E-book viewer: Allow configuring the actions triggered by touch gestures. Fixes #2023367 [Feature Request: Customizable Touchscreen Behaviors in Content Server's Web Viewer](https://bugs.launchpad.net/calibre/+bug/2023367)

src/pyj/read_book/gestures.pyj

@@ -32,7 +32,7 @@ def get_action_descriptions():
             },
             'highlight_or_inspect': {
                 'short': _('Highlight or inspect'),
-                'long': _('Highlight the word under the tap point or')
+                'long': _('Highlight the word under the tap point or view the image under the tap or select the highlight under the tap')
             },
             'decrease_font_size': {
                 'short': _('Make text smaller'),
@@ -67,14 +67,14 @@ def get_action_descriptions():
 
 only_flow_swipe_mode_actions = {'pan': True, 'animated_scroll': True}
 only_tap_actions = {'highlight_or_inspect': True}
-
 default_actions_for_gesture = {
     'common': {
         GESTURE.back_zone_tap: 'prev_page',
         GESTURE.forward_zone_tap: 'next_page',
         GESTURE.control_zone_tap: 'show_chrome',
-        GESTURE.two_finger_tap: 'show_chrome',
         GESTURE.long_tap: 'highlight_or_inspect',
+
+        GESTURE.two_finger_tap: 'show_chrome',
         GESTURE.pinch_in: 'decrease_font_size',
         GESTURE.pinch_out: 'increase_font_size',
     },
@@ -98,15 +98,30 @@ default_actions_for_gesture = {
     },
 }
 
-def action_for_gesture(gesture, in_flow_mode):
+def current_action_for_gesture_type(overrides, gesture_type, in_flow_mode):
-    overrides = opts.gesture_overrides
     mode = 'flow_mode' if in_flow_mode else 'paged_mode'
     mode_overrides = overrides[mode] or {}
-    if mode_overrides[gesture.type]:
+    if mode_overrides[gesture_type]:
-        return mode_overrides[gesture.type]
+        return mode_overrides[gesture_type]
     common_overrides = overrides.common or {}
-    if common_overrides[gesture.type]:
+    if common_overrides[gesture_type]:
-        return common_overrides[gesture.type]
+        return common_overrides[gesture_type]
-    if default_actions_for_gesture[mode][gesture.type]:
+    if default_actions_for_gesture[mode][gesture_type]:
-        return default_actions_for_gesture[mode][gesture.type]
+        return default_actions_for_gesture[mode][gesture_type]
-    return default_actions_for_gesture.common[gesture.type] or 'none'
+    return default_actions_for_gesture.common[gesture_type] or 'none'
+
+def action_for_gesture(gesture, in_flow_mode):
+    return current_action_for_gesture_type(opts.gesture_overrides, gesture.type, in_flow_mode)
+
+def allowed_actions_for_tap():
+    return [ac for ac in Object.keys(get_action_descriptions()) if not only_flow_swipe_mode_actions[ac]]
+
+def allowed_actions_for_paged_mode_swipe():
+    return [ac for ac in Object.keys(get_action_descriptions()) if not only_flow_swipe_mode_actions[ac] and not only_tap_actions[ac]]
+allowed_actions_for_two_fingers = allowed_actions_for_paged_mode_swipe
+
+def allowed_actions_for_flow_mode_flick():
+    return [ac for ac in Object.keys(get_action_descriptions()) if not only_tap_actions[ac]]
+
+def allowed_actions_for_flow_mode_drag():
+    return ['pan', 'none']

