Question

我在这个问题上被困了一段时间。我想做的是获得图形来自-(BOOL)plotSpace:(CPTPlotSpace *)space shouldHandlePointingDeviceDownEvent:(id)event atPoint:(CGPoint)point事件的数据。我不希望该用户只能使用plotSymbol触及-(void)scatterPlot:(CPTScatterPlot *)plot plotSymbolWasSelectedAtRecordIndex:(NSUInteger)index。所以我想要做的就是触摸我Scatter Plot上的任何地方，例如在绘制线上方，触摸我在触摸点触摸事件下方的线，然后在屏幕上绘制该点。我已经看到了这个：Using core-plot, how can you convert a touched point to the plot space?但是没有用。

修改这是plotSymbol touch。我想触摸图表上的任何位置并在图表上显示点。我不想触摸情节符号只是为了显示我的价值。我希望能够在图形上的绘制线的上方或下方触摸它，它应该能够识别出我的CGPoint)point有一个绘图符号。

-(void)scatterPlot:(CPTScatterPlot *)plot plotSymbolWasSelectedAtRecordIndex:(NSUInteger)index{

CPTXYGraph *graph = (self.graphs)[0];

if ( symbolTextAnnotation ) {
    [graph.plotAreaFrame.plotArea removeAnnotation:symbolTextAnnotation];
    symbolTextAnnotation = nil;
}

// Setup a style for the annotation
CPTMutableTextStyle *hitAnnotationTextStyle = [CPTMutableTextStyle textStyle];
hitAnnotationTextStyle.color    = [CPTColor whiteColor];
hitAnnotationTextStyle.fontSize = 16.0;
hitAnnotationTextStyle.fontName = @"Helvetica-Bold";

// Determine point of symbol in plot coordinates
NSDictionary *dataPoint = plotData[index];

NSNumber *x = dataPoint[@(CPTScatterPlotFieldX)];
NSNumber *y = dataPoint[@(CPTScatterPlotFieldY)];

NSArray *anchorPoint = @[x, y];

// Add annotation
// First make a string for the y value
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
[formatter setMaximumFractionDigits:2];
NSString *yString = [formatter stringFromNumber:y];

// Now add the annotation to the plot area
CPTTextLayer *textLayer = [[CPTTextLayer alloc] initWithText:yString style:hitAnnotationTextStyle] ;


CPTImage *background = [CPTImage imageForPNGFile:@"check"];
textLayer.fill          = [CPTFill fillWithImage:background];
textLayer.paddingLeft   = 2.0;
textLayer.paddingTop    = 2.0;
textLayer.paddingRight  = 2.0;
textLayer.paddingBottom = 2.0;

symbolTextAnnotation                    = [[CPTPlotSpaceAnnotation alloc] initWithPlotSpace:graph.defaultPlotSpace anchorPlotPoint:anchorPoint];
symbolTextAnnotation.contentLayer       = textLayer;
symbolTextAnnotation.contentAnchorPoint = CGPointMake(0.5, 0.0);
symbolTextAnnotation.displacement       = CGPointMake(0.0, 10.0);
[graph.plotAreaFrame.plotArea addAnnotation:symbolTextAnnotation];
}

Answer 1

在绘图空间委托中，使用绘图上的-dataIndexFromInteractionPoint:方法查找到触摸点的最近数据点的索引。获得数据索引后，使用已有的代码创建并显示注释。

Core Plot iOS从CPTPlotSpace点的数据获取点

1 个答案: