Add support for conversion from python bytes (#79)

* Allow conversion from python bytes

* Update function name

* Add convert_pixels_to_svg python function

* Update README.md

* Update README.md

cmdapp/src/python.rs

@@ -1,5 +1,7 @@
 use crate::*;
-use pyo3::prelude::*;
+use image::{io::Reader, ImageFormat};
+use pyo3::{exceptions::PyException, prelude::*};
+use std::io::{BufReader, Cursor};
 use std::path::PathBuf;
 use visioncortex::PathSimplifyMode;
 
@@ -23,6 +25,148 @@ fn convert_image_to_svg_py(
     let input_path = PathBuf::from(image_path);
     let output_path = PathBuf::from(out_path);
 
+    let config = construct_config(
+        colormode,
+        hierarchical,
+        mode,
+        filter_speckle,
+        color_precision,
+        layer_difference,
+        corner_threshold,
+        length_threshold,
+        max_iterations,
+        splice_threshold,
+        path_precision,
+    );
+
+    convert_image_to_svg(&input_path, &output_path, config).unwrap();
+    Ok(())
+}
+
+#[pyfunction]
+fn convert_raw_image_to_svg(
+    img_bytes: Vec<u8>,
+    img_format: Option<&str>, // Format of the image (e.g. 'jpg', 'png'... A full list of supported formats can be found [here](https://docs.rs/image/latest/image/enum.ImageFormat.html)). If not provided, the image format will be guessed based on its contents.
+    colormode: Option<&str>,  // "color" or "binary"
+    hierarchical: Option<&str>, // "stacked" or "cutout"
+    mode: Option<&str>,       // "polygon", "spline", "none"
+    filter_speckle: Option<usize>, // default: 4
+    color_precision: Option<i32>, // default: 6
+    layer_difference: Option<i32>, // default: 16
+    corner_threshold: Option<i32>, // default: 60
+    length_threshold: Option<f64>, // in [3.5, 10] default: 4.0
+    max_iterations: Option<usize>, // default: 10
+    splice_threshold: Option<i32>, // default: 45
+    path_precision: Option<u32>, // default: 8
+) -> PyResult<String> {
+    let config = construct_config(
+        colormode,
+        hierarchical,
+        mode,
+        filter_speckle,
+        color_precision,
+        layer_difference,
+        corner_threshold,
+        length_threshold,
+        max_iterations,
+        splice_threshold,
+        path_precision,
+    );
+    let mut img_reader = Reader::new(BufReader::new(Cursor::new(img_bytes)));
+    let img_format = img_format.and_then(|ext_name| ImageFormat::from_extension(ext_name));
+    let img = match img_format {
+        Some(img_format) => {
+            img_reader.set_format(img_format);
+            img_reader.decode()
+        }
+        None => img_reader
+            .with_guessed_format()
+            .map_err(|_| PyException::new_err("Unrecognized image format. "))?
+            .decode(),
+    };
+    let img = match img {
+        Ok(img) => img.to_rgba8(),
+        Err(_) => return Err(PyException::new_err("Failed to decode img_bytes. ")),
+    };
+    let (width, height) = (img.width() as usize, img.height() as usize);
+    let img = ColorImage {
+        pixels: img.as_raw().to_vec(),
+        width,
+        height,
+    };
+    let svg =
+        convert(img, config).map_err(|_| PyException::new_err("Failed to convert the image. "))?;
+    Ok(format!("{}", svg))
+}
+
+#[pyfunction]
+fn convert_pixels_to_svg(
+    rgba_pixels: Vec<(u8, u8, u8, u8)>,
+    size: (usize, usize),
+    colormode: Option<&str>,       // "color" or "binary"
+    hierarchical: Option<&str>,    // "stacked" or "cutout"
+    mode: Option<&str>,            // "polygon", "spline", "none"
+    filter_speckle: Option<usize>, // default: 4
+    color_precision: Option<i32>,  // default: 6
+    layer_difference: Option<i32>, // default: 16
+    corner_threshold: Option<i32>, // default: 60
+    length_threshold: Option<f64>, // in [3.5, 10] default: 4.0
+    max_iterations: Option<usize>, // default: 10
+    splice_threshold: Option<i32>, // default: 45
+    path_precision: Option<u32>,   // default: 8
+) -> PyResult<String> {
+    let expected_pixel_count = size.0 * size.1;
+    if rgba_pixels.len() != expected_pixel_count {
+        return Err(PyException::new_err(format!(
+            "Length of rgba_pixels does not match given image size. Expected {} ({} * {}), got {}. ",
+            expected_pixel_count,
+            size.0,
+            size.1,
+            rgba_pixels.len()
+        )));
+    }
+    let config = construct_config(
+        colormode,
+        hierarchical,
+        mode,
+        filter_speckle,
+        color_precision,
+        layer_difference,
+        corner_threshold,
+        length_threshold,
+        max_iterations,
+        splice_threshold,
+        path_precision,
+    );
+    let mut flat_pixels: Vec<u8> = vec![];
+    for (r, g, b, a) in rgba_pixels {
+        flat_pixels.push(r);
+        flat_pixels.push(g);
+        flat_pixels.push(b);
+        flat_pixels.push(a);
+    }
+    let mut img = ColorImage::new();
+    img.pixels = flat_pixels;
+    (img.width, img.height) = size;
+
+    let svg =
+        convert(img, config).map_err(|_| PyException::new_err("Failed to convert the image. "))?;
+    Ok(format!("{}", svg))
+}
+
+fn construct_config(
+    colormode: Option<&str>,
+    hierarchical: Option<&str>,
+    mode: Option<&str>,
+    filter_speckle: Option<usize>,
+    color_precision: Option<i32>,
+    layer_difference: Option<i32>,
+    corner_threshold: Option<i32>,
+    length_threshold: Option<f64>,
+    max_iterations: Option<usize>,
+    splice_threshold: Option<i32>,
+    path_precision: Option<u32>,
+) -> Config {
     // TODO: enforce color mode with an enum so that we only
     // accept the strings 'color' or 'binary'
     let color_mode = match colormode.unwrap_or("color") {
@@ -52,7 +196,7 @@ fn convert_image_to_svg_py(
     let splice_threshold = splice_threshold.unwrap_or(45);
     let max_iterations = max_iterations.unwrap_or(10);
 
