SetIsInline — Set the output image to be “inline” - without HTTP headers
$plot->SetIsInline($is_inline)
SetIsInline determines if HTTP headers are sent along
with the output image or not. By default, HTTP headers are sent,
identifying the image type for browsers. If PHPlot output is not being
directed to a browser, or in other special-purpose applications, you can
turn off the HTTP content type header using this function.
The default is to include the headers. However, the PHP CLI (command line interface) never outputs headers, so using this function is not necessary if you are using the PHP CLI to create image files by redirecting standard output to a file.
You must call SetIsInline(True) if you are sending PHPlot output to a file with SetOutputFile, or by supplying a filename argument to the PHPlot constructor.