I am using openlayers-3 modify interaction to edit vector layers. When a polygon/polyline is being edited, if mouse is close to a line segment, a small circle is drawn and dragging it creates a new vertex or moves an existing vertex, depending on where on the segment I was hovering.
Now, sometimes this is very difficult to understand if I am hovering on an existing vertex, or on middle of a segment. I have thought about two solutions to the problem:
Highlight the segment I am hovering with a different style so that I
can see its edges.
When hovering on an vertex, style the small
circle with a different style.
Is there a way to achieve any of the two?
It can be done changing the interaction condition like:
var selectPointerMove_Highlight = new ol.interaction.Select({
condition: ol.events.condition.pointerMove
});
map.addInteraction(selectPointerMove_Highlight);
I have an online example.
Related
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)
I know how to draw an object arrow on the chart, which I usually do like this:
ObjectCreate(0,"prevHigh",OBJ_ARROW_DOWN,0,Time[0],High[highestCandle]);
ObjectSetInteger(0, "prevHigh", OBJPROP_COLOR, clrRed);
Now I have an indicator which (I didn't code myself and is a .ex4 file which) draws up/down arrows on the chart as seen in the image (https://imgur.com/a/8yG0suw).
How can I when for example a Magenta down arrow has been drawn and the candle (index) at which it is drawn?
Please note that the arrows not in the list of objects on the chart
Q : "How can I recognise programmatically when an up/down arrow is drawn on a chart?"
Given the facts above, your test ought evaluate the moment the CustomIndicator ( via a published / used iCustom()-call signature ) by checking it as it goes from EMPTY_VALUE to any value != EMPTY_VALUE.
Given the CustomIndicator is a closed source ( *.ex4 ) you may need to check, if it did set its own ( hidden from our sight ) value, other than a current visible EMPTY_VALUE, yet this "re-calibration" will work, after you get a few manual tests of the CustomIndicator values for bars, that do not show any arrow - like for the 2020-Apr-08 09:30 et al v/s the displayed arrows are not the MQL4-Objects on their own, they are the closed-source CustomIndicator's SetIndexStyle() / SetIndexArrow() by-products, thus not inspectable either in the Object-List, or in the *.mq4 source-code.
Yet, detectable
I have a simple program in C++ builder with VCL that i need to migrate to Firemonkey. In this application i need to draw on a TChart, but i don't know how to get it to work. My application is really simple; a user inputs data in a stringgrid and then the data is displayed in two different TChart by clicking two different buttons.
The first button click is to divide the TChart into equal parts (generally in two parts, but the user can divide the TChart into more than two parts). In the first example there is a column, with two long rectangles with texts, in it. In this example it's two rectangles with "CH PL".
The second button is supposed to draw on the same TChart this:
It's essentially two or more rectangles which go from the beginning of the chart until the end.
To make it simple i need to divide the TChart into two or more equal parts horizontally and then draw rectangles with texts on it, which is the simplest solution.
I'm really lost because by searching on the net i came across a similar problem by simply using the TChart.AfterDraw() method, but I don't know how to use it, it's not really clear.
The drawing are generated once the user clicks a button, else there should be nothing.
My method for drawing so far:
void __fastcall TForm1::rbComprChange()
{
Series5->Clear(); //used for clearing the series to regenerate them from the user input
for(int i=0;i<StringGrid1->RowCount;i++)
{
Series5->AddGantt(StrToDate(StringGrid1->Cells[4][i]),StrToDate(StringGrid1->Cells[5][i]),i,StringGrid1->Cells[1][i]);
Series5->NextTask->Value[i]=i;
}
// How and where should i draw these rectangles?!
}
Can someone guide me or explain to me how to do that either in C++ Builder or Delphi.
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'm drawing a chart in an iOS app and I want the gridlines to start in the x axis but end in the data point instead of extending all the way up to the top.
Is this possible?
Thanks in advance.
NC
Disclaimer: I work for ShinobiControls
The shinobicharts framework doesn't currently support this as an out-of-the-box feature.
A workaround may exist though. You may be able to add your own gridline subviews by using the SChartAxis method pixelValueForDataValue: to work out where in the plot area coordinate space you should draw your vertical line up to for a given data point.
Once you have your coordinates there are various ways you could draw your gridlines:
Add a canvas view behind or in front of the chart (depending on what effect you want). Then use your coordinates to draw your gridlines using CoreGraphics or some other drawing technique.
Create individual UIViews that each represent a gridline using your coordinates and add these behind or in front of the chart.
One thing to be aware of with this technique is that the gridlines will not automatically update when you pan and zoom. In order to do this you will need to override one of the chart's delegate methods that notify you of range changes and update your drawn gridlines to match the new data point positions.
Another potential workaround could be to use a column series to mimic gridlines. If you create a column series and feed it the same data points as your original series this will result in columns that go up to the y-value of each data point. You could then use the property interSeriesSetPadding on SChartAxisStyle to cause the columns to appear very thin.
I hope that information is useful!