graphael bar chart with text x-axis - raphael

Question

I was wondering how I can make a simple bar chart that perhaps has day as the x-axis, with values 'today' and 'yesterday', and the y-axis as perhaps 'time' with corresponding values '1' and '2'. I guess I'm confused as to how to set text as the values for the x-axis, how to show the y axis, and what exactly r.g.axis does...
(I found an example using axis = r.g.axis(0,300,400,0,500,8,2) and I only know it's the xpos, ypos,width, ??, ?? num ticks, ??). Any insight would be great! Or a page with more fully featured bar chart examples (labels, etc). Thanks.

Answer 1

For the sake of all those googling this:
r.g.axis(x_start, y_start, x_width, from, to, steps, orientation, labels, type, dashsize)
x_start and y_start: distance of the axis text from the bottom left corner
x_width: position of the end of the text along the x axis
from and to: used to specify and range to use instead of using the labels argument
steps: is the number of ticks - 1
orientation: seems to specify x-axis vs. y-axis
type: is the type of tick mark used.
This was all deduced from the source code. I think I'll be switching to a charting library with documentation now...

Answer 2

The current code (Raphaeljs 2.0) has changed and has to be slightly adapted to use Raphael.g.axis instead of r.g.axis:
Raphael.g.axis(85,230,310,null,null,4,2,["Today", "Yesterday",
"Tomorrow", "Future"], "|", 0, r)

Answer 3

You're on the right track. You use g.axis and the positional arguments for setting the text is found in the 'text' arg (positional) and for toggling the y using the 'orientation' args. I added an example here,
Barchart with text x-axis

Answer 4

Reading this Q&A and a dozen like it, I still could not get gRaphaël to show proper labels for a bar chart. The recipes all seemed to refer to older versions of the library, or to github pages that are no longer there. gRaphaël produces some great looking output--but its docs leave much to be desired.
I was, however, able to use a combination of Firebug and Inspect This Element to follow the code and see what it produced. Diving into the barchart object, the required geometry is right there. To save others the frustration, here's how I solved the problem:
<script>
function labelBarChart(r, bc, labels, attrs) {
// Label a bar chart bc that is part of a Raphael object r
// Labels is an array of strings. Attrs is a dictionary
// that provides attributes such as fill (text color)
// and font (text font, font-size, font-weight, etc) for the
// label text.
for (var i = 0; i<bc.bars.length; i++) {
var bar = bc.bars[i];
var gutter_y = bar.w * 0.4;
var label_x = bar.x
var label_y = bar.y + bar.h + gutter_y;
var label_text = labels[i];
var label_attr = { fill: "#2f69bf", font: "16px sans-serif" };
r.text(label_x, label_y, label_text).attr(label_attr);
}
}
// what follows is just setting up a bar chart and calling for labels
// to be applied
window.onload = function () {
var r = Raphael("holder"),
data3 = [25, 20, 13, 32, 15, 5, 6, 10],
txtattr = { font: "24px 'Allerta Stencil', sans-serif", fill: "rgb(105, 136, 39)"};
r.text(250, 10, "A Gratuitous Chart").attr(txtattr);
var bc = r.barchart(10, 10, 500, 400, data3, {
stacked: false,
type: "soft"});
bc.attr({fill: "#2f69bf"});
var x = 1;
labelBarChart(r, bc,
['abc','b','card','d','elph','fun','gurr','ha'],
{ fill: "#2f69bf", font: "16px sans-serif" }
);
};
</script>
<div id="holder"></div>
There are a bunch of little cleanups you could do to labelBarChart(), but this basically gets the job done.

Answer 5

Here's a function I wrote for adding the labels. It's not particularly elegant but it will add the labels:
Raphael.fn.labelBarChart = function(x_start, y_start, width, labels, textAttr) {
var paper = this;
// offset width and x_start for bar chart gutters
x_start += 10;
width -= 20;
var labelWidth = width / labels.length;
// offset x_start to center under each column
x_start += labelWidth / 2;
for ( var i = 0, len = labels.length; i < len; i++ ) {
paper.text( x_start + ( i * labelWidth ), y_start, labels[i] ).attr( textAttr );
}
};
Usage is as follows:
var paper = Raphael(0, 0, 600, 400);
var chart = paper.barchart(0, 0, 600, 380, [[63, 86, 26, 15, 36, 62, 18, 78]]);
var labels = ['Col 1', 'Col 2', 'Col 3', 'Col 4', 'Col 5', 'Col 6', 'Col 7', 'Col 8'];
paper.labelBarChart(0, 390, 600, labels, {'font-size': 14});

Answer 6

I would like to propose a solution of an issue of the labelBarChart function proposed by Jonathan Eunice.
considering stacked bar-graphes (or other bar-graphes with more than one array of values), I added a test on bc.bars[0] in case the bc.bars.length means the number of arrays of values stacked.
This lead to the code :
<script>
function labelBarChart(r, bc, labels, attrs) {
// Label a bar chart bc that is part of a Raphael object r
// Labels is an array of strings. Attrs is a dictionary
// that provides attributes such as fill (text color)
// and font (text font, font-size, font-weight, etc) for the
// label text.
//Added test : replace bc.bars by generic variable barsRef
var barsRef = (typeof bc.bars[0].length === 'undefined') ? bc.bars : bc.bars[0];
var bar, gutter_y, label_x, label_y, label_text;
//Added consideration of set attrs (if set)
var label_attr = (typeof attrs === 'undefined') ? {} : attrs;
label_attr['fill'] = (typeof label_attr['fill'] === 'undefined') ? "#2f69bf" : label_attr['fill'];
label_attr['font'] = (typeof label_attr['font'] === 'undefined') ? "16px sans-serif" : label_attr['font'];
for (var i = 0; i<barsRef.length; i++) {
bar = barsRef[i];
gutter_y = bar.w * 0.4;
label_x = bar.x
label_y = bar.y + bar.h + gutter_y;
label_text = labels[i];
r.text(label_x, label_y, label_text).attr(label_attr);
}
}
// what follows is just setting up a bar chart and calling for labels
// to be applied
// I added an array of data to illustrate : data4
window.onload = function () {
var r = Raphael("holder"),
data3 = [25, 20, 13, 32, 15, 5, 6, 10],
data4 = [0, 2, 1, 40, 1, 65, 46, 11],
txtattr = { font: "24px 'Allerta Stencil', sans-serif", fill: "rgb(105, 136, 39)"};
r.text(250, 10, "A Gratuitous Chart").attr(txtattr);
var bc = r.barchart(10, 10, 500, 400, [data3, data4] {
stacked: true,
type: "soft"});
bc.attr({fill: "#2f69bf"});
labelBarChart(r, bc,
['abc','b','card','d','elph','fun','gurr','ha'],
{ fill: "#2f69bf", font: "16px sans-serif" }
);
};
</script>
<div id="holder"></div>
I just tested it with 2 arrays of values stacked.