Stock charts are used to display data values where one is interested in 4 different values for each data point. This could for example be used to display a stocks open,close, min and max value during a specific day. Hence the name Stock chart (or Stock plot).
Stock plots are created as an instance of
class StockPlot so the
jpgraph_stock.php" must first be included in the
Figure 15.62. A stock graph
For this type of plot the y-data array must be consist of a number of quadruples of data where each quadruple consists of (open,close,min,max). The open and close values determine the min max for the middle bar and the min,max determine the end points of the "error-lines" at the top and bottom of each bar as shown in ??.
For this type of plot the y-data array must be consist of a number of quadruples of data where each quadruple consists of an even number of (open,close,min,max).
The open and close values determine the min max for the middle bar and the min,max determine the end points of the "error-lines" at the top and bottom of each bar as shown in Figure 15.63. Explaining stock graphs.
Note that the data follows the rules
To separate the two cases where "open > close" or "open < close " two different colors are used.
These colors are specified with the method
$aFill, The frame and fill color
when open <= close
$aFillNeg, The frame and fill
color when open > close
StockPlot::SetColor() method. By default a positive bar (close >
open) have a fill color of white and for the negative case where (close < open)
the bars have a red color.
The final possible variation of stock plots is the option to determine whether or not the end point for the min,max lines should have the horizontal line marking the end of the line or not. This can be adjusted with a call to method
A minor variation of stock charts is the
BoxPlot plot type. this
is almost the same as
StockPlot but with the very small difference
that in addition to the open,close,min, max values it is also possible to
specify a fifth, median value .
A box plot is created as in instance of
class BoxPlot which is
defined in "
The median lies between the open and close value and is illustrated as a horizontal line within the bar. An example of this is shown in
Figure 15.64. A typical boxplot
The color of the median line can be modified with a call to
In the same way as for other plots it is possible to associate an image map with these plots. The "hot" area for each plot is the mid "bar" section. In the same way as other plot types the method
is used to set the URL:s for the hot areas