utils.py

import subprocess

import torch


def increase_object_size(renderer, args):
    """Restore the object's original size and position on the renderer canvas."""
    with torch.no_grad():
        # scaling factors for x and y
        w, h = args.scale_w, args.scale_h
        canvas_width, canvas_height = args.render_size, args.render_size
        for path in renderer.shapes:
            # Normalize points to [-1, 1] relative coordinates
            path.points = path.points / canvas_width
            path.points = 2 * path.points - 1
            # Apply inverse scale
            path.points[:, 0] /= w
            path.points[:, 1] /= h
            # Convert back to pixel coordinates
            path.points = 0.5 * (path.points + 1.0) * canvas_width
            # Recenter paths to original object center
            center_x, center_y = canvas_width / 2, canvas_height / 2
            path.points[:, 0] += args.original_center_x * canvas_width - center_x
            path.points[:, 1] += args.original_center_y * canvas_height - center_y


def make_video(args):
    """Render PNG frames in `svg_to_png` to a video file using ffmpeg."""
    # Output resolution for the generated video
    output_width = args.render_size
    output_height = args.render_size

    # Use ffmpeg to assemble frames into an mp4 video
    subprocess.run(
        [
            "ffmpeg",
            "-y",
            "-framerate",
            "10",
            "-pattern_type",
            "glob",
            "-i",
            f"{args.output_dir}/svg_to_png/iter_*.png",
            "-vb",
            "20M",
            "-vf",
            f"scale={output_width}:{output_height}",
            f"{args.output_dir}/sketch.mp4",
        ],
        stdout=subprocess.DEVNULL if not args.debug else None,
        stderr=subprocess.DEVNULL if not args.debug else None,
    )