Add blurhash (#10630)

* Add blurhash

* Use fallback color for spoiler when blurhash missing

* Federate the blurhash and accept it as long as it's at most 5x5

* Display unknown media attachments as blurhash placeholders

* Improve style of embed actions and spoiler button

* Change blurhash resolution from 3x3 to 4x4

* Improve dependency definitions

* Fix code style issues

22 files changed, 234 insertions, 60 deletions

diff --git a/Gemfile b/Gemfile
index 6fe97412b..fa8478d89 100644
--- a/Gemfile
+++ b/Gemfile
@@ -21,6 +21,7 @@ gem 'fog-openstack', '~> 0.3', require: false
 gem 'paperclip', '~> 6.0'
 gem 'paperclip-av-transcoder', '~> 0.6'
 gem 'streamio-ffmpeg', '~> 3.0'
+gem 'blurhash', '~> 0.1'
 
 gem 'active_model_serializers', '~> 0.10'
 gem 'addressable', '~> 2.6'
diff --git a/Gemfile.lock b/Gemfile.lock
index 66fc8d1f4..0148cb5ea 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -99,6 +99,8 @@ GEM
       rack (>= 0.9.0)
     binding_of_caller (0.8.0)
       debug_inspector (>= 0.0.1)
+    blurhash (0.1.2)
+      ffi (~> 1.10.0)
     bootsnap (1.4.4)
       msgpack (~> 1.0)
     brakeman (4.5.0)
@@ -661,6 +663,7 @@ DEPENDENCIES
   aws-sdk-s3 (~> 1.36)
   better_errors (~> 2.5)
   binding_of_caller (~> 0.7)
+  blurhash (~> 0.1)
   bootsnap (~> 1.4)
   brakeman (~> 4.5)
   browser
diff --git a/app/javascript/mastodon/components/media_gallery.js b/app/javascript/mastodon/components/media_gallery.js
index a2bc95255..f548296d0 100644
--- a/app/javascript/mastodon/components/media_gallery.js
+++ b/app/javascript/mastodon/components/media_gallery.js
@@ -7,6 +7,7 @@ import { defineMessages, injectIntl, FormattedMessage } from 'react-intl';
 import { isIOS } from '../is_mobile';
 import classNames from 'classnames';
 import { autoPlayGif, displayMedia } from '../initial_state';
+import { decode } from 'blurhash';
 
 const messages = defineMessages({
   toggle_visible: { id: 'media_gallery.toggle_visible', defaultMessage: 'Toggle visibility' },
@@ -21,6 +22,7 @@ class Item extends React.PureComponent {
     size: PropTypes.number.isRequired,
     onClick: PropTypes.func.isRequired,
     displayWidth: PropTypes.number,
+    visible: PropTypes.bool.isRequired,
   };
 
   static defaultProps = {
@@ -29,6 +31,10 @@ class Item extends React.PureComponent {
     size: 1,
   };
 
+  state = {
+    loaded: false,
+  };
+
   handleMouseEnter = (e) => {
     if (this.hoverToPlay()) {
       e.target.play();
@@ -62,8 +68,40 @@ class Item extends React.PureComponent {
     e.stopPropagation();
   }
 
+  componentDidMount () {
+    if (this.props.attachment.get('blurhash')) {
+      this._decode();
+    }
+  }
+
+  componentDidUpdate (prevProps) {
+    if (prevProps.attachment.get('blurhash') !== this.props.attachment.get('blurhash') && this.props.attachment.get('blurhash')) {
+      this._decode();
+    }
+  }
+
+  _decode () {
+    const hash   = this.props.attachment.get('blurhash');
+    const pixels = decode(hash, 32, 32);
+
+    if (pixels) {
+      const ctx       = this.canvas.getContext('2d');
+      const imageData = new ImageData(pixels, 32, 32);
+
+      ctx.putImageData(imageData, 0, 0);
+    }
+  }
+
+  setCanvasRef = c => {
+    this.canvas = c;
+  }
+
+  handleImageLoad = () => {
+    this.setState({ loaded: true });
+  }
+
   render () {
-    const { attachment, index, size, standalone, displayWidth } = this.props;
+    const { attachment, index, size, standalone, displayWidth, visible } = this.props;
 
     let width  = 50;
     let height = 100;
@@ -116,12 +154,20 @@ class Item extends React.PureComponent {
 
     let thumbnail = '';
 
