feature/android 69c4bbc0d69: Update Android port

[Po Lu]

branch: feature/android
commit 69c4bbc0d694594f43b02e9da5c236f3b9271b1d
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Update Android port
    
    * doc/emacs/input.texi (Other Input Devices, Touchscreens)
    (On-Screen Keyboards):
    * doc/lispref/commands.texi (Misc Events):
    * src/android.c (android_faccessat): Improve word choices and
    commentary.
    * lisp/touch-screen.el (touch-screen-handle-scroll): Make
    precision scrolling work better with horizontal movement.
---
 doc/emacs/input.texi      | 61 +++++++++++++++++++++++------------------------
 doc/lispref/commands.texi | 38 +++++++++++++----------------
 lisp/touch-screen.el      | 14 ++++++++---
 src/android.c             | 28 ++++++++++------------
 4 files changed, 70 insertions(+), 71 deletions(-)

diff --git a/doc/emacs/input.texi b/doc/emacs/input.texi
index 96743349a1c..0df3162ce97 100644
--- a/doc/emacs/input.texi
+++ b/doc/emacs/input.texi
@@ -5,14 +5,14 @@
 @appendix Emacs and unconventional input devices
 @cindex other input devices
 
-  Emacs was originally developed with the assumption that users will
-be sitting in front of a desktop computer, with a keyboard and perhaps
-a suitable pointing device such as a mouse.
+  Emacs was originally developed with the assumption that its users
+have access to a desktop computer or computer terminal, with a
+keyboard and perhaps a suitable pointing device such as a mouse.
 
-  However, recent developments in the X Window System, and in other
-operating systems such as Android, mean that this assumption no longer
-holds true.  As a result, Emacs now has support for other kinds of
-input devices, which is detailed here.
+  However, recent developments in the X Window System and operating
+systems such as Android mean that this assumption no longer holds
+true.  Emacs supports input from various other kinds of input devices,
+which is detailed here.
 
 @menu
 * Touchscreens::                Using Emacs on touchscreens.
@@ -23,21 +23,21 @@ input devices, which is detailed here.
 @section Using Emacs on touchscreens
 @cindex touchscreens
 
-  Touchscreen input works by having the user press tools onto the
-screen, which can be his own fingers, or a pointing device such as a
-stylus, in order to manipulate the contents there in.
+  Touchscreen input works by pressing and moving tools (which include
+fingers and some pointing devices--styluses, for example) onto a frame
+in order to manipulate its contents.
 
   When running under the X Window System or Android, Emacs
-automatically detects and maps the following touchscreen gestures to
-common actions:
+automatically detects and maps the following sequences of movements
+(``gestures'') to common actions:
 
 @itemize @bullet
 @item
 @cindex tapping, touchscreens
-  ``Tapping'', meaning to briefly place and lift a tool from the
-display, will result in Emacs selecting the window that was tapped,
-and executing any command bound to @code{mouse-1} at that location in
-the window.  If the tap happened on top of a link (@pxref{Mouse
+  ``Tapping'', briefly placing and lifting a tool from the display,
+will result in Emacs selecting the window that was tapped, and
+executing any command bound to @code{mouse-1} at that location in the
+window.  If the tap happened on top of a link (@pxref{Mouse
 References}), then Emacs will follow the link instead.
 
 @item
@@ -52,12 +52,11 @@ window horizontally to follow (@pxref{Horizontal 
Scrolling}.)
 @item
 @cindex dragging, touchscreens
 @cindex long-press, touchscreens
-  ``Dragging'', meaning to perform a @dfn{long-press} (placing a tool
-on the display and leaving it there for a while) before moving the
-tool around, will make Emacs set the point to where the tool was and
-begin selecting text under the tool as it moves around, much like what
-would happen if @code{mouse-1} were to be held down.  @xref{Mouse
-Commands}.
+  ``Dragging'', which is performing a @dfn{long-press} by placing a
+tool on the display and leaving it there for a while prior to moving
+the tool around will make Emacs set the point to where the tool was
+and begin selecting text under the tool as it moves around, as if
+@code{mouse-1} were to be held down.  @xref{Mouse Commands}.
 @end itemize
 
 @vindex touch-screen-delay
@@ -99,9 +98,9 @@ that the user is about to enter text in to the current buffer.
 
