CODEWITHSUNDEEP
iosobjective-ciphonexcodecore-plot
ClockWise
ClockWise

Reputation: 1519

Scale scatter plot to Y-axis based on Circle radius using core plot

I have a scatter-plot where I plot circles. It draws fine and I scale it depending on aspect ratio from the users device. The circles can vary in size incredibly, so I want to scale the plotspace accordingly. The problem is that when I use

[graph.defaultPlotSpace scaleToFitPlots:graph.allPlots];

the scaling is done with respect to the y-axis. I get perfect circles, since I work with aspect ratio, but since this is a portrait orientation, and the scaling is done with respect to y-axis, the circles get cut off in the x-axis. Since the x-axis is shorter in regard of aspect ratio I'd like to scale with respect to it instead. Is that possible?

What I'm trying to achieve is to "zoom out" or "scale" my plotSpace so all my circles fit in the plotSpace, which I can't seem to figure out without breaking aspect ratio and thus getting stretches circles.

It looks like this: enter image description here

And I want it to look like this: enter image description here

EDIT:

Code I currently use to scale:

[self.mGraph layoutIfNeeded];
[self.mGraph.defaultPlotSpace scaleToFitPlots:self.mGraph.allPlots];

float width = self.mGraph.plotAreaFrame.bounds.size.width;
float height = self.mGraph.plotAreaFrame.bounds.size.height;

float aspectRatio = width / height;

CPTMutablePlotRange *xRange = [plotSpace.xRange mutableCopy];
[xRange expandRangeByFactor:CPTDecimalFromCGFloat(1.0f * aspectRatio)];
plotSpace.xRange = xRange;
CPTMutablePlotRange *yRange = [plotSpace.yRange mutableCopy];
[yRange expandRangeByFactor:CPTDecimalFromCGFloat(1.0f)];
plotSpace.yRange = yRange;

Upvotes: 0

Views: 203

Answers (1)

Eric Skroch
Eric Skroch

Reputation: 27381

You can compute the aspect ratio of the plot area from the size of the plotArea layer. Call -layoutIfNeeded on the graph first to make sure the size is up-to-date. Use the computed aspect ratio to adjust the plot ranges computed by -scaleToFitPlots:.

After scaling, get the size of the plot area and the lengths of the plot ranges:

CGSize paSize = self.mGraph.plotAreaFrame.plotArea.bounds.size;
double xLen = plotSpace.xRange.lengthDouble;
double yLen = plotSpace.yRange.lengthDouble;

You want the ratio xLen / yLen to end up the same as paSize.width / paSize.height. Expand the xRange or yRange by a factor greater than one (1) to make the ratios equal.

Upvotes: 1

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