У меня есть работоспособное решение, но оно нарушает обычно рекомендуемое действие для отображения оси Y.Примечания в приведенном ниже фрагменте кода указывают, где, по-моему, я отклонился от условных обозначений и где, по-моему, я добавил уникальное решение для фиксации оси Y на месте при последующем перерисовке графика.
#pragma mark - Choose returns to chart
- (IBAction)returnsToChart:(int)startPt andInteger:(int)endPt; {
contentArray1 = [[NSMutableArray alloc] initWithObjects:nil];
dataContent = [[NSMutableArray alloc] initWithObjects:nil];
int xPosition = 0;
for (int i=startPt; i<endPt+1; ++i) {
[dataContent addObject:[returnsAll objectAtIndex:i]];
id x = [NSNumber numberWithFloat:xPosition];
id y = [NSNumber numberWithFloat:[[returnsAll objectAtIndex:i] floatValue]];
if ([[returnsAll objectAtIndex:i] isEqualToString:@""]) {
[contentArray1 addObject:[NSMutableDictionary dictionaryWithObjectsAndKeys:x, @"x", @"", @"y", nil]];
}
else {
[contentArray1 addObject:[NSMutableDictionary dictionaryWithObjectsAndKeys:x, @"x", y, @"y", nil]]; }
xPosition = xPosition + 1;
}
dataForPlot = contentArray1;
quarterlyReturnView.frame = CGRectMake(0.0f, 8.0f, 320.0f, 240.0f);
graph = [[CPTXYGraph alloc] initWithFrame:CGRectZero];
quarterlyReturnView.hostedGraph = graph;
//paddingLeft leaves room for y-axis labels
//paddingBottom must be set at zero otherwise and the space that must be added in order for the bottom-most label text to show will be handled by extending the length of the y-axis downward by a little bit
graph.paddingLeft = 8.0;
graph.paddingTop = 5.0;
graph.paddingRight = 5.0;
graph.paddingBottom = 0.0;
//convention says that paddingLeft should be some number greater than zero
//convention says that paddingBottom should be some number greater than zero, but if greater than zero, then each subsequent redrawing of plot results in a label shift upwards by the non-zero amount
graph.plotAreaFrame.paddingLeft = 0.0;
graph.plotAreaFrame.paddingTop = 5.0;
graph.plotAreaFrame.paddingRight = 5.0;
graph.plotAreaFrame.paddingBottom = 0.0;
// Setup plot space
CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)graph.defaultPlotSpace;
//this is where the magic happens...
//I tweaked the percentage adjustments for the location as a function of the number of data points along the x-axis that had to be plotted
//I settled on 8% plus and minus to provide room for the y-axis labels
//this percentage is expressed as -0.08*(datacontent.count-1.0) and 1.08*(datacontent.count-1.0)
//in other words, I put 8% on the left-hand side of the x-axis and made the whole x-axis 108% of the number of data points
plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(-0.08 * (dataContent.count-1.0)) length:CPTDecimalFromFloat(1.08 * (dataContent.count-1.0))];
//Text styles
CPTMutableTextStyle *axisTitleTextStyle = [CPTTextStyle textStyle];
axisTitleTextStyle.fontName = @"Helvetica";
axisTitleTextStyle.fontSize = 9.0;
//Grid styles
CPTMutableLineStyle *majorGridLineStyle = [CPTLineStyle lineStyle];
majorGridLineStyle.lineWidth = 0.5f;
//Axis styles
CPTMutableLineStyle *axisLineStyle = [CPTLineStyle lineStyle];
axisLineStyle.lineColor = [CPTColor blueColor];
axisLineStyle.lineWidth = 1.0f;
float maxNum = -100.0;
float minNum = 100.0;
float testMaxNum = 0.0;
float testMinNum = 0.0;
for (int i=0; i<[dataContent count]; ++i) {
if ([[dataContent objectAtIndex:i] isEqualToString:@""]) { }
else {
testMaxNum = [[dataContent objectAtIndex:i] floatValue];
if (maxNum < testMaxNum) { maxNum = testMaxNum; }
testMinNum = [[dataContent objectAtIndex:i] floatValue];
if (minNum > testMinNum) { minNum = testMinNum; } }
}
int maxInt = (maxNum + 1.0) / 1.0;
float yMax = 1.0 * maxInt;
int minInt = (minNum - 1.0) / 1.0;
float yMin = 1.0 * minInt;
//here is where the y-axis is stretched a bit to allow the labels to show unclipped
plotSpace.yRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(yMin-0.2) length:CPTDecimalFromFloat(yMax-yMin+0.2)];
// Axes (x is horizontal; y is vertical)
CPTXYAxisSet *axisSet = (CPTXYAxisSet *)graph.axisSet;
CPTXYAxis *x = axisSet.xAxis;
x.axisLineStyle = axisLineStyle;
x.labelOffset = 1.0f;
x.labelTextStyle = nil;
x.majorTickLength = 5.0f;
x.majorIntervalLength = CPTDecimalFromString(@"16");
x.orthogonalCoordinateDecimal = CPTDecimalFromString(@"0");
x.minorTicksPerInterval = 0;
x.minorTickLength = 0.0f;
x.tickDirection =CPTSignNone;
x.visibleRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(0.0) length:CPTDecimalFromFloat(dataContent.count-1.0)];
CPTXYAxis *y = axisSet.yAxis;
y.axisLineStyle = axisLineStyle;
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
[formatter setMaximumFractionDigits:0];
y.labelFormatter = formatter;
y.labelOffset = 2.0f;
y.labelAlignment = CPTAlignmentLeft;
y.labelTextStyle = axisTitleTextStyle;
y.tickDirection = CPTSignNegative;
y.majorTickLength = 3.0f;
y.majorIntervalLength = CPTDecimalFromString(@"2");
y.majorGridLineStyle = majorGridLineStyle;
//y.gridLinesRange is needed because the x-axis has been stretched 8% as described above
y.gridLinesRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromInt(0) length:CPTDecimalFromInt(dataContent.count-1)];
y.minorTicksPerInterval = 1;
y.minorTickLength = 2.0f;
y.orthogonalCoordinateDecimal = CPTDecimalFromString(@"0");
// Create plot area
CPTScatterPlot *boundLinePlot = [[CPTScatterPlot alloc] init];
CPTMutableLineStyle *lineStyle = [CPTMutableLineStyle lineStyle];
lineStyle.miterLimit = 1.0f;
lineStyle.lineWidth = 2.0f;
lineStyle.lineColor = [CPTColor blueColor];
boundLinePlot.dataLineStyle = lineStyle;
boundLinePlot.dataSource = self;
[graph addPlot:boundLinePlot];
[boundLinePlot reloadData];
}