When I draw 2d candle stick series with the following simple code the Y value of open/close is 0 but it doesn't match the 0 of the axis. The former is 1 or 2 pixel higher than the latter(the grid of the axis).
Series1.AddCandle(0, 0, 1, -1, 0);
Is there any solution for this?
This is a bug I added to the defect list (TV52016642) to be investigated. For High and Low points you have two options:
1- Changing axis offset:
Chart1.Axes.Left.MinimumOffset:=-1;
Chart1.Axes.Left.MaximumOffset:=-1;
2- Changing axes minimum and maximum:
Chart1.Axes.Left.SetMinMax(Series1.MinYValue, Series1.MaxYValue);
Related
Scenario: I need to draw a plot that has a background image. Based on the information on that image there have to be multiple origins (let's call them 'targets') that can move over time. The movements of these targets will have to be indicated by arrows/vectors where the first vector originates at the location of the target, the second vector originates where the previous vector ended and so on.
The result should look similar to this:
Plot with targets and movement vectors
While trying to implement this, i stumbled upon different questions:
I would use a chart with combined series: a Scatter plot to add the targets at exact x/y locations and a vector plot to insert the vectors. Would this be a correct way?
Since i want to set each vectors starting point to exact x/y coordinates i use rotationOrigin: 'start'. When i now change vectorLength to something other than 20 the vector is still shifted by 10 pixels (http://jsfiddle.net/Chop_Suey/cx35ptrh/) this looks like a bug to me. Can it be fixed or is there a workaround?
When i define a vector it looks like [x, y, length, direction]. But length is a relative unit that is calculated with some magic relative to the longest vector which is 20 (pixels) by default or whatever i set vectorLength to. Thus, the vectors are not connected and the space between them changes depending on plot size axes min/max). I actually want to corellate the length with the plot axis (which might be tricky since the x-axis and y-axis might have different scales). A workaround could be to add a redraw event and recalculate the vectors on every resize and set the vectorLength to the currently longest vector (which again can be calculated to correlate to the axes). This is very cumbersome and i would prefer to be able to set the vectors somehow like [x1, y1, x2, y2] where (x1/y2) denotes the starting- and (x2/y2) the ending-point of the vector. Is this possible somehow? any recommendations?
Since the background image is not just a decoration but relevant for the displayed data to make sense it should change when i zoom in. Is it possible to 'lock' the background image to the original plot min/max so that when i zoom in, the background image is also zoomed (image quality does not matter)?
Combining these two series shoudn't be problematic at all, and that will be the correct way, but it is necessary to change the prototype functions a bit for that the vectors will draw in a different way. Here is the example: https://jsfiddle.net/6vkjspoc/
There is probably the bug in this module and we will report it as new issue as soon as it is possible. However, we made the workaround (or fix) for that and now it's working well, what you can notice in example above.
Vector length is currently calculated using scale, namely - if vectorLength value is equal to 100 (for example), and vector series has two points which looks like that:
{
type: 'vector',
vectorLength: 100,
rotationOrigin: 'start',
data: [
[1, 50000, 1, 120],
[1, 50000, 2, -120]
]
}
Then the highest length of all points is taken and basing on it the scale is calculated for each point, so first one length is equal to 50, because the algorithm is point.length / lengthMax, what you can deduce from the code below:
H.seriesTypes.vector.prototype.arrow = function(point) {
var path,
fraction = point.length / this.lengthMax,
u = fraction * this.options.vectorLength / 20,
o = {
start: 10 * u,
center: 0,
end: -10 * u
}[this.options.rotationOrigin] || 0;
// The stem and the arrow head. Draw the arrow first with rotation 0,
// which is the arrow pointing down (vector from north to south).
path = [
'M', 0, 7 * u + o, // base of arrow
'L', -1.5 * u, 7 * u + o,
0, 10 * u + o,
1.5 * u, 7 * u + o,
0, 7 * u + o,
0, -10 * u + o // top
];
return path;
}
Regarding your question about defining start and end of a vector by two x, y values, you need to refactor entire series code, so that it won't use the vectorLength at all as like as scale, because you will define the points length. I suspect that will be very complex solution, so you can try to do it by yourself, and let me know about the results.
In order to make it works, you need to recalculate and update vectorLength of your vector series inside of chart.events.selection handler. Here is the example: https://jsfiddle.net/nh7b6qx9/
I am using the great iOS-charts pod for doing my graphics. Now I have to display a bar chart with y-value in a range from -120 to 0. When I add those values, I get the bars displays from the top - 0 - to the bottom.
What I am looking for is a way to let the bar be drawn from the bottom of the chart up to it's value, because 0 means a lot for the application while -120 means nothing. So I would like to get a big bar for 0 and nothing for -120 like this.
