Core Plot X轴图像在设备中显示不正确

Question

我正在ios app中实现核心情节。我在X轴上使用图像。要在X轴上实现图像，我使用以下代码

    UIImage *image = [UIImage imageNamed:@"tick_16.png"];
    CPTImage *background = [CPTImage imageWithCGImage:image.CGImage];
    CPTBorderedLayer *imageLayer = [[CPTBorderedLayer alloc] initWithFrame:CGRectMake(0, 0, 16, 16)];
    imageLayer.fill = [CPTFill fillWithImage:background];
    CPTAxisLabel *iconLabel = [[CPTAxisLabel alloc] initWithContentLayer:imageLayer];
    iconLabel.offset = 8;
    iconLabel.tickLocation = CPTDecimalFromCGFloat(location+0.5);        

    if (iconLabel) {
        [xLabels2 addObject:iconLabel];
        [xLocations2 addObject:[NSNumber numberWithFloat:location]];
    }

并设置“x3.axisLabels = xLabels2;”

在模拟器中运行这些代码时，它工作正常，图像如下所示 但是当在真实设备中运行时，它看起来像下面

图像未在真实设备中完全显示...