flickering iOS core plot Graph - ios

Question

I have a case where my app connects to the server to get data and plot on the graph. When the function to initialise the plot is called, the graph is redrawn at a wrong place and auto corrects itself back where it is supposed to be. This causes a flickering in the process.
I have a rised a timer for every 10 seconds to connect to the server.
Below is the plot initialization code.
-(id)initWithHostingView:(CPTGraphHostingView *)hostingView andData:(NSMutableArray *)data
{
self = [super init];
if ( self != nil ) {
self.hostingView = hostingView;
self.graphData = data;
self.graph = nil;
}
return self;
}
// This does the actual work of creating the plot if we don't already have a graph object.
-(void)initialisePlot:(NSUInteger)indexOfPlot
{
// Start with some simple sanity checks before we kick off
if ( (self.hostingView == nil) || (self.graphData == nil) ) {
NSLog(#"TUTSimpleScatterPlot: Cannot initialise plot without hosting view or data.");
return;
}
if ( self.graph != nil ) {
NSLog(#"TUTSimpleScatterPlot: Graph object already exists.");
return;
}
// Create a graph object which we will use to host just one scatter plot.
CGRect frame;
//CGRect frame = [self.hostingView bounds];
if(indexOfPlot == 0){
self.graph = [[CPTXYGraph alloc] initWithFrame:frame];
// Add some padding to the graph, with more at the bottom for axis labels.
self.graph.plotAreaFrame.paddingTop = 500.0f;
self.graph.plotAreaFrame.paddingRight = 20.0f;
self.graph.plotAreaFrame.paddingBottom = 50.0f;
self.graph.plotAreaFrame.paddingLeft= 20.0f;
// Tie the graph we've created with the hosting view.
self.hostingView.hostedGraph = self.graph;
// If you want to use one of the default themes - apply that here.
[self.graph applyTheme:[CPTTheme themeNamed:kCPTPlainWhiteTheme]];
// Create a line style that we will apply to the axis and data line.
CPTMutableLineStyle *lineStyle = [CPTMutableLineStyle lineStyle];
lineStyle.lineColor = [CPTColor redColor];
lineStyle.lineWidth = 2.0f;
// Create a text style that we will use for the axis labels.
CPTMutableTextStyle *textStyle = [CPTMutableTextStyle textStyle];
textStyle.fontName = #"Helvetica";
textStyle.fontSize = 14;
textStyle.color = [CPTColor blackColor];
// Create the plot symbol we're going to use.
CPTPlotSymbol *plotSymbol = [CPTPlotSymbol ellipsePlotSymbol];
plotSymbol.lineStyle = lineStyle;
plotSymbol.size = CGSizeMake(8.0, 8.0);
// Setup some floats that represent the min/max values on our axis.
float xAxisMin = -10;
float xAxisMax = 10;
float yAxisMin = 0;
float yAxisMax = 100;
// We modify the graph's plot space to setup the axis' min / max values.
CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)self.graph.defaultPlotSpace;
plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(xAxisMin) length:CPTDecimalFromFloat(xAxisMax - xAxisMin)];
plotSpace.yRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(yAxisMin) length:CPTDecimalFromFloat(yAxisMax - yAxisMin)];
// Modify the graph's axis with a label, line style, etc.
CPTXYAxisSet *axisSet = (CPTXYAxisSet *)self.graph.axisSet;
axisSet.xAxis.title = #"Data X";
axisSet.xAxis.titleTextStyle = textStyle;
axisSet.xAxis.titleOffset = 30.0f;
axisSet.xAxis.axisLineStyle = lineStyle;
axisSet.xAxis.majorTickLineStyle = lineStyle;
axisSet.xAxis.minorTickLineStyle = lineStyle;
axisSet.xAxis.labelTextStyle = textStyle;
axisSet.xAxis.labelOffset = 3.0f;
axisSet.xAxis.majorIntervalLength = CPTDecimalFromFloat(2.0f);
axisSet.xAxis.minorTicksPerInterval = 1;
axisSet.xAxis.minorTickLength = 5.0f;
axisSet.xAxis.majorTickLength = 7.0f;
axisSet.yAxis.title = #"Data Y";
axisSet.yAxis.titleTextStyle = textStyle;
axisSet.yAxis.titleOffset = 40.0f;
axisSet.yAxis.axisLineStyle = lineStyle;
axisSet.yAxis.majorTickLineStyle = lineStyle;
axisSet.yAxis.minorTickLineStyle = lineStyle;
axisSet.yAxis.labelTextStyle = textStyle;
axisSet.yAxis.labelOffset = 3.0f;
axisSet.yAxis.majorIntervalLength = CPTDecimalFromFloat(10.0f);
