CorePlot：majorTickLocations（graph）和setYRange（plot space）有什么区别？ [英] CorePlot: what is the difference between majorTickLocations (graph) and setYRange (plot space)?

问题描述

我想在图表中创建 3个色带，但我认为我做错了什么。 y的值应该在 0到1024 的范围内，我想要第一个颜色带从0到300，第二个从300到600，第三个从600到1024.但是，代码我写的创建了6个乐队而不是3个，它似乎忽略了1024个限制。下面是结果图和我使用的代码：

图：

它应该只有3个乐队，再加上它似乎忽略了我在绘图空间中设置1024的范围。但是我不确定主要的地点的含义和用法。我开始认为与剧情空间范围没有直接关系。

代码：

  self。 graph = [[CPTXYGraph alloc] initWithFrame：self.graphHostView.bounds]; 
 self.graphHostView.hostedGraph = self.graph; 
 
 CPTMutableTextStyle * titleStyle = [CPTMutableTextStyle textStyle]; 
 titleStyle.color = [CPTColor blackColor]; 
 titleStyle.fontName = @Helvetica; 
 titleStyle.fontSize = 12.0f; 
 
 //轴
 //用固定间隔策略标记x轴
 CPTXYAxisSet * axisSet =（CPTXYAxisSet *）self.graph.axisSet; 
 CPTXYAxis * x = axisSet.xAxis; 
 x.separateLayers = NO; 
 x.minorTicksPerInterval = 4; 
 x.minorTickLength = 8.0; 
 x.title = @X Axis; 
 x.titleTextStyle = titleStyle; 
 x.delegate = self; 
 
 CPTXYAxis * y = axisSet.yAxis; 
 y.labelingPolicy = CPTAxisLabelingPolicyAutomatic; 
 y.separateLayers = YES; 
 y.majorTickLocations = [NSSet setWithObjects：
 [NSDecimalNumber numberWithDouble：0]，
 [NSDecimalNumber numberWithDouble：300]，
 [NSDecimalNumber numberWithDouble：600]，
 [ NSDecimalNumber numberWithDouble：1024]，
 nil]; 
 y.title = @Y轴; 
 y.titleTextStyle = titleStyle; 
 $ b $ y.alternatingBandFills = [NSArray arrayWithObjects：[CPTColor whiteColor]，
 [[CPTColor greenColor] colorWithAlphaComponent：CPTFloat（0.3）]，
 [[CPTColor redColor] colorWithAlphaComponent：CPTFloat （0.3）]，
无]; 
 
 y.delegate = self; 
 
 //将y2轴添加到轴设置
 self.graph.axisSet.axes = @ [x，y]; 
 
 self.graph.title = @My graph; 
 self.graph.titleDisplacement = CGPointMake（0.0f，-68.0f）; 
 self.graph.titleTextStyle = titleStyle; 
 
 CPTMutableLineStyle * axisLineStyle = [CPTMutableLineStyle lineStyle]; 
 axisLineStyle.lineWidth = 2.0f; 
 axisLineStyle.lineColor = [[CPTColor blackColor] colorWithAlphaComponent：1]; 
 
 
 //从图表中获取（默认）图形空间，以便我们可以设置其x / y范围
 CPTXYPlotSpace * plotSpace =（CPTXYPlotSpace *）self.graph.defaultPlotSpace; 
 
 //请注意，这些CPTPlotRange由START和LENGTH（而不是START和END）定义！ 
 
 [plotSpace setYRange：[CPTPlotRange plotRangeWithLocation：[NSNumber numberWithInt：0] length：[NSNumber numberWithInt：1024]]]; 
 [plotSpace setXRange：[CPTPlotRange plotRangeWithLocation：[NSNumber numberWithInt：0] length：[NSNumber numberWithInt：100]]]; 
 
 //创建图（我们没有定义实际的x / y值，这些将由数据源提供...）
 self.plot = [[CPTScatterPlot alloc] initWithFrame ：CGRectZero]; 
 
 //让我们保持简单并让这个类作为数据源（因此我们实现< CPTPlotDataSource>）
 self.plot.dataSource = self; 
 
