Animate Bar Plot

Question

我正在试图制作条形图，这是我到目前为止所做的：

CGContextBeginPath(context);
        for (int i=0; i<[data count]; ++i) {
            CGContextMoveToPoint(context,kOffsetX+i*kStepX, kGraphHeight-kOffsetY);
            CGContextAddLineToPoint(context, kOffsetX+i*kStepX, (kGraphHeight-kOffsetY)-(kGraphHeight-kOffsetY-kGraphTop)*([[data objectAtIndex:i]floatValue]/maxDataPoint));
        }
        CAShapeLayer *pathLayer = [CAShapeLayer layer];
        pathLayer.path=CGContextCopyPath(context);
        [self.layer addSublayer:pathLayer];
        CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
        pathAnimation.duration = 0.5;
        pathAnimation.fromValue = @0;
        pathAnimation.toValue = @1;
        [pathLayer addAnimation:pathAnimation forKey:@"strokeEnd"];

由于路径是从左到右的条形，＆＃34; strokeEnd＆＃34; -Animation从左到右动画，但我想要一个从下到上的动画，所以条形图上升。我是否需要更改动画的键或其他方式来绘制路径？

谢谢！