• Kivy 内部嵌入web页面——CEFPython3


    在Kiv应用里嵌入web页面

    环境

    • Windwos 10
    • python 3.6.6
    • Kivy 1.11.1
    • cefpython3 66.0

    Demo 代码

    
    from cefpython3 import cefpython as cef
    
    # import pygtk
    # import gtk
    import sys
    import os
    import time
    
    from kivy.app import App
    from kivy.uix.button import Button
    from kivy.uix.popup import Popup
    from kivy.uix.label import Label
    from kivy.uix.widget import Widget
    from kivy.graphics import Color, Rectangle
    from kivy.clock import Clock
    from kivy.graphics.texture import Texture
    from kivy.uix.boxlayout import BoxLayout
    from kivy.base import EventLoop
    
    # Global variables
    g_switches = None
    
    # PyGTK required
    # pygtk.require('2.0')
    
    
    class BrowserLayout(BoxLayout):
    
        def __init__(self, **kwargs):
            super(BrowserLayout, self).__init__(**kwargs)
            self.orientation = "vertical"
    
            self.browser_widget = CefBrowser(id="browser")
    
            layout = BoxLayout()
            layout.size_hint_y = None
            layout.height = 40
            layout.add_widget(Button(text="Back",
                                     on_press=self.browser_widget.go_back))
            layout.add_widget(Button(text="Forward",
                                     on_press=self.browser_widget.go_forward))
            layout.add_widget(Button(text="Reload",
                                     on_press=self.browser_widget.reload))
            layout.add_widget(Button(text="Print",
                                     on_press=self.browser_widget.print_page))
            layout.add_widget(Button(text="DevTools",
                                     on_press=self.browser_widget.devtools))
    
            self.add_widget(layout)
            self.add_widget(self.browser_widget)
    
    
    class CefBrowser(Widget):
        """Represent a browser widget for kivy, which can be used
        like a normal widget."""
    
        # Keyboard mode: "global" or "local".
        # 1. Global mode forwards keys to CEF all the time.
        # 2. Local mode forwards keys to CEF only when an editable
        #    control is focused (input type=text|password or textarea).
        keyboard_mode = "global"
    
        def __init__(self, start_url='https://www.google.com/', **kwargs):
            super(CefBrowser, self).__init__(**kwargs)
    
            for arg in sys.argv:
                if arg.startswith("http://") or arg.startswith("https://"):
                    start_url = arg
            self.start_url = start_url
    
            # Workaround for flexible size:
            # start browser when the height has changed (done by layout)
            # This has to be done like this because I wasn't able to change
            # the texture size
            # until runtime without core-dump.
            # noinspection PyArgumentList
            self.bind(size=self.size_changed)
    
            self.browser = None
    
        starting = True
    
        def size_changed(self, *_):
            """When the height of the cefbrowser widget got changed,
            create the browser."""
            if self.starting:
                if self.height != 100:
                    self.start_cef()
                    self.starting = False
            else:
                # noinspection PyArgumentList
                self.texture = Texture.create(
                    size=self.size, colorfmt='rgba', bufferfmt='ubyte')
                self.texture.flip_vertical()
                with self.canvas:
                    Color(1, 1, 1)
                    # This will cause segmentation fault:
                    # | self.rect = Rectangle(size=self.size, texture=self.texture)
                    # Update only the size:
                    self.rect.size = self.size
                self.browser.WasResized()
    
        count = 0
    
        def _message_loop_work(self, *_):
            """Get called every frame."""
            self.count += 1
            # print(self.count)
            cef.MessageLoopWork()
            self.on_mouse_move_emulate()
    
            # From Kivy docs:
            # Clock.schedule_once(my_callback, 0) # call after the next frame
            # Clock.schedule_once(my_callback, -1) # call before the next frame
    
            # When scheduling "after the next frame" Kivy calls _message_loop_work
            # in about 13ms intervals. We use a small trick to make this 6ms
            # interval by scheduling it alternately before and after the next
            # frame. This gives better User Experience when scrolling.
            # See Issue #240 for more details on OSR performance.
            if self.count % 2 == 0:
                Clock.schedule_once(self._message_loop_work, 0)
            else:
                Clock.schedule_once(self._message_loop_work, -1)
    
        def update_rect(self, *_):
            """Get called whenever the texture got updated.
            => we need to reset the texture for the rectangle
            """
            self.rect.texture = self.texture
    
        def start_cef(self):
            """Starts CEF."""
            # create texture & add it to canvas
            # noinspection PyArgumentList
            self.texture = Texture.create(
                    size=self.size, colorfmt='rgba', bufferfmt='ubyte')
            self.texture.flip_vertical()
            with self.canvas:
                Color(1, 1, 1)
                self.rect = Rectangle(size=self.size, texture=self.texture)
    