 @vindex touch-screen-display-keyboard
   The user option @code{touch-screen-display-keyboard} forces Emacs to
-always display the on screen keyboard; it may also be bound buffer
-locally, meaning to always display the keyboard when the buffer is
-selected.
+always display the on screen keyboard; it may also be set buffer
+locally, which means that Emacs should always display the keyboard
+when the buffer is selected.
 
   Emacs also provides a set of functions to show or hide the on-screen
 keyboard.  For more details, @pxref{On-Screen Keyboards,,, elisp, The
@@ -109,15 +108,15 @@ Emacs Lisp Reference Manual}.
 
 @cindex quitting, without a keyboard
   Since it may not be possible for Emacs to display the on screen
-keyboard when it is executing a command, Emacs implements a feature on
-devices with only an on-screen keyboard, by which two rapid clicks of
-a hardware button that is always present on the device results in
+keyboard while it is executing a command, Emacs implements a feature
+on devices with only an on-screen keyboard, by which two rapid clicks
+of a hardware button that is always present on the device results in
 Emacs quitting.  @xref{Quitting}.
 
 @vindex x-quit-keysym
-  The exact button is used to do this varies by system: on X, it is
-defined in the variable @code{x-quit-keysym}, and on Android, it is
-always the volume down button.
+  Which button is used to do this depends on the window system in use:
+on X, it is defined in the variable @code{x-quit-keysym}, and on
+Android, it is always the volume down button.
 
 @cindex text conversion, keyboards
   Most input methods designed to work with on-screen keyboards perform
diff --git a/doc/lispref/commands.texi b/doc/lispref/commands.texi
index 783ab583ec4..edeea9ab27c 100644
--- a/doc/lispref/commands.texi
+++ b/doc/lispref/commands.texi
@@ -2212,13 +2212,11 @@ This kind of event is sent @strong{after} a system-wide 
input method
 performs an edit to one or more buffers.
 
 @vindex text-conversion-edits
-Once the event is sent, the input method may already have made
-changes to multiple buffers inside many different frames.  To
-determine which buffers have been changed, and what edits have
-been made to them, use the variable
-@code{text-conversion-edits}, which is set prior to each
-@code{text-conversion} event being sent; it is a list of the
-form:
+Once the event is sent, the input method may already have made changes
+to multiple buffers inside many different frames.  To determine which
+buffers have been changed, and what edits have been made to them, use
+the variable @code{text-conversion-edits}, which is set prior to each
+@code{text-conversion} event being sent; it is a list of the form:
 
 @example
 @w{@code{((@var{buffer} @var{beg} @var{end} @var{ephemeral}) ...)}}
@@ -2227,10 +2225,9 @@ form:
 Where @var{ephemeral} is the buffer which was modified, @var{beg} and
 @var{end} are markers set to the positions of the edit at the time it
 was completed, and @var{ephemeral} is either a string, containing any
-text which was inserted, or any text before point which was deleted,
+text which was inserted (or any text before point which was deleted),
 @code{t}, meaning that the edit is a temporary edit made by the input
-method, and @code{nil}, meaning that some text was deleted after
-point.
+method, or @code{nil}, meaning that some text was deleted after point.
 
 @vindex text-conversion-style
 Whether or not this event is sent depends on the value of the
@@ -2247,26 +2244,25 @@ events will be sent instead of text conversion events.
 
 @item action
 This means that the input method will be enabled, but @key{RET} will
-be sent wherever the input method wanted to insert a new line.
+be sent whenever the input method wants to insert a new line.
 