-    if (attachment.get('type') === 'image') {
+    if (attachment.get('type') === 'unknown') {
+      return (
+        <div className={classNames('media-gallery__item', { standalone })} key={attachment.get('id')} style={{ left: left, top: top, right: right, bottom: bottom, width: `${width}%`, height: `${height}%` }}>
+          <a className='media-gallery__item-thumbnail' href={attachment.get('remote_url')} target='_blank' style={{ cursor: 'pointer' }} >
+            <canvas width={32} height={32} ref={this.setCanvasRef} className='media-gallery__preview' />
+          </a>
+        </div>
+      );
+    } else if (attachment.get('type') === 'image') {
       const previewUrl   = attachment.get('preview_url');
       const previewWidth = attachment.getIn(['meta', 'small', 'width']);
 
-      const originalUrl    = attachment.get('url');
-      const originalWidth  = attachment.getIn(['meta', 'original', 'width']);
+      const originalUrl   = attachment.get('url');
+      const originalWidth = attachment.getIn(['meta', 'original', 'width']);
 
       const hasSize = typeof originalWidth === 'number' && typeof previewWidth === 'number';
 
@@ -147,6 +193,7 @@ class Item extends React.PureComponent {
             alt={attachment.get('description')}
             title={attachment.get('description')}
             style={{ objectPosition: `${x}% ${y}%` }}
+            onLoad={this.handleImageLoad}
           />
         </a>
       );
@@ -176,7 +223,8 @@ class Item extends React.PureComponent {
 
     return (
       <div className={classNames('media-gallery__item', { standalone })} key={attachment.get('id')} style={{ left: left, top: top, right: right, bottom: bottom, width: `${width}%`, height: `${height}%` }}>
-        {thumbnail}
+        <canvas width={32} height={32} ref={this.setCanvasRef} className={classNames('media-gallery__preview', { 'media-gallery__preview--hidden': visible && this.state.loaded })} />
+        {visible && thumbnail}
       </div>
     );
   }
@@ -225,6 +273,7 @@ class MediaGallery extends React.PureComponent {
     if (node /*&& this.isStandaloneEligible()*/) {
       // offsetWidth triggers a layout, so only calculate when we need to
       if (this.props.cacheWidth) this.props.cacheWidth(node.offsetWidth);
+
       this.setState({
         width: node.offsetWidth,
       });
@@ -242,7 +291,7 @@ class MediaGallery extends React.PureComponent {
 
     const width = this.state.width || defaultWidth;
 
-    let children;
+    let children, spoilerButton;
 
     const style = {};
 
@@ -256,35 +305,28 @@ class MediaGallery extends React.PureComponent {
       style.height = height;
     }
 
-    if (!visible) {
-      let warning;
+    const size = media.take(4).size;
 
-      if (sensitive) {
-        warning = <FormattedMessage id='status.sensitive_warning' defaultMessage='Sensitive content' />;
-      } else {
-        warning = <FormattedMessage id='status.media_hidden' defaultMessage='Media hidden' />;
-      }
+    if (this.isStandaloneEligible()) {
+      children = <Item standalone onClick={this.handleClick} attachment={media.get(0)} displayWidth={width} visible={visible} />;
+    } else {
+      children = media.take(4).map((attachment, i) => <Item key={attachment.get('id')} onClick={this.handleClick} attachment={attachment} index={i} size={size} displayWidth={width} visible={visible} />);
+    }
 
-      children = (
-        <button type='button' className='media-spoiler' onClick={this.handleOpen} style={style} ref={this.handleRef}>
-          <span className='media-spoiler__warning'>{warning}</span>
-          <span className='media-spoiler__trigger'><FormattedMessage id='status.sensitive_toggle' defaultMessage='Click to view' /></span>
+    if (visible) {
+      spoilerButton = <IconButton title={intl.formatMessage(messages.toggle_visible)} icon={visible ? 'eye' : 'eye-slash'} overlay onClick={this.handleOpen} />;
+    } else {
+      spoilerButton = (
+        <button type='button' onClick={this.handleOpen} className='spoiler-button__overlay'>
+          <span className='spoiler-button__overlay__label'>{sensitive ? <FormattedMessage id='status.sensitive_warning' defaultMessage='Sensitive content' /> : <FormattedMessage id='status.media_hidden' defaultMessage='Media hidden' />}</span>
         </button>
       );
-    } else {
-      const size = media.take(4).size;
-
-      if (this.isStandaloneEligible()) {
-        children = <Item standalone onClick={this.handleClick} attachment={media.get(0)} displayWidth={width} />;
-      } else {
-        children = media.take(4).map((attachment, i) => <Item key={attachment.get('id')} onClick={this.handleClick} attachment={attachment} index={i} size={size} displayWidth={width} />);
-      }
     }
 
