Renko Acceleration

//@version=4
// Renko Acceleration
//
//   Renko is a very useful charting method for analyzing stock movement.  
//   It does a great job of filtering out all the excess noise so that all we're
//   left with is pure price action. But, what about time? Time is a fundamental
//   part of chart analysis and without it we're only seeing part of the 
//   picture. After all, shouldn't we take a very different approach to trading
//   signals from a block that renders in 2 seconds as opposed to a block that
//   renders in 30 minutes?
//
//   This indicator provides the best of both worlds, enabling us to correlate 
//   the passing of time with price movement and see clearly when squeezes and
//   breakouts occur. 
//
//   As the indicator turns up to green we can see that volatility is on the 
//   move and the market is accelerating (breakout), and as it turns down to red 
//   the market is stagnating (squeeze). There is also an alternate 'Precise' 
//   view which renders the exact time per block for more granular analysis.
//
study("Renko Acceleration", overlay=false)

// Allow selection of signal content.
IncludeFilter = input(true, 'Include Filter')

mode = input("Momentum", "Display Mode", options=["Momentum", "Precise"])
smoothing = input(10, "Smoothing", input.integer, minval=0)

float duration = (time-time[1]) / (1000*60) // block time in seconds
float accel = na
color accelColor = na
         
if mode == "Momentum"
    bline = sma(duration, 100) * 1.25
    accel := max(bline-duration, -20) // trim negative outliers
    accel := smoothing ? sma(accel, smoothing) : accel
    accelColor := accel > 15 ? color.lime : 
         accel > 5 ? color.green : 
         accel > 0 ? color.olive : 
         accel > -5 ? color.yellow : 
         accel > -10 ? color.orange : color.red

if mode == "Precise"
    accel := duration
    accelColor := duration > 30 ? color.red : 
         duration > 15 ? color.orange : 
         duration > 5 ? color.yellow : color.silver
     
plot(accel, "Time", style=plot.style_histogram, color=accelColor)

// ————— Filter.
FilterLong = accel > 0
FilterShort = accel > 0

// ————— Build required values corresponding to states.
Filter = FilterLong ? 0.001 : FilterShort ? 0.001 : 0

// ————— We must decide which value will be sent in case more than one is different than 0, since only one value can be sent at each bar.
// Priority is given to exits, with filter states coming last.
Signal = IncludeFilter and Filter != -0.001 ? Filter : na
// ————— Plot signal which is to be connected to the Engine through the External Indicator field at the very bottom of the Engine's Settings/Inputs.
plot(Signal, 'Signal')