where to set background color? - iphone

i was just browsing the classes for an hour and cant find it! i started with searching the example of the AAPLot project.
i changed the graph a bit and was expecting to find all settings in the CPTTradingRangePlot class but it´s not there.
there are a lot of properties which i can change, but i can´t find the background settings in any of the classes.
could anybody give me a hint?
// OHLC plot
CPTMutableLineStyle *whiteLineStyle = [CPTMutableLineStyle lineStyle];
whiteLineStyle.lineColor = [CPTColor whiteColor];
whiteLineStyle.lineWidth = 1.0f;
CPTTradingRangePlot *ohlcPlot = [[[CPTTradingRangePlot alloc] initWithFrame:graph.bounds] autorelease];
ohlcPlot.identifier = #"OHLC";
ohlcPlot.lineStyle = whiteLineStyle;
ohlcPlot.barWidth = 4.0f;
ohlcPlot.increaseFill = [(CPTFill *)[CPTFill alloc] initWithColor:[CPTColor greenColor]];
ohlcPlot.decreaseFill = [(CPTFill *)[CPTFill alloc] initWithColor:[CPTColor redColor]];
CPTMutableTextStyle *whiteTextStyle = [CPTMutableTextStyle textStyle];
whiteTextStyle.color = [CPTColor whiteColor];
whiteTextStyle.fontSize = 12.0;
ohlcPlot.labelTextStyle = whiteTextStyle;
ohlcPlot.labelOffset = 5.0;
ohlcPlot.stickLength = 2.0f;
ohlcPlot.dataSource = self;
ohlcPlot.plotStyle = CPTTradingRangePlotStyleCandleStick;
[graph addPlot:ohlcPlot];

Here's a very simple example. This:
CPTColor *your_color = [CPTColor colorWithComponentRed:1 green:0 blue:0 alpha:1];
your_graph.fill = [CPTFill fillWithColor:your_color];
will turn your graph's background red. But as Eric Skroch said, you may want to do this...
your_graph.plotAreaFrame.fill = [CPTFill fillWithColor:your_color];
and / or this...
your_graph.plotAreaFrame.plotArea.fill = [CPTFill fillWithColor:your_color];
depending on the result you want to achieve.

Backgrounds in Core Plot are set using CPTFill objects similar to the increaseFill and decreaseFill in your code sample. Depending on the look you want to achieve, you need to set the fill on graph, graph.plotAreaFrame, and/or graph.plotAreaFrame.plotArea. The axis demo in the Mac version of CPTTestApp uses fills in all three areas so you can see the different parts.

You may set it in xAxis or yAxis using CPTColor.
axisSet.yAxis.alternatingBandFills = [NSArray arrayWithObjects:[CPTColor redColor],
[CPTColor whiteColor], [CPTColor purpleColor], nil];

i finally found it by myself. the background of the chart is managed by a theme. there are several theme files in the folder theme of the core-plot library and one of them is CPTStocksTheme. The CPTStocksTheme creates a blue gradient background which can be changed there.

Related

iPhone : How to change gradient color for negative values in Core Plot?