            # Configure CEF
            settings = {
                # This directories must be set on Linux
                "locales_dir_path": cef.GetModuleDirectory()+"/locales",
                "resources_dir_path": cef.GetModuleDirectory(),
                "browser_subprocess_path": "%s/%s" % (
                    cef.GetModuleDirectory(), "subprocess"),
                "windowless_rendering_enabled": True,
                "context_menu": {
                    # Disable context menu, popup widgets not supported
                    "enabled": False,
                },
                "external_message_pump": False,  # See Issue #246
            }
            switches = {
                # Tweaking OSR performance by setting the same Chromium flags
                # as in upstream cefclient (# Issue #240).
                "disable-surfaces": "",
                "disable-gpu": "",
                "disable-gpu-compositing": "",
                "enable-begin-frame-scheduling": "",
            }
            browserSettings = {
                # Tweaking OSR performance (Issue #240)
                "windowless_frame_rate": 60
            }
    
            # Initialize CEF
    
            # To shutdown all CEF processes on error
            sys.excepthook = cef.ExceptHook
    
            # noinspection PyArgumentList
            cef.WindowUtils.InstallX11ErrorHandlers()
    
            global g_switches
            g_switches = switches
            cef.Initialize(settings, switches)
    
            # Start idle - CEF message loop work.
            Clock.schedule_once(self._message_loop_work, 0)
    
            # TODO: For printing to work in off-screen-rendering mode
            #       it is enough to call gtk_init(). It is not required
            #       to provide window handle when calling SetAsOffscreen().
            #       However it still needs to be tested whether providing
            #       window handle is required for mouse context menu and
            #       popup widgets to work.
            # gtkwin = gtk.Window()
            # gtkwin.realize()
    
            # WindowInfo offscreen flag
            windowInfo = cef.WindowInfo()
            windowInfo.SetAsOffscreen(0)
    
            # Create Broswer and naviagte to empty page <= OnPaint won't get
            # called yet
            # The render handler callbacks are not yet set, thus an
            # error report will be thrown in the console (when release
            # DCHECKS are enabled), however don't worry, it is harmless.
            # This is happening because calling GetViewRect will return
            # false. That's why it is initially navigating to "about:blank".
            # Later, a real url will be loaded using the LoadUrl() method
            # and the GetViewRect will be called again. This time the render
            # handler callbacks will be available, it will work fine from
            # this point.
            # --
            # Do not use "about:blank" as navigateUrl - this will cause
            # the GoBack() and GoForward() methods to not work.
            #
            self.browser = cef.CreateBrowserSync(
                    windowInfo,
                    browserSettings,
                    navigateUrl=self.start_url)
    
            # Set focus
            self.browser.SendFocusEvent(True)
    
            self._client_handler = ClientHandler(self)
            self.browser.SetClientHandler(self._client_handler)
            self.set_js_bindings()
    
            # Call WasResized() => force cef to call GetViewRect() and OnPaint
            # afterwards
            self.browser.WasResized()
    
            # The browserWidget instance is required in OnLoadingStateChange().
            self.browser.SetUserData("browserWidget", self)
    
            if self.keyboard_mode == "global":
                self.request_keyboard()
    
            # Clock.schedule_once(self.change_url, 5)
    
        _client_handler = None
        _js_bindings = None
    
        def set_js_bindings(self):
            if not self._js_bindings:
                self._js_bindings = cef.JavascriptBindings(
                    bindToFrames=True, bindToPopups=True)
                self._js_bindings.SetFunction("__kivy__request_keyboard",
                                              self.request_keyboard)
                self._js_bindings.SetFunction("__kivy__release_keyboard",
                                              self.release_keyboard)
            self.browser.SetJavascriptBindings(self._js_bindings)
    
        def change_url(self, *_):
            # Doing a javascript redirect instead of Navigate()
            # solves the js bindings error. The url here need to
            # be preceded with "http://". Calling StopLoad()
            # might be a good idea before making the js navigation.
    
            self.browser.StopLoad()
            self.browser.GetMainFrame().ExecuteJavascript(
                   "window.location='http://www.youtube.com/'")
    
