Use Qt's builtin swipe gesture recognizer instead of rolling our own

src/calibre/gui2/viewer/documentview.py

@@ -12,14 +12,13 @@
                      QPainter, QPalette, QBrush, QFontDatabase, QDialog,
                      QColor, QPoint, QImage, QRegion, QVariant, QIcon,
                      QFont, pyqtSignature, QAction, QByteArray, QMenu,
-                     pyqtSignal)
+                     pyqtSignal, QSwipeGesture)
 from PyQt4.QtWebKit import QWebPage, QWebView, QWebSettings
 
 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
@@ -514,7 +513,6 @@ 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')
@@ -582,6 +580,7 @@ def __init__(self, *args):
             else:
                 m.addAction(name, a[key], self.shortcuts.get_sequences(key)[0])
         self.goto_location_action.setMenu(self.goto_location_menu)
+        self.grabGesture(Qt.SwipeGesture)
 
     def goto_next_section(self, *args):
         if self.manager is not None:
@@ -1047,28 +1046,24 @@ def viewport_resized(self):
             self.manager.viewport_resized(self.scroll_fraction)
 
     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()
+        if ev.type() == ev.Gesture:
+            swipe = ev.gesture(Qt.SwipeGesture)
+            if swipe is not None:
+                self.handle_swipe(swipe)
                 return True
         return QWebView.event(self, ev)
 
+    def handle_swipe(self, swipe):
+        if swipe.state() == Qt.GestureFinished:
+            if swipe.horizontalDirection() == QSwipeGesture.Left:
+                self.previous_page()
+            elif swipe.horizontalDirection() == QSwipeGesture.Right:
+                self.next_page()
+            elif swipe.verticalDirection() == QSwipeGesture.Up:
+                self.goto_previous_section()
+            elif swipe.horizontalDirection() == QSwipeGesture.Down:
+                self.goto_next_section()
+
     def mouseReleaseEvent(self, ev):
         opos = self.document.ypos
         ret = QWebView.mouseReleaseEvent(self, ev)

src/calibre/gui2/viewer/gestures.py

@@ -1,61 +0,0 @@
-#!/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
-
-
-