the top-left corner of the
+                surface of the node on which the event was fired
 
-      buttons: a bitfield of the buttons pressed, from the following
-               list:
-                 1: primary mouse button (not available on stylus)
-                 2: secondary mouse button, primary stylus button
-                 3: middle mouse button, secondary stylus button
-                 4: back button
-                 5: forward button
-               additional buttons can be represented by numbers
-               greater than six:
-                 n: (n-2)th mouse button, ignoring any buttons that
-                    are explicitly back or forward buttons
-                    (n-4)th stylus button, again ignoring any
-                    explictly back or forward buttons
+       buttons: a bitfield of the buttons pressed, from the following
+                list:
+                  1: primary mouse button (not available on stylus)
+                  2: secondary mouse button, primary stylus button
+                  3: middle mouse button, secondary stylus button
+                  4: back button
+                  5: forward button
+                additional buttons can be represented by numbers
+                greater than six:
+                  n: (n-2)th mouse button, ignoring any buttons that
+                     are explicitly back or forward buttons
+                     (n-4)th stylus button, again ignoring any
+                     explictly back or forward buttons
 
-         down: true if the pointer is down (in pointer-down event or
-               subsequent pointer-move events); false otherwise (in
-               pointer-added, pointer-up, and pointer-removed events,
-               and in pointer-move events that aren't between
-               pointer-down and pointer-up events)
+          down: true if the pointer is down (in pointer-down event or
+                subsequent pointer-move events); false otherwise (in
+                pointer-added, pointer-up, and pointer-removed events,
+                and in pointer-move events that aren't between
+                pointer-down and pointer-up events)
 
-      primary: true if this is a primary pointer/touch (see above)
+       primary: true if this is a primary pointer/touch (see above)
 
-     obscured: true if the system was rendering another view on top of
-               the sky application at the time of the event (this is
-               intended to enable click-jacking protections)
+      obscured: true if the system was rendering another view on top
+                of the sky application at the time of the event (this
+                is intended to enable click-jacking protections)
 
 
 When primary is true, the following fields are available:
 
-           dx: if primary, then this is the delta from the x-position
-               at the time that the pointer became primary.
+            dx: if primary, then this is the delta from the x-position
+                at the time that the pointer became primary.
 
-           dy: if primary, then this is the delta from the x-position
-               at the time that the pointer became primary.
+            dy: if primary, then this is the delta from the x-position
+                at the time that the pointer became primary.
 
 
 When down is true:
 
-     pressure: the pressure of the touch as a number ranging from 0.0,
-               indicating a touch with no discernible pressure, to
-               1.0, indicating a touch with "normal" pressure, and
-               possibly beyond, indicating a stronger touch; for
-               devices that do not detect pressure (e.g. mice),
-               returns 1.0
+      pressure: the pressure of the touch as a number ranging from
+                0.0, indicating a touch with no discernible pressure,
+                to 1.0, indicating a touch with "normal" pressure, and
+                possibly beyond, indicating a stronger touch; for
+                devices that do not detect pressure (e.g. mice),
+                returns 1.0
 
- pressure-min: the minimum value that pressure can return for this
-               pointer
+  pressure-min: the minimum value that pressure can return for this
+                pointer
 
- pressure-max: the maximum value that pressure can return for this
-               pointer
+  pressure-max: the maximum value that pressure can return for this
+                pointer
 
 
 When kind is 'touch', 'stylus', or 'stylus-inverted':
 
-     distance: distance of detected object from surface (e.g. distance
-               of stylus or finger from screen), if supported and down
-               is not true, otherwise 0.0.
+      distance: distance of detected object from surface (e.g.
+                distance of stylus or finger from screen), if
+                supported and down is not true, otherwise 0.0.
 
- distance-min: the minimum value that distance can return for this
-               pointer (always 0.0)
+  distance-min: the minimum value that distance can return for this
+                pointer (always 0.0)
 
- distance-max: the maximum value that distance can return for this
-               pointer (0.0 if not supported)
+  distance-max: the maximum value that distance can return for this
+                pointer (0.0 if not supported)
 
 
 When kind is 'touch', 'stylus', or 'stylus-inverted' and down is true:
 
- radius-major: the radius of the contact ellipse along the major axis,
-               in pixels
+  radius-major: the radius of the contact ellipse along the major
+                axis, in pixels
 
- radius-minor: the radius of the contact ellipse along the major axis,
-               in pixels
+  radius-minor: the radius of the contact ellipse along the major
+                axis, in pixels
 
-   radius-min: the minimum value that could be reported for
-               radius-major or radius-minor for this pointer
+    radius-min: the minimum value that could be reported for
+                radius-major or radius-minor for this pointer
 
-   radius-max: the maximum value that could be reported for
-               radius-major or radius-minor for this pointer
+    radius-max: the maximum value that could be reported for
+                radius-major or radius-minor for this pointer
 
