element-web/src/components/views/elements/ImageView.js

/*
Copyright 2015, 2016 OpenMarket Ltd
Copyright 2019 Michael Telatynski <7t3chguy@gmail.com>

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import React, { createRef } from 'react';
import PropTypes from 'prop-types';
import { _t } from '../../../languageHandler';
import AccessibleTooltipButton from "./AccessibleTooltipButton";
import {Key} from "../../../Keyboard";
import FocusLock from "react-focus-lock";
import MemberAvatar from "../avatars/MemberAvatar";
import {ContextMenuTooltipButton} from "../../../accessibility/context_menu/ContextMenuTooltipButton";
import MessageContextMenu from "../context_menus/MessageContextMenu";
import {aboveLeftOf, ContextMenu} from '../../structures/ContextMenu';
import MessageTimestamp from "../messages/MessageTimestamp";
import SettingsStore from "../../../settings/SettingsStore";
import {formatFullDate} from "../../../DateUtils";
import dis from '../../../dispatcher/dispatcher';
import {replaceableComponent} from "../../../utils/replaceableComponent";

const MIN_ZOOM = 100;
const MAX_ZOOM = 300;
const ZOOM_STEP = 10;

@replaceableComponent("views.elements.ImageView")
export default class ImageView extends React.Component {
    static propTypes = {
        src: PropTypes.string.isRequired, // the source of the image being displayed
        name: PropTypes.string, // the main title ('name') for the image
        link: PropTypes.string, // the link (if any) applied to the name of the image
        width: PropTypes.number, // width of the image src in pixels
        height: PropTypes.number, // height of the image src in pixels
        fileSize: PropTypes.number, // size of the image src in bytes
        onFinished: PropTypes.func.isRequired, // callback when the lightbox is dismissed

        // the event (if any) that the Image is displaying. Used for event-specific stuff like
        // redactions, senders, timestamps etc.  Other descriptors are taken from the explicit
        // properties above, which let us use lightboxes to display images which aren't associated
        // with events.
        mxEvent: PropTypes.object,
        permalinkCreator: PropTypes.object,
    };

    constructor(props) {
        super(props);
        this.state = {
            rotation: 0,
            zoom: 100,
            translationX: 0,
            translationY: 0,
            moving: false,
            contextMenuDisplayed: false,
        };
    }

    contextMenuButton = createRef();
    initX = 0;
    initY = 0;
    lastX = 0;
    lastY = 0;

    componentDidMount() {
        // We have to use addEventListener() because the listener
        // needs to be passive in order to work with Chromium
        this.focusLock.addEventListener('wheel', this.onWheel, { passive: false });
    }

    componentWillUnmount() {
        this.focusLock.removeEventListener('wheel', this.onWheel);
    }

    onKeyDown = (ev) => {
        if (ev.key === Key.ESCAPE) {
            ev.stopPropagation();
            ev.preventDefault();
            this.props.onFinished();
        }
    };

    onWheel = (ev) => {
        ev.stopPropagation();
        ev.preventDefault();
        const newZoom = this.state.zoom - ev.deltaY;

        if (newZoom <= MIN_ZOOM) {
            this.setState({
                zoom: MIN_ZOOM,
                translationX: 0,
                translationY: 0,
            });
            return;
        }
        if (newZoom >= MAX_ZOOM) {
            this.setState({zoom: MAX_ZOOM});
            return;
        }

        this.setState({
            zoom: newZoom,
        });
    }

    onRotateCounterClockwiseClick = () => {
        const cur = this.state.rotation;
        const rotationDegrees = (cur - 90) % 360;
        this.setState({ rotation: rotationDegrees });
    };

    onRotateClockwiseClick = () => {
        const cur = this.state.rotation;
        const rotationDegrees = (cur + 90) % 360;
        this.setState({ rotation: rotationDegrees });
    };

    onZoomInClick = () => {
        if (this.state.zoom >= MAX_ZOOM) {
            this.setState({zoom: MAX_ZOOM});
            return;
        }

        this.setState({
            zoom: this.state.zoom + ZOOM_STEP,
        });
    };

    onZoomOutClick = () => {
        if (this.state.zoom <= MIN_ZOOM) {
            this.setState({
                zoom: MIN_ZOOM,
                translationX: 0,
                translationY: 0,
            });
            return;
        }
        this.setState({
            zoom: this.state.zoom - ZOOM_STEP,
        });
    }

    onDownloadClick = () => {
        const a = document.createElement("a");
        a.href = this.props.src;
        a.download = this.props.name;
        a.click();
    }

    onOpenContextMenu = () => {
        this.setState({
            contextMenuDisplayed: true,
        });
    }

    onCloseContextMenu = () => {
        this.setState({
            contextMenuDisplayed: false,
        });
    }

    onPermalinkClicked = (ev) => {
        // This allows the permalink to be opened in a new tab/window or copied as
        // matrix.to, but also for it to enable routing within Element when clicked.
        ev.preventDefault();
        dis.dispatch({
            action: 'view_room',
            event_id: this.props.mxEvent.getId(),
            highlighted: true,
            room_id: this.props.mxEvent.getRoomId(),
        });
        this.props.onFinished();
    };

    onStartMoving = (ev) => {
        ev.stopPropagation();
        ev.preventDefault();

        this.setState({moving: true});
        this.initX = ev.pageX - this.lastX;
        this.initY = ev.pageY - this.lastY;
    }

    onMoving = (ev) => {
        ev.stopPropagation();
        ev.preventDefault();

        if (!this.state.moving) return false;

