I want line chart in my application can any one tell me how can we make line chart & display it in view.& which frame work is needed for that.
You mean a graph done with lines showing relationships between coordinates?
If so, Quartz drawing might be easiest. The framework is CoreGraphics. You get a reference to the CGContext, tell it where the line starts (moveToPoint, x, y) and ends (addLineToPoint, x, y), and stroke the path.
Check out Core-plot.
http://code.google.com/p/core-plot/
Related
I have a series of straight line segments of varying thickness connected end-to-end to create meandering path. Does anyone know a way to paint this as a smooth meandering line, sort of like vectorizing it? I am using QPainter. I haven't had any success finding an appropriate function in QPainterPath.
The data looks something like this:
[(QPointF, width), (QPointF, width), (QPointF, width), ... ]
Thanks!
EDIT: Added example image
I wanted to leave it open to creative responses, but I am just looking to move from linear interpolation (QPainter::drawLine()) to spline interpolation.
If I understand your question correctly...
Don't draw a line, draw a filled polygon that encloses your line data with the right thickness. Drawback: That requires calculations on your data beforehand.
I'm trying to get and set the position of a draggable legend in matplotlib. My application consists of an interactive GUI, which has a redraw/plot function that should perform the follow steps:
save the position of the current legend.
clear the current axes and perform various plotting operations, which may or may add labels to their plots.
build a new draggable legend (ax.legend().draggable()) and restore the old position of the legend.
In between these steps the user is free to drag the legend around, and the goal is to persist the legend position when the plots are redrawn.
My first approach was to use oldpos = legend.get_bbox_to_anchor() and legend.set_bbox_to_anchor(oldpos) in steps 1 and 3. However this causes to move the legend completely off the visible area.
Note that I have to use ax.legend() and cannot use fig.legend(lines, labels), since step 2 is completely decoupled, i.e., I don't know anything about lines and labels in step 3. According to answers to the question How to position and align a matplotlib figure legend? there seems to be a difference between these two possibilities regarding axes or figure coordinates. Obviously my problem calls for figure coordinates, but I haven't fully understood how to convert the bbox to a "bbox in figure coordinates".
The even more severe problem I just realized is that apparently legend.get_bbox_to_anchor() always seems to return the same values irrespective of the drag position. So maybe the anchor can only be (ab-)used to manipulate the position of static legends? Is there another/proper way to save and restore the position of a draggable legend?
By looking at the implementation of Legend I found out that there is an undocumented property _loc, which exactly does what I want. My solution now looks astonishingly simple:
oldLegPos = ax.get_legend()._loc
# perform all plotting operations...
legend = ax.legend().draggable()
legend._loc = oldLegPos
It looks like _loc automatically stores figure coordinates, since I do not have to convert the coordinates in any way (eg. when the plotting operations completely change the axes ranges/coordinates).
does anyone know the method or code to add a second x axis to a TGraph in CERN's ROOT program? Ive been searching the root website and its documentation almost always confuses me. What i need is just one plot of data, but a second X axis on top whose values are a function of the bottom x axis' values. Its basically so lazy people dont have to convert from the numbers of the bottom x axis to the top x axis.
For a simple example (if i wasnt clear)
Say you have a sine curve which is some function of theta. On the top x axis we could have degrees whereas on the bottom we could have radians with 360deg corresponding to 2pi rad...
Any help would be appreciated!
TGaxis is the class you are looking for to draw extra axes wherever you desire. Grabbing the world coordinate for your pad you can then superimpose like so. Replace low and high with the appropriate limits.
// your graph code here...
TGraph->Draw("AP");
TGaxis *axis = new TGaxis(gPad->GetUxmin(),gPad->GetUymax(),gPad->GetUxmax(),gPad->GetUymax(),low,high,510,"+L");
axis->Draw();
Check out TGaxis documentation for more examples.
(A previous answer I had was deleted as it was just a link to the site listed as a reference below. I hope this is more in line with the community guidelines.)
I think this might do what you want.
void axis2() {
TH1F *h = new TH1F("h","test",30,-3,3);
h->FillRandom("gaus",10000);
h->Draw();
TText t;
t.SetTextSize(0.02);
t.SetTextAlign(22);
Double_t yt = - h->GetMaximum()/15.;
for (Int_t i=1;i<=30;i++) t.DrawText(h->GetBinCenter(i),yt,Form("%d",i%10));
}
It doesn't create another taxis but shows you how to draw text at the same location of the axis. The answer comes from Rene Brun himself (one of the main authors of root) so I don't think you can have two x axes.
Source:
http://root.cern.ch/phpBB3/viewtopic.php?f=3&t=7110
Here is an example showing how to proceed.
https://root.cern/doc/master/twoscales_8C.html
I am using core plot to make a line graph for my iPhone app. So far I successfully made the line graph from my xml data.
Furthermore I added a text layer that shows the value (for example 40) once I select the cell
holding the value 40. For this, I use the function:
(CPTLayer *)dataLabelForPlot:(CPTPlot *)plot recordIndex:(NSUInteger)index
So now I want to have a vertical line on the graph to indicate the selected value (the 40). I tried adding CPTBarplot but somehow the bars show only at the beginning of the graph axis.
Is there a function from core plot like the above that will create a line indicator?
I would appreciate if someone can give me some hint how to solve this problem and thank you very much in advance.
You could use a scatter plot for that. There's a point selection demo in the Mac CPTTestApp that draws a crosshair over the selected point. It would be trivial to modify that to only draw the vertical line.
The -numberOfRecordsForPlot: datasource method returns the number of points in the selection indicator (5 for the crosshairs) or zero (0) if there is no current selection. The -numberForPlot:field:recordIndex: method returns the points in the indicator. The points are drawn in this order:
Left
Right
Center (with plot symbol)
Top
Bottom
The -symbolForScatterPlot:recordIndex: method controls the plot symbol in the center. You can eliminate this method if you don't need any symbols on the indicator plot.
I'm trying to make a simple app where a chart is drawn with a line and X axis. I want to fill parts of the view enclosed by chart and X axis with gradient. To fill them I use the following code
CGContextSaveGState(c);
CGContextAddPath(c, CGContextCopyPath(c));
CGContextClip(c);
CGContextDrawLinearGradient(c, g, previousPointOfIntersection, intersectionPoint, 0);
CGContextRestoreGState(c);
every time the line crosses the X axis. However, the problem is that the gradient fills the whole view between previous point of intersection and current one.
Is this a right way to draw a gradient for a part of view enclosed by lines?
I'd be very happy to hear any suggestions regarding my problem :)
P.S. here's the code of my class http://pastebin.com/wYiHkuVi
I'd say you don't have the path in the context that you think you do.
If you've "stroked" the path for your graph it's been used up.
Replace your Add Path with:
CGContextAddEllipseInRect(c, self.bounds);
to see if you get some clipping occurring.
If so, then you need to rebuild your path here instead of the AddPath/Ellipse code.