We've recently upgraded our amCharts library from version 2 to version 4. In version 2, when the user hovered over the chart, the tooltips on the step line series showed up between the samples; whereas, in version 4, they only show up when the cursor is hovering exactly over one of the value points. (See screen shot.) We haven't changed our code in any appreciable way (other than what we had to do to get it to work with version 4), and we'd really like to get that old behaviour back, as it's difficult to get the cursor exactly over a data point in order to see what the value is. (Note: It's often the case in our charts that some series may have more data points than others in a given time/date range, as is the case in the screen shot, where the line series has more data points than the other two series.)
What can we do to get the tooltips on the various series in the chart to show up when the cursor is between data points? (It doesn't necessarily need to follow the cursor exactly as long as it shows up somewhere (e.g., on one or the other data point to either side of the cursor).)
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In Vaadin 14.6.1, I tried to create a Vaadin heatmap foollowing the documentation / example from here.
However, I encountered a few problems/questions, listed in descending order of importance below:
The heatmap supported 30 rows by 30 columns; but when I tried 40 rows by 40 columns, the entire heatmap showed a single color (blue in my case).
Is it possible to manually set the minimum numeric value and maximum numeric value for the color scheme. This way, if I plot my data one day and it has values in the range of 0 to 1, but on another dataset from another day, the numeric values range from between 0 and 0.5, the color scheme range won't automatically change (to being between 0 and 0.5) and confuse the user.
In the documentation, it has the following methods listed, but they do not seem to exist in Vaadin 14.6.1
plotOptions.setBorderColor(SolidColor.WHITE);
plotOptions.setBorderWidth(2);
When I hover over the datapoints, is there a way that the tooltip can only show the numeric value (and not the x, y coordinate or the series name etc.?)
Is there any limit to the number of datapoints? I'm hoping that if #1 above is resolved that I can plot a 100 by 100 (ie 10,000) point heatmap.
If I plot 100by100, there will be many labels on the x and y axis. In my case, the x and y axis are actually numerical, so I did what the documentation suggested and just placed category labels in the xaxis and yaxis spots. However, is there any way to only display every "nth" label, so that the x-axis and y-axis is not so crowded? (This would essentially mimic what Vaadin does for normal line charts' xaxis and yaxis).
I'm not that experienced with Vaadin Chart, but these are the questions that I can comment on:
(1) With 40x40 items you go over the threshold of 1000 in which the Chart switches into "turbo" mode for performance reasons. This seems to not be compatible with the heatmap series. You can disable turbo mode by setting plotOptions.setTurboThreshold(0);
(2) Unfortunately the ColorAxis doesn't support this, it only has an API for min and max color. Definitely a valid use-case though, and it seems to be supported by the Highcharts library that the Vaadin Chart uses under the hood. You should consider opening a feature request for this in the Github repo.
(3) This seems to be a documentation issue. The methods are available in later Vaadin platform versions, but not in 14.6.
(5) In theory not, but in practice there will be a huge performance hit in the browser due to the excessive amount of DOM elements (quick test of 100x100 froze the browser for 10s). I'm afraid the component isn't really made for such extreme use-cases. In this case it might be better to utilize a low-level JS drawing library using the canvas, or draw an image on the server-side and display that in the browser. Maybe you can also consider modifying your use-case so that you only display one slice of your data and allow the user to switch between slices.
Earlier, I asked how to create "spectra" charts in Vaadin (see How to create a "spectrum" chart using Vaadin 14+). It turned out that one didn't actually need to create barcharts -- the only real need seemed to be to set the pointwidth to 1. (This solved the "very wide" widths lines when zooming.)
HOWEVER: I think there's a bug in vaadin charts when one has more than 1 series presents and when one zooms: the line moves to an inccorrect position on the x-axis (or the x-axis is no longer placed correctly.) Any thoughts on how to resolve? Here are two screenshots showing the problem. In the first one, only ONE series is visible and the line is at the correct x-axis point of ~598.36. In the second screenshot, though, (where the only change I have made is to enable the 2nd series), the line moves to an INCORRECT x-axis coordinate (it seems like it's ~598.25!!!).
One theory I have is that adding the second series somehow confuses the chart from determining the correct x-axes....maybe because each series has it's own x axis logic in some way? Not sure....(I'm using Vaadin 14 and I tested this both in my dev env and on production.)
While using Delphi Seattle 10 and Steema TeeChart Pro VCL FMX 2016.18, I am looking to Highlight a Selection of a Line Graph (multiple series) in the way that Zooming allows / makes a square around a highlighted selection of a Line Graph to indicate which part of it to zoom into (as long as the onmousedown action is in progress).
The purpose of this would be to allow the selection to remain highlighted while the mouse is no longer being clicked, to potentially "Delete" the highlighted Data points. All I need this for is to obtain the (X0 Y0 X1 Y1) values to possibly obtain the CalcPosPoint(X) and remove all the points inside. The data is currently obtained through a Record Struct (Memory Mapped) file, and it will there for be used to set/check for a property "deleted" to indicate on the next redraw of the graph which rows to completely ignore and which to continue printing.
I hope to be able to do this (select from 1 chart), and have it simultaneously draw on multiple graphs. I have tried to look for an example of this feature through the use of TSelectorTool (FMXTee). One of the pages I found referring to such a tool is Interactive data point selection as well as Multiple selections with Selector Tool
And my second question has to do with TeeCharts directly. Where would I find fmx240.bpl as TeeChart_Pro_Firemonkey_Demo.exe requires this file in order to run? I did manage to copy vcl240.bpl from "Embarcadero\Studio\18.0\bin" and put it into "Embarcadero\Studio\17.0\bin"
[Edited]
I have managed to capture / create a sample code (MVCE) from which I can now select a portion and create a square around a particular sample of graph lines.
The control graph right now is the bottom graph (Chart5). If anyone is interested in seeing the code, I have put up a pastebin sample.
PasteBin Sample Code
And a TeeCharts.tar.gz is accessible to anyone who wishes to see a sample of the code, as well as the data sample.
filetolink.com Source Files
I no longer feel the need for mathematical equation to differentiate the top graphs from the bottom (because the bottom axes are automatic where as the top are defined). I intend to only use the space which is adherent to the visible space, and do not intend to extend in either direction (left or right). That means at this point the size of the graph does not matter, because once I over populate the charts above, the position in the bottom graph would become irrelevant, and therefor I do not intend to use the bottom chart.
The next step is to save the positions of the boxes so that they can reappear when the graph is shift from left (past data) to the right (live data). And then uses the buttons above to make the appropriate action to the graphs.
I would like to know what way would be the most sufficient way to record the positions of the rectangles, so when the chart is shifted (via the ScrollBar1), the rectangles are moving with the direction of the scrollbar. But I'm sure I can achieve that.
I think I have found a solution. The red squares are only prevalent for the visual aspect, they can be drawn on, I don't need to do anything special with each chart, as I already know what the X0..Y1 parameters are, they are known from the initial chart. The problem h/e has to do with the initial chart. As long as the screens are all full, I can zoom in correctly w/ alignment with on all the charts (ZoomRect/Rectf(X0..Y1))
But what kind of equation would it take to adjust the charts that are not in the same zoom / max / min when the Chart5.Axes.Bottom.Automatic = True?
From there I just simply have to disable the immediate zoom feature, and allow buttons to become functional, to decide what the next course of action would be.
I am using the TeeChart VCL Delphi module. I am trying to plot a candlestick chart. I have the following questions:
When I run the code it shows me the last date data on the right hand side. However, the y-axis is not automatically scaling at all. If I scroll backwards, it automatically adjust the y-axis scales. However, if I go far to the right which is the end, it does not auto-scale the y-axis anymore. What am I doing wrong?
The x-axis is the days of the week. However, I have no data for the weekend. It shows as empty space. How do I remove that?
How do you change the cursor so it shows the date/time for the X,Y you choose?
When I run the code it shows me the last date data on the right hand
side. However, the y-axis is not automatically scaling at all. If I
scroll backwards, it automatically adjust the y-axis scales. However,
if I go far to the right which is the end, it does not auto-scale the
y-axis anymore. What am I doing wrong?
What about setting the Y axis (left axis) to be automatic? For example:
Chart1.Axes.Left.Automatic:=True;
A more drastic solution would be also forcing the chart to repaint after adding each point.
Series1.Add(value);
Chart1.Draw;
If any of that helps please send us a simple example project we can run "as-is" to reproduce the problem here. You can attach your files here.
The x-axis is the days of the week. However, I have no data for the
weekend. It shows as empty space. How do I remove that?
You should do as in the All Features\Welcome!\Chart Styles\Financial\Candle (OHLC)\Axis Labels no Weekends example in the new features demo. This demo is included with registered and evaluation versions. Otherwise you can download it here.
How do you change the cursor so it shows the date/time for the X,Y you
choose?
There are two examples in the demo that can help you on this:
All Features\Welcome!\Tools\Annotation\Annotation Callout
All Features\Welcome!\Tools\Cursor\Synchronizing Two
I'm getting a bug in my stacked area implementation when a user filters to a specific line.
In the image linked below, you'll see we're tracking two trends. When I turn off the "Dialup" trend, the orange area should remain where it is. Instead, it moves up to fill the entire area. Likewise, if I were to turn off the orange "Broadband" trend, the green dialup area fills the entire area below it, rather than falling to the baseline as it should.
(stackoverflow will not allow me to post images yet.)
You can see the value in the tooltip remains accurate.
Could anyone provide some insight into what may be causing this? In case this may be a factor, the chart is generated based on a table of data using Highcharts.visualize().
I can see that you're using Highcharts 3.0.0. According to this, there was a bug in this version of Highcharts. If you upgrade Highcharts to the latest version, it should work as intended.