Question

我正在使用核心图并需要反转x轴，使其从5000开始，到0结束。我怎么能这样做？

这是我的x轴范围，

plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(0.0) length:CPTDecimalFromFloat(500)]

Answer 1

Plot Gallery应用程序（Plot Space Demo）中有一个例子。如果查看PlotSpaceDemo.m中的相应代码，则负轴设置如下：

...

CPTXYPlotSpace *negativeLinearPlotSpace = [[[CPTXYPlotSpace alloc] init] autorelease];
negativeLinearPlotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromUnsignedInteger(100) length:CPTDecimalFromInteger(-100)];
negativeLinearPlotSpace.yRange = linearPlotSpace.yRange;

[graph removePlotSpace:graph.defaultPlotSpace];
[graph addPlotSpace:negativeLinearPlotSpace];

CPTXYAxis *negativeLinearAxis = [[[CPTXYAxis alloc] init] autorelease];
negativeLinearAxis.plotSpace                   = negativeLinearPlotSpace;
//The rest of the set up is just formatting labels, ticks, etc.
...

因此，对于您的情况，您要声明5000的位置和-5000的长度，如下所示：

negativeLinearPlotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromUnsignedInteger(5000) length:CPTDecimalFromInteger(-5000)];
//Add plot space to the graph
//assign plot space to the x axis

希望有所帮助！

Answer 2

尝试使用以下代码

plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromDouble(0.0)
                                                length:CPTDecimalFromDouble(5000)]; // Or set it -5000

如何反转x轴？

2 个答案: