From 4a41f77eb32fa7f9ecd0273b763e2f4b48251d95 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 21 Dec 2010 17:51:46 -0700
Subject: [PATCH] Preliminary code for touchscreen swipe based page flipping

---
 src/calibre/gui2/viewer/documentview.py | 25 ++++++++++
 src/calibre/gui2/viewer/gestures.py     | 61 +++++++++++++++++++++++++
 2 files changed, 86 insertions(+)
 create mode 100644 src/calibre/gui2/viewer/gestures.py

diff --git a/src/calibre/gui2/viewer/documentview.py b/src/calibre/gui2/viewer/documentview.py
index 683951400c..343d85e63e 100644
--- a/src/calibre/gui2/viewer/documentview.py
+++ b/src/calibre/gui2/viewer/documentview.py
@@ -18,6 +18,7 @@ from calibre.utils.config import Config, StringConfig
 from calibre.utils.localization import get_language
 from calibre.gui2.viewer.config_ui import Ui_Dialog
 from calibre.gui2.viewer.flip import SlideFlip
+from calibre.gui2.viewer.gestures import Gestures
 from calibre.gui2.shortcuts import Shortcuts, ShortcutConfig
 from calibre.constants import iswindows
 from calibre import prints, guess_type
@@ -474,6 +475,7 @@ class DocumentView(QWebView): # {{{
     def __init__(self, *args):
         QWebView.__init__(self, *args)
         self.flipper = SlideFlip(self)
+        self.gestures = Gestures()
         self.is_auto_repeat_event = False
         self.debug_javascript = False
         self.shortcuts =  Shortcuts(SHORTCUTS, 'shortcuts/viewer')
@@ -959,6 +961,29 @@ class DocumentView(QWebView): # {{{
             self.manager.viewport_resized(self.scroll_fraction)
         return ret
 
+    def event(self, ev):
+        typ = ev.type()
+        if typ == ev.TouchBegin:
+            try:
+                self.gestures.start_gesture('touch', ev)
+            except:
+                import traceback
+                traceback.print_exc()
+        elif typ == ev.TouchEnd:
+            try:
+                gesture = self.gestures.end_gesture('touch', ev, self.rect())
+            except:
+                import traceback
+                traceback.print_exc()
+            if gesture is not None:
+                ev.accept()
+                if gesture == 'lineleft':
+                    self.next_page()
+                elif gesture == 'lineright':
+                    self.previous_page()
+                return True
+        return QWebView.event(self, ev)
+
     def mouseReleaseEvent(self, ev):
         opos = self.document.ypos
         ret = QWebView.mouseReleaseEvent(self, ev)
diff --git a/src/calibre/gui2/viewer/gestures.py b/src/calibre/gui2/viewer/gestures.py
new file mode 100644
index 0000000000..86d2f842b9
--- /dev/null
+++ b/src/calibre/gui2/viewer/gestures.py
@@ -0,0 +1,61 @@
+#!/usr/bin/env python
+# vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
+
+__license__   = 'GPL v3'
+__copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
+__docformat__ = 'restructuredtext en'
+
+import time
+
+class Gestures(object):
+
+    def __init__(self):
+        self.in_progress = {}
+
+    def get_boundary_point(self, event):
+        t = time.time()
+        id_ = None
+        if hasattr(event, 'touchPoints'):
+            tps = list(event.touchPoints())
+            tp = None
+            for t in tps:
+                if t.isPrimary():
+                    tp = t
+                    break
+            if tp is None:
+                tp = tps[0]
+            gp, p = tp.screenPos(), tp.pos()
+            id_ = tp.id()
+        else:
+            gp, p = event.globalPos(), event.pos()
+        return (t, gp, p, id_)
+
+    def start_gesture(self, typ, event):
+        self.in_progress[typ] = self.get_boundary_point(event)
+
+    def is_in_progress(self, typ):
+        return typ in self.in_progress
+
+    def end_gesture(self, typ, event, widget_rect):
+        if not self.is_in_progress(typ):
+            return
+        start = self.in_progress[typ]
+        end = self.get_boundary_point(event)
+        if start[3] != end[3]:
+            return
+        timespan = end[0] - start[0]
+        start_pos, end_pos = start[1], end[1]
+        xspan = end_pos.x() - start_pos.x()
+        yspan = end_pos.y() - start_pos.y()
+
+        width = widget_rect.width()
+
+        if timespan < 1.1 and abs(xspan) >= width/5. and \
+                abs(yspan) < abs(xspan)/5.:
+            # Quick horizontal gesture
+            return 'line'+('left' if xspan < 0 else 'right')
+
+        return None
+
+
+