What Causes This Error?
The error in .call.graphics(c_palette2, .call(c_palette2, null)) : invalid graphics state is commonly encountered in the R programming environment, specifically while dealing with graphical functions. This issue arises due to improper handling of the graphics state when calling plotting functions. Typically, it occurs when the graphics device is either closed or improperly initialized before executing a graphical operation.
Common Scenarios Leading to the Error
Several factors can trigger this error, including:
Closed or Uninitialized Graphics Device
If the graphics device has been closed or has not been properly initialized before calling a plotting function, R will fail to execute the command.
Corrupt Graphics Parameters
Corrupt or improperly defined graphical parameters within c_palette2 can result in an invalid graphics state, leading to this error message.
Issues with Graphical Packages
Certain graphical libraries or packages may interfere with the graphics system, causing unexpected behavior and triggering this error.
Nested Function Calls
In some cases, nested function calls such as .call.graphics() might not be executed correctly due to improper state management within the R environment.

How to Fix the Error?
To resolve the error in .call.graphics(c_palette2, .call(c_palette2, null)) : invalid graphics state, follow these solutions:
Check If a Graphics Device Is Active
Before executing any plotting function, ensure that a graphics device is active by running:
if (dev.cur() == 1) dev.new()
This command checks if a graphics device is open and, if not, initializes a new one.
Reset Graphical Parameters
Resetting graphical parameters can help resolve any corrupted settings:
par(mfrow = c(1,1))
This ensures that the plotting layout is properly configured.
Reinstall and Load Necessary Packages
Sometimes, package conflicts or missing dependencies can cause this error. Try reinstalling graphical packages:
install.packages("ggplot2")
library(ggplot2)
If you are using grid or lattice, ensure they are also properly loaded.
Avoid Nested Function Calls
Instead of calling .call.graphics() within another call() function, consider breaking down the process into separate steps to avoid invalid states.
Restart the R Session
If none of the above solutions work, restart your R session to clear any persistent issues with the graphics state.
Preventive Measures
To avoid encountering the error in .call.graphics(c_palette2, .call(c_palette2, null)) : invalid graphics state in the future:
- Always check the active graphics device before plotting.
- Avoid unnecessary nesting of function calls.
- Regularly update R and relevant packages.
- Use
dev.off()
cautiously to prevent premature closing of graphics devices.
Also Read : What Will the Initial Rate Be if [A] is Halved and [B] is Tripled?

Deduction
The error in .call.graphics(c_palette2, .call(c_palette2, null)) : invalid graphics state is a graphics-related issue that can be resolved through proper graphics device management, resetting parameters, reinstalling necessary packages, and avoiding nested function calls. By following the troubleshooting steps outlined above, you can efficiently resolve and prevent this error in your R programming workflow.