use Rust-CUDA to accelerate vtracer

[onefish51]

That's really great work!

I tested converting PNG to SVG, and the results are excellent. However, I noticed a problem: it takes a bit too long to convert a 2048*2048 image to SVG, taking about 1.005 seconds.

import time
import numpy as np
from PIL import Image

def convert_img2svg(img):
    start_time = time.time()
    
    if isinstance(img, np.ndarray):
        img = Image.fromarray(img.astype('uint8'))
    else:
        img = img.convert('RGBA')
    
    if img.mode == 'L':
        gray_pixels = list(img.getdata())
        pixels = [(value, value, value, 255) for value in gray_pixels]  # 转换为 RGBA
    else:
        img = img.convert('RGBA')
        pixels = list(img.getdata())

    print("Convert to RGBA Cost: {} s".format(time.time() - start_time))
    
    size = img.size
    svg_str = vtracer.convert_pixels_to_svg(
        pixels,
        size=size,
        colormode='binary'
    )
    print("Convert pixels to SVG Cost: {} s".format(time.time() - start_time))

    return svg_str

running log:

img_pil.size:  (2048, 2048)
convert RGBA Cost: 0.008136510848999023 s/img2svg
getdata Cost: 0.4795377254486084 s/img2svg
convert_pixels_to_svg Cost: 1.0046734809875488 s/img2svg

I need to convert a sequence of such masks to SVG, which will increase the total time significantly. Are there any acceleration solutions?

Is it possible to use Rust-CUDA to accelerate vtracer? I haven't used Rust before; I mainly work with Python. How much effort would it take to refactor vtracer using Rust-CUDA?

Additionally, I found that the time taken by vtracer.convert_pixels_to_svg(pixels, size=size, colormode='binary') and vtracer.convert_image_to_svg_py(temp_path, out, colormode='binary') differs significantly. Why is that? Theoretically, the vtracer.convert_image_to_svg_py method should be faster than vtracer.convert_pixels_to_svg since it skips the image reading and saving to SVG steps. Instead, it is slower.

import vtracer
import os
import numpy as np
from PIL import Image
import time

inp = "output/mask_6.png"
out = "output/mask_6_vtracer.svg"
temp_path = "output/mask_6_temp.png"

img_pil = Image.open(inp)
print("img_pil.size: ", img_pil.size)
img_pil = img_pil.resize((768, 768))
print("img_pil.size: ", img_pil.size)
img_pil.save(temp_path)

# Single-color example. Good for line art, and much faster than full color:
start_time = time.time()
vtracer.convert_image_to_svg_py(temp_path, out, colormode='binary')
print("convert_pixels_to_svg Cost: {} s/img2svg".format(time.time() - start_time))

running log:

# vtracer.convert_pixels_to_svg(pixels, size=size, colormode='binary')

img_pil.size:  (768, 768)
convert RGBA Cost: 0.0005877017974853516 s/img2svg
getdata Cost: 0.06665635108947754 s/img2svg
convert_pixels_to_svg Cost: 0.13504505157470703 s/img2svg
######################################
img_pil.size:  (1000, 1000)
img_pil.mode:  L
convert RGBA Cost: 0.005483865737915039 s/img2svg
getdata Cost: 0.12675023078918457 s/img2svg
convert_pixels_to_svg Cost: 0.2476341724395752 s/img2svg
######################################
img_pil.size:  (1024, 1024)
convert RGBA Cost: 0.0010349750518798828 s/img2svg
getdata Cost: 0.1203470230102539 s/img2svg
convert_pixels_to_svg Cost: 0.24472641944885254 s/img2svg
######################################
img_pil.size:  (2048, 2048)
convert RGBA Cost: 0.008136510848999023 s/img2svg
getdata Cost: 0.4795377254486084 s/img2svg
convert_pixels_to_svg Cost: 1.0046734809875488 s/img2svg

######################################################################
# vtracer.convert_image_to_svg_py(temp_path, out, colormode='binary')

img_pil.size:  (768, 768)
convert_pixels_to_svg Cost: 0.03275275230407715 s/img2svg
######################################
img_pil.size:  (1000, 1000)
convert_pixels_to_svg Cost: 0.055071115493774414 s/img2svg
######################################
img_pil.size:  (1024, 1024)
convert_pixels_to_svg Cost: 0.058161020278930664 s/img2svg
######################################
img_pil.size:  (2048, 2048)
convert_pixels_to_svg Cost: 0.23955154418945312 s/img2svg

Thanks!

[tyt2y3]

Use the rust library directly, this should more room for optimization.
The algorithm is essentially CPU-oriented, but it's possible to multi-thread it.
If you have a lot of images to process, the easiest is to distribute the tasks on multiple threads.

[onefish51]

Thank you very much! That’s a great idea! I will give it a try later.

Additionally, why do the functions vtracer.convert_pixels_to_svg and vtracer.convert_image_to_svg_py, which both use let svg = convert(img, config)?;, have a performance difference of 5 times?

# vtracer.convert_pixels_to_svg(pixels, size=size, colormode='binary')

img_pil.size:  (768, 768)
convert RGBA Cost: 0.0005877017974853516 s/img2svg
getdata Cost: 0.06665635108947754 s/img2svg
convert_pixels_to_svg Cost: 0.13504505157470703 s/img2svg
######################################
img_pil.size:  (1000, 1000)
img_pil.mode:  L
convert RGBA Cost: 0.005483865737915039 s/img2svg
getdata Cost: 0.12675023078918457 s/img2svg
convert_pixels_to_svg Cost: 0.2476341724395752 s/img2svg
######################################
img_pil.size:  (1024, 1024)
convert RGBA Cost: 0.0010349750518798828 s/img2svg
getdata Cost: 0.1203470230102539 s/img2svg
convert_pixels_to_svg Cost: 0.24472641944885254 s/img2svg
######################################
img_pil.size:  (2048, 2048)
convert RGBA Cost: 0.008136510848999023 s/img2svg
getdata Cost: 0.4795377254486084 s/img2svg
convert_pixels_to_svg Cost: 1.0046734809875488 s/img2svg

######################################################################
# vtracer.convert_image_to_svg_py(temp_path, out, colormode='binary')

img_pil.size:  (768, 768)
convert_pixels_to_svg Cost: 0.03275275230407715 s/img2svg
######################################
img_pil.size:  (1000, 1000)
convert_pixels_to_svg Cost: 0.055071115493774414 s/img2svg
######################################
img_pil.size:  (1024, 1024)
convert_pixels_to_svg Cost: 0.058161020278930664 s/img2svg
######################################
img_pil.size:  (2048, 2048)
convert_pixels_to_svg Cost: 0.23955154418945312 s/img2svg

[tyt2y3]

I don't know how to read the above, so I can't comment.