Expected Behavior

circuit_drawer() working on Windows machine

Current Behavior

I tested the function tools/visualization/circuit_drawer under Windows and got an OSError at the conversion step from pdf to png using the poppler tool pdftocairo. Apparently pdftocairo was working properly, but what threw the error was Image.open and os.remove using just the filenames instead of a full path.

Possible Solution

I could fix this by using the full paths to the .png images, i.e.

Image.open("{}".format(os.path.join(tmpdirname, filename + '.png')))
os.remove("{}".format(os.path.join(tmpdirname, filename + '.png')))

Steps to Reproduce (for bugs)

execute circuit_drawer() on Windows machine

Your Environment

• Version used: QISKit 0.5.1 installed from pip
• Operating System and version: Windows 10, cygwin