How to change area gradient color for negative values in Gradient Scatter Plot in Core-Plot in iPhone?
I want gradient colors as below:
For positive values to be Green
For negative values to be Red.
How should I do that?
Just implement the following method of the CPBarPlotDataSource is OK:
- (CPFill *)barFillForBarPlot:(CPBarPlot *)barPlot recordIndex:(NSUInteger)index
{
if (barPlot.identifier == #"profit") {
id item = [self.profits objectAtIndex:index];
double profit = [[item objectForKey:#"profit"] doubleValue];
if (profit < 0.0) {
return [CPFill fillWithGradient:[CPGradient gradientWithBeginningColor:[CPColor redColor] endingColor:[CPColor blackColor]]];
}
}
return nil;
}
Hope to help:)
Well, I don't know if it's too pretty, but I suppose you could do two separate plots with the same dataSource, let's say positivePlot and negativePlot.
CPScatterPlot *positivePlot = [[[CPScatterPlot alloc] init] autorelease];
positivePlot.identifier = #"PositivePlot";
positivePlot.dataSource = self;
[graph addPlot:positivePlot];
CPScatterPlot *negativevePlot = [[[CPScatterPlot alloc] init] autorelease];
negativevePlot.identifier = #"NegativePlot";
negativePlot.dataSource = self;
[graph addPlot:negativePlot];
Now, if you configure your plotSpaces properly, you can separate positive and negative values and configure each plot properly, including area gradient:
CPXYPlotSpace *positivePlotSpace = [graph newPlotSpace];
positivePlotSpace.xRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(0)
length:CPDecimalFromFloat(100)];
positivePlotSpace.yRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(0)
length:CPDecimalFromFloat(100)];
CPXYPlotSpace *negativevePlotSpace = [graph newPlotSpace];
negativePlotSpace.xRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-100)
length:CPDecimalFromFloat(100)];
negativePlotSpace.yRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(0)
length:CPDecimalFromFloat(100)];
// Plots configuration
//POSITIVE VALUES
positivePlot.plotSpace = positivePlotSpace;
// Green for positive
CPColor *areaColor = [CPColor colorWithComponentRed:0.0
green:1.0
blue:0.0
alpha:1.0];
CPGradient *areaGradient = [CPGradient gradientWithBeginningColor:areaColor
endingColor:[CPColor clearColor]];
areaGradient.angle = -90.0f;
CPFill *areaGradientFill = [CPFill fillWithGradient:areaGradient];
positivePlot.areaFill = areaGradientFill;
//NEGATIVE VALUES
negativePlot.plotSpace = negativePlotSpace;
// Red for negative
areaColor = [CPColor colorWithComponentRed:1.0
green:0.0
blue:0.0
alpha:1.0];
areaGradient = [CPGradient gradientWithBeginningColor:areaColor
endingColor:[CPColor clearColor]];
areaGradient.angle = -90.0f;
areaGradientFill = [CPFill fillWithGradient:areaGradient];
negativePlot.areaFill = areaGradientFill;
NOTE: This is off the top of my head, as I dont have Core-Plot docs here, or a working configuration to test this in, so the syntax or something might be off, but I think the general concept should work.
Cheers

core plot custom Theme?

