BTerm set() with float data point

This might be a dump question, I'm new to Rust lang. 
I was trying to use ```ctx.set(X, Y, fg, bg, glyph)``` to render a tile on my console, but I realized ```set()``` only takes ```int``` as its ```X``` and ```Y``` coordinates, which will make my character moves not smoothly enough. I want it to take float data points as its coordinates,  is there a good way to work around this? 