I would like my Scatter graph I am making with Core Plot library to show Y value near every point relative to X data.
I looked at CPTTestApp project from Core Plot examples, but I simply don't get it. First I thought the secret lies in
-(CPTPlotSymbol *)symbolForScatterPlot:(CPTScatterPlot *)plot recordIndex:(NSUInteger)index
method and I have implemented it in my project. Yes, I got points drawn, which is nice, but I found out this probably has nothing to do with values being shown near points....
This suspicion was confirmed when I opened Candlestick demo from Plot_Galley_Mac demo. There is no method from above and it shows numbers nicely!
If anyone can, please, help me. Otherwise, I would like to thank developers for sharing this library with us. Beside over usage of NSDecimal structure and a bit thin manual and reference data, this is fabulous project.
You're looking for "data labels". CPTPlot has a number of properties that control the built-in labeling functions:
labelOffset: distance between the point and the label
labelRotation: rotation angle
labelTextStyle: text style used to draw the labels
labelFormatter: number (or date) formatter used to format the labels
labelShadow: shadow properties applied to the labels
If the built-in labels don't meet your needs, you can create your own. Implement the -dataLabelForPlot:recordIndex: datasource method and return the desired label for each point. Custom labels can be any CPTLayer so you can make anything you want—text, images, or any custom layer that you create.
Related
If I select one of these co-ordinates, I want to highlight that point on the diagram (by a circle or whatever shape possible). Also I would like to save it later on.
I'm not sure if Appcelerator is flexible enough to do all these things (My search didn't yield much apart from here, this only supports Android), If not I'll have to generate this diagram in my webservice and pull it back on UI once there is an update in the co-ordinate array.
I've used Chartist inside a webview and it worked great. It produces a SVG graph instead of a canvas object which performs better.
If you want to use hyperloop you can use Ti.AndroidCharts
I'm trying to bevel paths in core graphics. Has anyone done this already for arbitrary shapes and if so are they willing to share code?
I've included my implementation below. I use three variables to determine the bevel: CGFloat bevelSize, UIColor highlightColor, UIColor shadow. Note that the angle of the light source is always 135 degrees. I haven't finished implementing this yet, but here's essentially what I'm trying to do, split into two parts. Part one, generate focal points:
I find the bisectors for the angles between each adjacent lines in the path.
For arcs, the bisector is the line perpendicular to the line created by the two end points of the arc, originating from the mid-point. This should take care of the majority of situations in which an arc is used. I do not take the bisector of an arc and a line. The arc bisector should work fine in those cases.
I then calculate focal points based on the intersection of each adjacent bisectors.
If a focal point is within the shape it's used, otherwise it's discarded.
The purpose of generating the focal points is to 'shrink' the shape proportionally.
The second part is a little more complicated. I essential create each side/segment of the bevelled shape. I do this by drawing 'in' (by the bevelSize) each point of the original shape along radius of the line that extends from the nearest focal point to the point in question. When I have two consecutive 'bevelPoints', I create a UIBezierPath that extends along from the bevelPoints to the original points and back to the bevelPoints (note, this includes arcs). This creates a 'side/segment' I can use to fill. On straight sides, I simply fill with either the shadow or highlight color, depending on the angle of the side. For arcs, I determine the radian 'arc'. If that arc contains a transition angle (M_PI_4 or M_PI + M_PI_4) I fill it with a gradient (from shadow to highlight or highlight to shadow, which ever is appropriate). Otherwise I fill it with a solid color.
Update
I've split out my answer (see below) into a separate blog post. I'm not longer using the implementation details you see above but I'm keeping it all there for reference. I hope this helps anybody else looking to use Core Graphics.
So I did finally manage to write a routine to bevel arbitrary shapes in core graphics. It ended up being a lot of work, a lot more than I originally anticipated, but it's been a fun project. I've posted an explanation and the code to perform the bevel on my blog. Just note that I didn't create a full class (or set of classes) for this. This code was integrated into a much larger class I use to do all my core graphics drawing. However, all the code you need to bevel most arbitrary shapes is there.
UPDATE
I've rewritten the code as straight c and moved it into a separate file. It no longer depends on any other instance variables so that the beveling function can be called from within any context.
I explain the code and process I used to bevel here: Beveling Shapes In Core Graphics
Here is the code: Github : CGPathBevel.
The code isn't perfect: I'm open to suggestions/corrections/better ways of doing things.
I have a Core-Plot Graph within a Mac Application. But the inside table is appearing shifted down and to the left of the containing "frame/border" so that neither of the axis' are showing. I cannot figure out how to change this does anyone know what parameters I need to change to fix this?
Update: Sorry I did not realize I could upload an image, I have done so know and will try your suggestions in the mean-time.
Not sure what you mean by "inside table". It would be easier to offer suggestions if you could post a screenshot.
Without seeing what's wrong, here are some common areas to look at:
If you haven't already done so, look at the example apps included with Core Plot for ideas. The Plot Gallery app has many sample plots and the others are useful, too.
You may need to add padding (paddingLeft, paddingBottom, etc.) on the graph and/or plot area frame. Padding the graph pushes everything in away from the edges of the graph. Padding the plot area frame pushes the plot area in so the axes and titles can hang outside the plot area (the area where the plots are drawn).
If you want to keep an axes pinned to a specific place, e.g., the edge of the graph, set up a floating axis. Otherwise make sure the orthogonal coordinate is set (it defaults to 0). For example, the orthogonal coordinate for the x-axis is the y-value where the x-axis crosses the y-axis.
