[ui] Viewer2D: add FeaturesViewer + dedicated overlay

Make FeaturesViewer available in Viewer2D to display the feature points of the current view, based on the current FeatureExtraction node.

* FeaturesInfoOverlay: overlay that displays info and provides controls over a FeaturesViewer component.
* ColorChart: color picker based on a set of predefined colors.

meshroom/ui/qml/Controls/ColorChart.qml

@@ -0,0 +1,66 @@
+import QtQuick 2.10
+import QtQuick.Controls 2.10
+
+import Utils 1.0
+
+/**
+ * ColorChart is a color picker based on a set of predefined colors.
+ * It takes the form of a ToolButton that pops-up its palette when pressed.
+ */
+ToolButton {
+    id: root
+
+    property var colors: ["red", "green", "blue"]
+    property int currentIndex: 0
+
+    signal colorPicked(var colorIndex)
+
+    background: Rectangle {
+        color: root.colors[root.currentIndex]
+        border.width: hovered ? 1 : 0
+        border.color: Colors.sysPalette.midlight
+    }
+
+    onPressed: palettePopup.open()
+
+    // Popup for the color palette
+    Popup {
+        id: palettePopup
+
+        padding: 4
+        // content width is missing side padding (hence the + padding*2)
+        implicitWidth: colorChart.contentItem.width + padding*2
+
+        // center the current color
+        y: - (root.height - padding) / 2
+        x: - colorChart.currentItem.x - padding
+
+        // Colors palette
+        ListView {
+            id: colorChart
+            implicitHeight: contentItem.childrenRect.height
+            implicitWidth: contentWidth
+            orientation: ListView.Horizontal
+            spacing: 2
+            currentIndex: root.currentIndex
+            model: root.colors
+            // display each color as a ToolButton with a custom background
+            delegate: ToolButton {
+                padding: 0
+                width: root.width
+                height: root.height
+                background: Rectangle {
+                    color: modelData
+                    // display border of current/selected item
+                    border.width: hovered || index === colorChart.currentIndex ? 1 : 0
+                    border.color: Colors.sysPalette.midlight
+                }
+
+                onClicked: {
+                    colorPicked(index);
+                    palettePopup.close();
+                }
+            }
+        }
+    }
+}

meshroom/ui/qml/Controls/qmldir

@@ -1,5 +1,6 @@
 module Controls
 
+ColorChart 1.0 ColorChart.qml
 FloatingPane 1.0 FloatingPane.qml
 Group 1.0 Group.qml
 MessageDialog 1.0 MessageDialog.qml

meshroom/ui/qml/Viewer/FeaturesInfoOverlay.qml

@@ -0,0 +1,111 @@
+import QtQuick 2.11
+import QtQuick.Controls 2.11
+import QtQuick.Layouts 1.3
+import MaterialIcons 2.2
+
+import Utils 1.0
+import Controls 1.0
+
+/**
+ * FeaturesInfoOverlay is an overlay that displays info and
+ * provides controls over a FeaturesViewer component.
+ */
+FloatingPane {
+    id: root
+
+    property int pluginStatus: Loader.Null
+    property Item featuresViewer: null
+    property var featureExtractionNode: null
+
+    ColumnLayout {
+
+        // Header
+        RowLayout {
+            // FeatureExtraction node name
+            Label {
+                text: featureExtractionNode.label
+                Layout.fillWidth: true
+            }
+            // Settings menu
+            Loader {
+                active: root.pluginStatus === Loader.Ready
+                sourceComponent: MaterialToolButton {
+                    text: MaterialIcons.settings
+                    font.pointSize: 10
+                    onClicked: settingsMenu.popup(width, 0)
+                    Menu {
+                        id: settingsMenu
+                        padding: 4
+                        implicitWidth: 210
+
+                        RowLayout {
+                            Label {
+                                text: "Display Mode:"
+                            }
+                            ComboBox {
+                                id: displayModeCB
+                                flat: true
+                                Layout.fillWidth: true
+                                model: featuresViewer.displayModes
+                                onActivated: featuresViewer.displayMode = currentIndex
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        // Error message if AliceVision plugin is unavailable
+        Label {
+            visible: root.pluginStatus === Loader.Error
+            text: "AliceVision plugin is required to display Features"
+            color: Colors.red
+        }
+
+        // Feature types
+        ListView {
+            implicitHeight: contentHeight
+            implicitWidth: contentItem.childrenRect.width
+
+            model: featuresViewer !== null ? featuresViewer.model : 0
+
+            delegate: RowLayout {
+                id: featureType
+
+                property var viewer: featuresViewer.itemAt(index)
+                spacing: 4
+
+                // Visibility toogle
+                MaterialToolButton {
+                    text: featureType.viewer.visible ? MaterialIcons.visibility : MaterialIcons.visibility_off
+                    onClicked: featureType.viewer.visible = !featureType.viewer.visible
+                    font.pointSize: 10
+                    opacity: featureType.viewer.visible ? 1.0 : 0.6
+                }
+                // ColorChart picker
+                ColorChart {
+                    implicitWidth: 12
+                    implicitHeight: implicitWidth
+                    colors: featuresViewer.colors
+                    currentIndex: featureType.viewer.colorIndex
+                    // offset FeaturesViewer color set when changing the color of one feature type
+                    onColorPicked: featuresViewer.colorOffset = colorIndex - index
+                }
+                // Feature type name
+                Label {
+                    text: featureType.viewer.describerType + (featureType.viewer.loading ? "" : ": " + featureType.viewer.features.length)
+                }
+                // Feature loading status
+                Loader {
+                    active: featureType.viewer.loading
+                    sourceComponent: BusyIndicator {
+                        padding: 0
+                        implicitWidth: 12
+                        implicitHeight: 12
+                        running: true
+                    }
+                }
+            }
+        }
+    }
+}

