Merge lp:~vanvugt/mir/touch-demo-shell into lp:~mir-team/mir/trunk

[Daniel van Vugt]

Add touch support to demo-shell:
  3-finger drag to move a surface
  4-finger swipe to switch apps

Tested on Nexus 4 and regression-tested on desktop.

I may have gone too far with demo-shell now. But it's a great test of Mir/Android multi-touch. And a great demo of how a shell's event filter should handle system/shell-level gestures while not interfering with client input.

[PS Jenkins bot (ps-jenkins)]

PASSED: Continuous integration, rev:733
http://jenkins.qa.ubuntu.com/job/mir-ci/694/
Executed test runs:
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-android-raring-i386-build/858
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-clang-raring-amd64-build/740
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-raring-amd64-ci/179
        deb: http://jenkins.qa.ubuntu.com/job/mir-raring-amd64-ci/179/artifact/work/output/*zip*/output.zip
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-vm-ci-build/./distribution=quantal,flavor=amd64/386

Click here to trigger a rebuild:
http://s-jenkins:8080/job/mir-ci/694/rebuild

review: Approve (continuous-integration)

[Alexandros Frantzis (afrantzis)]

24 +mir::geometry::Point average_pointer(MirMotionEvent const& motion)

Perhaps the average value is good enough for demo purposes, but the proper way would be to use the geometric median (the centerpoint) as the effective pointer position.

29 + int x = 0, y = 0, count = (int)motion.pointer_count;
59 + int fingers = (int)event.motion.pointer_count;

C++ cast... but why change type in the first place?

Since this is demo code, a weak "Needs Fixing".

review: Needs Fixing

[Alexandros Frantzis (afrantzis)]

> 24 +mir::geometry::Point average_pointer(MirMotionEvent const& motion)
>
> Perhaps the average value is good enough for demo purposes, but the proper way
> would be to use the geometric median (the centerpoint) as the effective
> pointer position.

Although, for this use case of tracking relative movement offsets, it doesn't really matter.

[Kevin DuBois (kdub)]

aside from the casting Alexandros mentioned, looks good to me!

review: Approve

[Daniel van Vugt (vanvugt)]

Geometric median:
I think using geometric median is a bad idea because:
http://en.wikipedia.org/wiki/Geometric_median#Computation

The mean however (average_pointer) feels perfectly natural in my testing, it is smooth and won't ever jitter as much as your finger does (assuming 2+ fingers), and clearly very simple to compute.

Why cast to an int? Because the code is simpler to understand mixing ints with ints. pointer_count is a size_t and I don't want the central algorithm polluted with typecasts. Also, I prefer the readability of a C-cast over static_cast, but don't care enough to argue more than once...

[PS Jenkins bot (ps-jenkins)]

PASSED: Continuous integration, rev:736
http://jenkins.qa.ubuntu.com/job/mir-ci/701/
Executed test runs:
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-android-raring-i386-build/866
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-clang-raring-amd64-build/748
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-raring-amd64-ci/186
        deb: http://jenkins.qa.ubuntu.com/job/mir-raring-amd64-ci/186/artifact/work/output/*zip*/output.zip
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-vm-ci-build/./distribution=quantal,flavor=amd64/392

Click here to trigger a rebuild:
http://s-jenkins:8080/job/mir-ci/701/rebuild

review: Approve (continuous-integration)

[Alan Griffiths (alan-griffiths)]

ok

review: Approve

[Daniel van Vugt (vanvugt)]

Alexandros,

I made changes and comments per your review. Please review again.