 
 When kind is 'touch' and down is true:
 
-  orientation: the angle of the contact ellipse, in radians in the range
-                  -pi/2 < orientation <= pi/2
-               ...giving the angle of the major axis of the ellipse with
-               the y-axis (negative angles indicating an orientation
-               along the top-left / bottom-right diagonal, positive
-               angles indicating an orientation along the top-right /
-               bottom-left diagonal, and zero indicating an orientation
-               parallel with the y-axis)
+   orientation: the angle of the contact ellipse, in radians in the
+                range
+                   -pi/2 < orientation <= pi/2
+                ...giving the angle of the major axis of the ellipse
+                with the y-axis (negative angles indicating an
+                orientation along the top-left / bottom-right
+                diagonal, positive angles indicating an orientation
+                along the top-right / bottom-left diagonal, and zero
+                indicating an orientation parallel with the y-axis)
 
 
 When kind is 'stylus' or 'stylus-inverted':
 
-  orientation: the angle of the stylus, in radians in the range
-                  -pi < orientation <= pi
-               ...giving the angle of the axis of the stylus projected
-               onto the screen, relative to the positive y-axis of the
-               screen (thus 0 indicates the stylus, if projected onto
-               the screen, would go from the contact point vertically
-               up in the positive y-axis direction, pi would indicate
-               that the stylus would go down in the negative y-axis
-               direction; pi/4 would indicate that the stylus goes up
-               and to the right, -pi/2 would indicate that the stylus
-               goes to the left, etc)
+   orientation: the angle of the stylus, in radians in the range
+                   -pi < orientation <= pi
+                ...giving the angle of the axis of the stylus
+                projected onto the screen, relative to the positive
+                y-axis of the screen (thus 0 indicates the stylus, if
+                projected onto the screen, would go from the contact
+                point vertically up in the positive y-axis direction,
+                pi would indicate that the stylus would go down in the
+                negative y-axis direction; pi/4 would indicate that
+                the stylus goes up and to the right, -pi/2 would
+                indicate that the stylus goes to the left, etc)
 
-         tilt: the angle of the stylus, in radians in the range
-                  0 <= tilt <= pi/2
-
-               ...giving the angle of the axis of the stylus, relative
-               to the axis perpendicular to the screen (thus 0
-               indicates the stylus is orthogonal to the plane of the
-               screen, while pi/2 indicates that the stylus is flat on
-               the screen)
+          tilt: the angle of the stylus, in radians in the range
+                   0 <= tilt <= pi/2
+                ...giving the angle of the axis of the stylus,
+                relative to the axis perpendicular to the screen (thus
+                0 indicates the stylus is orthogonal to the plane of
+                the screen, while pi/2 indicates that the stylus is
+                flat on the screen)
 
 
 Wheel events
 ------------
 
 When a wheel input device is turned, a 'wheel' event that bubbles is
 fired at the application's document, with the following fields:
 
-     wheel: an integer assigned to this wheel by the system. The same
-            wheel on the same system must always be given the same ID.
-            The primary wheel (e.g. the vertical wheel on a mouse)
-            must be given ID 1.
+         wheel: an integer assigned to this wheel by the system. The
+                same wheel on the same system must always be given the
+                same ID. The primary wheel (e.g. the vertical wheel on
+                a mouse) must be given ID 1.
 
-     delta: an floating point number representing the fraction of the
-            wheel that was turned, with positive numbers representing
-            a downward movement on vertical wheels, rightward movement
-            on horizontal wheels, and a clockwise movement on wheels
-            with a user-facing side.
- 
-Additionally, if the wheel is associated with a pointer (e.g. a mouse
-wheel), the following fields must be present also:
+         delta: an floating point number representing the fraction of
+                the wheel that was turned, with positive numbers
+                representing a downward movement on vertical wheels,
+                rightward movement on horizontal wheels, and a
+                clockwise movement on wheels with a user-facing side.
 
-   pointer: the integer assigned to the pointer in its 'pointer-add'
-            event (see above).
+    Additionally, if the wheel is associated with a pointer (e.g. a
+    mouse wheel), the following fields must be present also:
 
-         x: x-position relative to the top-left corner of the display,
-            in global layout coordinates
- 
-         y: x-position relative to the top-left corner of the display,
-            in global layout coordinates
+       pointer: the integer assigned to the pointer in its
+                'pointer-add' event (see above).
+
+             x: x-position relative to the top-left corner of the
+                display, in global layout coordinates
+
+             y: x-position relative to the top-left corner of the
+                display, in global layout coordinates
 
 Note: The only wheels that are supported are mouse wheels and physical
 dials. Track balls are not reported as mouse wheels.
 
 
 Text input events
 -----------------
 
 TODO(ianh): keyboard events