            # Do not use Navigate() or GetMainFrame()->LoadURL(),
            # as it causes the js bindings to be removed. There is
            # a bug in CEF, that happens after a call to Navigate().
            # The OnBrowserDestroyed() callback is fired and causes
            # the js bindings to be removed. See this topic for more
            # details:
            # http://www.magpcss.org/ceforum/viewtopic.php?f=6&t=11009
    
            # OFF:
            # | self.browser.Navigate("http://www.youtube.com/")
    
        _keyboard = None
    
        def request_keyboard(self):
            print("[kivy_.py] request_keyboard()")
            self._keyboard = EventLoop.window.request_keyboard(
                    self.release_keyboard, self)
            self._keyboard.bind(on_key_down=self.on_key_down)
            self._keyboard.bind(on_key_up=self.on_key_up)
            self.is_shift1 = False
            self.is_shift2 = False
            self.is_ctrl1 = False
            self.is_ctrl2 = False
            self.is_alt1 = False
            self.is_alt2 = False
            # Not sure if it is still required to send the focus
            # (some earlier bug), but it shouldn't hurt to call it.
            self.browser.SendFocusEvent(True)
    
        def release_keyboard(self):
            # When using local keyboard mode, do all the request
            # and releases of the keyboard through js bindings,
            # otherwise some focus problems arise.
            self.is_shift1 = False
            self.is_shift2 = False
            self.is_ctrl1 = False
            self.is_ctrl2 = False
            self.is_alt1 = False
            self.is_alt2 = False
            if not self._keyboard:
                return
            print("[kivy_.py] release_keyboard()")
            self._keyboard.unbind(on_key_down=self.on_key_down)
            self._keyboard.unbind(on_key_up=self.on_key_up)
            self._keyboard.release()
    
        # Kivy does not provide modifiers in on_key_up, but these
        # must be sent to CEF as well.
        is_shift1 = False
        is_shift2 = False
        is_ctrl1 = False
        is_ctrl2 = False
        is_alt1 = False
        is_alt2 = False
    
        def on_key_down(self, _, key, text, modifiers):
            # NOTE: Right alt modifier is not sent by Kivy through modifiers param.
            # print("---- on_key_down")
            # print("-- key="+str(key))
            # print(text) - utf-8 char
            # print("-- modifiers="+str(modifiers))
            if text:
                # print("-- ord(text)="+str(ord(text)))
                pass
    
            # CEF key event type:
            #   KEYEVENT_RAWKEYDOWN = 0
            #   KEYEVENT_KEYDOWN = 1
            #   KEYEVENT_KEYUP = 2
            #   KEYEVENT_CHAR = 3
    
            # Kivy code -1 is a special key eg. Change keyboard layout.
            # Sending it to CEF would crash it.
            if key[0] == -1:
                return
    
            # On escape release the keyboard, see the injected in OnLoadStart()
            if key[0] == 27:
                self.browser.GetFocusedFrame().ExecuteJavascript(
                        "__kivy__on_escape()")
                return
    
            # CEF modifiers
            # When pressing ctrl also set modifiers for ctrl
            if key[0] in (306, 305):
                modifiers.append('ctrl')
            cef_modifiers = cef.EVENTFLAG_NONE
            if "shift" in modifiers:
                cef_modifiers |= cef.EVENTFLAG_SHIFT_DOWN
            if "ctrl" in modifiers:
                cef_modifiers |= cef.EVENTFLAG_CONTROL_DOWN
            if "alt" in modifiers:
                cef_modifiers |= cef.EVENTFLAG_ALT_DOWN
            if "capslock" in modifiers:
                cef_modifiers |= cef.EVENTFLAG_CAPS_LOCK_ON
    
            keycode = self.get_windows_key_code(key[0])
            charcode = key[0]
            if text:
                charcode = ord(text)
    
            # Send key event to cef: RAWKEYDOWN
            keyEvent = {
                    "type": cef.KEYEVENT_RAWKEYDOWN,
                    "windows_key_code": keycode,
                    "character": charcode,
                    "unmodified_character": charcode,
                    "modifiers": cef_modifiers,
            }
            # print("- SendKeyEvent: %s" % keyEvent)
            self.browser.SendKeyEvent(keyEvent)
    