[Alexandros Frantzis (afrantzis)]

Looks good.

review: Approve

=== modified file 'examples/demo-shell/window_manager.cpp'
--- examples/demo-shell/window_manager.cpp	2013-06-07 02:44:18 +0000
+++ examples/demo-shell/window_manager.cpp	2013-06-11 06:25:33 +0000
@@ -25,12 +25,19 @@
 
 #include <linux/input.h>
 
-#include <assert.h>
+#include <cassert>
+#include <cstdlib>
 
 namespace me = mir::examples;
 namespace msh = mir::shell;
 
+namespace
+{
+const int min_swipe_distance = 100;  // How long must a swipe be to act on?
+}
+
 me::WindowManager::WindowManager()
+    : max_fingers(0)
 {
 }
 
@@ -45,6 +52,25 @@
     session_manager = sm;
 }
 
+mir::geometry::Point average_pointer(MirMotionEvent const& motion)
+{
+    using namespace mir;
+    using namespace geometry;
+
+    int x = 0, y = 0, count = static_cast<int>(motion.pointer_count);
+
+    for (int i = 0; i < count; i++)
+    {
+        x += motion.pointer_coordinates[i].x;
+        y += motion.pointer_coordinates[i].y;
+    }
+
+    x /= count;
+    y /= count;
+
+    return Point{X{x}, Y{y}};
+}
+
 bool me::WindowManager::handle(MirEvent const& event)
 {
     assert(focus_controller);
@@ -60,9 +86,20 @@
     else if (event.type == mir_event_type_motion &&
              session_manager)
     {
+        geometry::Point cursor = average_pointer(event.motion);
+
+        // FIXME: https://bugs.launchpad.net/mir/+bug/1189379
+        MirMotionAction action =
+            (MirMotionAction)(event.motion.action & ~0xff00);
+
         std::shared_ptr<msh::Session> app =
             session_manager->focussed_application().lock();
 
+        int fingers = static_cast<int>(event.motion.pointer_count);
+
+        if (action == mir_motion_action_down || fingers > max_fingers)
+            max_fingers = fingers;
+
         if (app)
         {
             // FIXME: We need to be able to select individual surfaces in
@@ -70,24 +107,37 @@
             std::shared_ptr<msh::Surface> surf = app->default_surface();
 
             if (surf &&
-                event.motion.modifiers & mir_key_modifier_alt)
+                (event.motion.modifiers & mir_key_modifier_alt ||
+                 fingers >= 3))
             {
-                geometry::Point cursor{
-                    geometry::X{event.motion.pointer_coordinates[0].x},
-                    geometry::Y{event.motion.pointer_coordinates[0].y}};
-
-                if (event.motion.button_state == 0)
+                // Start of a gesture: When the latest finger/button goes down
+                if (action == mir_motion_action_down ||
+                    action == mir_motion_action_pointer_down)
                 {
                     relative_click = cursor - surf->top_left();
+                    click = cursor;
                 }
-                else if (event.motion.button_state & mir_motion_button_primary)
-                {
+                else if (event.motion.action == mir_motion_action_move)
+                { // Movement is happening with one or more fingers/button down
                     geometry::Point abs = cursor - relative_click;
-                    surf->move_to(abs);
-                    return true;
+                    if (max_fingers <= 3)  // Avoid accidental movement
+                    {
+                        surf->move_to(abs);
+                        return true;
+                    }
                 }
             }
         }
+
+        if (max_fingers == 4 && action == mir_motion_action_up)
+        { // Four fingers released
+            geometry::Displacement dir = cursor - click;
+            if (abs(dir.dx.as_int()) >= min_swipe_distance)
+            {
+                focus_controller->focus_next();
+                return true;
+            }
+        }
     }
     return false;
 }

=== modified file 'examples/demo-shell/window_manager.h'
--- examples/demo-shell/window_manager.h	2013-06-07 02:44:18 +0000
+++ examples/demo-shell/window_manager.h	2013-06-11 06:25:33 +0000
@@ -53,6 +53,8 @@
     std::shared_ptr<shell::FocusController> focus_controller;
     std::shared_ptr<shell::SessionManager> session_manager;
     geometry::Displacement relative_click;  // Click location in window space
+    geometry::Point click;                  // Click location in screen space
+    int max_fingers;  // Maximum number of fingers touched during gesture
 };
 
 }