I'm using Core-Plot for a trend chart in an iPhone app and haven't found how to customize the background. I can create a theme using the built-in themes, like kCPPlainWhiteTheme, but how can I change them? or create a new one?
What i basically need to do is make the background transparent.
EDIT / UPDATE
I jus tested this code but it doesn't seem to work:
//CPTheme *theme = [CPTheme themeNamed:kCPPlainWhiteTheme];
CPTheme *theme = [[CPTheme alloc]init];
chartTrend5 = (CPXYGraph *)[theme newGraph];
chartView.hostedGraph = chartTrend5;
chartTrend5.paddingLeft = 0.0;
chartTrend5.paddingTop = 0.0;
chartTrend5.paddingRight = 0.0;
chartTrend5.paddingBottom = 0.0;
chartTrend5.fill = nil;
chartTrend5.borderLineStyle = nil;
chartView.hostedGraph.fill = nil;
chartTrend5PlotSpace = (CPXYPlotSpace *)chartTrend5.defaultPlotSpace;
chartTrend5PlotSpace.xRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(0)
length:CPDecimalFromFloat(5)];
// range is 0-125, but since the frame heights is 90,
// we need to convert the points to this adjusted scale. The factor is 0.72 => (90/125)
chartTrend5PlotSpace.yRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(0)
length:CPDecimalFromFloat(90)];
CPXYAxisSet *axisSet = (CPXYAxisSet *)chartTrend5.axisSet;
CPXYAxis *x = axisSet.xAxis;
x.majorIntervalLength = CPDecimalFromFloat(100);
//x.constantCoordinateValue = CPDecimalFromFloat(2);
x.minorTicksPerInterval = 2;
x.borderWidth = 0;
x.labelExclusionRanges = [NSArray arrayWithObjects:
[CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-1)
length:CPDecimalFromFloat(800)],
nil];;
CPXYAxis *y = axisSet.yAxis;
y.majorIntervalLength = CPDecimalFromFloat(100);
y.minorTicksPerInterval = 1;
//y.constantCoordinateValue = length:CPDecimalFromFloat(2);
y.labelExclusionRanges = [NSArray arrayWithObjects:
[CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-26)
length:CPDecimalFromFloat(100)],
nil];
CPScatterPlot *dataSourceLinePlot = [[[CPScatterPlot alloc] init] autorelease];
dataSourceLinePlot.identifier = #"TrendChart";
dataSourceLinePlot.dataLineStyle.lineWidth = 2.f;
dataSourceLinePlot.dataLineStyle.lineColor = [CPColor colorWithComponentRed:(16/255.f)
green:(101/255.f)
blue:(122/255.f)
alpha:1];
dataSourceLinePlot.dataSource = self;
[chartTrend5 addPlot:dataSourceLinePlot];
chartTrend5.fill = nil;
// Put an area gradient under the plot above
CPColor *areaColor = [CPColor colorWithComponentRed:(212/255.f)
green:(233/255.f)
blue:(216/255.f)
alpha:1];
CPGradient *areaGradient = [CPGradient gradientWithBeginningColor:areaColor
endingColor:areaColor];
areaGradient.angle = -90.0f;
CPFill *areaGradientFill = [CPFill fillWithGradient:areaGradient];
dataSourceLinePlot.areaFill = areaGradientFill;
dataSourceLinePlot.areaBaseValue = CPDecimalFromString(#"5.25");
here I set the the fill property of CPXYGraph *chartTrend5 and *CPXYPlotSpace *chartTrend5PlotSpace to nil.
In addition to what Eric suggests, you can also try setting the fill to a clear color. For example, I've used this in the past to provide a transparent background to graphs:
CPTTheme *theme = [CPTTheme themeNamed:kCPPlainWhiteTheme];
graph = (CPTXYGraph *)[theme newGraph];
graph.fill = [CPTFill fillWithColor:[CPTColor clearColor]];
graph.plotAreaFrame.fill = [CPTFill fillWithColor:[CPTColor clearColor]];
Themes are just a convenient way to set a lot of the style properties at once. You can set any of them individually to customize the look. Any time you want an area to be transparent, you can set its fill to nil. Same with line styles--set them to nil to prevent a line from being drawn.
There are two "background" areas that you might be concerned with. The graph has a fill as does the plot area. The plot area is the region where the plots are drawn. Set the fill property on both of these to nil to make the background transparent.
I tried this & it works for me:
// Here 'hostingView' is your CPTGraphHostingView to
// which you add your graph
UIImageView *backgroundImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"background.png"]];
[hostingView addSubview:backgorundImage];
[hostingView sendSubviewToBack:backgroundImage];
I used the .fill and .plot.AreaFrame.fill properties :
plot = [[CPTXYGraph alloc] initWithFrame:CGRectZero];
CPTTheme *theme = [CPTTheme themeNamed:kCPTSlateTheme];
[plot applyTheme:theme];
self.graph.collapsesLayers = NO;
self.graph.hostedGraph = plot;
plot.paddingLeft = 1.0;
plot.paddingTop = 1.0;
plot.paddingRight = 1.0;
plot.paddingBottom = 1.0;
plot.fill = [CPTFill fillWithColor:[CPTColor clearColor]];
plot.plotAreaFrame.fill = [CPTFill fillWithColor:[CPTColor clearColor]];
This works for me.

core data line labels

I have created a CPScatterPlot using Core Plot and have several lines on the graph:
for(int i=0; i<nLines; ++i){
CPScatterPlot *xSquaredPlot = [[[CPScatterPlot alloc] initWithFrame:graph.frame] autorelease];
xSquaredPlot.identifier = [NSString stringWithFormat:#"%d",i];
xSquaredPlot.dataLineStyle.lineWidth = 1.0f;
xSquaredPlot.name = #"dd";
if(i==0)
xSquaredPlot.dataLineStyle.lineColor = [CPColor redColor];
else if (i ==1)
xSquaredPlot.dataLineStyle.lineColor = [CPColor blueColor];
else
xSquaredPlot.dataLineStyle.lineColor = [CPColor greenColor];
xSquaredPlot.dataSource = self;
[graph addPlot:xSquaredPlot];
CPPlotSymbol *greenCirclePlotSymbol = [CPPlotSymbol ellipsePlotSymbol];
if(i==0)
greenCirclePlotSymbol.fill = [CPFill fillWithColor:[CPColor blueColor]];
else if (i ==1)
greenCirclePlotSymbol.fill = [CPFill fillWithColor:[CPColor greenColor]];
else
greenCirclePlotSymbol.fill = [CPFill fillWithColor:[CPColor redColor]];
greenCirclePlotSymbol.size = CGSizeMake(2.0, 2.0);
xSquaredPlot.plotSymbol = greenCirclePlotSymbol;
}
The lines show up great, but I can't seem to find a way to label each line with it's title, or provide a legend.
Any ideas on this?
Thanks in advance!
Update: CorePlot 0.4 has the class CPTLegend:
_graph.legend = [CPTLegend legendWithGraph:_graph];
_graph.legend.textStyle = x.titleTextStyle;
_graph.legend.fill = [CPTFill fillWithColor:[CPTColor darkGrayColor]];
_graph.legend.borderLineStyle = x.axisLineStyle;
_graph.legend.cornerRadius = 5.0;
_graph.legend.swatchSize = CGSizeMake(25.0, 25.0);
_graph.legendAnchor = CPTRectAnchorBottom;
_graph.legendDisplacement = CGPointMake(0.0, 12.0);
See CorePlot_0.4/Source/examples/CorePlotGallery/src/plots/SimpleScatterPlot.m.
Legends have not yet been implemented in Core Plot. You're more than welcome to contribute an implementation of them to the framework.
In the meantime, you could construct a custom UIView with UILabels and colored lines to act as the legend for the graph, then add it as a sibling to the graph (not a subview, or it will not be rendered properly) and order it to show above the graph.