     return (
       <div className='media-gallery' style={style} ref={this.handleRef}>
-        <div className={classNames('spoiler-button', { 'spoiler-button--visible': visible })}>
-          <IconButton title={intl.formatMessage(messages.toggle_visible)} icon={visible ? 'eye' : 'eye-slash'} overlay onClick={this.handleOpen} />
+        <div className={classNames('spoiler-button', { 'spoiler-button--minified': visible })}>
+          {spoilerButton}
         </div>
 
         {children}
diff --git a/app/javascript/mastodon/components/status.js b/app/javascript/mastodon/components/status.js
index cea9a0c2e..95ca4a548 100644
--- a/app/javascript/mastodon/components/status.js
+++ b/app/javascript/mastodon/components/status.js
@@ -274,7 +274,7 @@ class Status extends ImmutablePureComponent {
     if (status.get('poll')) {
       media = <PollContainer pollId={status.get('poll')} />;
     } else if (status.get('media_attachments').size > 0) {
-      if (this.props.muted || status.get('media_attachments').some(item => item.get('type') === 'unknown')) {
+      if (this.props.muted) {
         media = (
           <AttachmentList
             compact
@@ -289,6 +289,7 @@ class Status extends ImmutablePureComponent {
             {Component => (
               <Component
                 preview={video.get('preview_url')}
+                blurhash={video.get('blurhash')}
                 src={video.get('url')}
                 alt={video.get('description')}
                 width={this.props.cachedMediaWidth}
diff --git a/app/javascript/mastodon/features/report/components/status_check_box.js b/app/javascript/mastodon/features/report/components/status_check_box.js
index 2552d94d8..c29e517da 100644
--- a/app/javascript/mastodon/features/report/components/status_check_box.js
+++ b/app/javascript/mastodon/features/report/components/status_check_box.js
@@ -35,6 +35,7 @@ export default class StatusCheckBox extends React.PureComponent {
             {Component => (
               <Component
                 preview={video.get('preview_url')}
+                blurhash={video.get('blurhash')}
                 src={video.get('url')}
                 alt={video.get('description')}
                 width={239}
diff --git a/app/javascript/mastodon/features/status/components/detailed_status.js b/app/javascript/mastodon/features/status/components/detailed_status.js
index 5c79f9f19..84471f9a3 100644
--- a/app/javascript/mastodon/features/status/components/detailed_status.js
+++ b/app/javascript/mastodon/features/status/components/detailed_status.js
@@ -5,7 +5,6 @@ import Avatar from '../../../components/avatar';
 import DisplayName from '../../../components/display_name';
 import StatusContent from '../../../components/status_content';
 import MediaGallery from '../../../components/media_gallery';
-import AttachmentList from '../../../components/attachment_list';
 import { Link } from 'react-router-dom';
 import { FormattedDate, FormattedNumber } from 'react-intl';
 import Card from './card';
@@ -109,14 +108,13 @@ export default class DetailedStatus extends ImmutablePureComponent {
     if (status.get('poll')) {
       media = <PollContainer pollId={status.get('poll')} />;
     } else if (status.get('media_attachments').size > 0) {
-      if (status.get('media_attachments').some(item => item.get('type') === 'unknown')) {
-        media = <AttachmentList media={status.get('media_attachments')} />;
-      } else if (status.getIn(['media_attachments', 0, 'type']) === 'video') {
+      if (status.getIn(['media_attachments', 0, 'type']) === 'video') {
         const video = status.getIn(['media_attachments', 0]);
 