0
X
X X
X X X
-120 x X X
Any idea how I can achieve this behavior?
Thanks a lot
Andy
You need to set logical values for the correct visibility - and the use a formatter for showing the values as negative values.
In Charts 3.0 it is easier to format the values.
Please refer the fiddle codehttp://jsfiddle.net/yuvarajkumarg/az290eyq/1/
In Highchart of type Chart, when we plot for height = 0 and pressure = 2, we get a gap as shown in jsfiddle. I want point to be plotted on the X-axis(2,0). But the graph looks like it is plotted on (2,2) since the y-axis plot starts way above the x-axis. How to remove the gap ?
The issue is the categorized axis.
There are probably a few ways around the issue, but I would do it this way (on your xAxis):
tickmarkPlacement: 'on',
min:0.5,
max:6.5
Example:
http://jsfiddle.net/az290eyq/2/
You could also do it by not using categories, and using the axis label formatter in order to display the numeric sequence that you need.
[[ edit for comments:
For the min and max values - the x axis values for a categorized axis are the category array index values. So the first category is x = 0, the second is x = 1, etc.
Because Highcharts puts the the label in the center of the value's space, setting the min/max to the actual min/max value +/- 0.5 will align the center of the space with the start/end of the axis.
So, you can calculate this dynamically by using 0.5 for the min, and counting the categories array and using (count -1.5) as the max.
Additionally, setting the tickmarkPlacement proerty to 'on' moves the tick mark to the center of the space as well, aligning the ticks with the start/end of the axis as well.
I'm using Delphi and Fast reports, specifically the TeeChart object inside Fast Reports.
I'm trying to plot a scatter graph (preferably with a line between the points)
Four points of typical X,Y data might look like this
X=10, Y=35
X=15, Y=40
X=23, Y=44
X=27, Y=8
I've set the X axis automatic to false and set a min of 0 and a max of 30.
However, when Teechart plots the points it plots the Y values at the correct height but puts them in X positions 0, 1, 2, 3 instead of 10, 15, 23, 27
This even happens when I hard code the data by setting 'Data Source' to 'Fixed Data' and putting 35;40;44;8 in the Y values box and 10;15;23;27 in the X values box.
How do I set up Teechart to plot the points at the correct X-Y coordinates?
You should use AddXY method, for example:
Series1.AddXY(10, 35);
Series1.AddXY(15, 40);
Series1.AddXY(23, 44);
Series1.AddXY(27, 8);
You should also be able to modify values like this:
Chart1[0].XValues[0]:=10;
Chart1[0].XValues[1]:=15;
Chart1[0].XValues[2]:=23;
Chart1[0].XValues[3]:=27;
Chart1[0].XValues[0]:=35;
Chart1[0].XValues[1]:=40;
Chart1[0].XValues[2]:=44;
Chart1[0].XValues[3]:=8;
That's how it should be done in TeeChart outside of FastReports. If none of those solutions works you might need to contact FastReports technical support.
Introduction
I am using the TChart component and am finding the options rather confusing and hard to find what I need.
The Left Axis of the chart has a minimum of 0 and a maximum of 5000, the Bottom Axis has a minimum of 0 and a maximum of 52 (weeks in a year).
In my chart I have 2 series that are populated based on values from a record I have created which can be edited at runtime, everything is working good so far.
Problem
Take a look at the below image of part of the chart filled with some random values:
I am not sure if such an option exists or not, but notice from week 4 onwards where no values have been added there is a solid red line.
I don't want the chart to plot values that are less than 0, so in this example from week 4 onwards there should be no more lines (I can confirm that from week 4 onwards I have the values set at -1)
Week 1 to 4 does not show this bottom red line, obviously because the values are greater than 0 and are therefore plotted above the line, but this should make my problem a bit more clearer.
So, how do I prevent the chart from plotting / drawing values that are less than 0, importantly for the Bottom Axis of the chart?
I am sure there must be a simple option somewhere, I just cannot find it if there is one as I am not too familiar with the TChart Component.
You have the possibility when adding values to a series to add them as null.
This will prevent them from showing.
Ken is correct saying that a tricky situation is to handle a single value surrounded by null values.
Picking another series type than FastLine and show dots as well as lines might work better.
For a FastLine series to show gaps, set:
Series1.IgnoreNulls := False;
And to discriminate values below zero:
if (y < 0) then
Series1.AddNullXY(x, y, '')
else
Series1.AddXY(x, y, '');
if y < 0 then
LineSeries1.AddXY(x, y, '', clNone)
else
LineSeries1.AddXY(x, y, '', clRed);