src/pyj/read_book/prefs/main.pyj

@@ -17,6 +17,7 @@ from read_book.prefs.layout import commit_layout, create_layout_panel
 from read_book.prefs.misc import commit_misc, create_misc_panel
 from read_book.prefs.scrolling import commit_scrolling, create_scrolling_panel
 from read_book.prefs.selection import commit_selection, create_selection_panel
+from read_book.prefs.touch import commit_touch, create_touch_panel
 from read_book.prefs.user_stylesheet import (
     commit_user_stylesheet, create_user_stylesheet_panel
 )
@@ -106,6 +107,7 @@ class Prefs:
         ci(_('Headers and footers'), 'head_foot', _('Customize the headers and footers'))
         ci(_('Scrolling behavior'), 'scrolling', _('Control how the viewer scrolls'))
         ci(_('Selection behavior'), 'selection', _('Control how the viewer selects text'))
+        ci(_('Touch behavior'), 'touch', _('Customize what various touchscreen gestures do'))
         ci(_('Keyboard shortcuts'), 'keyboard', _('Customize the keyboard shortcuts'))
         if runtime.is_standalone_viewer:
             ci(_('Fonts'), 'fonts', _('Font choices'))
@@ -166,6 +168,13 @@ class Prefs:
     def close_selection(self):
         commit_selection(self.onchange, self.container)
 
+    def display_touch(self, container):
+        self.create_panel(container, 'touch', create_touch_panel)
+
+    def close_touch(self):
+        commit_touch(self.onchange, self.container)
+
+
 
 def create_prefs_panel(container, close_func, on_change):
     return Prefs(container, close_func, on_change)

