WebUI/javascript/imageMaskFix.js

/**
 * temporary fix for https://github.com/AUTOMATIC1111/stable-diffusion-webui/issues/668
 * @see https://github.com/gradio-app/gradio/issues/1721
 */
window.addEventListener( 'resize', () => imageMaskResize());
function imageMaskResize() {
    const canvases = gradioApp().querySelectorAll('#img2maskimg .touch-none canvas');
    if ( ! canvases.length ) {
    canvases_fixed = false;
    window.removeEventListener( 'resize', imageMaskResize );
    return;
    }

    const wrapper = canvases[0].closest('.touch-none');
    const previewImage = wrapper.previousElementSibling;

    if ( ! previewImage.complete ) {
        previewImage.addEventListener( 'load', () => imageMaskResize());
        return;
    }

    const w = previewImage.width;
    const h = previewImage.height;
    const nw = previewImage.naturalWidth;
    const nh = previewImage.naturalHeight;
    const portrait = nh > nw;
    const factor = portrait;

    const wW = Math.min(w, portrait ? h/nh*nw : w/nw*nw);
    const wH = Math.min(h, portrait ? h/nh*nh : w/nw*nh);

    wrapper.style.width = `${wW}px`;
    wrapper.style.height = `${wH}px`;
    wrapper.style.left = `0px`;
    wrapper.style.top = `0px`;

    canvases.forEach( c => {
        c.style.width = c.style.height = '';
        c.style.maxWidth = '100%';
        c.style.maxHeight = '100%';
        c.style.objectFit = 'contain';
    });
 }
  
 onUiUpdate(() => imageMaskResize());