Focal points (#6520)

* Add focus param to media API, center thumbnails on focus point

* Add UI for setting a focal point

* Improve focal point icon on upload item

* Use focal point in upload preview

* Add focalPoint property to ActivityPub

* Don't show focal point button for non-image attachments

2 files changed, 124 insertions, 0 deletions

diff --git a/app/javascript/mastodon/features/ui/components/focal_point_modal.js b/app/javascript/mastodon/features/ui/components/focal_point_modal.js
new file mode 100644
index 000000000..ee5c791d4
--- /dev/null
+++ b/app/javascript/mastodon/features/ui/components/focal_point_modal.js
@@ -0,0 +1,122 @@
+import React from 'react';
+import ImmutablePropTypes from 'react-immutable-proptypes';
+import ImmutablePureComponent from 'react-immutable-pure-component';
+import { connect } from 'react-redux';
+import ImageLoader from './image_loader';
+import classNames from 'classnames';
+import { changeUploadCompose } from '../../../actions/compose';
+import { getPointerPosition } from '../../video';
+
+const mapStateToProps = (state, { id }) => ({
+  media: state.getIn(['compose', 'media_attachments']).find(item => item.get('id') === id),
+});
+
+const mapDispatchToProps = (dispatch, { id }) => ({
+
+  onSave: (x, y) => {
+    dispatch(changeUploadCompose(id, { focus: `${x.toFixed(2)},${y.toFixed(2)}` }));
+  },
+
+});
+
+@connect(mapStateToProps, mapDispatchToProps)
+export default class FocalPointModal extends ImmutablePureComponent {
+
+  static propTypes = {
+    media: ImmutablePropTypes.map.isRequired,
+  };
+
+  state = {
+    x: 0,
+    y: 0,
+    focusX: 0,
+    focusY: 0,
+    dragging: false,
+  };
+
+  componentWillMount () {
+    this.updatePositionFromMedia(this.props.media);
+  }
+
+  componentWillReceiveProps (nextProps) {
+    if (this.props.media.get('id') !== nextProps.media.get('id')) {
+      this.updatePositionFromMedia(nextProps.media);
+    }
+  }
+
+  componentWillUnmount () {
+    document.removeEventListener('mousemove', this.handleMouseMove);
+    document.removeEventListener('mouseup', this.handleMouseUp);
+  }
+
+  handleMouseDown = e => {
+    document.addEventListener('mousemove', this.handleMouseMove);
+    document.addEventListener('mouseup', this.handleMouseUp);
+
+    this.updatePosition(e);
+    this.setState({ dragging: true });
+  }
+
+  handleMouseMove = e => {
+    this.updatePosition(e);
+  }
+
+  handleMouseUp = () => {
+    document.removeEventListener('mousemove', this.handleMouseMove);
+    document.removeEventListener('mouseup', this.handleMouseUp);
+
+    this.setState({ dragging: false });
+    this.props.onSave(this.state.focusX, this.state.focusY);
+  }
+
+  updatePosition = e => {
+    const { x, y } = getPointerPosition(this.node, e);
+    const focusX   = (x - .5) *  2;
+    const focusY   = (y - .5) * -2;
+
+    this.setState({ x, y, focusX, focusY });
+  }
+
+  updatePositionFromMedia = media => {
+    const focusX = media.getIn(['meta', 'focus', 'x']);
+    const focusY = media.getIn(['meta', 'focus', 'y']);
+
+    if (focusX && focusY) {
+      const x = (focusX /  2) + .5;
+      const y = (focusY / -2) + .5;
+
+      this.setState({ x, y, focusX, focusY });
+    } else {
+      this.setState({ x: 0.5, y: 0.5, focusX: 0, focusY: 0 });
+    }
+  }
+
+  setRef = c => {
+    this.node = c;
+  }
+
+  render () {
+    const { media } = this.props;
+    const { x, y, dragging } = this.state;
+
+    const width  = media.getIn(['meta', 'original', 'width']) || null;
+    const height = media.getIn(['meta', 'original', 'height']) || null;
+
+    return (
+      <div className='modal-root__modal media-modal'>
+        <div className={classNames('media-modal__content focal-point', { dragging })} ref={this.setRef}>
+          <ImageLoader
+            previewSrc={media.get('preview_url')}
+            src={media.get('url')}
+            width={width}
+            height={height}
+          />
+
+          <div className='focal-point__reticle' style={{ top: `${y * 100}%`, left: `${x * 100}%` }} />
+          <div className='focal-point__overlay' onMouseDown={this.handleMouseDown} />
+        </div>
+      </div>
+    );
+  }
+
+}
diff --git a/app/javascript/mastodon/features/ui/components/modal_root.js b/app/javascript/mastodon/features/ui/components/modal_root.js
index 5839ba40a..20bf21153 100644
--- a/app/javascript/mastodon/features/ui/components/modal_root.js
+++ b/app/javascript/mastodon/features/ui/components/modal_root.js
@@ -8,6 +8,7 @@ import MediaModal from './media_modal';
 import VideoModal from './video_modal';
 import BoostModal from './boost_modal';
 import ConfirmationModal from './confirmation_modal';
+import FocalPointModal from './focal_point_modal';
 import {
   OnboardingModal,
   MuteModal,
@@ -27,6 +28,7 @@ const MODAL_COMPONENTS = {
   'ACTIONS': () => Promise.resolve({ default: ActionsModal }),
   'EMBED': EmbedModal,
   'LIST_EDITOR': ListEditor,
+  'FOCAL_POINT': () => Promise.resolve({ default: FocalPointModal }),
 };
 
 export default class ModalRoot extends React.PureComponent {