diff --git a/src/app/ui/editor/play_state.cpp b/src/app/ui/editor/play_state.cpp
index 242d32d91..5c6e75431 100644
--- a/src/app/ui/editor/play_state.cpp
+++ b/src/app/ui/editor/play_state.cpp
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2001-2015  David Capello
+// Copyright (C) 2001-2016  David Capello
 //
 // This program is free software; you can redistribute it and/or modify
 // it under the terms of the GNU General Public License version 2 as
@@ -70,7 +70,7 @@ void PlayState::onEnterState(Editor* editor)
 
   m_toScroll = false;
   m_nextFrameTime = getNextFrameTime();
-  m_curFrameTick = ui::clock();
+  m_curFrameTick = base::current_tick();
   m_pingPongForward = true;
 
   // Maybe we came from ScrollingState and the timer is already
@@ -146,7 +146,7 @@ void PlayState::onPlaybackTick()
   if (m_nextFrameTime < 0)
     return;
 
-  m_nextFrameTime -= (ui::clock() - m_curFrameTick);
+  m_nextFrameTime -= (base::current_tick() - m_curFrameTick);
 
   doc::Sprite* sprite = m_editor->sprite();
   doc::FrameTag* tag = get_animation_tag(sprite, m_refFrame);
@@ -188,7 +188,7 @@ void PlayState::onPlaybackTick()
     m_editor->invalidate();
   }
 
-  m_curFrameTick = ui::clock();
+  m_curFrameTick = base::current_tick();
 }
 
 // Before executing any command, we stop the animation
diff --git a/src/app/ui/editor/play_state.h b/src/app/ui/editor/play_state.h
index 4ada6d9c3..cb33332ca 100644
--- a/src/app/ui/editor/play_state.h
+++ b/src/app/ui/editor/play_state.h
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2001-2015  David Capello
+// Copyright (C) 2001-2016  David Capello
 //
 // This program is free software; you can redistribute it and/or modify
 // it under the terms of the GNU General Public License version 2 as
@@ -11,6 +11,7 @@
 
 #include "app/ui/editor/state_with_wheel_behavior.h"
 #include "base/connection.h"
+#include "base/time.h"
 #include "doc/frame.h"
 #include "ui/timer.h"
 
@@ -46,7 +47,7 @@ namespace app {
     // Number of milliseconds to go to the next frame if m_playTimer
     // is activated.
     double m_nextFrameTime;
-    int m_curFrameTick;
+    base::tick_t m_curFrameTick;
 
     bool m_pingPongForward;
     doc::frame_t m_refFrame;
diff --git a/src/app/ui/file_list.cpp b/src/app/ui/file_list.cpp
index aa06a36c3..9ddcdfb55 100644
--- a/src/app/ui/file_list.cpp
+++ b/src/app/ui/file_list.cpp
@@ -15,6 +15,7 @@
 #include "app/thumbnail_generator.h"
 #include "app/ui/skin/skin_theme.h"
 #include "base/string.h"
+#include "base/time.h"
 #include "she/font.h"
 #include "she/surface.h"
 #include "ui/ui.h"
@@ -245,7 +246,7 @@ bool FileList::onProcessMessage(Message* msg)
                  std::tolower(unicodeChar) <= 'z') ||
                 (unicodeChar >= '0' &&
                  unicodeChar <= '9')) {
-              if (ui::clock() - m_isearchClock > ISEARCH_KEYPRESS_INTERVAL_MSECS)
+              if ((base::current_tick() - m_isearchClock) > ISEARCH_KEYPRESS_INTERVAL_MSECS)
                 m_isearch.clear();
 
               m_isearch.push_back(unicodeChar);
@@ -261,7 +262,7 @@ bool FileList::onProcessMessage(Message* msg)
                   break;
                 }
               }
-              m_isearchClock = ui::clock();
+              m_isearchClock = base::current_tick();
               // Go to selectIndex...
             }
             else
diff --git a/src/app/ui/file_list.h b/src/app/ui/file_list.h
index 8e4a8cc68..2db4d8d99 100644
--- a/src/app/ui/file_list.h
+++ b/src/app/ui/file_list.h
@@ -11,6 +11,7 @@
 
 #include "app/file_system.h"
 #include "base/signal.h"
+#include "base/time.h"
 #include "ui/timer.h"
 #include "ui/widget.h"
 
@@ -72,7 +73,7 @@ namespace app {
 
     // Incremental-search
     std::string m_isearch;
-    int m_isearchClock;
+    base::tick_t m_isearchClock;
 
