Trying to make a simple window creation program, but it fails

[jarnos]

I am trying to translate a sample code using python-xcb to respective code using python3-xcffib (0.8.1):
http://rosettacode.org/wiki/Window_creation/X11#XCB_2
I am using python 3.8.2 in Ubuntu 20.04.

#!/usr/bin/python3
import xcffib
from xcffib.xproto import *
import xcffib.render

def main():
  conn = xcffib.connect()
  conn.render = conn(xcffib.render.key)

  setup = conn.get_setup()
  root = setup.roots[0].root
  depth = setup.roots[0].root_depth
  visual = setup.roots[0].root_visual
  white = setup.roots[0].white_pixel

  window = conn.generate_id()
  conn.core.CreateWindow(depth, window, root,
                         0, 0, 640, 480, 0,
                         WindowClass.InputOutput,
                         visual,
                         CW.BackPixel | CW.EventMask,
                         [ white, EventMask.Exposure |
                                  EventMask.KeyPress ])

  conn.core.MapWindow(window)
  conn.flush()

  while True:
    print("pre")
    event = conn.wait_for_event()
    print("post")
    if isinstance(event, ExposeEvent):
      color = (0, 0, 65535, 65535)
      #rectangle = (20, 20, 40, 40)
      rectangle = [xcffib.xproto.RECTANGLE.synthetic(20, 20, 40, 40)]
      conn.render.FillRectangles(xcffib.render.PictOp.Src, window, color, 1, rectangle)
      conn.flush()

    elif isinstance(event, KeyPressEvent):
      break

  conn.disconnect()

main()

If I use simple assignment to rectangle, it prints TypeError and "pre" only once. If I use the other way, the outcome is:

pre
post
pre
Traceback (most recent call last):
File "./create-xcffib.py", line 44, in
main()
File "./create-xcffib.py", line 30, in main
event = conn.wait_for_event()
File "/usr/lib/python3/dist-packages/xcffib/init.py", line 570, in wrapper
return f(*args)
File "/usr/lib/python3/dist-packages/xcffib/init.py", line 604, in wait_for_event
return self.hoist_event(e)
File "/usr/lib/python3/dist-packages/xcffib/init.py", line 684, in hoist_event
return self._process_error(ffi.cast("xcb_generic_error_t *", e))
File "/usr/lib/python3/dist-packages/xcffib/init.py", line 647, in _process_error
raise error(buf)
xcffib.render.PictureError

[tych0]

What's the TypeError? If you use a list instead of a tuple does it work?

…

On Sun, Sep 27, 2020, at 7:16 AM, Jarno Suni wrote: I am trying to translate a sample code using python-xcb to respective code using python3-xcffib: http://rosettacode.org/wiki/Window_creation/X11#XCB_2 I am using python 3.8.2 in Ubuntu 20.04. `#!/usr/bin/python3 import xcffib from xcffib.xproto import * import xcffib.render def main(): conn = xcffib.connect() conn.render = conn(xcffib.render.key) setup = conn.get_setup() root = setup.roots[0].root depth = setup.roots[0].root_depth visual = setup.roots[0].root_visual white = setup.roots[0].white_pixel window = conn.generate_id() conn.core.CreateWindow(depth, window, root, 0, 0, 640, 480, 0, WindowClass.InputOutput, visual, CW.BackPixel | CW.EventMask, [ white, EventMask.Exposure | EventMask.KeyPress ]) conn.core.MapWindow(window) conn.flush() while True: print("pre") event = conn.wait_for_event() print("post") if isinstance(event, ExposeEvent): color = (0, 0, 65535, 65535) #rectangle = (20, 20, 40, 40) rectangle = [xcffib.xproto.RECTANGLE.synthetic(20, 20, 40, 40)] conn.render.FillRectangles(xcffib.render.PictOp.Src, window, color, 1, rectangle) conn.flush() elif isinstance(event, KeyPressEvent): break conn.disconnect() main() ` If I use simple assignment to rectangle, it prints TypeError and "pre" only once. If I use the other way, the outcome is: > pre > post > pre > Traceback (most recent call last): > File "./create-xcffib.py", line 44, in > main() > File "./create-xcffib.py", line 30, in main > event = conn.wait_for_event() > File "/usr/lib/python3/dist-packages/xcffib/*init*.py", line 570, in wrapper > return f(*args) > File "/usr/lib/python3/dist-packages/xcffib/*init*.py", line 604, in wait_for_event > return self.hoist_event(e) > File "/usr/lib/python3/dist-packages/xcffib/*init*.py", line 684, in hoist_event > return self._process_error(ffi.cast("xcb_generic_error_t *", e)) > File "/usr/lib/python3/dist-packages/xcffib/*init*.py", line 647, in _process_error > raise error(buf) > xcffib.render.PictureError — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#112>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAF7VVY4VXJU2MSF5NVEIBLSH43K5ANCNFSM4R3RU6QA>.