CorePlot problems

I started with core-plot now and came to some problems. I followed the tutorial from this page: http://www.switchonthecode.com/tutorials/using-core-plot-in-an-iphone-application
and completed with the instructions from this page: http://code.google.com/p/core-plot/wiki/UsingCorePlotInApplications (such as -all_load).
But I still have some problems, I get the following errors:
error: incompatible type for argument 1 of 'setMajorIntervalLength:'
error: request for member 'axisLabelOffset' in something not a structure or union
error: incompatible type for argument 1 of 'setMajorIntervalLength:'
error: request for member 'axisLabelOffset' in something not a structure or union
error: request for member 'bounds' in something not a structure or union
error: request for member 'defaultPlotSymbol' in something not a structure or union
error: request for member 'bounds' in something not a structure or union
Anyone who knows what I am doing wrong?
This is my code:
- (void)viewDidLoad {
[super viewDidLoad];
graph = [[CPXYGraph alloc] initWithFrame: self.view.bounds];
CPLayerHostingView *hostingView = (CPLayerHostingView *)self.view;
hostingView.hostedLayer = graph;
graph.paddingLeft = 20.0;
graph.paddingTop = 20.0;
graph.paddingRight = 20.0;
graph.paddingBottom = 20.0;
CPXYPlotSpace *plotSpace = (CPXYPlotSpace *)graph.defaultPlotSpace;
plotSpace.xRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-6)
length:CPDecimalFromFloat(12)];
plotSpace.yRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-5)
length:CPDecimalFromFloat(30)];
CPXYAxisSet *axisSet = (CPXYAxisSet *)graph.axisSet;
CPLineStyle *lineStyle = [CPLineStyle lineStyle];
lineStyle.lineColor = [CPColor blackColor];
lineStyle.lineWidth = 2.0f;
axisSet.xAxis.majorIntervalLength = [NSDecimalNumber decimalNumberWithString:#"5"];
axisSet.xAxis.minorTicksPerInterval = 4;
axisSet.xAxis.majorTickLineStyle = lineStyle;
axisSet.xAxis.minorTickLineStyle = lineStyle;
axisSet.xAxis.axisLineStyle = lineStyle;
axisSet.xAxis.minorTickLength = 5.0f;
axisSet.xAxis.majorTickLength = 7.0f;
axisSet.xAxis.axisLabelOffset = 3.0f;
axisSet.yAxis.majorIntervalLength = [NSDecimalNumber decimalNumberWithString:#"5"];
axisSet.yAxis.minorTicksPerInterval = 4;
axisSet.yAxis.majorTickLineStyle = lineStyle;
axisSet.yAxis.minorTickLineStyle = lineStyle;
axisSet.yAxis.axisLineStyle = lineStyle;
axisSet.yAxis.minorTickLength = 5.0f;
axisSet.yAxis.majorTickLength = 7.0f;
axisSet.yAxis.axisLabelOffset = 3.0f;
CPScatterPlot *xSquaredPlot = [[[CPScatterPlot alloc]
initWithFrame:graph.defaultPlotSpace.bounds] autorelease];
xSquaredPlot.identifier = #"X Squared Plot";
xSquaredPlot.dataLineStyle.lineWidth = 1.0f;
xSquaredPlot.dataLineStyle.lineColor = [CPColor redColor];
xSquaredPlot.dataSource = self;
[graph addPlot:xSquaredPlot];
CPPlotSymbol *greenCirclePlotSymbol = [CPPlotSymbol ellipsePlotSymbol];
greenCirclePlotSymbol.fill = [CPFill fillWithColor:[CPColor greenColor]];
greenCirclePlotSymbol.size = CGSizeMake(2.0, 2.0);
xSquaredPlot.defaultPlotSymbol = greenCirclePlotSymbol;
CPScatterPlot *xInversePlot = [[[CPScatterPlot alloc]
initWithFrame:graph.defaultPlotSpace.bounds] autorelease];
xInversePlot.identifier = #"X Inverse Plot";
xInversePlot.dataLineStyle.lineWidth = 1.0f;
xInversePlot.dataLineStyle.lineColor = [CPColor blueColor];
xInversePlot.dataSource = self;
[graph addPlot:xInversePlot];
}
The example you're pointing to is out of date and no longer matches the current API for the Core Plot framework. I'd suggest starting with the sample applications that ship with the framework (in the examples directory), as we've kept those updated to match any API changes.
For example axisLabelOffset has been renamed to labelOffset, defaultPlotSymbol no longer exists (you set the plotSymbol property on a CPPlot instance), the plot space no longer has a bounds property, and you no longer need to use -initWithFrame: for the CPPlot instances.
Again, just use the sample applications that ship with the framework as a template, and work from there. We haven't reached a 1.0 release yet, so the API will change as we stabilize and enhance the framework.
you are getting the incompatible type error because majorIntervalLength expects a NSDecimal and you are returning a NSDecimalNumber. see if this works for those errors:
axisSet.xAxis.majorIntervalLength = [[NSDecimalNumber decimalNumberWithString:#"5"] decimalValue];
for the others are you including the header files somewhere?
set the header search and other link (Users..../framework & -ObjC respectively)
I guess you are providing Absolute path. If you go through the corePlot Documentation you shall see that they have clearly mentioned "You should give relative path at Header Search path Field"
to learn what is a relative path follow,
"http://webdesign.about.com/od/beginningtutorials/a/aa040502a.htm"
get full path of core-plot thru terminal command "mdfind" as below.
In terminal type, mdfind -name coreplot
will get full path name.
Take full path and insert in HEADERS SEARCH PATH
along with above... add -Objc to "Othetr Linker Flags" and add Quartz frame work in "Link Binary With Libraries"
It will WORK :)
ive done the following:
1) added #import "CorePlot-CocoaTouch.h"
2) added the : UIViewController to the .h vc file
3) added the exact same code from CPTest app
4) added the coreplot-cocoatouch framework to my project, set the dependency in target settings, set the header search and other link (Users..../framework & -ObjC respectively) in project settings, added the QuartzCore framework and when i compile i get:
import "CorePlot-CocoaTouch.h" NO SUCH FILE OR DIRECTORY....
i dont understand why its not finding the header files...