     // Timer to start generating the thumbnail after an item is
     // selected.
diff --git a/src/app/ui/status_bar.cpp b/src/app/ui/status_bar.cpp
index 679592580..62951eed9 100644
--- a/src/app/ui/status_bar.cpp
+++ b/src/app/ui/status_bar.cpp
@@ -263,7 +263,7 @@ void StatusBar::updateFromEditor(Editor* editor)
 
 bool StatusBar::setStatusText(int msecs, const char *format, ...)
 {
-  if ((ui::clock() > m_timeout) || (msecs > 0)) {
+  if ((base::current_tick() > m_timeout) || (msecs > 0)) {
     char buf[256];              // TODO warning buffer overflow
     va_list ap;
 
@@ -271,7 +271,7 @@ bool StatusBar::setStatusText(int msecs, const char *format, ...)
     vsprintf(buf, format, ap);
     va_end(ap);
 
-    m_timeout = ui::clock() + msecs;
+    m_timeout = base::current_tick() + msecs;
     m_state = SHOW_TEXT;
 
     setText(buf);
@@ -315,7 +315,7 @@ void StatusBar::showTip(int msecs, const char *format, ...)
   m_tipwindow->startTimer();
 
   // Set the text in status-bar (with inmediate timeout)
-  m_timeout = ui::clock();
+  m_timeout = base::current_tick();
   setText(buf);
   invalidate();
 }
diff --git a/src/app/ui/status_bar.h b/src/app/ui/status_bar.h
index e54a5f66d..1a53a3167 100644
--- a/src/app/ui/status_bar.h
+++ b/src/app/ui/status_bar.h
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2001-2015  David Capello
+// Copyright (C) 2001-2016  David Capello
 //
 // This program is free software; you can redistribute it and/or modify
 // it under the terms of the GNU General Public License version 2 as
@@ -11,6 +11,7 @@
 
 #include "app/color.h"
 #include "base/observers.h"
+#include "base/time.h"
 #include "doc/context_observer.h"
 #include "doc/document_observer.h"
 #include "doc/documents_observer.h"
@@ -86,7 +87,7 @@ namespace app {
 
     enum State { SHOW_TEXT, SHOW_COLOR, SHOW_TOOL };
 
-    int m_timeout;
+    base::tick_t m_timeout;
     State m_state;
 
     // Showing a tool
diff --git a/src/base/time.cpp b/src/base/time.cpp
index 8c788bd52..ce8030edf 100644
--- a/src/base/time.cpp
+++ b/src/base/time.cpp
@@ -1,5 +1,5 @@
 // Aseprite Base Library
-// Copyright (c) 2001-2013, 2015 David Capello
+// Copyright (c) 2001-2016 David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -14,6 +14,11 @@
   #include <windows.h>
 #else
   #include <ctime>
+  #include <sys/time.h>
+#endif
+
+#if __APPLE__
+  #include <mach/mach_time.h>
 #endif
 
 namespace base {
@@ -37,4 +42,22 @@ Time current_time()
 #endif
 }
 
+tick_t current_tick()
+{
+#if _WIN32
+  // TODO use GetTickCount64 (available from Vista)
+  return GetTickCount();
+#elif defined(__APPLE__)
+  static mach_timebase_info_data_t timebase = { 0, 0 };
+  if (timebase.denom == 0)
+    (void)mach_timebase_info(&timebase);
+  return tick_t(double(mach_absolute_time()) * double(timebase.numer) / double(timebase.denom) / 1.0e6);
+#else
+  // TODO use clock_gettime(CLOCK_MONOTONIC, &now); if it's possible
+  struct timeval now;
+  gettimeofday(&now, nullptr);
+  return now.tv_sec*1000 + now.tv_usec/1000;
+#endif
+}
+
 } // namespace base
diff --git a/src/base/time.h b/src/base/time.h
index 85235bb92..0d52bf9a8 100644
--- a/src/base/time.h
+++ b/src/base/time.h
@@ -1,5 +1,5 @@
 // Aseprite Base Library
-// Copyright (c) 2001-2013, 2015 David Capello
+// Copyright (c) 2001-2016 David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -8,10 +8,15 @@
 #define BASE_TIME_H_INCLUDED
 #pragma once
 
+#include "base/ints.h"
+
 #include <string>
 
 namespace base {
 
+  // ~1000 per second
+  typedef uint64_t tick_t;
+
   class Time {
   public:
     int year, month, day;
@@ -47,6 +52,7 @@ namespace base {
   };
 
   Time current_time();
+  tick_t current_tick();
 