            # Send key event to cef: CHAR
            if text:
                keyEvent = {
                        "type": cef.KEYEVENT_CHAR,
                        "windows_key_code": keycode,
                        "character": charcode,
                        "unmodified_character": charcode,
                        "modifiers": cef_modifiers
                }
                # print("- SendKeyEvent: %s" % keyEvent)
                self.browser.SendKeyEvent(keyEvent)
    
            if key[0] == 304:
                self.is_shift1 = True
            elif key[0] == 303:
                self.is_shift2 = True
            elif key[0] == 306:
                self.is_ctrl1 = True
            elif key[0] == 305:
                self.is_ctrl2 = True
            elif key[0] == 308:
                self.is_alt1 = True
            elif key[0] == 313:
                self.is_alt2 = True
    
        def on_key_up(self, _, key):
            # print("---- on_key_up")
            # print("-- key="+str(key))
    
            # Kivy code -1 is a special key eg. Change keyboard layout.
            # Sending it to CEF would crash it.
            if key[0] == -1:
                return
    
            # CEF modifiers
            cef_modifiers = cef.EVENTFLAG_NONE
            if self.is_shift1 or self.is_shift2:
                cef_modifiers |= cef.EVENTFLAG_SHIFT_DOWN
            if self.is_ctrl1 or self.is_ctrl2:
                cef_modifiers |= cef.EVENTFLAG_CONTROL_DOWN
            if self.is_alt1:
                cef_modifiers |= cef.EVENTFLAG_ALT_DOWN
    
            keycode = self.get_windows_key_code(key[0])
            charcode = key[0]
    
            # Send key event to cef: KEYUP
            keyEvent = {
                    "type": cef.KEYEVENT_KEYUP,
                    "windows_key_code": keycode,
                    "character": charcode,
                    "unmodified_character": charcode,
                    "modifiers": cef_modifiers
            }
            # print("- SendKeyEvent: %s" % keyEvent)
            self.browser.SendKeyEvent(keyEvent)
    
            if key[0] == 304:
                self.is_shift1 = False
            elif key[0] == 303:
                self.is_shift2 = False
            elif key[0] == 306:
                self.is_ctrl1 = False
            elif key[0] == 305:
                self.is_ctrl2 = False
            elif key[0] == 308:
                self.is_alt1 = False
            elif key[0] == 313:
                self.is_alt2 = False
    
        def get_windows_key_code(self, kivycode):
            cefcode = kivycode
    
            # NOTES:
            # - Map on all platforms to OnPreKeyEvent.event["windows_key_code"]
            # - Mapping all keys was not necessary on Linux, for example
            #   'comma' worked fine, while 'dot' did not, but mapping all keys
            #   to make sure it will work correctly on all platforms.
            # - If some key mapping is missing launch wxpython.py and see
            #   OnPreKeyEvent info for key events and replacate it here.
            #   (key codes can also be found on MSDN Virtual-key codes page)
    
            # Must map basic letters, otherwise eg. ctrl+a to select all
            # text won't work. (97-122 kivy <> 65-90 cef)
            if 97 <= kivycode <= 122:
                cefcode = kivycode - 32
    
            other_keys_map = {
                # Escape
                "27": 27,
                # F1-F12
                "282": 112, "283": 113, "284": 114, "285": 115,
                "286": 116, "287": 117, "288": 118, "289": 119,
                "290": 120, "291": 121, "292": 122, "293": 123,
                # Tab
                "9": 9,
                # Left Shift, Right Shift
                "304": 16, "303": 16,
                # Left Ctrl, Right Ctrl
                "306": 17, "305": 17,
                # Left Alt, Right Alt
                # TODO: left alt is_system_key=True in CEF but only when RAWKEYDOWN
                "308": 18, "313": 225,
                # Backspace
                "8": 8,
                # Enter
                "13": 13,
                # PrScr, ScrLck, Pause
                "316": 42, "302": 145, "19": 19,
                # Insert, Delete,
                # Home, End,
                # Pgup, Pgdn
                "277": 45, "127": 46,
                "278": 36, "279": 35,
                "280": 33, "281": 34,
                # Arrows (left, up, right, down)
                "276": 37, "273": 38, "275": 39, "274": 40,
                # tilde
                "96": 192,
                # minus, plus
                "45": 189, "61": 187,
                # square brackets / curly brackets, backslash
                "91": 219, "93": 221, "92": 220,
                # windows key
                "311": 91,
                # colon / semicolon
                "59": 186,
                # single quote / double quote
                "39": 222,
                # comma, dot, slash
                "44": 188, "46": 190, "47": 91,
                # context menu key is 93, but disable as it crashes app after
                # context menu is shown.
                "319": 0,
            }
            if str(kivycode) in other_keys_map:
                cefcode = other_keys_map[str(kivycode)]
    
