Generally HH and HL shows up-trend, LL and LH shows down-trend.
If price breaks resistance levels it means the trend is up or if price breaks support level it means the trend is down, so the script changes bar color blue or black. if there is up-trend then bar color is blue, or if down-trend then bar color is black. also as you can see support and resistance levels change dynamically.
If you use smaller numbers for left/right bars then it will be more sensitive.
source code of :
added color options
fix: right bar is used instead of left bar for the labels/lines (Thanks to @hankoman for the feedback)
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.