I'm completely new to ArcGIS and ArcMap, but someone suggested this program to me for a project I'm working on.
I would like to animate individual entities on a map, and was wondering if it is possible to do so in ArcMap. I asked this earlier here and a member directed me to a tutorial on animating in ArcGIS. The animation in the guide was over a map spread (ie. each pixel on the map displays, say, a different color to indicate population data in the area). However I realized that if I zoom in a lot, eventually the image will degenerate into pixels, which is why I need an actual object to mark a certain point. I checked some online tutorials and it seems like we can place markers on the map. Can someone tell me if it is possible to animate these markers (for example via a for-loop)? And if so, could you point me in a direction where to start?
Thanks in advance!
You can animate layers in ArcMap is the short answer. Its not as simple as using the timeline feature in Google Earth for example though. But then ArcMap is much more than just a visualization tool.
This help page on the ESRI web help looks like a good place to start.
I'm not 100% sure what you mean by the image degenerates into pixels. Are you saying that the markers were single points in the layer. Unlike Google Earth you are not confined to simply plotting points on the map. You can draw completely arbitrary shapes in ArcMap, which can be defined to cover actual areas of the map, so when you zoom-in the shape gets larger.
The way you need to load data into ArcMap to produce an animation isn't too simple. There might be other ways to do this, but the way I know of is to generate a NetCDF file. This file contains a 3D matrix of layer data, where each layer is separated through time. Because you generate a matrix, you are effectively placing a raster image over the map. Thus if you want to cover a large area, each matrix becomes large, and you multiply that by the number of time slices you wish to animate over.
Once you have a NetCDF file with your data in however, getting ArcMap to animate it and produce say a .avi file is pretty simple.
You could try just loading some of the example NetCDF datasets into ArcMap to see how/if they will work to get you started.
Hope that helps.
The upcoming v10 will have better time-aware capabilities, which will allow for animation.
i want to show a grapph/bar chart in iphone how do i do this without custom API;s
You may want to investigate the Core Plot project [code.google.com]. Core Plot was the subject of this year's scientific coding project at WWDC and is pretty useable for some cases already. From its inception, Core Plot was intended for both OS X and iPhone uses. The source distribution (there hasn't been a binary release yet) comes with both OS X and iPhone example applications and there's info on the project wiki for using it as a library in an iPhone app. Here's an example of it's current plotting capabilities.
(source: googlecode.com)
Write your own. It's not easy, I'm in the process of doing the same thing right now. Here's how I'm doing it:
First, ignore any desire you may have to try using a UIScrollView if you want to allow zooming. It's totally not worth it.
Second, create something like a GraphElement protocol. I have a hierarchy that looks something like this:
GraphElement
GraphPathElement
GraphDataElement
GraphDataSupplierElement
GraphElement contains the basic necessary methods for a graph element, including how to draw, a maximum width (for zooming in), whether a point is within that element (for touches) and the standard touchBegan, touchMoved, and touchEnded functions.
GraphPathElement contains a CGPath, a line color and width, a fill color and a drawing mode. Whenever it's prompted to draw, it simply adds the path to the context, sets the colors and line width, and draws the path with the given drawing mode.
GraphDataElement, as a subclass of GraphPathElement, takes in a set of data in x-y coordinates, a graph type (bar or line), a frame, and a bounds. The frame is the actual size of the created output CGPath. The bounds is the size of the data in input coordinates. Essentially, it lets you scale the data to the screen size.
It creates a graph by first calculating an affine transform to transform the bounds to the frame, then it loops through each point and adds it as data to a path, applying that transform to the point before adding it. How it adds data depends on the type.
If it's a bar graph, it creates a rectangle of width 0, origin at (x,frame.size.height-y), and height=y. Then it "insets" the graph by -3 pixels horizontally, and adds that to the path.
If it's a line graph, it's much simpler. It just moves to the first point, then for each other point, it adds a line to that point, adds a circle in a rect around that point, then moves back to that point to go on to the next point.
GraphDataSupplierElement is the interface to my database that actually contains all the data. It determines what kind of graph it should be, formats the data into the required type for GraphDataElement, and passes it on, with the color to use for that particular graph.
For me, the x-axis is time, and is represented as NSTimeIntervals. The GraphDataSupplierElement contains a minDate and maxDate so that a GraphDateElement can draw the x-axis labels as required.
Once all this is done, you need to create the actual graph. You can go about it several ways. One option is to keep all the elements in an NSArray and whenever drawRect: is called, loop through each element and draw it. Another option is to create a CALayer for each element, and use the GraphPathElement as the CALayer's delegate. Or you could make GraphPathElement extend from CALayer directly. It's up to you on this one. I haven't gotten as far as trying CALayers yet, I'm still stuck in the simple NSArray stage. I may move to CALayers at some point, once I'm satisfied with how everything looks.
So, all in all, the idea is that you create the graph as one or many CGPaths beforehand, and just draw that when you need to draw the graph, rather than trying to actually parse data whenever you get a drawRect: call.
Scaling can be done by keeping the source data in your GraphDataElement, and just change the frame so that the scaling of the bounds to the frame creates a CGPath wider than the screen, or whatever your needs are. I basically re-implemented my own pinch-zoom for my Graph UIView subclass that only scales horizontally, by changing its transform, then on completion, get the current frame, reset the transform to identity, set the frame to the saved value, and set the frame of all of the GraphElements to the new frame as well, to make them scale. Then just call [self setNeedsDisplay] to draw.
Anyway, that's a bit ramble-ish, but it's an outline of how I made it happen. If you have more specific questions, feel free to comment.