            return cefcode
    
        def go_forward(self, *_):
            """Going to forward in browser history."""
            print( "go forward")
            self.browser.GoForward()
    
        def go_back(self, *_):
            """Going back in browser history."""
            print( "go back")
            self.browser.GoBack()
    
        def reload(self, *_):
            self.browser.Reload()
    
        def print_page(self, *_):
            self.browser.Print()
    
        def devtools(self, *_):
            # ShowDevTools doesn't work with the 'enable-begin-frame-scheduling'
            # switch. This might be fixed by implementing native popup widgets,
            # see Issue #69. The solution for now is to remove that switch,
            # but this will impact performance.
            if "enable-begin-frame-scheduling" in g_switches:
                text = ("To enable DevTools you need to remove the
    "
                        "'enable-begin-frame-scheduling' switch that
    "
                        "is passed to cef.Initialize(). See also
    "
                        "comment in CefBrowser.devtools().")
                popup = Popup(title='DevTools INFO', content=Label(text=text),
                              size_hint=(None, None), size=(400, 400))
                popup.open()
    
            else:
                self.browser.ShowDevTools()
    
        is_mouse_down = False
        is_drag = False
        is_drag_leave = False  # Mouse leaves web view
        drag_data = None
        current_drag_operation = cef.DRAG_OPERATION_NONE
    
        def on_touch_down(self, touch, *kwargs):
            # Mouse scrolling
            if "button" in touch.profile:
                if touch.button in ["scrollup", "scrolldown"]:
                    # Handled in on_touch_up()
                    return
    
            if not self.collide_point(*touch.pos):
                return
            touch.grab(self)
    
            y = self.height-touch.pos[1]
            if touch.is_double_tap:
                # is_double_tap seems not to work in Kivy 1.7.
                # Context menu is currently disabled see
                # settings["context_menu"] in cef_start().
                self.browser.SendMouseClickEvent(
                    touch.x, y, cef.MOUSEBUTTON_RIGHT,
                    mouseUp=False, clickCount=1
                )
                self.browser.SendMouseClickEvent(
                    touch.x, y, cef.MOUSEBUTTON_RIGHT,
                    mouseUp=True, clickCount=1
                )
            else:
                self.browser.SendMouseClickEvent(touch.x, y,
                                                 cef.MOUSEBUTTON_LEFT,
                                                 mouseUp=False, clickCount=1)
                self.is_mouse_down = True
    
        def on_touch_up(self, touch, *kwargs):
            # Mouse scrolling
            if "button" in touch.profile:
                if touch.button in ["scrollup", "scrolldown"]:
                    x = touch.x
                    y = self.height-touch.pos[1]
                    deltaY = -40 if "scrollup" == touch.button else 40
                    self.browser.SendMouseWheelEvent(x, y, deltaX=0, deltaY=deltaY)
                    return
    
            if touch.grab_current is not self:
                return
    
            y = self.height-touch.pos[1]
            self.browser.SendMouseClickEvent(touch.x, y, cef.MOUSEBUTTON_LEFT,
                                             mouseUp=True, clickCount=1)
            self.is_mouse_down = False
    
            if self.is_drag:
                # print("on_touch_up=%s/%s" % (touch.x,y))
                if self.is_drag_leave or not self.is_inside_web_view(touch.x, y):
                    # See comment in is_inside_web_view() - x/y at borders
                    # should be treated as outside of web view.
                    x = touch.x
                    if x == 0:
                        x = -1
                    if x == self.width-1:
                        x = self.width
                    if y == 0:
                        y = -1
                    if y == self.height-1:
                        y = self.height
                    print("[kivy_.py] ~~ DragSourceEndedAt")
                    print("[kivy_.py] ~~ current_drag_operation=%s"
                          % self.current_drag_operation)
                    self.browser.DragSourceEndedAt(x, y,
                                                   self.current_drag_operation)
                    self.drag_ended()
                else:
                    print("[kivy_.py] ~~ DragTargetDrop")
                    print("[kivy_.py] ~~ DragSourceEndedAt")
                    print("[kivy_.py] ~~ current_drag_operation=%s"
                          % self.current_drag_operation)
                    self.browser.DragTargetDrop(touch.x, y)
                    self.browser.DragSourceEndedAt(touch.x, y,
                                                   self.current_drag_operation)
                    self.drag_ended()
    
