ZingChart: Is it possible to generate a 180-degree pie chart?

It sure is! The aperture property of the scaleR object reduces the size of the pie chart by the specified number amount.

scaleR: {
  aperture:180
},

The refAngle property of the plot object will flip the graph 180 degrees because the aperture will appear to cut the graph in a top down fashion.

plot: {
  refAngle: 180,
  ...
}