iphone - coreplot :Converted coordinates, 有问题。 [plotSpaceplotPoint:plotPoint forPlotAreaViewPoint:point];

Question

我想将接触到的点转换为 CPTXYPlotSpace 点。但是我发现有与真实坐标的偏移。 我发现，它从边界计算了x轴的一部分。 我想要将点映射到 x&y 轴的值。

我的英语很差...... 我想知道哪里错了？请告诉我。

这是代码。

-(BOOL)plotSpace:(CPTPlotSpace *)space shouldHandlePointingDeviceDownEvent:(id)event atPoint:(CGPoint)point
{    NSDecimal plotPoint[2]; 
    CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)graph.defaultPlotSpace;
    [plotSpace plotPoint:plotPoint forPlotAreaViewPoint:point]; 


   //HERE HAVE SOME OFFSET. I FIND ,it Calculated part of the x-axis from the border
    NSLog(@"touch plotPoint = %d, %f", 
    [[NSDecimalNumber decimalNumberWithDecimal:plotPoint[CPTCoordinateX]] intValue],
    [[NSDecimalNumber decimalNumberWithDecimal:plotPoint[CPTCoordinateY]] doubleValue]);
    return YES;
}

Answer 1

先将点转换到绘图区域的坐标系:

CGPoint plotAreaPoint = [graph convertPoint:point toLayer:graph.plotAreaFrame.plotArea];
[plotSpace plotPoint:plotPoint forPlotAreaViewPoint:plotAreaPoint];