 }
 
diff --git a/src/she/alleg4/alleg_display.cpp b/src/she/alleg4/alleg_display.cpp
index 61bbb5305..521dfcda9 100644
--- a/src/she/alleg4/alleg_display.cpp
+++ b/src/she/alleg4/alleg_display.cpp
@@ -54,7 +54,6 @@
 #include <sstream>
 #include <vector>
 
-#include "she/alleg4/clock.h"
 #include "she/alleg4/display_events.h"
 
 #ifdef USE_KEY_POLLER
diff --git a/src/she/alleg4/clock.cpp b/src/she/alleg4/clock.cpp
deleted file mode 100644
index 572f0ab73..000000000
--- a/src/she/alleg4/clock.cpp
+++ /dev/null
@@ -1,43 +0,0 @@
-// SHE library
-// Copyright (C) 2012-2014  David Capello
-//
-// This file is released under the terms of the MIT license.
-// Read LICENSE.txt for more information.
-
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
-
-#include <allegro.h>
-
-static volatile int clock_var = 0; // Global timer.
-
-static void clock_inc()
-{
-  ++clock_var;
-}
-
-END_OF_STATIC_FUNCTION(clock_inc);
-
-namespace she {
-
-void clock_init()
-{
-  // Install timer related stuff
-  LOCK_VARIABLE(clock_var);
-  LOCK_FUNCTION(clock_inc);
-
-  install_int_ex(clock_inc, BPS_TO_TIMER(1000));
-}
-
-void clock_exit()
-{
-  remove_int(clock_inc);
-}
-
-int clock_value()
-{
-  return clock_var;
-}
-
-} // namespace she
diff --git a/src/she/alleg4/clock.h b/src/she/alleg4/clock.h
deleted file mode 100644
index 34888cf10..000000000
--- a/src/she/alleg4/clock.h
+++ /dev/null
@@ -1,18 +0,0 @@
-// SHE library
-// Copyright (C) 2012-2014  David Capello
-//
-// This file is released under the terms of the MIT license.
-// Read LICENSE.txt for more information.
-
-#ifndef SHE_ALLEG4_CLOCK_H_INCLUDED
-#define SHE_ALLEG4_CLOCK_H_INCLUDED
-#pragma once
-
-namespace she {
-
-  void clock_init();
-  void clock_exit();
-
-} // namespace she
-
-#endif
diff --git a/src/she/alleg4/mouse_poller.cpp b/src/she/alleg4/mouse_poller.cpp
index 6e55ab9f9..c586f84b8 100644
--- a/src/she/alleg4/mouse_poller.cpp
+++ b/src/she/alleg4/mouse_poller.cpp
@@ -8,8 +8,8 @@
 #include "config.h"
 #endif
 
+#include "base/time.h"
 #include "she/alleg4/alleg_display.h"
-#include "she/clock.h"
 #include "she/display.h"
 #include "she/event.h"
 #include "she/event_queue.h"
@@ -49,7 +49,7 @@ bool mouse_left = false;
 
 DlbClk double_click_level;
 Event::MouseButton double_click_button = Event::NoneButton;
-int double_click_ticks;
+base::tick_t double_click_ticks;
 
 #if !defined(__APPLE__) && !defined(_WIN32)
 // Mouse enter/leave
@@ -121,11 +121,11 @@ void generate_mouse_event_for_button(Event::MouseButton button, int old_b, int n
   ev.setButton(button);
 
   // Double Click
-  int current_ticks = clock_value();
+  base::tick_t current_ticks = base::current_tick();
   if (ev.type() == Event::MouseDown) {
     if (double_click_level != DOUBLE_CLICK_NONE) {
       // Time out, back to NONE
-      if (current_ticks - double_click_ticks > DOUBLE_CLICK_TIMEOUT_MSECS) {
+      if ((current_ticks - double_click_ticks) > DOUBLE_CLICK_TIMEOUT_MSECS) {
         double_click_level = DOUBLE_CLICK_NONE;
       }
       else if (double_click_button == button) {
@@ -152,7 +152,7 @@ void generate_mouse_event_for_button(Event::MouseButton button, int old_b, int n
   else if (ev.type() == Event::MouseUp) {
     if (double_click_level != DOUBLE_CLICK_NONE) {
       // Time out, back to NONE
-      if (current_ticks - double_click_ticks > DOUBLE_CLICK_TIMEOUT_MSECS) {
+      if ((current_ticks - double_click_ticks) > DOUBLE_CLICK_TIMEOUT_MSECS) {
         double_click_level = DOUBLE_CLICK_NONE;
       }
       else if (double_click_level == DOUBLE_CLICK_DOWN) {
diff --git a/src/she/alleg4/she.cpp b/src/she/alleg4/she.cpp
index 1f9738f11..48c4ed176 100644
--- a/src/she/alleg4/she.cpp
+++ b/src/she/alleg4/she.cpp
@@ -1,5 +1,5 @@
 // SHE library
-// Copyright (C) 2012-2015  David Capello
+// Copyright (C) 2012-2016  David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -55,7 +55,6 @@
 #include <list>
 #include <vector>
 
