all: rename the gioui.org/ui module to gioui.org

The "ui" is redundant and stutters.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

pointer/doc.go

@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+/*
+Package pointer implements pointer events and operations.
+A pointer is either a mouse controlled cursor or a touch
+object such as a finger.
+
+The InputOp operation is used to declare a handler ready for pointer
+events. Use a ui.Queue to receive events.
+
+Areas
+
+The area operations are used for specifying the area where
+subsequent InputOp are active.
+
+For example, to set up a rectangular hit area:
+
+	var ops ui.Ops
+	var h *Handler = ...
+
+	r := image.Rectangle{...}
+	pointer.RectAreaOp{Rect: r}.Add(ops)
+	pointer.InputOp{Key: h}.Add(ops)
+
+Note that areas compound: the effective area of multiple area
+operations is the intersection of the areas.
+
+Matching events
+
+StackOp operations and input handlers form an implicit tree.
+Each stack operation is a node, and each input handler is associated
+with the most recent node.
+
+For example:
+
+	ops := new(ui.Ops)
+	var stack ui.StackOp
+	var h1, h2 *Handler
+
+	stack.Push(ops)
+	pointer.InputOp{Key: h1}.Add(Ops)
+	stack.Pop()
+
+	stack.Push(ops)
+	pointer.InputOp{Key: h2}.Add(ops)
+	stack.Pop()
+
+implies a tree of two inner nodes, each with one pointer handler.
+
+When determining which handlers match an Event, only handlers whose
+areas contain the event position are considered. The matching
+proceeds as follows.
+
+First, the foremost matching handler is included. If the handler
+has pass-through enabled, this step is repeated.
+
+Then, all matching handlers from the current node and all parent
+nodes are included.
+
+In the example above, all events will go to h2 only even though both
+handlers have the same area (the entire screen).
+
+Pass-through
+
+The PassOp operations controls the pass-through setting. A handler's
+pass-through setting is recorded along with the InputOp.
+
+Pass-through handlers are useful for overlay widgets such as a hidden
+side drawer. When the user touches the side, both the (transparent)
+drawer handle and the interface below should receive pointer events.
+
+Disambiguation
+
+When more than one handler matches a pointer event, the event queue
+follows a set of rules for distributing the event.
+
+As long as the pointer has not received a Press event, all
+matching handlers receive all events.
+
+When a pointer is pressed, the set of matching handlers is
+recorded. The set is not updated according to the pointer position
+and hit areas. Rather, handlers stay in the matching set until they
+no longer appear in a InputOp or when another handler in the set
+grabs the pointer.
+
+A handler can exclude all other handler from its matching sets
+by setting the Grab flag in its InputOp. The Grab flag is sticky
+and stays in effect until the handler no longer appears in any
+matching sets.
+
+The losing handlers are notified by a Cancel event.
+
+For multiple grabbing handlers, the foremost handler wins.
+
+Priorities
+
+Handlers know their position in a matching set of a pointer through
+event priorities. The Shared and Foremost priorities are for matching sets
+with multiple handlers; the Grabbed priority indicate exclusive access.
+
+Priorities are useful for deferred gesture matching.
+
+Consider a scrollable list of clickable elements. When the user touches an
+element, it is unknown whether the gesture is a click on the element
+or a drag (scroll) of the list. While the click handler might light up
+the element in anticipation of a click, the scrolling handler does not
+scroll on finger movements with lower than Grabbed priority.
+
+Should the user release the finger, the click handler registers a click.
+
+However, if the finger moves beyond a threshold, the scrolling handler
+determines that the gesture is a drag and sets its Grab flag. The
+click handler receives a Cancel (removing the highlight) and further
+movements for the scroll handler has priority Grabbed, scrolling the
+list.
+*/
+package pointer