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Merge pull request #379 from neilmunday/master
pysdl2 example for issue #324
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‎Authors

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Original file line numberDiff line numberDiff line change
@@ -13,3 +13,4 @@ Greg Farrell <gregfarrell.org@@gmail.com>
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Finn Hughes <finn.hughes1@@gmail.com>
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Marcelo Fernandez <fernandezm@@gmail.com>
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Simon Hatt <9hatt2@@gmail.com>
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Neil Munday <www.mundayweb.com>

‎examples/pysdl2.py

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"""
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Simple SDL2 / cefpython3 example.
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Requires pysdl2 (and SDL2 library).
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Tested configurations:
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- SDL2 2.0.5 with PySDL2 0.9.3 on Fedora 25 (x86_64)
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- SDL2 with PySDL2 0.9.5 on Ubuntu 14.04
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Install instructions.
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1. Install SDL libraries for your OS, e.g:
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Fedora:
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sudo dnf install SDL2 SDL2_ttf SDL2_image SDL2_gfx SDL2_mixer
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Ubuntu:
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sudo apt-get install libsdl2-dev
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2. Install PySDL via PIP:
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sudo pip2 install PySDL2
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Event handling:
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Where possible SDL2 events are mapped to CEF ones. Not all keyboard
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modifiers are handled in this example but these could be
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added by the reader (if desired). Modifiers that do not work
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for example:
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- Ctrl
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- Mouse dragging
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- Marking text inputs with the shift key
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Due to SDL2's lack of GUI widgets there are no GUI controls
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for the user. However, as an exercise this example could
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be extended by create some simple SDL2 widgets. An example of
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widgets made using PySDL2 can be found as part of the Pi
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Entertainment System at:
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https://github.com/neilmunday/pes/blob/master/lib/pes/ui.py
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"""
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import os
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import sys
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try:
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from cefpython3 import cefpython as cef
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except ImportError:
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print("cefpython3 module not found - please install")
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sys.exit(1)
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try:
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import sdl2
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import sdl2.ext
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except ImportError:
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print("SDL2 module not found - please install")
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sys.exit(1)
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try:
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from PIL import Image
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except ImportError:
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print("PIL module not found - please install")
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sys.exit(1)
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def main():
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# The following variables control the dimensions of the window
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# and browser display area
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width = 1024
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height = 768
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# headerHeight is useful for leaving space for controls
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# at the top of the window (future implementation?)
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headerHeight = 0
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browserHeight = height - headerHeight
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browserWidth = width
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# Mouse wheel fudge to enhance scrolling
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scrollEnhance = 20
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# Initialise CEF for offscreen rendering
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WindowUtils = cef.WindowUtils()
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sys.excepthook = cef.ExceptHook
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cef.Initialize(settings={"windowless_rendering_enabled": True})
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window_info = cef.WindowInfo()
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window_info.SetAsOffscreen(0)
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# Initialise SDL2 for video (add other init constants if you
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# require other SDL2 functionality e.g. mixer,
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# TTF, joystick etc.
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sdl2.SDL_Init(sdl2.SDL_INIT_VIDEO)
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# Create the window
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window = sdl2.video.SDL_CreateWindow(
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'cefpython3 SDL2 Demo',
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sdl2.video.SDL_WINDOWPOS_UNDEFINED,
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sdl2.video.SDL_WINDOWPOS_UNDEFINED,
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width,
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height,
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0
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)
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# Define default background colour (black in this case)
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backgroundColour = sdl2.SDL_Color(0, 0, 0)
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# Create the renderer using hardware acceleration
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renderer = sdl2.SDL_CreateRenderer(window, -1, sdl2.render.SDL_RENDERER_ACCELERATED)
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# Set-up the RenderHandler, passing in the SDL2 renderer
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renderHandler = RenderHandler(renderer, width, height - headerHeight)
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# Create the browser instance
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browser = cef.CreateBrowserSync(window_info, url="https://www.google.com/")
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browser.SetClientHandler(LoadHandler())
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browser.SetClientHandler(renderHandler)
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# Must call WasResized at least once to let know CEF that
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# viewport size is available and that OnPaint may be called.