meshroom/ui/qml/Viewer/Viewer2D.qml

@@ -77,8 +77,39 @@ FocusScope {
 
             visible: image.status === Image.Loading
         }
+
+        // FeatureViewer: display view extracted feature points
+        // note: requires QtAliceVision plugin - use a Loader to evaluate plugin avaibility at runtime
+        Loader {
+            id: featuresViewerLoader
+
+            active: displayFeatures.checked
+
+            // handle rotation/position based on available metadata
+            rotation: {
+                var orientation = metadata ? metadata["Orientation"] : 0
+                switch(orientation) {
+                    case "6": return 90;
+                    case "8": return -90;
+                    default: return 0;
+                }
+            }
+            x: rotation === 90 ? image.paintedWidth : 0
+            y: rotation === -90 ? image.paintedHeight : 0
+
+            Component.onCompleted: {
+                // instantiate and initialize a FeaturesViewer component dynamically using Loader.setSource
+                setSource("FeaturesViewer.qml", {
+                    'active':  Qt.binding(function() { return displayFeatures.checked; }),
+                    'viewId': Qt.binding(function() { return _reconstruction.selectedViewId; }),
+                    'model': Qt.binding(function() { return _reconstruction.featureExtraction.attribute("describerTypes").value; }),
+                    'folder': Qt.binding(function() { return Filepath.stringToUrl(_reconstruction.featureExtraction.attribute("output").value); }),
+                })
+            }
+        }
     }
 
+
     // Busy indicator
     BusyIndicator {
         anchors.centerIn: parent
@@ -147,6 +178,21 @@ FocusScope {
         metadata: visible ? root.metadata : {}
     }
 
+
+    Loader {
+        id: featuresOverlay
+        anchors.bottom: bottomToolbar.top
+        anchors.left: parent.left
+        anchors.margins: 2
+        active: displayFeatures.checked
+
+        sourceComponent: FeaturesInfoOverlay {
+            featureExtractionNode: _reconstruction.featureExtraction
+            pluginStatus: featuresViewerLoader.status
+            featuresViewer: featuresViewerLoader.item
+        }
+    }
+
     FloatingPane {
         id: bottomToolbar
         anchors.bottom: parent.bottom
@@ -163,6 +209,13 @@ FocusScope {
                 text: (image.status == Image.Ready ? image.scale.toFixed(2) : "1.00") + "x"
                 state: "xsmall"
             }
+            MaterialToolButton {
+                id: displayFeatures
+                font.pointSize: 11
+                ToolTip.text: "Display Features"
+                checkable: true
+                text: MaterialIcons.scatter_plot
+            }
 
             Item {
                 Layout.fillWidth: true