axisSet.yAxis.minorTicksPerInterval = 1;
axisSet.yAxis.minorTickLength = 5.0f;
axisSet.yAxis.majorTickLength = 7.0f;
// Add a plot to our graph and axis. We give it an identifier so that we
// could add multiple plots (data lines) to the same graph if necessary.
CPTScatterPlot *plot = [[CPTScatterPlot alloc] init];
plot.dataSource = self;
plot.identifier = #"mainplot";
plot.dataLineStyle = lineStyle;
plot.plotSymbol = plotSymbol;
//[self.graph reloadData];
[self.graph addPlot:plot];
}
if(indexOfPlot == 1){
self.graph = [[CPTXYGraph alloc] initWithFrame:frame];
// Add some padding to the graph, with more at the bottom for axis labels.
self.graph.plotAreaFrame.paddingTop = 20.0f;
self.graph.plotAreaFrame.paddingRight = 20.0f;
self.graph.plotAreaFrame.paddingBottom = 600.0f;
self.graph.plotAreaFrame.paddingLeft= 20.0f;
// Tie the graph we've created with the hosting view.
self.hostingView.hostedGraph = self.graph;
// If you want to use one of the default themes - apply that here.
[self.graph applyTheme:[CPTTheme themeNamed:kCPTPlainWhiteTheme]];
// Create a line style that we will apply to the axis and data line.
CPTMutableLineStyle *lineStyle = [CPTMutableLineStyle lineStyle];
lineStyle.lineColor = [CPTColor redColor];
lineStyle.lineWidth = 2.0f;
// Create a text style that we will use for the axis labels.
CPTMutableTextStyle *textStyle = [CPTMutableTextStyle textStyle];
textStyle.fontName = #"Helvetica";
textStyle.fontSize = 14;
textStyle.color = [CPTColor blackColor];
// Create the plot symbol we're going to use.
CPTPlotSymbol *plotSymbol = [CPTPlotSymbol crossPlotSymbol];
plotSymbol.lineStyle = lineStyle;
plotSymbol.size = CGSizeMake(8.0, 8.0);
// Setup some floats that represent the min/max values on our axis.
float xAxisMin = -10;
float xAxisMax = 10;
float yAxisMin = 0;
float yAxisMax = 100;
// We modify the graph's plot space to setup the axis' min / max values.
CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)self.graph.defaultPlotSpace;
plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(xAxisMin) length:CPTDecimalFromFloat(xAxisMax - xAxisMin)];
plotSpace.yRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(yAxisMin) length:CPTDecimalFromFloat(yAxisMax - yAxisMin)];
// Modify the graph's axis with a label, line style, etc.
CPTXYAxisSet *axisSet = (CPTXYAxisSet *)self.graph.axisSet;
axisSet.xAxis.title = #"Data X";
axisSet.xAxis.titleTextStyle = textStyle;
axisSet.xAxis.titleOffset = 30.0f;
axisSet.xAxis.axisLineStyle = lineStyle;
axisSet.xAxis.majorTickLineStyle = lineStyle;
axisSet.xAxis.minorTickLineStyle = lineStyle;
axisSet.xAxis.labelTextStyle = textStyle;
axisSet.xAxis.labelOffset = 3.0f;
axisSet.xAxis.majorIntervalLength = CPTDecimalFromFloat(2.0f);
axisSet.xAxis.minorTicksPerInterval = 1;
axisSet.xAxis.minorTickLength = 5.0f;
axisSet.xAxis.majorTickLength = 7.0f;
axisSet.yAxis.title = #"Data Y";
axisSet.yAxis.titleTextStyle = textStyle;
axisSet.yAxis.titleOffset = 40.0f;
axisSet.yAxis.axisLineStyle = lineStyle;
axisSet.yAxis.majorTickLineStyle = lineStyle;
axisSet.yAxis.minorTickLineStyle = lineStyle;
axisSet.yAxis.labelTextStyle = textStyle;
axisSet.yAxis.labelOffset = 3.0f;
axisSet.yAxis.majorIntervalLength = CPTDecimalFromFloat(10.0f);
axisSet.yAxis.minorTicksPerInterval = 1;
axisSet.yAxis.minorTickLength = 5.0f;
axisSet.yAxis.majorTickLength = 7.0f;
// Add a plot to our graph and axis. We give it an identifier so that we
// could add multiple plots (data lines) to the same graph if necessary.
CPTScatterPlot *plot = [[CPTScatterPlot alloc] init];
plot.dataSource = self;
plot.identifier = #"mainplot";
plot.dataLineStyle = lineStyle;
plot.plotSymbol = plotSymbol;
//[self.graph reloadData];
[self.graph addPlot:plot];
}
}
Do i have to reconsider the way it is being initialised?

Answer 1

Initialize the frame. You probably have junk values in there when graph is initialized that then get corrected when you add the graph to the hosting view.
CGRect frame = [self.hostingView bounds];
or even just
CGRect frame = CGRectZero;