[jarnos]

Well, if I use list rectangle = [20, 20, 40, 40] or the tuple, I get the following output:

pre
post
Traceback (most recent call last):
File "./create-xcffib.py", line 45, in
main()
File "./create-xcffib.py", line 37, in main
conn.render.FillRectangles(xcffib.render.PictOp.Src, window, color, 1, rectangle)
File "/usr/lib/python3/dist-packages/xcffib/render.py", line 752, in FillRectangles
buf.write(xcffib.pack_list(rects, xproto.RECTANGLE))
File "/usr/lib/python3/dist-packages/xcffib/init.py", line 792, in pack_list
buf.write(item)
TypeError: a bytes-like object is required, not 'int'

[tych0]

So I xtraced it and I get:

000:<:0001: 16: Request(98): QueryExtension name='RENDER'
000:>:0001:32: Reply to QueryExtension: present=true(0x01) major-opcode=139 first-event=0 first-error=142
pre
000:<:0002: 40: Request(1): CreateWindow depth=0x18 window=0x04e00000 parent=0x000005cd x=0 y=0 width=640 height=480 border-width=0 class=InputOutput(0x0001) visual=0x00000021 value-list={background-pixel=0x00ffffff event-mask=KeyPress,Exposure}
000:<:0003:  8: Request(8): MapWindow window=0x04e00000
000:>:0003: Event Expose(12) window=0x04e00000 x=0 y=0 width=958 height=1162 count=0x0000
post
000:<:0004: 16: Request(98): QueryExtension name='RENDER'
000:>:0004:32: Reply to QueryExtension: present=true(0x01) major-opcode=139 first-event=0 first-error=142
pre
000:<:0005: 28: RENDER-Request(139,26): FillRectangles op=Src(0x01) dst=0x04e00000 color={red=0x0000 green=0x0000 blue=0xffff alpha=0xffff}; rects={x=20 y=20 w=40 h=40};
000:>:0005:Error 143=BadPicture: major=139, minor=26, bad=0x04e00000, seq=0005
Traceback (most recent call last):
  File "tester.py", line 44, in <module>
    main()
  File "tester.py", line 30, in main
    event = conn.wait_for_event()
  File "/home/tycho/.local/lib/python3.8/site-packages/xcffib/__init__.py", line 571, in wrapper
    return f(*args)
  File "/home/tycho/.local/lib/python3.8/site-packages/xcffib/__init__.py", line 605, in wait_for_event
    return self.hoist_event(e)
  File "/home/tycho/.local/lib/python3.8/site-packages/xcffib/__init__.py", line 685, in hoist_event
    return self._process_error(ffi.cast("xcb_generic_error_t *", e))
  File "/home/tycho/.local/lib/python3.8/site-packages/xcffib/__init__.py", line 648, in _process_error
    raise error(buf)
xcffib.render.PictureError

That basically looks like the request I expect to send, so I don't think there's an encoding error there.

Given that the code in your link doesn't look like it was ever tested, is it possible there's just an API issue here? I don't really know anything about the render extension.

[ldo]

Aren’t you required to do a QueryVersion call for an extension before using it? Otherwise the specs say the behaviour is “undefined”.

[tych0]

Yes, I think you're right that users are required to QueryVersion.

[tych0]

I think the picture argument here needs to be an xid that has had CreatePicture run on it; you're just using a window id.