-#include "she/alleg4/clock.h"
 #include "she/alleg4/display_events.h"
 #ifdef USE_KEY_POLLER
   #include "she/alleg4/key_poller.h"
@@ -123,7 +122,6 @@ public:
     register_bitmap_file_type("png", load_png, save_png);
 
     // Init event sources
-    clock_init();
     display_events_init();
 #ifdef USE_KEY_POLLER
     key_poller_init();
@@ -136,7 +134,6 @@ public:
   }
 
   ~Alleg4System() {
-    clock_exit();
     remove_timer();
     allegro_exit();
 
diff --git a/src/she/clock.h b/src/she/clock.h
deleted file mode 100644
index 82aae2ac4..000000000
--- a/src/she/clock.h
+++ /dev/null
@@ -1,17 +0,0 @@
-// SHE library
-// Copyright (C) 2012-2014  David Capello
-//
-// This file is released under the terms of the MIT license.
-// Read LICENSE.txt for more information.
-
-#ifndef SHE_CLOCK_H_INCLUDED
-#define SHE_CLOCK_H_INCLUDED
-#pragma once
-
-namespace she {
-
-  int clock_value();
-
-} // namespace she
-
-#endif
diff --git a/src/she/skia/she.cpp b/src/she/skia/she.cpp
index 9482dab8e..94c03b07e 100644
--- a/src/she/skia/she.cpp
+++ b/src/she/skia/she.cpp
@@ -1,5 +1,5 @@
 // SHE library
-// Copyright (C) 2012-2015  David Capello
+// Copyright (C) 2012-2016  David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -20,7 +20,6 @@
 #if __APPLE__
   #include "she/osx/app.h"
   #include <CoreServices/CoreServices.h>
-  #include <mach/mach_time.h>
 #endif
 
 namespace she {
@@ -47,20 +46,6 @@ void clear_keyboard_buffer()
   // Do nothing
 }
 
-int clock_value()
-{
-#if _WIN32
-  return (int)GetTickCount();
-#elif defined(__APPLE__)
-  static mach_timebase_info_data_t timebase = { 0, 0 };
-  if (timebase.denom == 0)
-    (void)mach_timebase_info(&timebase);
-  return int(float(mach_absolute_time()) * float(timebase.numer) / float(timebase.denom) / 1.0e6f);
-#else
-  return 0; // TODO
-#endif
-}
-
 } // namespace she
 
 extern int app_main(int argc, char* argv[]);
diff --git a/src/ui/manager.cpp b/src/ui/manager.cpp
index 4b583f12d..4ec3db145 100644
--- a/src/ui/manager.cpp
+++ b/src/ui/manager.cpp
@@ -15,6 +15,7 @@
 #include "ui/manager.h"
 
 #include "base/scoped_value.h"
+#include "base/time.h"
 #include "she/display.h"
 #include "she/event.h"
 #include "she/event_queue.h"
@@ -1189,13 +1190,13 @@ void Manager::onSizeHint(SizeHintEvent& ev)
 void Manager::pumpQueue()
 {
 #ifdef LIMIT_DISPATCH_TIME
-  int t = ui::clock();
+  base::tick_t t = base::current_tick();
 #endif
 
   Messages::iterator it = msg_queue.begin();
   while (it != msg_queue.end()) {
 #ifdef LIMIT_DISPATCH_TIME
-    if (ui::clock()-t > 250)
+    if (base::current_tick()-t > 250)
       break;
 #endif
 
diff --git a/src/ui/system.cpp b/src/ui/system.cpp
index f3b1298ea..820c4e518 100644
--- a/src/ui/system.cpp
+++ b/src/ui/system.cpp
@@ -1,5 +1,5 @@
 // Aseprite UI Library
-// Copyright (C) 2001-2013, 2015  David Capello
+// Copyright (C) 2001-2016  David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -11,7 +11,6 @@
 #include "ui/system.h"
 
 #include "gfx/point.h"
-#include "she/clock.h"
 #include "she/display.h"
 #include "she/surface.h"
 #include "she/system.h"
@@ -150,11 +149,6 @@ UISystem::~UISystem()
   update_mouse_overlay(NULL);
 }
 