        this.lastX = ev.pageX - this.initX;
        this.lastY = ev.pageY - this.initY;
        this.setState({
            translationX: this.lastX,
            translationY: this.lastY,
        });
    }

    onEndMoving = () => {
        this.setState({moving: false});
    }

    renderContextMenu() {
        let contextMenu = null;
        if (this.state.contextMenuDisplayed) {
            contextMenu = (
                <ContextMenu
                    {...aboveLeftOf(this.contextMenuButton.current.getBoundingClientRect())}
                    onFinished={this.onCloseContextMenu}
                >
                    <MessageContextMenu
                        mxEvent={this.props.mxEvent}
                        permalinkCreator={this.props.permalinkCreator}
                        onFinished={this.onCloseContextMenu}
                    />
                </ContextMenu>
            );
        }

        return (
            <React.Fragment>
                { contextMenu }
            </React.Fragment>
        );
    }

    render() {
        const showEventMeta = !!this.props.mxEvent;

        const rotationDegrees = this.state.rotation + "deg";
        const zoomPercentage = this.state.zoom/100;
        const translatePixelsX = this.state.translationX + "px";
        const translatePixelsY = this.state.translationY + "px";
        // The order of the values is important!
        // First, we translate and only then we rotate, otherwise
        // we would apply the translation to an already rotated
        // image causing it translate in the wrong direction.
        const style = {
            cursor: this.state.moving ? "grabbing" : "grab",
            transform: `translateX(${translatePixelsX})
                        translateY(${translatePixelsY})
                        scale(${zoomPercentage})
                        rotate(${rotationDegrees})`,
        };

        let info;
        if (showEventMeta) {
            const mxEvent = this.props.mxEvent;
            const showTwelveHour = SettingsStore.getValue("showTwelveHourTimestamps");
            let permalink = "#";
            if (this.props.permalinkCreator) {
                permalink = this.props.permalinkCreator.forEvent(this.props.mxEvent.getId());
            }

            const senderName = mxEvent.sender ? mxEvent.sender.name : mxEvent.getSender();
            const messageTimestamp = (
                <a
                    href={permalink}
                    onClick={this.onPermalinkClicked}
                    aria-label={formatFullDate(new Date(this.props.mxEvent.getTs()), this.props.isTwelveHour)}
                >
                    <MessageTimestamp showFullDate={true} showTwelveHour={showTwelveHour} ts={mxEvent.getTs()} />
                </a>

            );
            const avatar = (
                <MemberAvatar
                    member={mxEvent.sender}
                    width={32} height={32}
                    viewUserOnClick={true}
                />
            );

            info = (
                <div className="mx_ImageView_info_wrapper">
                    {avatar}
                    <div className="mx_ImageView_info">
                        {senderName}
                        {messageTimestamp}
                    </div>
                </div>
            );
        } else {
            // If there is no event - we're viewing an avatar, we set
            // an empty div here, since the panel uses space-between
            // and we want the same placement of elements
            info = (
                <div></div>
            );
        }

        return (
            <FocusLock
                returnFocus={true}
                lockProps={{
                    onKeyDown: this.onKeyDown,
                    role: "dialog",
                }}
                className="mx_ImageView"
                ref={ref => this.focusLock = ref}
            >
                    <div className="mx_ImageView_panel">
                        {info}
                        <div className="mx_ImageView_toolbar">
                            <AccessibleTooltipButton
                                className="mx_ImageView_button mx_ImageView_button_rotateCW"
                                title={_t("Rotate Right")}
                                onClick={this.onRotateClockwiseClick}>
                            </AccessibleTooltipButton>
                            <AccessibleTooltipButton
                                className="mx_ImageView_button mx_ImageView_button_rotateCCW"
                                title={_t("Rotate Left")}
                                onClick={ this.onRotateCounterClockwiseClick }>
                            </AccessibleTooltipButton>
                            <AccessibleTooltipButton
                                className="mx_ImageView_button mx_ImageView_button_zoomOut"
                                title={_t("Zoom out")}
                                onClick={ this.onZoomOutClick }>
                            </AccessibleTooltipButton>
                            <AccessibleTooltipButton
                                className="mx_ImageView_button mx_ImageView_button_zoomIn"
                                title={_t("Zoom in")}
                                onClick={ this.onZoomInClick }>
                            </AccessibleTooltipButton>
                            <AccessibleTooltipButton
                                className="mx_ImageView_button mx_ImageView_button_download"
                                title={_t("Download")}
                                onClick={ this.onDownloadClick }>
                            </AccessibleTooltipButton>
                            <ContextMenuTooltipButton
                                className="mx_ImageView_button mx_ImageView_button_more"
                                title={_t("Options")}
                                onClick={this.onOpenContextMenu}
                                inputRef={this.contextMenuButton}
                            />
                            <AccessibleTooltipButton
                                className="mx_ImageView_button mx_ImageView_button_close"
                                title={_t("Close")}
                                onClick={ this.props.onFinished }>
                            </AccessibleTooltipButton>
                            {this.renderContextMenu()}
                        </div>
                    </div>
                    <div className="mx_ImageView_image_wrapper">
                        <img
                            src={this.props.src}
                            title={this.props.name}
                            style={style}
                            className="mx_ImageView_image"
                            draggable={true}
                            onMouseDown={this.onStartMoving}
                            onMouseMove={this.onMoving}
                            onMouseUp={this.onEndMoving}
                            onMouseLeave={this.onEndMoving}
                        />
                    </div>
            </FocusLock>
        );
    }
}