            touch.ungrab(self)
    
        last_mouse_pos = None
    
        def on_mouse_move_emulate(self):
            if not hasattr(self.get_root_window(), "mouse_pos"):
                # Not all Kivy window providers have the "mouse_pos" attribute.
                # WindowPygame does have (kivy/kivy#325).
                return
            mouse_pos = self.get_root_window().mouse_pos
            if self.last_mouse_pos == mouse_pos:
                return
            self.last_mouse_pos = mouse_pos
            # Fix mouse pos: realy = 0, kivy y = 600 / realy = 600, kivy y = 0
            x = mouse_pos[0]
            y = int(mouse_pos[1]-self.height)
            if x >= 0 >= y:
                y = abs(y)
                if not self.is_mouse_down and not self.is_drag:
                    # When mouse is down on_touch_move will be called. Calling
                    # mouse move event here caused issues with drag&drop.
                    self.browser.SendMouseMoveEvent(x, y, mouseLeave=False)
    
        def on_touch_move(self, touch, *kwargs):
            if touch.grab_current is not self:
                return
    
            y = self.height-touch.pos[1]
    
            modifiers = cef.EVENTFLAG_LEFT_MOUSE_BUTTON
            self.browser.SendMouseMoveEvent(touch.x, y, mouseLeave=False,
                                            modifiers=modifiers)
            if self.is_drag:
                # print("on_touch_move=%s/%s" % (touch.x, y))
                if self.is_inside_web_view(touch.x, y):
                    if self.is_drag_leave:
                        print("[kivy_.py] ~~ DragTargetDragEnter")
                        self.browser.DragTargetDragEnter(
                                self.drag_data, touch.x, y,
                                cef.DRAG_OPERATION_EVERY)
                        self.is_drag_leave = False
                    print("[kivy_.py] ~~ DragTargetDragOver")
                    self.browser.DragTargetDragOver(
                            touch.x, y, cef.DRAG_OPERATION_EVERY)
                    self.update_drag_icon(touch.x, y)
                else:
                    if not self.is_drag_leave:
                        self.is_drag_leave = True
                        print("[kivy_.py] ~~ DragTargetDragLeave")
                        self.browser.DragTargetDragLeave()
    
        def is_inside_web_view(self, x, y):
            # When mouse is out of app window Kivy still generates move events
            # at the borders with x=0, x=width-1, y=0, y=height-1.
            if (0 < x < self.width-1) and (0 < y < self.height-1):
                return True
            return False
    
        def drag_ended(self):
            # Either success or cancelled.
            self.is_drag = False
            self.is_drag_leave = False
            del self.drag_data
            self.current_drag_operation = cef.DRAG_OPERATION_NONE
            self.update_drag_icon(None, None)
            print("[kivy_.py] ~~ DragSourceSystemDragEnded")
            self.browser.DragSourceSystemDragEnded()
    
        drag_icon = None
    
        def update_drag_icon(self, x, y):
            if self.is_drag:
                if self.drag_icon:
                    self.drag_icon.pos = self.flip_pos_vertical(x, y)
                else:
                    image = self.drag_data.GetImage()
                    width = image.GetWidth()
                    height = image.GetHeight()
                    abuffer = image.GetAsBitmap(
                            1.0,
                            cef.CEF_COLOR_TYPE_BGRA_8888,
                            cef.CEF_ALPHA_TYPE_PREMULTIPLIED)
                    # noinspection PyArgumentList
                    texture = Texture.create(size=(width, height))
                    texture.blit_buffer(abuffer, colorfmt='bgra', bufferfmt='ubyte')
                    texture.flip_vertical()
                    self.drag_icon = Rectangle(texture=texture,
                                               pos=self.flip_pos_vertical(x, y),
                                               size=(width, height))
                    self.canvas.add(self.drag_icon)
            elif self.drag_icon:
                self.canvas.remove(self.drag_icon)
                del self.drag_icon
    
        def flip_pos_vertical(self, x, y):
            half = self.height / 2
            if y > half:
                y = half - (y-half)
            elif y < half:
                y = half + (half-y)
            # Additionally position drag icon to the center of mouse cursor
            y -= 20
            x -= 20
            return x, y
    
    
    class ClientHandler:
    
        def __init__(self, browserWidget):
            self.browserWidget = browserWidget
    