         media = (
           <Video
             preview={video.get('preview_url')}
+            blurhash={video.get('blurhash')}
             src={video.get('url')}
             alt={video.get('description')}
             width={300}
diff --git a/app/javascript/mastodon/features/ui/components/media_modal.js b/app/javascript/mastodon/features/ui/components/media_modal.js
index 2120746da..848cb20b3 100644
--- a/app/javascript/mastodon/features/ui/components/media_modal.js
+++ b/app/javascript/mastodon/features/ui/components/media_modal.js
@@ -144,6 +144,7 @@ class MediaModal extends ImmutablePureComponent {
         return (
           <Video
             preview={image.get('preview_url')}
+            blurhash={image.get('blurhash')}
             src={image.get('url')}
             width={image.get('width')}
             height={image.get('height')}
diff --git a/app/javascript/mastodon/features/ui/components/video_modal.js b/app/javascript/mastodon/features/ui/components/video_modal.js
index 7cf3eb4d4..52457a630 100644
--- a/app/javascript/mastodon/features/ui/components/video_modal.js
+++ b/app/javascript/mastodon/features/ui/components/video_modal.js
@@ -20,6 +20,7 @@ export default class VideoModal extends ImmutablePureComponent {
         <div>
           <Video
             preview={media.get('preview_url')}
+            blurhash={media.get('blurhash')}
             src={media.get('url')}
             startTime={time}
             onCloseVideo={onClose}
diff --git a/app/javascript/mastodon/features/video/index.js b/app/javascript/mastodon/features/video/index.js
index 55dd249e1..7b6113e6a 100644
--- a/app/javascript/mastodon/features/video/index.js
+++ b/app/javascript/mastodon/features/video/index.js
@@ -7,6 +7,7 @@ import classNames from 'classnames';
 import { isFullscreen, requestFullscreen, exitFullscreen } from '../ui/util/fullscreen';
 import { displayMedia } from '../../initial_state';
 import Icon from 'mastodon/components/icon';
+import { decode } from 'blurhash';
 
 const messages = defineMessages({
   play: { id: 'video.play', defaultMessage: 'Play' },
@@ -102,6 +103,7 @@ class Video extends React.PureComponent {
     inline: PropTypes.bool,
     cacheWidth: PropTypes.func,
     intl: PropTypes.object.isRequired,
+    blurhash: PropTypes.string,
   };
 
   state = {
@@ -139,6 +141,7 @@ class Video extends React.PureComponent {
 
   setVideoRef = c => {
     this.video = c;
+
     if (this.video) {
       this.setState({ volume: this.video.volume, muted: this.video.muted });
     }
@@ -152,6 +155,10 @@ class Video extends React.PureComponent {
     this.volume = c;
   }
 
+  setCanvasRef = c => {
+    this.canvas = c;
+  }
+
   handleClickRoot = e => e.stopPropagation();
 
   handlePlay = () => {
@@ -170,7 +177,6 @@ class Video extends React.PureComponent {
   }
 
   handleVolumeMouseDown = e => {
-
     document.addEventListener('mousemove', this.handleMouseVolSlide, true);
     document.addEventListener('mouseup', this.handleVolumeMouseUp, true);
     document.addEventListener('touchmove', this.handleMouseVolSlide, true);
@@ -190,7 +196,6 @@ class Video extends React.PureComponent {
   }
 
   handleMouseVolSlide = throttle(e => {
-
     const rect = this.volume.getBoundingClientRect();
     const x = (e.clientX - rect.left) / this.volWidth; //x position within the element.
 
@@ -261,6 +266,10 @@ class Video extends React.PureComponent {
     document.addEventListener('webkitfullscreenchange', this.handleFullscreenChange, true);
     document.addEventListener('mozfullscreenchange', this.handleFullscreenChange, true);
     document.addEventListener('MSFullscreenChange', this.handleFullscreenChange, true);
+
+    if (this.props.blurhash) {
+      this._decode();
+    }
   }
 
   componentWillUnmount () {
@@ -270,6 +279,24 @@ class Video extends React.PureComponent {
     document.removeEventListener('MSFullscreenChange', this.handleFullscreenChange, true);
   }
 
+  componentDidUpdate (prevProps) {
+    if (prevProps.blurhash !== this.props.blurhash && this.props.blurhash) {
+      this._decode();
+    }
+  }
+
+  _decode () {
+    const hash   = this.props.blurhash;
+    const pixels = decode(hash, 32, 32);
+
+    if (pixels) {
+      const ctx       = this.canvas.getContext('2d');
+      const imageData = new ImageData(pixels, 32, 32);
+
+      ctx.putImageData(imageData, 0, 0);
+    }
+  }
+
   handleFullscreenChange = () => {
     this.setState({ fullscreen: isFullscreen() });
   }
@@ -314,6 +341,7 @@ class Video extends React.PureComponent {
 
   handleOpenVideo = () => {
     const { src, preview, width, height, alt } = this.props;
+
     const media = fromJS({
       type: 'video',
       url: src,
@@ -351,6 +379,7 @@ class Video extends React.PureComponent {
     }
 
     let preload;
+
     if (startTime || fullscreen || dragging) {
       preload = 'auto';
     } else if (detailed) {
@@ -360,6 +389,7 @@ class Video extends React.PureComponent {
     }
 
