matrixion/resources/qml/delegates/ImageMessage.qml

import QtQuick 2.6
import im.nheko 1.0

Item {
    property double tempWidth: Math.min(parent ? parent.width : undefined, model.data.width < 1 ? parent.width : model.data.width)
    property double tempHeight: tempWidth * model.data.proportionalHeight
    property double divisor: model.isReply ? 4 : 2
    property bool tooHigh: tempHeight > timelineRoot.height / divisor

    height: Math.round(tooHigh ? timelineRoot.height / divisor : tempHeight)
    width: Math.round(tooHigh ? (timelineRoot.height / divisor) / model.data.proportionalHeight : tempWidth)

    Image {
        id: blurhash

        anchors.fill: parent
        visible: img.status != Image.Ready
        source: model.data.blurhash ? ("image://blurhash/" + model.data.blurhash) : ("image://colorimage/:/icons/icons/ui/do-not-disturb-rounded-sign@2x.png?" + colors.buttonText)
        asynchronous: true
        fillMode: Image.PreserveAspectFit
        sourceSize.width: parent.width
        sourceSize.height: parent.height
    }

    Image {
        id: img

        anchors.fill: parent
        source: model.data.url.replace("mxc://", "image://MxcImage/")
        asynchronous: true
        fillMode: Image.PreserveAspectFit

        MouseArea {
            id: mouseArea
            enabled: model.data.type == MtxEvent.ImageMessage && img.status == Image.Ready
            hoverEnabled: true
            anchors.fill: parent
            onClicked: TimelineManager.openImageOverlay(model.data.url, model.data.id)
        }

        Item {
            id: overlay
        
            anchors.fill: parent
            visible: mouseArea.containsMouse
            
            Rectangle {
                id: container
                width: parent.width
                implicitHeight: imgcaption.implicitHeight
                anchors.bottom: overlay.bottom 
                color: "black"
                opacity: 0.75

                Text {
                    id: imgcaption

                    anchors.fill: parent
                    elide: Text.ElideMiddle
                    horizontalAlignment: Text.AlignHCenter
                    verticalAlignment: Text.AlignVCenter
                    // See this MSC: https://github.com/matrix-org/matrix-doc/pull/2530
                    text: model.data.filename ? model.data.filename : model.data.body
                    font.pointSize: 11
                    color: "white"
                }
            }
        }
    }
}