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Touchscreen input is the manipulation of a frame’s contents by the placement and motion of tools (instanced by fingers and such pointing devices as styluses) on a monitor or computer terminal where it is displayed.
Two factors, the order and position on which such tools are placed, are compared against predefined patterns dubbed gestures, after which any gesture those factors align with designates a series of actions to be taken on the text beneath the tools; the gestures presently recognized are:
mouse-1
at that location in the window. If a link (see マウスで参照をフォローする) exists there, then Emacs will follow that link instead (insofar
as such action differs from that taken upon the simulation of a
mouse-1
event).
touch-screen-enable-hscroll
governs whether horizontal scrolling
(see 水平スクロール) is performed in reaction to this gesture.
mouse-1
were to be held down and a mouse moved analogously.
See 編集のためのマウスコマンド.
To the detriment of text selection, it can prove challenging to position a
tool accurately on a touch screen display. The user option
touch-screen-word-select
, which when enabled, prompts dragging to
select the complete word under the tool. (Normally, the selection is only
extended to encompass the character beneath the tool.)
In the same vein, it may be difficult to select all of the text intended
within a single gesture. If the user option
touch-screen-extend-selection
is enabled, taps on the locations of
the point or the mark within a window will begin a new “drag” gesture,
where the region will be extended in the direction of any subsequent
movement.
Difficulties in making accurate adjustments to the region from the cursor
being physically obscured by the tool can be mitigated by indicating the
position of the point within the echo area. If
touch-screen-preview-select
is non-nil
, the line surrounding
point is displayed in the echo area (see エコーエリア) during the motion
of the tool, below which is another line indicating the position of point
relative to the first.
Emacs registers a long-press after the time a tool has been placed upon the
screen exceeds 0.7 seconds. This delay can be adjusted through customizing
the variable touch-screen-delay
.