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browser.SendFocusEvent(True)
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browser.WasResized()
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# Begin the main rendering loop
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shiftDown = False
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running = True
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while running:
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# Convert SDL2 events into CEF events (where appropriate)
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events = sdl2.ext.get_events()
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for event in events:
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if event.type == sdl2.SDL_QUIT or (event.type == sdl2.SDL_KEYDOWN and event.key.keysym.sym == sdl2.SDLK_ESCAPE):
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running = False
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break
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if event.type == sdl2.SDL_MOUSEBUTTONDOWN:
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if event.button.button == sdl2.SDL_BUTTON_LEFT:
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if event.button.y > headerHeight:
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# Mouse click triggered in browser region
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browser.SendMouseClickEvent(
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event.button.x,
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event.button.y - headerHeight,
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cef.MOUSEBUTTON_LEFT,
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False,
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1
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)
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elif event.type == sdl2.SDL_MOUSEBUTTONUP:
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if event.button.button == sdl2.SDL_BUTTON_LEFT:
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if event.button.y > headerHeight:
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# Mouse click triggered in browser region
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browser.SendMouseClickEvent(
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event.button.x,
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event.button.y - headerHeight,
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cef.MOUSEBUTTON_LEFT,
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True,
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1
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)
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elif event.type == sdl2.SDL_MOUSEMOTION:
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if event.motion.y > headerHeight:
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# Mouse move triggered in browser region
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browser.SendMouseMoveEvent(event.motion.x, event.motion.y - headerHeight, False)
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elif event.type == sdl2.SDL_MOUSEWHEEL:
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# Mouse wheel event
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x = event.wheel.x
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if x < 0:
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x -= scrollEnhance
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else:
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x += scrollEnhance
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y = event.wheel.y
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if y < 0:
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y -= scrollEnhance
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else:
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y += scrollEnhance
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browser.SendMouseWheelEvent(0, 0, x, y)
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elif event.type == sdl2.SDL_TEXTINPUT:
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# Handle text events to get actual characters typed rather than the key pressed
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keycode = ord(event.text.text)
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key_event = {
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"type": cef.KEYEVENT_CHAR,
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"windows_key_code": keycode,
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"character": keycode,
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"unmodified_character": keycode,
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"modifiers": cef.EVENTFLAG_NONE
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}
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browser.SendKeyEvent(key_event)
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key_event = {
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"type": cef.KEYEVENT_KEYUP,
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"windows_key_code": keycode,
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"character": keycode,
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"unmodified_character": keycode,
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"modifiers": cef.EVENTFLAG_NONE
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}
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browser.SendKeyEvent(key_event)
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elif event.type == sdl2.SDL_KEYDOWN:
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# Handle key down events for non-text keys
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if event.key.keysym.sym == sdl2.SDLK_RETURN:
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keycode = event.key.keysym.sym
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key_event = {
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"type": cef.KEYEVENT_CHAR,
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"windows_key_code": keycode,
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"character": keycode,
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"unmodified_character": keycode,
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"modifiers": cef.EVENTFLAG_NONE
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}
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browser.SendKeyEvent(key_event)
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elif event.key.keysym.sym in [
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sdl2.SDLK_BACKSPACE,
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sdl2.SDLK_DELETE,
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sdl2.SDLK_LEFT,
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sdl2.SDLK_RIGHT,
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sdl2.SDLK_UP,
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sdl2.SDLK_DOWN,
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sdl2.SDLK_HOME,
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sdl2.SDLK_END
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]:
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keycode = getKeyCode(event.key.keysym.sym)
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if keycode != None:
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key_event = {
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"type": cef.KEYEVENT_RAWKEYDOWN,
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"windows_key_code": keycode,
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"character": keycode,
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"unmodified_character": keycode,
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"modifiers": cef.EVENTFLAG_NONE
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}
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browser.SendKeyEvent(key_event)
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elif event.type == sdl2.SDL_KEYUP:
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# Handle key up events for non-text keys
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if event.key.keysym.sym in [
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sdl2.SDLK_RETURN,
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sdl2.SDLK_BACKSPACE,
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sdl2.SDLK_DELETE,
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sdl2.SDLK_LEFT,
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sdl2.SDLK_RIGHT,
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sdl2.SDLK_UP,
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sdl2.SDLK_DOWN,
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sdl2.SDLK_HOME,
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sdl2.SDLK_END
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]:
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keycode = getKeyCode(event.key.keysym.sym)
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if keycode != None:
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key_event = {
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"type": cef.KEYEVENT_KEYUP,
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"windows_key_code": keycode,
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"character": keycode,
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"unmodified_character": keycode,
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"modifiers": cef.EVENTFLAG_NONE
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}
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browser.SendKeyEvent(key_event)
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# Clear the renderer
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sdl2.SDL_SetRenderDrawColor(
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renderer,
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backgroundColour.r,
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backgroundColour.g,
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backgroundColour.b,
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255
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)
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sdl2.SDL_RenderClear(renderer)
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# Tell CEF to update which will trigger the OnPaint
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# method of the RenderHandler instance
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cef.MessageLoopWork()
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# Update display
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sdl2.SDL_RenderCopy(
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renderer,
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renderHandler.texture,
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None,
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sdl2.SDL_Rect(0, headerHeight, browserWidth, browserHeight)
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)
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sdl2.SDL_RenderPresent(renderer)
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# User exited
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exit_app()
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def getKeyCode(key):
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"""Helper function to convert SDL2 key codes to cef ones"""
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keyMap = {
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sdl2.SDLK_RETURN: 13,
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sdl2.SDLK_DELETE: 46,
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sdl2.SDLK_BACKSPACE: 8,
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sdl2.SDLK_LEFT: 37,
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sdl2.SDLK_RIGHT: 39,
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sdl2.SDLK_UP: 38,
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sdl2.SDLK_DOWN: 40,
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sdl2.SDLK_HOME: 36,
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sdl2.SDLK_END: 35,
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}
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if key in keyMap:
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return keyMap[key]
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# Key not mapped, raise exception
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print("Keyboard mapping incomplete: \
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unsupported SDL key %d. \
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See https://wiki.libsdl.org/SDLKeycodeLookup for mapping."