     let warning;
+
     if (sensitive) {
       warning = <FormattedMessage id='status.sensitive_warning' defaultMessage='Sensitive content' />;
     } else {
@@ -377,7 +407,9 @@ class Video extends React.PureComponent {
         onClick={this.handleClickRoot}
         tabIndex={0}
       >
-        <video
+        <canvas width={32} height={32} ref={this.setCanvasRef} className={classNames('media-gallery__preview', { 'media-gallery__preview--hidden': revealed })} />
+
+        {revealed && <video
           ref={this.setVideoRef}
           src={src}
           poster={preview}
@@ -397,12 +429,13 @@ class Video extends React.PureComponent {
           onLoadedData={this.handleLoadedData}
           onProgress={this.handleProgress}
           onVolumeChange={this.handleVolumeChange}
-        />
+        />}
 
-        <button type='button' className={classNames('video-player__spoiler', { active: !revealed })} onClick={this.toggleReveal}>
-          <span className='video-player__spoiler__title'>{warning}</span>
-          <span className='video-player__spoiler__subtitle'><FormattedMessage id='status.sensitive_toggle' defaultMessage='Click to view' /></span>
-        </button>
+        <div className={classNames('spoiler-button', { 'spoiler-button--hidden': revealed })}>
+          <button type='button' className='spoiler-button__overlay' onClick={this.toggleReveal}>
+            <span className='spoiler-button__overlay__label'>{warning}</span>
+          </button>
+        </div>
 
         <div className={classNames('video-player__controls', { active: paused || hovered })}>
           <div className='video-player__seek' onMouseDown={this.handleMouseDown} ref={this.setSeekRef}>
diff --git a/app/javascript/styles/mastodon/components.scss b/app/javascript/styles/mastodon/components.scss
index 0b1fd3652..48970f8bd 100644
--- a/app/javascript/styles/mastodon/components.scss
+++ b/app/javascript/styles/mastodon/components.scss
@@ -2412,7 +2412,7 @@ a.account__display-name {
 
     & > div {
       background: rgba($base-shadow-color, 0.6);
-      border-radius: 4px;
+      border-radius: 8px;
       padding: 12px 9px;
       flex: 0 0 auto;
       display: flex;
@@ -2423,19 +2423,18 @@ a.account__display-name {
     button,
     a {
       display: inline;
-      color: $primary-text-color;
+      color: $secondary-text-color;
       background: transparent;
       border: 0;
-      padding: 0 5px;
+      padding: 0 8px;
       text-decoration: none;
-      opacity: 0.6;
       font-size: 18px;
       line-height: 18px;
 
       &:hover,
       &:active,
       &:focus {
-        opacity: 1;
+        color: $primary-text-color;
       }
     }
 
@@ -2932,15 +2931,49 @@ a.status-card.compact:hover {
 }
 
 .spoiler-button {
-  display: none;
-  left: 4px;
+  top: 0;
+  left: 0;
+  width: 100%;
+  height: 100%;
   position: absolute;
-  text-shadow: 0 1px 1px $base-shadow-color, 1px 0 1px $base-shadow-color;
-  top: 4px;
   z-index: 100;
 
-  &.spoiler-button--visible {
+  &--minified {
     display: block;
+    left: 4px;
+    top: 4px;
+    width: auto;
+    height: auto;
+  }
+
+  &--hidden {
+    display: none;
+  }
+
+  &__overlay {
+    display: block;
+    background: transparent;
+    width: 100%;
+    height: 100%;
+    border: 0;
+
+    &__label {
+      display: inline-block;
+      background: rgba($base-overlay-background, 0.5);
+      border-radius: 8px;
+      padding: 8px 12px;
+      color: $primary-text-color;
+      font-weight: 500;
+      font-size: 14px;
+    }
+
+    &:hover,
+    &:focus,
+    &:active {
+      .spoiler-button__overlay__label {
+        background: rgba($base-overlay-background, 0.8);
+      }
+    }
   }
 }
 
@@ -4313,6 +4346,8 @@ a.status-card.compact:hover {
   text-decoration: none;
   color: $secondary-text-color;
   line-height: 0;
+  position: relative;
+  z-index: 1;
 