        def _fix_select_boxes(self, frame):
            # This is just a temporary fix, until proper Popup widgets
            # painting is implemented (PET_POPUP in OnPaint). Currently
            # there is no way to obtain a native window handle (GtkWindow
            # pointer) in Kivy, and this may cause things like context menus,
            # select boxes and plugins not to display correctly. Although,
            # this needs to be tested. The popup widget buffers are
            # available in a separate paint buffer, so they could positioned
            # freely so that it doesn't go out of the window. So the native
            # window handle might not necessarily be required to make it work
            # in most cases (99.9%). Though, this still needs testing to confirm.
            # --
            # See this topic on the CEF Forum regarding the NULL window handle:
            # http://www.magpcss.org/ceforum/viewtopic.php?f=6&t=10851
            # --
            # See also a related topic on the Kivy-users group:
            # https://groups.google.com/d/topic/kivy-users/WdEQyHI5vTs/discussion
            # --
            # The javascript select boxes library used:
            # http://marcj.github.io/jquery-selectBox/
            # --
            # Cannot use "file://" urls to load local resources, error:
            # | Not allowed to load local resource
            print("[kivy_.py] _fix_select_boxes()")
            resources_dir = os.path.join(
                    os.path.dirname(os.path.abspath(__file__)),
                    "kivy-select-boxes")
            if not os.path.exists(resources_dir):
                print("[kivy_.py] The kivy-select-boxes directory does not exist, "
                      "select boxes fix won't be applied.")
                return
            js_file = os.path.join(resources_dir, "kivy-selectBox.js")
            js_content = ""
            with open(js_file, "r") as myfile:
                js_content = myfile.read()
            css_file = os.path.join(resources_dir, "kivy-selectBox.css")
            css_content = ""
            with open(css_file, "r") as myfile:
                css_content = myfile.read()
            css_content = css_content.replace("
    ", "")
            css_content = css_content.replace("
    ", "")
            jsCode = """
                %(js_content)s
                var __kivy_temp_head = document.getElementsByTagName('head')[0];
                var __kivy_temp_style = document.createElement('style');
                __kivy_temp_style.type = 'text/css';
                __kivy_temp_style.appendChild(document.createTextNode("%(css_content)s"));
                __kivy_temp_head.appendChild(__kivy_temp_style);
            """ % locals()
            frame.ExecuteJavascript(
                jsCode,
                "kivy_.py > ClientHandler > OnLoadStart > _fix_select_boxes()")
    
        def OnLoadStart(self, browser, frame, **_):
            self.load_start_time = time.time()
            self._fix_select_boxes(frame)
            browserWidget = browser.GetUserData("browserWidget")
            if browserWidget and browserWidget.keyboard_mode == "local":
                print("[kivy_.py] OnLoadStart(): injecting focus listeners for"
                      " text controls")
                # The logic is similar to the one found in kivy-berkelium:
                # https://github.com/kivy/kivy-berkelium/blob/master/berkelium/__init__.py
                jsCode = """
                    var __kivy__keyboard_requested = false;
                    function __kivy__keyboard_interval() {
                        var element = document.activeElement;
                        if (!element) {
                            return;
                        }
                        var tag = element.tagName;
                        var type = element.type;
                        if (tag == "INPUT" && (type == "" || type == "text"
                                || type == "password") || tag == "TEXTAREA") {
                            if (!__kivy__keyboard_requested) {
                                __kivy__request_keyboard();
                                __kivy__keyboard_requested = true;
                            }
                            return;
                        }
                        if (__kivy__keyboard_requested) {
                            __kivy__release_keyboard();
                            __kivy__keyboard_requested = false;
                        }
                    }
                    function __kivy__on_escape() {
                        if (document.activeElement) {
                            document.activeElement.blur();
                        }
                        if (__kivy__keyboard_requested) {
                            __kivy__release_keyboard();
                            __kivy__keyboard_requested = false;
                        }
                    }
                    setInterval(__kivy__keyboard_interval, 100);
                """
                frame.ExecuteJavascript(
                        jsCode,
                        "kivy_.py > ClientHandler > OnLoadStart")
    
        def OnLoadEnd(self, browser, **_):
            # Browser lost its focus after the LoadURL() and the
            # OnBrowserDestroyed() callback bug. When keyboard mode
            # is local the fix is in the request_keyboard() method.
            # Call it from OnLoadEnd only when keyboard mode is global.
            browserWidget = browser.GetUserData("browserWidget")
            if browserWidget and browserWidget.keyboard_mode == "global":
                browser.SendFocusEvent(True)
    
        def OnLoadingStateChange(self, is_loading, **_):
            print("[kivy_.py] OnLoadingStateChange: isLoading = %s" % is_loading)
            # browserWidget = browser.GetUserData("browserWidget")
            if self.load_start_time:
                print("[kivy_.py] OnLoadingStateChange: load time = {time}"
                      .format(time=time.time()-self.load_start_time))
                self.load_start_time = None
    
        def OnPaint(self, element_type, paint_buffer, **_):
            # print "OnPaint()"
            if element_type != cef.PET_VIEW:
                print( "Popups aren't implemented yet")
                return
    