 //最后，将创建的图添加到我们在
之前创建的CPTGraph对象的默认绘图空间[self.graph addPlot：self.plot toPlotSpace：self.graph.defaultPlotSpace]; 
  

解决方案

尝试设置此政策：

  y.labelingPolicy = CPTAxisLabelingPolicyNone; 
  

I would like to create 3 colour bands in my graph but I think I am doing something wrong. The y values should range from 0 to 1024 and I would like to have a first colour band from 0 to 300, a second one from 300 to 600 and a third one from 600 to 1024. However the code I wrote creates 6 bands instead of 3 and it seems to ignore the 1024 limit. Here is the resulting graph and the code I used:

Graph:

It should have only 3 bands, plus it seems to ignore the fact that I set a range of 1024 in the plot space. However I am unsure on the meaning and usage of majorTickLocations. I am starting to think that there is no direct correlation with the plot space range.

Code:

self.graph = [[CPTXYGraph alloc] initWithFrame:self.graphHostView.bounds];
self.graphHostView.hostedGraph = self.graph;

CPTMutableTextStyle *titleStyle = [CPTMutableTextStyle textStyle];
titleStyle.color = [CPTColor blackColor];
titleStyle.fontName = @"Helvetica";
titleStyle.fontSize = 12.0f;

// Axes
// Label x axis with a fixed interval policy
CPTXYAxisSet *axisSet = (CPTXYAxisSet *)self.graph.axisSet;
CPTXYAxis *x          = axisSet.xAxis;
x.separateLayers              = NO;
x.minorTicksPerInterval       = 4;
x.minorTickLength             = 8.0;
x.title                       = @"X Axis";
x.titleTextStyle              = titleStyle;
x.delegate                    = self;

CPTXYAxis *y = axisSet.yAxis;
y.labelingPolicy        = CPTAxisLabelingPolicyAutomatic;
y.separateLayers        = YES;
y.majorTickLocations = [NSSet setWithObjects:
                        [NSDecimalNumber numberWithDouble:0],
                        [NSDecimalNumber numberWithDouble:300],
                        [NSDecimalNumber numberWithDouble:600],
                        [NSDecimalNumber numberWithDouble:1024],
                        nil];
y.title                 = @"Y Axis";
y.titleTextStyle        = titleStyle;

y.alternatingBandFills = [NSArray arrayWithObjects: [CPTColor whiteColor],
            [[CPTColor greenColor] colorWithAlphaComponent:CPTFloat(0.3)],
            [[CPTColor redColor] colorWithAlphaComponent:CPTFloat(0.3)],
            nil];

y.delegate              = self;

// Add the y2 axis to the axis set
self.graph.axisSet.axes = @[x, y];

self.graph.title = @"My graph";
self.graph.titleDisplacement = CGPointMake(0.0f, -68.0f);
self.graph.titleTextStyle = titleStyle;

CPTMutableLineStyle *axisLineStyle = [CPTMutableLineStyle lineStyle];
axisLineStyle.lineWidth = 2.0f;
axisLineStyle.lineColor = [[CPTColor blackColor] colorWithAlphaComponent:1];


// Get the (default) plotspace from the graph so we can set its x/y ranges
CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *) self.graph.defaultPlotSpace;

// Note that these CPTPlotRange are defined by START and LENGTH (not START and END) !!

[plotSpace setYRange: [CPTPlotRange plotRangeWithLocation:[NSNumber numberWithInt:0] length:[NSNumber numberWithInt:1024]]];
[plotSpace setXRange: [CPTPlotRange plotRangeWithLocation:[NSNumber numberWithInt:0] length:[NSNumber numberWithInt:100]]];

// Create the plot (we do not define actual x/y values yet, these will be supplied by the datasource...)
self.plot = [[CPTScatterPlot alloc] initWithFrame:CGRectZero];

// Let's keep it simple and let this class act as datasource (therefore we implemtn <CPTPlotDataSource>)
self.plot.dataSource = self;

// Finally, add the created plot to the default plot space of the CPTGraph object we created before
[self.graph addPlot:self.plot toPlotSpace:self.graph.defaultPlotSpace];

解决方案

Try to set this policy:

y.labelingPolicy = CPTAxisLabelingPolicyNone;

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