Graph example not writing to a file, but to a buffer not "working"

[manuelarte]

Hi, I would like to run the example of the graphs but instead of writing to a file, get the buffer so I can send the image. This is what I changed

use plotters::prelude::*; const OUT_FILE_NAME: &str = "plotters-doc-data/sample.png"; fn main() -> Result<Vec<u8>, Box<dyn std::error::Error>> { let width = 1024; let height = 768; let mut buffer = vec![0; (width as usize) * (height as usize) * 3]; { let root_area = BitMapBackend::with_buffer(&mut buffer, (width , height )).into_drawing_area(); root_area.fill(&WHITE)?; let root_area = root_area.titled("Image Title", ("sans-serif", 60))?; let (upper, lower) = root_area.split_vertically(512); let x_axis = (-3.4f32..3.4).step(0.1); let mut cc = ChartBuilder::on(&upper) .margin(5) .set_all_label_area_size(50) .caption("Sine and Cosine", ("sans-serif", 40)) .build_cartesian_2d(-3.4f32..3.4, -1.2f32..1.2f32)?; cc.configure_mesh() .x_labels(20) .y_labels(10) .disable_mesh() .x_label_formatter(&|v| format!("{:.1}", v)) .y_label_formatter(&|v| format!("{:.1}", v)) .draw()?; cc.draw_series(LineSeries::new(x_axis.values().map(|x| (x, x.sin())), &RED))? .label("Sine") .legend(|(x, y)| PathElement::new(vec![(x, y), (x + 20, y)], RED)); cc.draw_series(LineSeries::new( x_axis.values().map(|x| (x, x.cos())), &BLUE, ))? .label("Cosine") .legend(|(x, y)| PathElement::new(vec![(x, y), (x + 20, y)], BLUE)); cc.configure_series_labels().border_style(BLACK).draw()?; /*  // It's possible to use a existing pointing element  cc.draw_series(PointSeries::<_, _, Circle<_>>::new(  (-3.0f32..2.1f32).step(1.0).values().map(|x| (x, x.sin())),  5,  Into::<ShapeStyle>::into(&RGBColor(255,0,0)).filled(),  ))?;*/ // Otherwise you can use a function to construct your pointing element yourself cc.draw_series(PointSeries::of_element( (-3.0f32..2.1f32).step(1.0).values().map(|x| (x, x.sin())), 5, ShapeStyle::from(&RED).filled(), &|coord, size, style| { EmptyElement::at(coord) + Circle::new((0, 0), size, style) + Text::new(format!("{:?}", coord), (0, 15), ("sans-serif", 15)) }, ))?; let drawing_areas = lower.split_evenly((1, 2)); for (drawing_area, idx) in drawing_areas.iter().zip(1..) { let mut cc = ChartBuilder::on(drawing_area) .x_label_area_size(30) .y_label_area_size(30) .margin_right(20) .caption(format!("y = x^{}", 1 + 2 * idx), ("sans-serif", 40)) .build_cartesian_2d(-1f32..1f32, -1f32..1f32)?; cc.configure_mesh() .x_labels(5) .y_labels(3) .max_light_lines(4) .draw()?; cc.draw_series(LineSeries::new( (-1f32..1f32) .step(0.01) .values() .map(|x| (x, x.powf(idx as f32 * 2.0 + 1.0))), &BLUE, ))?; } // To avoid the IO failure being ignored silently, we manually call the present function root_area.present().expect("Unable to write result to file, please make sure 'plotters-doc-data' dir exists under current dir"); } Ok(buffer) } #[test] fn entry_point() { let buffer = main().unwrap() let image = image::RgbImage::from_raw(input.width, input.height, buffer.clone()).unwrap(); let path = format!("{}/{}", OUT_DIRECTORY, "graphs.png".to_string()); image.save(&Path::new(path.as_str()))?; println!("Result has been saved to {}", OUT_DIRECTORY); }

But I get a weird image (with the graphs overlapping), not the graphs, any idea what I am doing wrong? I have very similar code with the histogram and it works.