On Wed, Jun 8, 2011 at 6:44 PM, nonlinear <[email protected]> wrote:
> Judson, if you find time and motivation, perhaps you could do something
> about the other mildly annoying chart problem. Look at the attached chart.
> Notice how the "buy" and the "sell" annotations are positioned? It looks odd
> because the annotations are not on the price line. The chart is in fact
> totally correct, but because the price resolution is 5 minute OHLC bars and
> the executions are plotted with a 1-second resolution, they seem to exist as
> independent entities. I think the right way to handle it is to "snap" the
> "buy/sell" annotations to the corresponding price bar.
>
> What do you guys think?
>
In my opinion, the "correct" thing to do would be to make the width of the
bars such that there is very little gap between them. Then the bubble would
appear to occur somewhere in the middle of the bar. This might be terribly
ugly, though.
Actually, here is a quick implementation for that effect. Note it is
HORRIBLY SLOW because JFreeChart is a turd, performance wise, in general,
but this auto-width calculation method for the candles re-computes the width
for each individual bar, by sifting through the dataset and looking for the
smallest bar spacing (again, it does this calculation for every bar). This
could be implemented by hand because we already know the bar width, which
would be much much faster.
Anyways, here is the replacement chunk of code, which can easily be tweaked
to look a little bit better. You must zoom in substantially to see the
effect:
private void createChart() {
CandlestickRenderer candleRenderer = new CandlestickRenderer(-1);
candleRenderer.setDrawVolume(false);
candleRenderer.setAutoWidthMethod(CandlestickRenderer.WIDTHMETHOD_SMALLEST);
candleRenderer.setAutoWidthGap(0.0);
candleRenderer.setAutoWidthFactor(1.0);
candleRenderer.setUpPaint(Color.GREEN);
candleRenderer.setDownPaint(Color.RED);
candleRenderer.setSeriesPaint(0, new Color(250, 240, 150));
candleRenderer.setBaseStroke(new BasicStroke(1));
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