src/pyj/read_book/prefs/touch.pyj

@@ -0,0 +1,170 @@
+# vim:fileencoding=utf-8
+# License: GPL v3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
+from __python__ import bound_methods, hash_literals
+
+from elementmaker import E
+
+from book_list.globals import get_session_data
+from dom import unique_id
+from gettext import gettext as _
+from read_book.gestures import (
+    allowed_actions_for_flow_mode_drag, allowed_actions_for_flow_mode_flick,
+    allowed_actions_for_paged_mode_swipe, allowed_actions_for_tap,
+    allowed_actions_for_two_fingers, current_action_for_gesture_type,
+    get_action_descriptions
+)
+from read_book.prefs.utils import create_button_box
+from read_book.touch import GESTURE, GESTURE_NAMES
+
+CONTAINER = unique_id('touch-settings')
+
+def restore_defaults():
+    apply_settings_to_ui({})
+
+def get_container():
+    return document.getElementById(CONTAINER)
+
+
+def apply_settings_to_ui(overrides):
+    overrides = overrides or {}
+    for group in get_container().querySelectorAll('[data-group]'):
+        group_name = group.dataset.group
+        in_flow_mode = group_name.indexOf('flow') >= 0
+        for select in group.querySelectorAll('select'):
+            allowed_actions = v'[]'
+            for option in select.querySelectorAll('option'):
+                allowed_actions.push(option.value)
+            gesture_type = select.name
+            current_action = current_action_for_gesture_type(overrides, gesture_type, in_flow_mode)
+            if allowed_actions.indexOf(current_action) < 0:
+                current_action = current_action_for_gesture_type({}, gesture_type, in_flow_mode)
+            if not current_action or allowed_actions.indexOf(current_action) < 0:
+                current_action = 'none'
+            select.value = current_action
+
+def get_overrides_from_ui():
+    ans = {}
+    for group in get_container().querySelectorAll('[data-group]'):
+        group_name = group.dataset.group
+        in_flow_mode = group_name.indexOf('flow') >= 0
+        if group_name is 'paged_swipe':
+            attr = 'paged_mode'
+        elif group_name is 'flow_swipe':
+            attr = 'flow_mode'
+        else:
+            attr = 'common'
+        if not ans[attr]:
+            ans[attr] = {}
+        for select in group.querySelectorAll('select'):
+            val = select.value
+            defval = current_action_for_gesture_type({}, select.name, in_flow_mode)
+            if val is not defval:
+                ans[attr][select.name] = val
+    for which in Object.keys(ans):
+        if Object.keys(ans[which]).length is 0:
+            v'delete ans[which]'
+    return ans
+
+
+def create_touch_panel(container, apply_func, cancel_func):
+    container.appendChild(E.div(id=CONTAINER, style='margin: 1rem'))
+    container = container.lastChild
+    sd = get_session_data()
+    overrides = sd.get('gesture_overrides')
+    action_descriptions = get_action_descriptions()
+    in_flow_mode = False
+
+    def on_select_change(ev):
+        select = ev.target
+        ad = action_descriptions[select.value]
+        span = select.parentNode.querySelector('span')
+        span.textContent = ad.long
+
+    def make_setting(gesture_type, allowed_actions):
+        ans = E.div(style='margin-top: 1ex')
+        title = GESTURE_NAMES[gesture_type]
+        sid = unique_id(gesture_type)
+        ans.appendChild(E.h4(E.label(title, 'for'=sid)))
+        select = E.select(name=gesture_type, id=sid)
+        for action in allowed_actions:
+            ad = action_descriptions[action]
+            select.appendChild(E.option(ad.short, value=action))
+        select.addEventListener('change', on_select_change)
+        ans.appendChild(E.div(select, '\xa0', E.span(style='font-size: smaller; font-style: italic')))
+        on_select_change({'target': select})
+        return ans
+
+    container.appendChild(E.h2(_('Tapping')))
+    container.appendChild(E.div(_(
+        'There are three tap zones, depending on where on the screen you tap. When the tap is'
+        ' on a link, the link is followed, otherwise a configurable action based on the zone is performed.')))
+    c = E.div('data-group'='tap')
+    container.appendChild(c)
+    aat = allowed_actions_for_tap()
+    c.appendChild(make_setting(GESTURE.control_zone_tap, aat))
+    c.appendChild(make_setting(GESTURE.forward_zone_tap, aat))
+    c.appendChild(make_setting(GESTURE.back_zone_tap, aat))
+    c.appendChild(make_setting(GESTURE.long_tap, aat))
+    container.appendChild(E.hr())
+
+    container.appendChild(E.h2(_('Two finger gestures')))
+    c = E.div('data-group'='two_finger')
+    container.appendChild(c)
+    aat = allowed_actions_for_two_fingers()
+    c.appendChild(make_setting(GESTURE.two_finger_tap, aat))
+    c.appendChild(make_setting(GESTURE.pinch_in, aat))
+    c.appendChild(make_setting(GESTURE.pinch_out, aat))
+    container.appendChild(E.hr())
+
+
+    container.appendChild(E.h2(_('Swiping')))
+    container.appendChild(E.div(_(
+        'Swiping works differently in paged and flow mode, with different actions. For an English like language, swiping in'
+        ' the writing direction means swiping horizontally. For languages written vertically, it means swiping vertically.'
+        ' For languages written left-to-right "going forward" means swiping right-to-left, like turning a page with your finger.'
+    )))
+    container.appendChild(E.h3(_('Swiping in paged mode'), style='padding-top: 1ex'))
+    c = E.div('data-group'='paged_swipe')
+    container.appendChild(c)
+    aap = allowed_actions_for_paged_mode_swipe()
+    c.appendChild(make_setting(GESTURE.flick_block_forward, aap))
+    c.appendChild(make_setting(GESTURE.flick_block_backward, aap))
+    c.appendChild(make_setting(GESTURE.flick_inline_forward, aap))
+    c.appendChild(make_setting(GESTURE.flick_inline_backward, aap))
+    c.appendChild(make_setting(GESTURE.swipe_inline_forward_hold, aap))
+    c.appendChild(make_setting(GESTURE.swipe_inline_backward_hold, aap))
+    c.appendChild(make_setting(GESTURE.swipe_block_forward_hold, aap))
+    c.appendChild(make_setting(GESTURE.swipe_block_backward_hold, aap))
+    container.appendChild(E.hr())
+    container.appendChild(E.h3(_('Swiping in flow mode'), style='padding-top: 1ex'))
+    c = E.div('data-group'='flow_swipe')
+    container.appendChild(c)
+    in_flow_mode = True
+    in_flow_mode
+    aaf = allowed_actions_for_flow_mode_flick()
+    c.appendChild(make_setting(GESTURE.flick_block_forward, aaf))
+    c.appendChild(make_setting(GESTURE.flick_block_backward, aaf))
+    c.appendChild(make_setting(GESTURE.flick_inline_forward, aaf))
+    c.appendChild(make_setting(GESTURE.flick_inline_backward, aaf))
+    aaf = allowed_actions_for_flow_mode_drag()
+    c.appendChild(make_setting(GESTURE.swipe_inline_backward_in_progress, aaf))
+    c.appendChild(make_setting(GESTURE.swipe_inline_forward_in_progress, aaf))
+    c.appendChild(make_setting(GESTURE.swipe_block_backward_in_progress, aaf))
+    c.appendChild(make_setting(GESTURE.swipe_block_forward_in_progress, aaf))
+
+    container.appendChild(E.hr())
+    container.appendChild(create_button_box(restore_defaults, apply_func, cancel_func))
+    apply_settings_to_ui(overrides)
+
+
+develop = create_touch_panel
+
+
+def commit_touch(onchange):
+    sd = get_session_data()
+    current_overrides = sd.get('gesture_overrides')
+    overrides = get_overrides_from_ui()
+    changed = overrides != current_overrides
+    if changed:
+        sd.set('gesture_overrides', overrides)
+        onchange()