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% key)
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return None
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class LoadHandler(object):
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"""Simple handler for loading URLs."""
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def OnLoadingStateChange(self, browser, is_loading, **_):
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if not is_loading:
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print("loading complete")
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def OnLoadError(self, browser, frame, error_code, failed_url, **_):
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if not frame.IsMain():
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return
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print("Failed to load %s" % failed_url)
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class RenderHandler(object):
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"""
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Handler for rendering web pages to the
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screen via SDL2.
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The object's texture property is exposed
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to allow the main rendering loop to access
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the SDL2 texture.
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"""
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def __init__(self, renderer, width, height):
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self.__width = width
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self.__height = height
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self.__renderer = renderer
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self.texture = None
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def GetViewRect(self, rect_out, **_):
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rect_out.extend([0, 0, self.__width, self.__height])
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return True
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def OnPaint(self, browser, element_type, paint_buffer, **_):
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"""
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Using the pixel data from CEF's offscreen rendering
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the data is converted by PIL into a SDL2 surface
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which can then be rendered as a SDL2 texture.
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"""
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if element_type == cef.PET_VIEW:
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image = Image.frombuffer(
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'RGBA',
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(self.__width, self.__height),
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paint_buffer.GetString(mode="rgba", origin="top-left"),
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'raw',
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'BGRA'
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)
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# Following PIL to SDL2 surface code from pysdl2 source.
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mode = image.mode
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rmask = gmask = bmask = amask = 0
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if mode == "RGB":
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# 3x8-bit, 24bpp
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if sdl2.endian.SDL_BYTEORDER == sdl2.endian.SDL_LIL_ENDIAN:
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rmask = 0x0000FF
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gmask = 0x00FF00
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bmask = 0xFF0000
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else:
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rmask = 0xFF0000
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gmask = 0x00FF00
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bmask = 0x0000FF
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depth = 24
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pitch = self.__width * 3
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elif mode in ("RGBA", "RGBX"):
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# RGBX: 4x8-bit, no alpha
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# RGBA: 4x8-bit, alpha
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if sdl2.endian.SDL_BYTEORDER == sdl2.endian.SDL_LIL_ENDIAN:
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rmask = 0x00000000
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gmask = 0x0000FF00
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bmask = 0x00FF0000
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if mode == "RGBA":
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amask = 0xFF000000
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else:
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rmask = 0xFF000000
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gmask = 0x00FF0000
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bmask = 0x0000FF00
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if mode == "RGBA":
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amask = 0x000000FF
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depth = 32
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pitch = self.__width * 4
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else:
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print("Unsupported mode: %s" % mode)
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exit_app()
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pxbuf = image.tobytes()
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# Create surface
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surface = sdl2.SDL_CreateRGBSurfaceFrom(
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pxbuf,
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self.__width,
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self.__height,
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depth,
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pitch,
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rmask,
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gmask,
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bmask,
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amask
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)
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if self.texture:
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# free memory used by previous texture
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sdl2.SDL_DestroyTexture(self.texture)
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# Create texture
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self.texture = sdl2.SDL_CreateTextureFromSurface(self.__renderer, surface)
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# Free the surface
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sdl2.SDL_FreeSurface(surface)
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else:
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print("Unsupport element_type in OnPaint")
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def exit_app():
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"""Tidy up SDL2 and CEF before exiting."""
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sdl2.SDL_Quit()
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cef.Shutdown()
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print("exited")
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if __name__ == "__main__":
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main()

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