[ros-users] rxbag Exception when viewing bag files with sensor_msgs/Image topics

[William Woodall]

When playing around with the ccny's Augmented Reality demos I viewed one of
their provided bag files in rxbag and I received this exception:

Error loading image on topic /usb_cam/image_raw: buffer is not long enough
Exception in thread Thread-1:
Traceback (most recent call last):
  File "/usr/lib/python2.6/threading.py", line 532, in __bootstrap_inner
    self.run()
  File "/opt/ros/cturtle/ros/tools/rxbag/src/rxbag/timeline_cache.py", line
95, in run
    msg_stamp, item = self.loader(topic, stamp, item_details)
  File
"/opt/ros/cturtle/stacks/visualization/rxbag_plugins/src/rxbag_plugins/image_timeline_renderer.py",
line 177, in _load_thumbnail
    thumbnail_bitmap = image_helper.pil_to_cairo(thumbnail)
  File
"/opt/ros/cturtle/stacks/visualization/rxbag_plugins/src/rxbag_plugins/image_helper.py",
line 117, in pil_to_cairo
    return cairo.ImageSurface.create_for_data(data, cairo.FORMAT_ARGB32, w,
h)
TypeError: buffer is not long enough

It seems to me that problem is to do with how the images are being loaded
into cairo, or are a limitation of cario.

My system:
Guest Ubuntu Lucid Lynx 10.04 on a Host OS X Laptop:
CTurtle binary install 1.2.x
libcairo2-dev version 1.8.10-2ubuntu1

Steps to reproduce:
1. Get the bag files for the ccny ar_pose demo, instructions:
http://www.ros.org/wiki/ar_pose
2. roscd ar_pose/demo
3. rxbag usb_cam_topics_ar_multi.bag
4. Enable thumbnails
Or
5. View the "Image" of an Image topic
6. The images will not appear and the exception will be in the terminal
where rxbag was launched from.

If I need to create a ticket for this let me know and I will.

Thanks,

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Woodall
Graduate Software Engineering
Auburn University
w at auburn.edu
wjwwood at gmail.com
256-345-9938
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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