-    let config = Config {
+    Config {
         color_mode,
         hierarchical,
         filter_speckle,
@@ -65,15 +209,14 @@ fn convert_image_to_svg_py(
         splice_threshold,
         path_precision,
         ..Default::default()
-    };
-
-    convert_image_to_svg(&input_path, &output_path, config).unwrap();
-    Ok(())
+    }
 }
 
 /// A Python module implemented in Rust.
 #[pymodule]
 fn vtracer(_py: Python, m: &PyModule) -> PyResult<()> {
     m.add_function(wrap_pyfunction!(convert_image_to_svg_py, m)?)?;
+    m.add_function(wrap_pyfunction!(convert_raw_image_to_svg, m)?)?;
+    m.add_function(wrap_pyfunction!(convert_pixels_to_svg, m)?)?;
     Ok(())
 }

cmdapp/vtracer/README.md

@@ -52,7 +52,17 @@ vtracer.convert_image_to_svg_py(inp, out)
 # Single-color example. Good for line art, and much faster than full color:
 vtracer.convert_image_to_svg_py(inp, out, colormode='binary')
 
-# All the bells & whistles
+# Convert from raw image bytes
+input_img_bytes: bytes = get_bytes() # e.g. reading bytes from a file or a HTTP request body
+svg_str: str = vtracer.convert_raw_image_to_svg(input_img_bytes, img_format = 'jpg')
+
+# Convert from RGBA image pixels
+from PIL import Image
+img = Image.open(input_path).convert('RGBA')
+pixels: list[tuple[int, int, int, int]] = list(img.getdata())
+svg_str: str = vtracer.convert_pixels_to_svg(pixels)
+
+# All the bells & whistles, also applicable to convert_raw_image_to_svg and convert_pixels_to_svg. 
 vtracer.convert_image_to_svg_py(inp,
                                 out,
                                 colormode = 'color',        # ["color"] or "binary"

cmdapp/vtracer/__init__.py

@@ -1 +1,2 @@
-from .vtracer import convert_image_to_svg_py
+from .vtracer import (convert_image_to_svg_py, convert_pixels_to_svg,
+                      convert_raw_image_to_svg)

cmdapp/vtracer/vtracer.pyi

@@ -15,3 +15,35 @@ def convert_image_to_svg_py(image_path: str,
                             path_precision: Optional[int] = None,   # default: 8
                         ) -> None:
     ...
+
+def convert_raw_image_to_svg(img_bytes: bytes,
+                            img_format: Optional[str] = None,       # Format of the image (e.g. 'jpg', 'png'... A full list of supported formats can be found [here](https://docs.rs/image/latest/image/enum.ImageFormat.html)). If not provided, the image format will be guessed based on its contents. 
+                            colormode: Optional[str] = None,        # ["color"] or "binary"
+                            hierarchical: Optional[str] = None,     # ["stacked"] or "cutout"
+                            mode: Optional[str] = None,             # ["spline"], "polygon", "none"
+                            filter_speckle: Optional[int] = None,   # default: 4
+                            color_precision: Optional[int] = None,  # default: 6
+                            layer_difference: Optional[int] = None, # default: 16
+                            corner_threshold: Optional[int] = None, # default: 60   
+                            length_threshold: Optional[float] = None, # in [3.5, 10] default: 4.0
+                            max_iterations: Optional[int] = None,   # default: 10
+                            splice_threshold: Optional[int] = None, # default: 45
+                            path_precision: Optional[int] = None,   # default: 8
+                        ) -> str:
+    ...
+
+def convert_pixels_to_svg(rgba_pixels: list[tuple[int, int, int, int]],
+                            size: tuple[int, int],
+                            colormode: Optional[str] = None,        # ["color"] or "binary"
+                            hierarchical: Optional[str] = None,     # ["stacked"] or "cutout"
+                            mode: Optional[str] = None,             # ["spline"], "polygon", "none"
+                            filter_speckle: Optional[int] = None,   # default: 4
+                            color_precision: Optional[int] = None,  # default: 6
+                            layer_difference: Optional[int] = None, # default: 16
+                            corner_threshold: Optional[int] = None, # default: 60   
+                            length_threshold: Optional[float] = None, # in [3.5, 10] default: 4.0
+                            max_iterations: Optional[int] = None,   # default: 10
+                            splice_threshold: Optional[int] = None, # default: 45
+                            path_precision: Optional[int] = None,   # default: 8
+                        ) -> str:
+    ...