如何实现放大和缩小与核阴谋线图在iPhone上?

StackOverflow https://stackoverflow.com/questions/2264535

  •  20-09-2019
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题

它是可以实施缩小和缩小与核绘图组在iPhone上?如果可以请给我建议如何做到这一点？

在此先感谢。

有帮助吗？

解决方案

是，就我这样做是通过调整像这样的PlotSpace（可能不是最好的解决办法，但最好的我能想出）：

-(void)zoomOut 
{
    CPXYPlotSpace *plotSpace = (CPXYPlotSpace *)graph.defaultPlotSpace;

    graphScaleX+=5;
    graphScaleY+=5;

    plotSpace.xRange = [CPPlotRange plotRangeWithLocation:plotSpace.xRange.location length:CPDecimalFromFloat(graphScaleX)];
    plotSpace.yRange = [CPPlotRange plotRangeWithLocation:plotSpace.yRange.location length:CPDecimalFromFloat(graphScaleY)];
}

-(void)zoomIn
{
    CPXYPlotSpace *plotSpace = (CPXYPlotSpace *)graph.defaultPlotSpace;

    graphScaleX-=5;
    graphScaleY-=5;

    plotSpace.xRange = [CPPlotRange plotRangeWithLocation:plotSpace.xRange.location length:CPDecimalFromFloat(graphScaleX)];
    plotSpace.yRange = [CPPlotRange plotRangeWithLocation:plotSpace.yRange.location length:CPDecimalFromFloat(graphScaleY)];
}

其他提示

可以设置plotSpace委托符合CPTPlotSpaceDelegate协议（例如自我）[plotSpace setDelegate:self];一些类的实例。

配置plotSpace因此它可以与用户交互[plotSpace setAllowsUserInteraction:YES];

和然后在类实现此方法-(BOOL)plotSpace:(CPTPlotSpace *)space shouldScaleBy:(CGFloat)interactionScale aboutPoint:(CGPoint)interactionPoint。如果你想corePlot自动调整你的图表返回YES。或否，这样做在前面的回答。

请注意：如果你希望你的电流控制器类（个体经营）是一个代表，要确保你的界面看起来像这样@interface CurrentController : UISomeController<...,CPTPlotSpaceDelegate>{}。所以，现在它符合CPTPlotSpaceDelegate协议。

使用默认的用户相互作用是不够的，我因为：

  1. 它的尺度这两个X和Y轴同时，我仅想的规模 X轴
  2. 锅不能让你过去零和它的跳跃， 基本上不工作，正确的。

我的解决方案是做我自己

我加入2UIGestureRecognizer泛，放大 

    UIPanGestureRecognizer* pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panChart:)];
    [pan setMinimumNumberOfTouches:1];
    [pan setMaximumNumberOfTouches:1];
    [self.view addGestureRecognizer:pan];

    UIPinchGestureRecognizer* scale = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scaleChart:)];
    [self.view addGestureRecognizer:scale];

然后我实现的码做什么，我需要

泛的图表

- (void)panChart:(UIPinchGestureRecognizer *)gestureRecognizer {
    CPTGraph *theGraph = [graphs objectAtIndex:0];
    CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)theGraph.defaultPlotSpace;

    CGPoint point = [gestureRecognizer  locationInView:self.view];

    if([(UIPanGestureRecognizer*)gestureRecognizer state] == UIGestureRecognizerStateBegan) {

        firstX = point.x;
        firstY = point.y;
        originX = chartBounds.origin.x;
        originY = chartBounds.origin.y;
        //NSLog(@"first (%f,%f)", firstX, firstY);
    }
    CGRect frame = theGraph.frame;

    float xMove =  ((firstX-point.x)/(frame.size.width/chartBounds.size.width));
    float yMove = ((firstY-point.y)/(frame.size.height/chartBounds.size.height));
    if(firstX-point.x == 0){
        xMove = 0;
    }
    if(firstY-point.y == 0){
        yMove = 0;
    }
    //NSLog(@"frame: (%f, %f)",frame.size.width, frame.size.height);
    //NSLog(@"touch (%f,%f)",firstX-point.x,firstY-point.y);
    //NSLog(@"move (%f,%f)",xMove,yMove);

    chartBounds.origin.x = originX+xMove;
    chartBounds.origin.y = originY-yMove;

    plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(chartBounds.origin.x) length:CPTDecimalFromFloat(chartBounds.size.width)];
    plotSpace.yRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(chartBounds.origin.y) length:CPTDecimalFromFloat(chartBounds.size.height)];
}

规模的图表

- (void)scaleChart:(UIPinchGestureRecognizer *)gestureRecognizer {

if (kMaxDataPoints < kDataPointsHistory) {

    if ([gestureRecognizer scale] < 1) {
        if(kMaxDataPoints/10 < 1){
            kMaxDataPoints += 1;
        }else{
           kMaxDataPoints += kMaxDataPoints/10; 
        }
    }
}

if (kMaxDataPoints > 5) {
    if ([gestureRecognizer scale] > 1){
        if(kMaxDataPoints/10 < 1){
            kMaxDataPoints -= 1;
        }else{
            kMaxDataPoints -= kMaxDataPoints/10; 
        }
    }
}

if(kMaxDataPoints <= 5){
    kMaxDataPoints = 5;
}
if(kMaxDataPoints > kDataPointsHistory){
    kMaxDataPoints = kDataPointsHistory;
}

chartBounds.size.width = kMaxDataPoints;
CPTGraph *theGraph = [graphs objectAtIndex:0];
CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)theGraph.defaultPlotSpace;

plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(chartBounds.origin.x) length:CPTDecimalFromFloat(chartBounds.size.width)];

//Need to calculate if its horizontal or vertical pinch gesture (not doing that yet :) )
//plotSpace.yRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(chartBounds.origin.y) length:CPTDecimalFromFloat(chartBounds.size.height)];
}

要只缩放x轴只迫使新y规模是旧的代表：

-(BOOL)plotSpace:(CPTPlotSpace *)space shouldScaleBy:(CGFloat)interactionScale aboutPoint:(CGPoint)interactionPoint;
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