   &,
   img {
@@ -4325,6 +4360,21 @@ a.status-card.compact:hover {
   }
 }
 
+.media-gallery__preview {
+  width: 100%;
+  height: 100%;
+  object-fit: cover;
+  position: absolute;
+  top: 0;
+  left: 0;
+  z-index: 0;
+  background: $base-overlay-background;
+
+  &--hidden {
+    display: none;
+  }
+}
+
 .media-gallery__gifv {
   height: 100%;
   overflow: hidden;
diff --git a/app/lib/activitypub/activity/create.rb b/app/lib/activitypub/activity/create.rb
index dabdcbcf7..6b16c9986 100644
--- a/app/lib/activitypub/activity/create.rb
+++ b/app/lib/activitypub/activity/create.rb
@@ -194,7 +194,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
       next if attachment['url'].blank?
 
       href             = Addressable::URI.parse(attachment['url']).normalize.to_s
-      media_attachment = MediaAttachment.create(account: @account, remote_url: href, description: attachment['name'].presence, focus: attachment['focalPoint'])
+      media_attachment = MediaAttachment.create(account: @account, remote_url: href, description: attachment['name'].presence, focus: attachment['focalPoint'], blurhash: supported_blurhash?(attachment['blurhash']) ? attachment['blurhash'] : nil)
       media_attachments << media_attachment
 
       next if unsupported_media_type?(attachment['mediaType']) || skip_download?
@@ -369,6 +369,11 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     mime_type.present? && !(MediaAttachment::IMAGE_MIME_TYPES + MediaAttachment::VIDEO_MIME_TYPES).include?(mime_type)
   end
 
+  def supported_blurhash?(blurhash)
+    components = blurhash.blank? ? nil : Blurhash.components(blurhash)
+    components.present? && components.none? { |comp| comp > 5 }
+  end
+
   def skip_download?
     return @skip_download if defined?(@skip_download)
     @skip_download ||= DomainBlock.find_by(domain: @account.domain)&.reject_media?
diff --git a/app/lib/activitypub/adapter.rb b/app/lib/activitypub/adapter.rb
index 94eb2899c..c259c96f4 100644
--- a/app/lib/activitypub/adapter.rb
+++ b/app/lib/activitypub/adapter.rb
@@ -19,6 +19,7 @@ class ActivityPub::Adapter < ActiveModelSerializers::Adapter::Base
     conversation: { 'ostatus' => 'http://ostatus.org#', 'inReplyToAtomUri' => 'ostatus:inReplyToAtomUri', 'conversation' => 'ostatus:conversation' },
     focal_point: { 'toot' => 'http://joinmastodon.org/ns#', 'focalPoint' => { '@container' => '@list', '@id' => 'toot:focalPoint' } },
     identity_proof: { 'toot' => 'http://joinmastodon.org/ns#', 'IdentityProof' => 'toot:IdentityProof' },
+    blurhash: { 'toot' => 'http://joinmastodon.org/ns#', 'blurhash' => 'toot:blurhash' },
   }.freeze
 
   def self.default_key_transform
diff --git a/app/models/media_attachment.rb b/app/models/media_attachment.rb
index a57ba0b2e..ab794faa0 100644
--- a/app/models/media_attachment.rb
+++ b/app/models/media_attachment.rb
@@ -18,6 +18,7 @@
 #  account_id          :bigint(8)
 #  description         :text
 #  scheduled_status_id :bigint(8)
+#  blurhash            :string
 #
 
 class MediaAttachment < ApplicationRecord
@@ -32,6 +33,11 @@ class MediaAttachment < ApplicationRecord
   VIDEO_MIME_TYPES             = ['video/webm', 'video/mp4', 'video/quicktime'].freeze
   VIDEO_CONVERTIBLE_MIME_TYPES = ['video/webm', 'video/quicktime'].freeze
 
+  BLURHASH_OPTIONS = {
+    x_comp: 4,
+    y_comp: 4,
+  }.freeze
+
   IMAGE_STYLES = {
     original: {
       pixels: 1_638_400, # 1280x1280px
@@ -41,6 +47,7 @@ class MediaAttachment < ApplicationRecord
     small: {
       pixels: 160_000, # 400x400px
       file_geometry_parser: FastGeometryParser,
+      blurhash: BLURHASH_OPTIONS,
     },
   }.freeze
 
@@ -53,6 +60,8 @@ class MediaAttachment < ApplicationRecord
       },
       format: 'png',
       time: 0,
+      file_geometry_parser: FastGeometryParser,
+      blurhash: BLURHASH_OPTIONS,
     },
   }.freeze
 
@@ -166,11 +175,11 @@ class MediaAttachment < ApplicationRecord
 
     def file_processors(f)
       if f.file_content_type == 'image/gif'
-        [:gif_transcoder]
+        [:gif_transcoder, :blurhash_transcoder]
       elsif VIDEO_MIME_TYPES.include? f.file_content_type
-        [:video_transcoder]
+        [:video_transcoder, :blurhash_transcoder]
       else
-        [:lazy_thumbnail]
+        [:lazy_thumbnail, :blurhash_transcoder]
       end
     end
   end
diff --git a/app/serializers/activitypub/note_serializer.rb b/app/serializers/activitypub/note_serializer.rb
index d11cfa59a..67f596e78 100644
--- a/app/serializers/activitypub/note_serializer.rb
+++ b/app/serializers/activitypub/note_serializer.rb
@@ -2,7 +2,7 @@
 
 class ActivityPub::NoteSerializer < ActivityPub::Serializer
   context_extensions :atom_uri, :conversation, :sensitive,
-                     :hashtag, :emoji, :focal_point
+                     :hashtag, :emoji, :focal_point, :blurhash
 
   attributes :id, :type, :summary,
              :in_reply_to, :published, :url,
@@ -153,7 +153,7 @@ class ActivityPub::NoteSerializer < ActivityPub::Serializer
   class MediaAttachmentSerializer < ActivityPub::Serializer
     include RoutingHelper
 
-    attributes :type, :media_type, :url, :name
+    attributes :type, :media_type, :url, :name, :blurhash
     attribute :focal_point, if: :focal_point?
 
     def type
diff --git a/app/serializers/rest/media_attachment_serializer.rb b/app/serializers/rest/media_attachment_serializer.rb
index 51011788b..1b3498ea4 100644
--- a/app/serializers/rest/media_attachment_serializer.rb
+++ b/app/serializers/rest/media_attachment_serializer.rb
@@ -5,7 +5,7 @@ class REST::MediaAttachmentSerializer < ActiveModel::Serializer
 
   attributes :id, :type, :url, :preview_url,
              :remote_url, :text_url, :meta,
-             :description
+             :description, :blurhash
 