 @item t
 This, or any other value, means that the input method will be enabled
-and make edits terminated by @code{text-conversion} events.
+and make edits followed by @code{text-conversion} events.
 @end table
 
 @findex disable-text-conversion
-Changes to the value of this variable will only take effect upon
-the next redisplay after the buffer becomes the selected buffer
-of a frame.  If you need to disable text conversion in a way
-that takes immediate effect, call the function
-@code{set-text-conversion-style} instead.  This can potentially
-lock up the input method for a significant amount of time, so do
-not do this lightly!
+Changes to the value of this variable will only take effect upon the
+next redisplay after the buffer becomes the selected buffer of a
+frame.  If you need to disable text conversion in a way that takes
+immediate effect, call the function @code{set-text-conversion-style}
+instead.  This has the potential to lock up the input method for a
+significant amount of time, and should be used with care.
 
 @vindex disable-inhibit-text-conversion
 In addition, text conversion is automatically disabled after a prefix
-key is read by the command loop, or through @code{read-key-sequence}.
-This can be disabled by setting or binding the variable
+key is read by the command loop or @code{read-key-sequence}.  This can
+be disabled by setting or binding the variable
 @code{disable-inhibit-text-conversion} to a non-@code{nil} value.
 
 @cindex @code{delete-frame} event
diff --git a/lisp/touch-screen.el b/lisp/touch-screen.el
index 2db8b62f6f9..ba55374d090 100644
--- a/lisp/touch-screen.el
+++ b/lisp/touch-screen.el
@@ -108,9 +108,17 @@ horizontal scrolling according to the movement in DX."
   ;; Show a message instead.
   (condition-case nil
       (if touch-screen-precision-scroll
-          (if (> dy 0)
-              (pixel-scroll-precision-scroll-down-page dy)
-            (pixel-scroll-precision-scroll-up-page (- dy)))
+          (progn
+            (if (> dy 0)
+                (pixel-scroll-precision-scroll-down-page dy)
+              (pixel-scroll-precision-scroll-up-page (- dy)))
+            ;; Now set `lines-vscrolled' to an value that will result
+            ;; in hscroll being disabled if dy looks as if a
+            ;; significant amount of scrolling is about to take
+            ;; Otherwise, horizontal scrolling may then interfere with
+            ;; precision scrolling.
+            (when (> (abs dy) 10)
+              (setcar (nthcdr 7 touch-screen-current-tool) 10)))
         ;; Start conventional scrolling.  First, determine the
         ;; direction in which the scrolling is taking place.  Load the
         ;; accumulator value.
diff --git a/src/android.c b/src/android.c
index 625253bdfe0..43122f73be1 100644
--- a/src/android.c
+++ b/src/android.c
@@ -5989,20 +5989,6 @@ android_toggle_on_screen_keyboard (android_window 
window, bool show)
 
 
 
-/* When calling the system's faccessat, make sure to clear the flag
-   AT_EACCESS.
-
-   Android's faccessat simply fails upon using AT_EACCESS, so replace
-   it with zero here.  This isn't caught during configuration as Emacs
-   is being cross compiled.
-
-   This replacement is only done when building for Android 16 or
-   later, because earlier versions use the gnulib replacement that
-   lacks these issues.
-
-   This is unnecessary on earlier API versions, as gnulib's
-   rpl_faccessat will be used instead, which lacks these problems.  */
-
 /* Like faccessat, except it also understands DIRFD opened using
    android_dirfd.  */
 
@@ -6046,10 +6032,20 @@ android_faccessat (int dirfd, const char *pathname, int 
mode, int flags)
     }
 
 #if __ANDROID_API__ >= 16
+  /* When calling `faccessat', make sure to clear the flag AT_EACCESS.
+
+     Android's faccessat simply fails if FLAGS contains AT_EACCESS, so
+     replace it with zero here.  This isn't caught at configuration-time
+     as Emacs is being cross compiled.
+
+     This takes place only when building for Android 16 and later,
+     because earlier versions use a Gnulib replacement that lacks these
+     issues.  */
+
   return faccessat (dirfd, pathname, mode, flags & ~AT_EACCESS);
-#else
+#else /* __ANDROID_API__ < 16 */
   return faccessat (dirfd, pathname, mode, flags);
-#endif
+#endif /* __ANDROID_API__ >= 16 */
 }