Cura/resources/qml/ExpandableComponent.qml

import QtQuick 2.7
import QtQuick.Controls 2.3

import UM 1.2 as UM
import Cura 1.0 as Cura

import QtGraphicalEffects 1.0 // For the dropshadow

// The expandable component has 2 major sub components:
//      * The headerItem; Always visible and should hold some info about what happens if the component is expanded
//      * The contentItem; The content that needs to be shown if the component is expanded.
Item
{
    id: base

    // Enumeration with the different possible alignments of the content with respect of the headerItem
    enum ContentAlignment
    {
        AlignLeft,
        AlignRight
    }

    // The headerItem holds the QML item that is always displayed.
    property alias headerItem: headerItemLoader.sourceComponent

    // The contentItem holds the QML item that is shown when the "open" button is pressed
    property alias contentItem: content.contentItem

    property color contentBackgroundColor: UM.Theme.getColor("action_button")

    property color headerBackgroundColor: UM.Theme.getColor("action_button")
    property color headerActiveColor: UM.Theme.getColor("secondary")
    property color headerHoverColor: UM.Theme.getColor("action_button_hovered")

    property alias enabled: mouseArea.enabled

    // Defines the alignment of the content with respect of the headerItem, by default to the right
    property int contentAlignment: ExpandableComponent.ContentAlignment.AlignRight

    // How much spacing is needed around the contentItem
    property alias contentPadding: content.padding

    // How much spacing is needed for the contentItem by Y coordinate
    property var contentSpacingY: UM.Theme.getSize("narrow_margin").width

    // How much padding is needed around the header & button
    property alias headerPadding: background.padding

    // What icon should be displayed on the right.
    property alias iconSource: collapseButton.source

    property alias iconColor: collapseButton.color

    // The icon size (it's always drawn as a square)
    property alias iconSize: collapseButton.height

    // Is the "drawer" open?
    readonly property alias expanded: content.visible

    // What should the radius of the header be. This is also influenced by the headerCornerSide
    property alias headerRadius: background.radius

    // On what side should the header corners be shown? 1 is down, 2 is left, 3 is up and 4 is right.
    property alias headerCornerSide: background.cornerSide

    property alias headerShadowColor: shadow.color

    property alias enableHeaderShadow: shadow.visible

    property int shadowOffset: 2

    function toggleContent()
    {
        content.visible = !content.visible
    }

    implicitHeight: 100 * screenScaleFactor
    implicitWidth: 400 * screenScaleFactor

    RoundedRectangle
    {
        id: background
        property real padding: UM.Theme.getSize("default_margin").width

        color: headerBackgroundColor
        anchors.fill: parent

        Loader
        {
            id: headerItemLoader
            anchors
            {
                left: parent.left
                right: collapseButton.visible ? collapseButton.left : parent.right
                top: parent.top
                bottom: parent.bottom
                margins: background.padding
            }
        }

        UM.RecolorImage
        {
            id: collapseButton
            anchors
            {
                right: parent.right
                verticalCenter: parent.verticalCenter
                margins: background.padding
            }
            source: UM.Theme.getIcon("pencil")
            visible: source != "" && base.enabled
            width: UM.Theme.getSize("standard_arrow").width
            height: UM.Theme.getSize("standard_arrow").height
            color: UM.Theme.getColor("small_button_text")
        }

        MouseArea
        {
            id: mouseArea
            anchors.fill: parent
            onClicked: toggleContent()
            hoverEnabled: true
            onEntered: background.color = headerHoverColor
            onExited: background.color = expanded ? headerActiveColor : headerBackgroundColor
        }
    }

    DropShadow
    {
        id: shadow
        // Don't blur the shadow
        radius: 0
        anchors.fill: background
        source: background
        verticalOffset: base.shadowOffset
        visible: true
        color: UM.Theme.getColor("action_button_shadow")
        // Should always be drawn behind the background.
        z: background.z - 1
    }

    Control
    {
        id: content
        visible: false

        // Ensure that the content is located directly below the headerItem
        y: background.height + base.shadowOffset + base.contentSpacingY

        // Make the content aligned with the rest, using the property contentAlignment to decide whether is right or left.
        // In case of right alignment, the 3x padding is due to left, right and padding between the button & text.
        x: contentAlignment == ExpandableComponent.ContentAlignment.AlignRight ? -width + collapseButton.width + headerItemLoader.width + 3 * background.padding : 0
        padding: UM.Theme.getSize("default_margin").width

        background: Cura.RoundedRectangle
        {
            cornerSide: Cura.RoundedRectangle.Direction.Down
            color: contentBackgroundColor
            border.width: UM.Theme.getSize("default_lining").width
            border.color: UM.Theme.getColor("lining")
            radius: UM.Theme.getSize("default_radius").width
        }

        contentItem: Item {}

        onContentItemChanged:
        {
            // Since we want the size of the content to be set by the size of the content,
            // we need to do it like this.
            content.width = contentItem.width + 2 * content.padding
            content.height = contentItem.height + 2 * content.padding
        }
    }

    // DO NOT MOVE UP IN THE CODE: This connection has to be here, after the definition of the content item.
    // Apparently the order in which these are handled matters and so the height is correctly updated if this is here.
    Connections
    {
        // Since it could be that the content is dynamically populated, we should also take these changes into account.
        target: content.contentItem
        onWidthChanged: content.width = content.contentItem.width + 2 * content.padding
        onHeightChanged: content.height = content.contentItem.height + 2 * content.padding
    }
}