   def id
     object.id.to_s
diff --git a/app/views/stream_entries/_detailed_status.html.haml b/app/views/stream_entries/_detailed_status.html.haml
index 4459581d9..23f2920d8 100644
--- a/app/views/stream_entries/_detailed_status.html.haml
+++ b/app/views/stream_entries/_detailed_status.html.haml
@@ -28,7 +28,7 @@
   - elsif !status.media_attachments.empty?
     - if status.media_attachments.first.video?
       - video = status.media_attachments.first
-      = react_component :video, src: video.file.url(:original), preview: video.file.url(:small), sensitive: !current_account&.user&.show_all_media? && status.sensitive? || current_account&.user&.hide_all_media?, width: 670, height: 380, detailed: true, inline: true, alt: video.description do
+      = react_component :video, src: video.file.url(:original), preview: video.file.url(:small), blurhash: video.blurhash, sensitive: !current_account&.user&.show_all_media? && status.sensitive? || current_account&.user&.hide_all_media?, width: 670, height: 380, detailed: true, inline: true, alt: video.description do
         = render partial: 'stream_entries/attachment_list', locals: { attachments: status.media_attachments }
     - else
       = react_component :media_gallery, height: 380, sensitive: !current_account&.user&.show_all_media? && status.sensitive? || current_account&.user&.hide_all_media?, standalone: true, 'autoPlayGif': current_account&.user&.setting_auto_play_gif || autoplay, 'reduceMotion': current_account&.user&.setting_reduce_motion, media: status.media_attachments.map { |a| ActiveModelSerializers::SerializableResource.new(a, serializer: REST::MediaAttachmentSerializer).as_json } do
diff --git a/app/views/stream_entries/_simple_status.html.haml b/app/views/stream_entries/_simple_status.html.haml
index ba22c5340..0df7497e1 100644
--- a/app/views/stream_entries/_simple_status.html.haml
+++ b/app/views/stream_entries/_simple_status.html.haml
@@ -32,7 +32,7 @@
   - elsif !status.media_attachments.empty?
     - if status.media_attachments.first.video?
       - video = status.media_attachments.first
-      = react_component :video, src: video.file.url(:original), preview: video.file.url(:small), sensitive: !current_account&.user&.show_all_media? && status.sensitive? || current_account&.user&.hide_all_media?, width: 610, height: 343, inline: true, alt: video.description do
+      = react_component :video, src: video.file.url(:original), preview: video.file.url(:small), blurhash: video.blurhash, sensitive: !current_account&.user&.show_all_media? && status.sensitive? || current_account&.user&.hide_all_media?, width: 610, height: 343, inline: true, alt: video.description do
         = render partial: 'stream_entries/attachment_list', locals: { attachments: status.media_attachments }
     - else
       = react_component :media_gallery, height: 343, sensitive: !current_account&.user&.show_all_media? && status.sensitive? || current_account&.user&.hide_all_media?, 'autoPlayGif': current_account&.user&.setting_auto_play_gif || autoplay, media: status.media_attachments.map { |a| ActiveModelSerializers::SerializableResource.new(a, serializer: REST::MediaAttachmentSerializer).as_json } do
diff --git a/db/migrate/20190420025523_add_blurhash_to_media_attachments.rb b/db/migrate/20190420025523_add_blurhash_to_media_attachments.rb
new file mode 100644
index 000000000..f2bbe0a85
--- /dev/null
+++ b/db/migrate/20190420025523_add_blurhash_to_media_attachments.rb
@@ -0,0 +1,5 @@
+class AddBlurhashToMediaAttachments < ActiveRecord::Migration[5.2]
+  def change
+    add_column :media_attachments, :blurhash, :string
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 3060159d2..8613539d6 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2019_04_09_054914) do
+ActiveRecord::Schema.define(version: 2019_04_20_025523) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -362,6 +362,7 @@ ActiveRecord::Schema.define(version: 2019_04_09_054914) do
     t.bigint "account_id"
     t.text "description"
     t.bigint "scheduled_status_id"
+    t.string "blurhash"
     t.index ["account_id"], name: "index_media_attachments_on_account_id"
     t.index ["scheduled_status_id"], name: "index_media_attachments_on_scheduled_status_id"
     t.index ["shortcode"], name: "index_media_attachments_on_shortcode", unique: true
diff --git a/lib/paperclip/blurhash_transcoder.rb b/lib/paperclip/blurhash_transcoder.rb
new file mode 100644
index 000000000..08925a6dd
--- /dev/null
+++ b/lib/paperclip/blurhash_transcoder.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+module Paperclip
+  class BlurhashTranscoder < Paperclip::Processor
+    def make
+      return @file unless options[:style] == :small
+
+      pixels   = convert(':source RGB:-', source: File.expand_path(@file.path)).unpack('C*')
+      geometry = options.fetch(:file_geometry_parser).from_file(@file)
+
+      attachment.instance.blurhash = Blurhash.encode(geometry.width, geometry.height, pixels, options[:blurhash] || {})
+
+      @file
+    end
+  end
+end
diff --git a/package.json b/package.json
index 63cfa25b8..67396ccc3 100644
--- a/package.json
+++ b/package.json
@@ -78,6 +78,7 @@
     "babel-plugin-react-intl": "^3.0.1",
     "babel-plugin-transform-react-remove-prop-types": "^0.4.24",
     "babel-runtime": "^6.26.0",
+    "blurhash": "^1.0.0",
     "classnames": "^2.2.5",
     "compression-webpack-plugin": "^2.0.0",
     "cross-env": "^5.1.4",
diff --git a/yarn.lock b/yarn.lock
index 9d7f0eccb..329216cdb 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1743,6 +1743,11 @@ bluebird@^3.5.1, bluebird@^3.5.3:
   resolved "https://registry.yarnpkg.com/bluebird/-/bluebird-3.5.3.tgz#7d01c6f9616c9a51ab0f8c549a79dfe6ec33efa7"
   integrity sha512-/qKPUQlaW1OyR51WeCPBvRnAlnZFUJkCSG5HzGnuIqhgyJtF+T94lFnn33eiazjRm2LAHVy2guNnaq48X9SJuw==
 
+blurhash@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/blurhash/-/blurhash-1.0.0.tgz#9087bc5cc4d482f1305059d7410df4133adcab2e"
+  integrity sha512-x6fpZnd6AWde4U9m7xhUB44qIvGV4W6OdTAXGabYm4oZUOOGh5K1HAEoGAQn3iG4gbbPn9RSGce3VfNgGsX/Vw==
+
 bn.js@^4.0.0, bn.js@^4.1.0, bn.js@^4.1.1, bn.js@^4.4.0:
   version "4.11.8"
   resolved "https://registry.yarnpkg.com/bn.js/-/bn.js-4.11.8.tgz#2cde09eb5ee341f484746bb0309b3253b1b1442f"