-int clock()
-{
-  return she::clock_value();
-}
-
 void _internal_set_mouse_display(she::Display* display)
 {
   CursorType cursor = get_mouse_cursor();
diff --git a/src/ui/system.h b/src/ui/system.h
index 30193694b..72972c939 100644
--- a/src/ui/system.h
+++ b/src/ui/system.h
@@ -1,5 +1,5 @@
 // Aseprite UI Library
-// Copyright (C) 2001-2013, 2015  David Capello
+// Copyright (C) 2001-2016  David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -28,10 +28,6 @@ namespace ui {
   int display_w();
   int display_h();
 
-  // Timer related
-
-  int clock();
-
   // Mouse related
 
   // Updates the position of the mouse cursor overlay depending on the
diff --git a/src/ui/timer.cpp b/src/ui/timer.cpp
index b2e2871f5..5838e86c3 100644
--- a/src/ui/timer.cpp
+++ b/src/ui/timer.cpp
@@ -1,5 +1,5 @@
 // Aseprite UI Library
-// Copyright (C) 2001-2013  David Capello
+// Copyright (C) 2001-2016  David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -10,9 +10,9 @@
 
 #include "ui/timer.h"
 
+#include "base/time.h"
 #include "ui/manager.h"
 #include "ui/message.h"
-#include "ui/system.h"
 #include "ui/widget.h"
 
 #include <algorithm>
@@ -27,9 +27,10 @@ static Timers timers; // Registered timers
 Timer::Timer(int interval, Widget* owner)
   : m_owner(owner ? owner: Manager::getDefault())
   , m_interval(interval)
-  , m_lastTime(-1)
+  , m_running(false)
+  , m_lastTick(0)
 {
-  ASSERT(m_owner != NULL);
+  ASSERT(m_owner != nullptr);
 
   timers.push_back(this);
 }
@@ -44,19 +45,15 @@ Timer::~Timer()
   Manager::getDefault()->removeMessagesForTimer(this);
 }
 
-bool Timer::isRunning() const
-{
-  return (m_lastTime >= 0);
-}
-
 void Timer::start()
 {
-  m_lastTime = ui::clock();
+  m_lastTick = base::current_tick();
+  m_running = true;
 }
 
 void Timer::stop()
 {
-  m_lastTime = -1;
+  m_running = false;
 }
 
 void Timer::tick()
@@ -79,26 +76,16 @@ void Timer::pollTimers()
 {
   // Generate messages for timers
   if (!timers.empty()) {
-    int t = ui::clock();
-    int count;
+    base::tick_t t = base::current_tick();
 
     for (Timers::iterator it=timers.begin(), end=timers.end(); it != end; ++it) {
       Timer* timer = *it;
-      if (timer && timer->m_lastTime >= 0) {
-        count = 0;
-        while (t - timer->m_lastTime > timer->m_interval) {
-          timer->m_lastTime += timer->m_interval;
-          ++count;
-
-          /* we spend too much time here */
-          if (ui::clock() - t > timer->m_interval) {
-            timer->m_lastTime = ui::clock();
-            break;
-          }
-        }
-
+      if (timer && timer->isRunning()) {
+        int64_t count = ((t - timer->m_lastTick) / timer->m_interval);
         if (count > 0) {
-          ASSERT(timer->m_owner != NULL);
+          timer->m_lastTick += count * timer->m_interval;
+
+          ASSERT(timer->m_owner != nullptr);
 
           Message* msg = new TimerMessage(count, timer);
           msg->addRecipient(timer->m_owner);
diff --git a/src/ui/timer.h b/src/ui/timer.h
index bff5e7f34..049396e17 100644
--- a/src/ui/timer.h
+++ b/src/ui/timer.h
@@ -1,5 +1,5 @@
 // Aseprite UI Library
-// Copyright (C) 2001-2013, 2015  David Capello
+// Copyright (C) 2001-2016  David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -10,21 +10,23 @@
 
 #include "base/disable_copying.h"
 #include "base/signal.h"
+#include "base/time.h"
 
 namespace ui {
 
   class Widget;
 
-  class Timer
-  {
+  class Timer {
   public:
     Timer(int interval, Widget* owner = NULL);
     virtual ~Timer();
 
-    int getInterval() const;
+    int interval() const { return m_interval; }
     void setInterval(int interval);
 
-    bool isRunning() const;
+    bool isRunning() const {
+      return m_running;
+    }
 
     void start();
     void stop();
@@ -42,7 +44,8 @@ namespace ui {
   public:
     Widget* m_owner;
     int m_interval;
-    int m_lastTime;
+    bool m_running;
+    base::tick_t m_lastTick;
 
     DISABLE_COPYING(Timer);
   };