d3 bar chart transition y-axis upside down

Question

I am new in d3 and I am trying to draw animated bar chart (following this example). I was able to generate the chart but the problem I am facing is that the motion is upside down (start from height of the bar builds the bar towards the x-axis). I want the motion starts from the x-axis and go up!

This is my code

var y0 = d3.scale.linear().range([height, 0]);
var y1 = d3.scale.linear().range([height, 0]);
..
..

control.selectAll("rect")
       .data(function(d) { return d.category; })
       .enter().append("rect")
       .attr("width", x1.rangeBand())
       .attr("x", function(d) { return x1(d.name); })
       .attr("height", 0)
       .attr("y", function(d, i) { if(columnNum == 2 && i == 2) return y1(d.value); else return y0(d.value); })
       .on('mouseover', tip.show)
       .on('mouseout', tip.hide)
       .style("fill", function(d) { return color(d.name); });

control.selectAll("rect")
       .transition()
       .delay(function(d, i) { return i * 100; })
       .duration(1000)
       .attr("height", function(d, i) { if(columnNum == 2 && i == 2) return y1(d.value); else return y0(d.value); })
       .attr("y", function(d, i) { if(columnNum == 2 && i == 2) return height - y1(d.value); else return height - y0(d.value); });

columnNum is just an indicator to number of columns per group.

Thanks for all the help.

Answer 1

Initialise y to the x axis position (i.e. height) for this:

control.selectAll("rect")
   .data(function(d) { return d.category; })
   .enter().append("rect")
   .attr("height", 0)
   .attr("y", height);