Add_Trace issue in Plotly - r

Question

How can I increase the length of the green (lcl) and red line (lsl) so that they extend to the end of the plot (rather than stopping halfway) in the add_trace function?
Here is my code for my graph:
output$p <- renderPlotly({
plot1 %>%
add_trace(y = lcl(),type = "scatter", mode = "lines", line = list(color = 'lightgreen', width = 2, dash = 'solid'), inherit = FALSE, name = paste("LCL =", lcl()[1])) %>%
add_trace(y = lsl(),type = "scatter", mode = "lines", line = list(color = 'red', width = 2, dash = 'solid'), inherit = FALSE, name = paste("LSL =", lsl()[1])) %>%
%>%
layout(
title = paste(" cell culture", input$select),
yaxis = list( showline = TRUE,
mirror = "ticks",
linecolor = toRGB("grey"),
linewidth = 1.85
),
xaxis = list( showline = TRUE,
mirror = "ticks",
linecolor = toRGB("grey"),
linewidth = 1.85,
tickangle=70))
})
edit: i got rid of the code for the actual plot (the scatter plot) for simplicity, that graph is fine and does not need any tweaking.

Answer 1

Instead of using add_trace for creating horiontal lines that span the entire graph I would add horizontal lines as a shapes to the layout:
layout(shapes = list(
list(
type = "line",
x0 = 0,
x1 = 1,
xref = "paper",
y0 = 75,
y1 = 75,
line = list(color = 'lightgreen', width = 2)
),
list(
type = "line",
x0 = 0,
x1 = 1,
xref = "paper",
y0 = 100,
y1 = 100,
line = list(color = 'red', width = 2)
)
))
xref = "paper" is used so the line spans the entire graph.
Positioning in paper coordinates is not done in absolute pixel terms, but rather in terms relative to a coordinate system defined with an origin (0,0) at (layout.margin.l, layout.margin.b) and a point (1,1) at (layout.width-layout.margin.r, layout.height-layout.margin.t)...
https://plotly.com/python/figure-structure/#positioning-with-paper-container-coordinates-or-axis-domain-coordinates
Change the y values according to your requirements.