Understanding plot() and hline() Fill Functions in Pine Script

In Pine Script, the fill() function is essential for creating shaded areas between two plots or horizontal lines. It adds a visual component to your script, aiding in data interpretation. Here, we’ll explore its usage in conjunction with plot() and hline() functions.

Using fill() with plot()

Example 1: Shading between Sine and Cosine Waves

//@version=5
indicator("Example 1")
sinHigh = plot(math.sin(high))
cosLow = plot(math.cos(low))
sinClose = plot(math.sin(close))
fill(sinHigh, sinClose, color.new(color.red, 90))
fill(cosLow, sinClose, color.new(color.blue, 90))

In this snippet:

• sinHigh, cosLow, and sinClose store IDs returned by plot().
• fill() creates shaded areas between these plots.
• We use sine and cosine functions for dynamic visualization.

Key Points:

• fill() requires IDs from plot() to create fills.
• Math functions enhance visual representation.

Using fill() with hline()

Example 2: Shading between Horizontal Lines

//@version=5
indicator("Example 2")
horizLine1 = hline(0)
horizLine2 = hline(1.0)
horizLine3 = hline(0.5)
horizLine4 = hline(1.5)
fill(horizLine1, horizLine2, color.new(color.yellow, 90))
fill(horizLine3, horizLine4, color.new(color.lime, 90))

Here:

• horizLine1 to horizLine4 are horizontal lines at different levels.
• Shaded areas are created between these lines.

Key Points:

• hline() creates horizontal reference lines.
• Fills can visually distinguish different zones.

Combining plot() and hline()

Example 3: Shading between Plot and Zero Line

//@version=5
indicator("Example 2")
src = close
ma = ta.sma(src, 10)
osc = 100 * (ma - src) / ma
oscPlotID = plot(osc)
zeroPlotID = plot(0, "Zero", color.silver, 1, plot.style_circles)
fill(oscPlotID, zeroPlotID, color.new(color.blue, 90))

In this example:

• We plot an oscillator and a zero line.
• Shading helps identify when the oscillator is above or below zero.

Key Points:

• Use plot() for dynamic lines like oscillators.
• hline() is replaced with plot() to enable fill.

Dynamic Color Shading

Example 4: Color Shading Based on Conditions

//@version=5
indicator("Example 3", "", true)
line1 = ta.sma(close, 5)
line2 = ta.sma(close, 20)
p1PlotID = plot(line1)
p2PlotID = plot(line2)
fill(p1PlotID, p2PlotID, line1 > line2 ? color.new(color.green, 90) : color.new(color.red, 90))

Here:

• Shading color changes based on the condition (line1 > line2).
• It’s a dynamic way to visualize crossovers of moving averages.

Key Points:

• Conditional colors add depth to analysis.
• Useful for highlighting trends or crossovers.

Conclusion and Takeaways

• fill() is versatile for shading between plots or lines in Pine Script.
• It accepts IDs from plot() and hline().
• Color and opacity can be dynamic, enhancing visual analysis.