问题描述
Quartz中 CGContextSetInterpolationQuality 方法的效果如何？
How effective is the CGContextSetInterpolationQuality method in Quartz?
它是否会影响图像的质量？如果是这样，到什么程度？
Does it affect the quality of the image? If so, to what extent?
我看不出内插图像和非内插图像之间的任何差异。
I can't see any difference between the interpolated and the non-interpolated image.
推荐答案
虽然这是一个老问题，但我最近做了一些关于 CGContextSetInterpolationQuality 的影响的基准测试它的结果可能是其他人感兴趣的。
Although this is a bit of an old question, I have recently done some benchmarking about the effects of CGContextSetInterpolationQuality and thought that its outcomes might be of interest to someone else.
在我的基准测试中，我绘制了一组6个不同的649x649 b& w位图图像来构建一组12不同的拼图瓷砖。位图图像按比例缩小5.0倍（即129.8x129.8），使其适合320x480显示器（视网膜显示比例）。
In my benchmark test, I draw a set of 6 different 649x649 b&w bitmap images to build a set of 12 different jigsaw puzzle tiles. The bitmap images are scaled down by a factor of 5.0 (i.e., to 129.8x129.8) to make them fit on a 320x480 display (at retina display scale).
据Instruments报道，第四代iPod touch的运行时间如下：
Run times on a 4th gen iPod touch, as reported by Instruments, are the following:
-
kCGInterpolationLow：969 msec
kCGInterpolationLow: 969 msec
kCGInterpolationMedium：1690毫秒
kCGInterpolationMedium: 1690 msec
kCGInterpolationHigh：2694毫秒
kCGInterpolationHigh: 2694 msec
kCGInterpolationNone：545毫秒
kCGInterpolationNone: 545 msec
至于视觉结果，如果你比较高或中等到低或无，差异是惊人的。甚至引人注目的IMO，None和Low之间的区别;而在这个特定的测试中，高和中之间的差异并不是特别明显。很清楚的是运行时间的差异，所以在我的特定情况下，我最终使用 kCGInterpolationMedium 。
As to the visual outcome, if you compare High or Medium to Low or None, the difference is staggering. Even noticeable, IMO, the difference between None and Low; while the difference between High and Medium is not particularly noticeable in this particular test. What is clear is the difference in run times, so that in my particular case, I ended up using kCGInterpolationMedium.
kCGInterpolationNone
kCGInterpolationLow
kCGInterpolationMedium
kCGInterpolationHigh
这篇关于使用CGContextSetInterpolationQuality的ImageQuality的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！