如何将视图控制器上的核心绘图中心？

Question

我正在研究核心情节。我想让屏幕上绘制的图形需要居中。当应用程序从底部显示图表时加载它。我想让整个视图从中心可见，如下图所示。

@Thanks预先

Answer 1

//只需设置XRANGE和YRange与初始偏移：

CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)graph.defaultPlotSpace; 

/* Range which is visible on screen */ 

plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(offset) 
               length:CPTDecimalFromFloat(X_LENGTH)]; 
plotSpace.yRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(offset_Y) 
               length:CPTDecimalFromFloat(Y_LENGTH)]; 


/* Total Range which is visible on screen and can be scrolled up to */ 

CPTPlotRange *globalYRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromDouble(0) length:CPTDecimalFromDouble(Y_LENGTH)]; 
plotSpace.globalYRange = globalYRange; 

CPTPlotRange *globalXRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromDouble(0) length:CPTDecimalFromDouble(xRange)]; 
plotSpace.globalXRange = globalXRange; 

/*要约束X和Y轴*/

CPTXYAxisSet *axisSet = (CPTXYAxisSet *)graph.axisSet; 
axisSet.xAxis.axisConstraints = [CPTConstraints constraintWithLowerOffset:55.0]; 
axisSet.yAxis.axisConstraints = [CPTConstraints constraintWithLowerOffset:0.0];