highcharts SVG drawing mousemove - highcharts

we need to implement similar functionality as below..
http://www.barchart.com/interactive_charts/stocks/PFE
then click on Tools --> Trendline and then click on chart SVG and drag line and when you release mouse it draws line.

You can use Annotation plugin for that.

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Qt [PySide6] visual artefacts with custom paintEvent

I'm trying to have a custom painting of a pyqtgraph derived Plot widget (the code is found here https://github.com/danielhrisca/asammdf/blob/bfa09d0b46f1b4b98b9ad1d0a0bb90cbb876b43e/asammdf/gui/widgets/plot.py#L4271): since painting a Plot with thousands of curves is very expensive I want to store the result in a QPixmap, then if I have a cursor active (implemented using an InfiteLine (see https://github.com/pyqtgraph/pyqtgraph/blob/6ed7d4fa4762aaa895f7e9b2fb09ec6df4cc793f/pyqtgraph/graphicsItems/InfiniteLine.py#L16) I would first draw the QPixmap on the viewport then on top just the cursor item. This way moving the cursor would not trigger the repaint of all the curves.
The QPixmap looks like this
and this is what happens when I create a cursor and slide it around:
Note that at the end the plot is zoomed out, this causes the reset of the QPixmap and the "native" repaint which produces the correct image with the single vertical line of the cursor.
What could be causing this?
I found the problem to be that the paint events were set to update just certain regions of the viewport instead of the full viewport.
The fix was to set the viewport update mode to full update
self.setViewportUpdateMode(QtWidgets.QGraphicsView.FullViewportUpdate)

Change bokeh python hovertool tooltip layout

Is there a way to change the layout of the hovertool's tooltips? I mean, bokeh shows the standard square with some information, close to the point and linked by a small triangle.. Is there a way to change this triangle and put a line that connects the tooltip to the point but at some distance (like an annotation), but dynamic as a hovertool tooltip?
Thanks for all!!
standard tooltip
New tooltip type
It is possible but it requires quite some work. You have to create a custom subclass of Tooltip that renders the tooltip the way you want and a custom subclass of HoverTool that uses that tooltip class.

Google charts: is it possible to display tooltips when hovering areas in stacked area chart?

I have a stacked area chart using google charts. An example is here: https://code.google.com/apis/ajax/playground/?type=visualization#area_chart
The problem is, when I hover the cursor over an area, no tooltip is displayed. I need to hover the boundary of two neighboring areas to display the tooltip.
Is it possible to display tooltips when hovering areas? If not, do you know of some workaround?
You can use a SteppedAreaChart for this. Set isStacked to true, and by default the tooltips will be shown on hovering over an area.
No, you can't spawn the tooltips by hovering over the area. There is no way easy way to work around this, as the Visualization API does not trigger mouse events on the areas.
If you want to put the effort into this, you can create custom mouse event handlers on the chart's SVG/VML code. It might be possible to extrapolate which area the mouse is in, and given that, you can extrapolate the x-axis position from the mouse coordinates using the ChartLayoutInterface, and spawn a custom tooltip based on that information. Be aware that any solution involving the chart's SVG/VML code could break at any time, as the internal structure of the charts is not guaranteed to be stable from version to version.

What can I use to implement a doughnut chart in iOS?

I'm looking for a free iOS component that allows me to draw a doughnut chart with text in the center. So far I've only used Code Plot, but that is a full pie chart.
I'm attaching an example of the requirement.
Any help will be much appreciated.
I suggest searching on cocoacontrols.com. They have lots of open source controls for iOS and Mac. I didn't se any specifically called "doughnut chart" but some of the pie charts controls might offer that option.
In fact, it seems that this one does include what you're calling a doughnut chart. It doesn't look like it has built-in support for a label in the middle, but it does create a ring-shaped chart like you want.
You could also always create a pie chart and then put a view on top of it that is transparent except for a white circle in the middle, and then put a label on top of that.
Getting a little more complex you could modify the CorePlot control and add a filled CAShapeLayer to it.
Another option is to create svg chart and use UIWebView to display it. With svg chart, you get much more flexibility with libraries like highcharts and d3js. Here's an example with donut chart:
http://vida.io/documents/Byh8tTakzB59oGa9f
You can embed the link or save svg and display in UIWebView. Saving svg works offline.

Highstock - click drag on the portion of the graph to zoom?

In Highstock you have the navigator at the bottom which lets you zoom in and out of the chart.
But, is it also possible to click on the chart itself, drag to highlight a certain portion of the chart and zoom into that area?
I've seen this feature in some of the other charting tools.
Set chart.zoomType, see: http://jsfiddle.net/MKeWv/ - docs.

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