这个函数可能是你的答案:
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它的图表(对于 scaleMax = 3,xFactor = 1):
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此函数直接用于根据轮播偏移量计算比例因子。此外,您需要将元素向左和向右移动,以免重叠(就像您已经做过的那样)。这可以通过按函数的积分移动项目来完成,这很有效,但是这样中心的差距很大。或者可以通过对所有缩放项目求和来手动计算。间隙可以保持不变,也可以单独缩放。
请注意,中心的比例等于 1,边缘下降到 1/scale_max。这是因为按比例缩小不会产生不良的像素化效果。使您的项目视图显示在中心,边缘的视图将按比例缩小。
这可能是用法:
-(CGFloat) scaleForX:(CGFloat)x xFactor:(CGFloat)xFactor centerScale:(CGFloat)centerScale
{
return (1+1/(sqrtf(x*x*x*x*xFactor*xFactor*xFactor*xFactor+1))*(centerScale-1.0))/centerScale;
}
- (CATransform3D)carousel:(iCarousel *)carousel itemTransformForOffset:(CGFloat)offset baseTransform:(CATransform3D)transform
{
//items in the center are scaled by this factor
const CGFloat centerScale = 4.0f;
//the larger the xFactor, the smaller the magnified area
const CGFloat xFactor = 1.5f;
//should the gap also be scaled? or keep it constant.
const BOOL scaleGap = NO;
const CGFloat spacing = [self carousel:carousel valueForOption:iCarouselOptionSpacing withDefault:1.025];
const CGFloat gap = scaleGap?0.0:spacing-1.0;
//counting x offset to keep a constant gap
CGFloat scaleOffset = 0.0;
float x = fabs(offset);
for(;x >= 0.0; x-=1.0)
{
scaleOffset+=[self scaleForX:x xFactor:xFactor centerScale:centerScale];
scaleOffset+= ((x>=1.0)?gap:x*gap);
}
scaleOffset -= [self scaleForX:offset xFactor:xFactor centerScale:centerScale]/2.0;
scaleOffset += (x+0.5)*[self scaleForX:(x+(x>-0.5?0.0:1.0)) xFactor:xFactor centerScale:centerScale];
scaleOffset *= offset<0.0?-1.0:1.0;
scaleOffset *= scaleGap?spacing:1.0;
CGFloat scale = [self scaleForX:offset xFactor:xFactor centerScale:centerScale];
transform = CATransform3DTranslate(transform, scaleOffset*carousel.itemWidth, 0.0, 0.0);
transform = CATransform3DScale(transform, scale, scale, 1.0);
return transform;
}
结果:
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您可以尝试更改不同行为的常量。同样将指数更改为另一个偶数可以进一步扩大峰值并将下降幅度锐化到最小范围。