src/pyj/read_book/touch.pyj

@@ -21,18 +21,20 @@ GESTURE_NAMES = {
     'pinch_in': _('Pinch in'),
     'pinch_out': _('Pinch out'),
 
-    'flick_inline_backward': _('Flick in writing direction, backwards'),
+    'flick_inline_backward': _('Flick in writing direction, to go back'),
-    'flick_inline_forward': _('Flick in writing direction, forwards'),
+    'flick_inline_forward': _('Flick in writing direction, to go forward'),
-    'flick_block_backward': _('Flick perpendicular to writing direction, backwards'),
+    'flick_block_backward': _('Flick perpendicular to writing direction, to go forward'),
-    'flick_block_forward': _('Flick perpendicular to writing direction, forwards'),
+    'flick_block_forward': _('Flick perpendicular to writing direction, to go back'),
-    'swipe_inline_backward_in_progress': _('Swipe in writing direction, backwards, in-progress'),
+
-    'swipe_inline_forward_in_progress': _('Swipe in writing direction, forwards, in-progress'),
+    'swipe_inline_backward_in_progress': _('Drag finger in writing direction, to go back'),
-    'swipe_block_backward_in_progress': _('Swipe perpendicular to writing direction, backwards, in-progress'),
+    'swipe_inline_forward_in_progress': _('Drag finger in writing direction, to go forward'),
-    'swipe_block_forward_in_progress': _('Swipe perpendicular to writing direction, forwards, in-progress'),
+    'swipe_block_backward_in_progress': _('Drag finger perpendicular to writing direction, to go back'),
-    'swipe_inline_backward_hold': _('Swipe in writing direction, backwards and hold'),
+    'swipe_block_forward_in_progress': _('Drag finger perpendicular to writing direction, to go forward'),
-    'swipe_inline_forward_hold': _('Swipe in writing direction, forwards and hold'),
+
-    'swipe_block_backward_hold': _('Swipe perpendicular to writing direction, backwards and hold'),
+    'swipe_inline_backward_hold': _('Drag and hold finger in writing direction, to go back'),
-    'swipe_block_forward_hold': _('Swipe perpendicular to writing direction, forwards and hold'),
+    'swipe_inline_forward_hold': _('Drag and hold finger in writing direction, to go forward'),
+    'swipe_block_backward_hold': _('Drag and hold finger perpendicular to writing direction, to go back'),
+    'swipe_block_forward_hold': _('Drag and hold finger perpendicular to writing direction, to go forward'),
 }
 GESTURE = {k:k for k in Object.keys(GESTURE_NAMES)}
 GESTURE.tap = 'tap'