            # FPS meter ("fps" arg)
            if "fps" in sys.argv:
                if not hasattr(self, "last_paints"):
                    self.last_paints = []
                self.last_paints.append(time.time())
                while len(self.last_paints) > 30:
                    self.last_paints.pop(0)
                if len(self.last_paints) > 1:
                    fps = len(self.last_paints) /
                            (self.last_paints[-1] - self.last_paints[0])
                    print("[kivy_.py] FPS={fps}".format(fps=fps))
    
            # update buffer
            paint_buffer = paint_buffer.GetString(mode="bgra", origin="top-left")
    
            # update texture of canvas rectangle
            self.browserWidget.texture.blit_buffer(
                    paint_buffer,
                    colorfmt='bgra',
                    bufferfmt='ubyte')
    
            self.browserWidget.update_rect()
    
            return True
    
        def GetViewRect(self, rect_out, **_):
            width, height = self.browserWidget.texture.size
            rect_out.append(0)
            rect_out.append(0)
            rect_out.append(width)
            rect_out.append(height)
            return True
    
        """
        def GetRootScreenRect(self, rect_out, **_):
            width, height = self.browserWidget.texture.size
            rect_out.append(0)
            rect_out.append(0)
            rect_out.append(width)
            rect_out.append(height)
            return True
        def GetScreenRect(self, rect_out, **_):
            width, height = self.browserWidget.texture.size
            rect_out.append(0)
            rect_out.append(0)
            rect_out.append(width)
            rect_out.append(height)
            return True
        def GetScreenPoint(self, screen_coordinates_out, **kwargs):
            screen_coordinates_out.append(view_x)
            screen_coordinates_out.append(view_y)
            return True
        """
    
        def OnJavascriptDialog(self, suppress_message_out, **_):
            suppress_message_out[0] = True
            return False
    
        def OnBeforeUnloadJavascriptDialog(self, callback, **_):
            callback.Continue(allow=True, userInput="")
            return True
    
        def StartDragging(self, drag_data, x, y, **_):
            print("[kivy_.py] ~~ StartDragging")
            # Succession of d&d calls:
            #   DragTargetDragEnter
            #   DragTargetDragOver - in touch move event
            #   DragTargetDragLeave - optional
            #   DragSourceSystemDragEnded - optional, to cancel dragging
            #   DragTargetDrop - on mouse up
            #   DragSourceEndedAt - on mouse up
            #   DragSourceSystemDragEnded - on mouse up
            print("[kivy_.py] ~~ DragTargetDragEnter")
            self.browserWidget.browser.DragTargetDragEnter(
                    drag_data, x, y, cef.DRAG_OPERATION_EVERY)
            self.browserWidget.is_drag = True
            self.browserWidget.is_drag_leave = False
            self.browserWidget.drag_data = drag_data
            self.browserWidget.current_drag_operation = 
                cef.DRAG_OPERATION_NONE
            self.browserWidget.update_drag_icon(x, y)
            return True
    
        def UpdateDragCursor(self, **kwargs):
            # print("~~ UpdateDragCursor(): operation=%s" % operation)
            self.browserWidget.current_drag_operation = kwargs["operation"]
    
    
    class CefBrowserApp(App):
    
        def build(self):
            self.layout = BrowserLayout()
            return self.layout
    
        def on_stop(self):
            # This is required for a clean shutdown of CEF.
            self.layout.browser_widget.browser.CloseBrowser(True)
            del self.layout.browser_widget.browser
    
    
    if __name__ == '__main__':
        CefBrowserApp().run()
        cef.Shutdown()
    
    

    参考:

    cefpython3
    garden.cefpython
    Python GUI: cefpython3的简单分析和应用

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  • 原文地址:https://www.cnblogs.com/onsunsl/p/kivy_cefpython3_demo.html
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