iPhone UILabel text soft shadow

I know soft shadows are not supported by the UILabel out of the box, on the iPhone. So what would be the best way to implement my own one?
EDIT:
Obviously I will subclass the UILabel and draw in the -drawRect:
My question is, how do I get the contents of the label as graphics and draw around them, blur them etc...
EDIT 2:
I returned to this question about a year later. In the meantime I've built a class that allows you to easily add soft shadow to a label and tweak it's radius etc and also to draw gradients on the text itself. You can find it on GitHub: https://github.com/doukasd/iOS-Components/tree/master/Views
As of 3.2 there is direct support for shadows in the SDK.
label.layer.shadowColor = [label.textColor CGColor];
label.layer.shadowOffset = CGSizeMake(0.0, 0.0);
#import <QuartzCore/QuartzCore.h> and play with some parameters:
label.layer.shadowRadius = 3.0;
label.layer.shadowOpacity = 0.5;
And, if you find your shadow clipped by the label bounds:
label.layer.masksToBounds = NO;
finally set
label.layer.shouldRasterize = YES;
I advise you to use the shadowColor and shadowOffset properties of UILabel:
UILabel* label = [[UILabel alloc] init];
label.shadowColor = [UIColor whiteColor];
label.shadowOffset = CGSizeMake(0,1);
This answer to this similar question provides code for drawing a blurred shadow behind a UILabel. The author uses CGContextSetShadow() to generate the shadow for the drawn text.
Additionally to IIDan's answer:
For some purposes it is necessary to set
label.layer.shouldRasterize = YES
I think this is due to the blend mode that is used to render the shadow. For example I had a dark background and white text on it and wanted to "highlight" the text using a black shadowy glow. It wasn't working until I set this property.
Apply the (soft) shadow on the view's layer, like this:
UILabel *label = [[UIabel alloc] init];
label.layer.shadowColor = [[UIColor whiteColor] CGColor];
label.layer.shadowOpacity = 1.0;
To keep things up to date: Creating the shadow in Swift is as easy as that:
Import the QuartzCore Framework
import QuartzCore
And set the shadow attributes to your label
titleLabel.shadowColor = UIColor.blackColor()
titleLabel.shadowOffset = CGSizeMake(0.0, 0.0)
titleLabel.layer.shadowRadius = 5.0
titleLabel.layer.shadowOpacity = 0.8
titleLabel.layer.masksToBounds = false
titleLabel.layer.shouldRasterize = true
_nameLabel = [[UILabel alloc] initWithFrame:CGRectZero];
_nameLabel.font = [UIFont boldSystemFontOfSize:19.0f];
_nameLabel.textColor = [UIColor whiteColor];
_nameLabel.backgroundColor = [UIColor clearColor];
_nameLabel.shadowColor = [UIColor colorWithWhite:0 alpha:0.2];
_nameLabel.shadowOffset = CGSizeMake(0, 1);
i think you should use the [UIColor colorWithWhite:0 alpha:0.2] to set the alpha value.
I tried almost all of these techniques (except FXLabel) and couldn't get any of them to work with iOS 7. I did eventually find THLabel which is working perfectly for me. I used THLabel in Interface Builder and setup User Defined Runtime Attributes so that it's easy for a non programmer to control the look and feel.
https://github.com/MuscleRumble/THLabel
This like a trick,
UILabel *customLabel = [[UILabel alloc] init];
UIColor *color = [UIColor blueColor];
customLabel.layer.shadowColor = [color CGColor];
customLabel.layer.shadowRadius = 5.0f;
customLabel.layer.shadowOpacity = 1;
customLabel.layer.shadowOffset = CGSizeZero;
customLabel.layer.masksToBounds = NO;
I wrote a library that provides a UILabel subclass with soft shadow support and a bunch of other effects:
https://github.com/nicklockwood/FXLabel
In Swift 3, you can create an extension:
import UIKit
extension UILabel {
func shadow() {
self.layer.shadowColor = self.textColor.cgColor
self.layer.shadowOffset = CGSize.zero
self.layer.shadowRadius = 3.0
self.layer.shadowOpacity = 0.5
self.layer.masksToBounds = false
self.layer.shouldRasterize = true
}
}
and use it via:
label.shadow()
Subclass UILabel, as stated, then, in drawRect:, do [self drawTextInRect:rect]; to get the text drawn into the current context. Once it is in there, you can start working with it by adding filters and whatnot. If you want to make a drop shadow with what you just drew into the context, you should be able to use:
CGContextSetShadowWithColor()
Look that function up in the docs to learn how to use it.
As of iOS 5 Apple provides a private api method to create labels with soft shadows.
The labels are very fast: I'm using dozens at the same time in a series of transparent views and there is no slowdown in scrolling animation.
This is only useful for non-App Store apps (obviously) and you need the header file.
$SBBulletinBlurredShadowLabel = NSClassFromString("SBBulletinBlurredShadowLabel");
CGRect frame = CGRectZero;
SBBulletinBlurredShadowLabel *label = [[[$SBBulletinBlurredShadowLabel alloc] initWithFrame:frame] autorelease];
label.backgroundColor = [UIColor clearColor];
label.textColor = [UIColor whiteColor];
label.font = [UIFont boldSystemFontOfSize:12];
label.text = #"I am a label with a soft shadow!";
[label sizeToFit];
While it's impossible to set a blur radius directly on UILabel, you definitely could change it by manipulating CALayer.
Just set:
//Required properties
customLabel.layer.shadowRadius = 5.0 //set shadow radius to your desired value.
customLabel.layer.shadowOpacity = 1.0 //Choose an opacity. Make sure it's visible (default is 0.0)
//Other options
customLabel.layer.shadowOffset = CGSize(width: 10, height: 10)
customLabel.layer.shadowColor = UIColor.black.cgColor
customLabel.layer.masksToBounds = false
What I hope will help someone and other answers failed to clarify is that it will not work if you also set UILabel Shadow Color property directly on Interface Builder while trying to setup .layer.shadowRadius.
So if setting label.layer.shadowRadius didn't work, please verify Shadow Color for this UILabel on Interface Builder. It should be set to default. And then, please, if you want a shadow color other than black, set this color also through .layer property.
Subclass UILabel, and override -drawInRect: