I have data with negative numbers, but I only want to plot positive numbers, since the negatives indicate bad data of various kinds. I want the line plot to dive down to zero, but currently it actually plots -1, etc. This looks especially bad as it makes the x-axis unreadable.
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I am updating my charting code from 0.4.3, and in 0.4.3 I was able to get the effect I want, but I can't see how I did it. I don't see any clipping region, bounding box, set overflow:hidden, or any other usual tricks. It just seemed to work (without having to manually truncate the numbers in a loop before plotting). I'm guessing the ymin value actually did something more than place the y-axis in 0.4.3, but I don't know. It is also possible that I hacked the source, but it has been so long I do not recall.
I can't see any way to do this in the current charting. I'm wondering if maybe there is a setting in the Theme.plotarea I could use to cause data outside of some min/max bound to be clipped, but I can't even find where plotarea is used! (grep plotarea wasn't helpful).
Any advice, including where to hack on the source, would be appreciated, as manually truncating the data is likely to be more expensive than letting the rendering engine mask it.
Quick hack of what I mean, using one of the tests from the test page and making the data negative:
var chart11 = new dojox.charting.Chart2D("test11");
chart11.addPlot("default", {type: "StackedLines", markers: true, tension:3, shadows: {dx: 2, dy: 2, dw: 2}});
chart11.addSeries("Series A", [-1, 1.1, 1.2, 1.3, 1.4, 1.5, -1.6], {stroke: {color: "red", width: 2}, fill: "lightpink", marker: "m-3,-3 l0,6 6,0 0,-6 z"});
chart11.addSeries("Series B", [1, 1.6, 1.3, 1.4, 1.1, 1.5, 1.1], {stroke: {color: "blue", width: 2}, fill: "lightblue", marker: "m-3,0 c0,-4 6,-4 6,0 m-6,0 c0,4 6,4 6,0"});
chart11.addSeries("Series C", [1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6], {stroke: {color: "green", width: 2}, fill: "lightgreen", marker: "m0,-3 l3,3 -3,3 -3,-3 z"});
chart11.setTheme(dojox.charting.themes.PlotKit.blue);
chart11.addAxis("x");
chart11.addAxis("y", {vertical: true,min:0});
chart11.render();
thanks,
James
Try the nightly and see if you still have the same problem.
Until very recently, clipping was not implement in the charting engine at all; Eugene fixed that last week but obviously it's not released yet. You should be able to just push the nightly code for the charting engine right over your current checkout.
With the 0.4.3 engine, I'd done this via a couple a clipping techniques and then allowing you to set the min/max range on each axis. From what I can see, you've done this correctly here. I'll try out your code with the latest checkout and see if it works...
...and it does. With tonight's nightly, you'll see the change with Chart 12 (it has axes on it already and I wanted to be sure of the effect of things).