In my story, 孔琳's behavior has changed from ultra-depressed to ultra-optimistic in a matter of moments (she has an unstable personality). Her friends (陈叶 and 胡灵阳) are staring at her in amazement, and I want to write...
I want to describe this change using a chengyu, but the closest I found was 以耳代目 and 以耳为目 which are variants. It's not bad (it means something like "substitute ears for eyes"), but I don't think it works grammatically above. I'm also unsure that the context works here; perhaps it refers to blind people.
Question: How do I use a chengyu (idiom) to describe a "one extreme to the other" kind of transformation?
English derived from above Chinese; only to be used "in case of emergency" (i.e., if the Chinese is incomprehensible):
Now Chen Ye and Hu Lingyang [are] standing, surprisedly staring [at] Kong Lin's from-one-extreme-to-the-other change.