implement QR code scanning

electrum/gui/qml/components/QRScan.qml

@@ -1,25 +1,91 @@
-import QtQuick 2.6
+import QtQuick 2.12
+import QtQuick.Controls 2.0
 import QtMultimedia 5.6
 
 Item {
+    id: scanner
+
+    property bool active: false
+    property string url
+    property string scanData
+
+    property bool _pointsVisible
+
+    signal found
 
     VideoOutput {
         id: vo
         anchors.fill: parent
         source: camera
         fillMode: VideoOutput.PreserveAspectCrop
+
+        Rectangle {
+            width: parent.width
+            height: (parent.height - parent.width) / 2
+            anchors.top: parent.top
+            color: Qt.rgba(0,0,0,0.5)
+        }
+        Rectangle {
+            width: parent.width
+            height: (parent.height - parent.width) / 2
+            anchors.bottom: parent.bottom
+            color: Qt.rgba(0,0,0,0.5)
+        }
     }
 
-    MouseArea {
-        anchors.fill: parent
-        onClicked: {
-            vo.grabToImage(function(result) {
-                console.log("grab: image=" + (result.image !== undefined) + " url=" + result.url)
-                if (result.image !== undefined) {
-                    console.log('scanning image for QR')
-                    QR.scanImage(result.image)
-                }
-            })
+    Image {
+        id: still
+        anchors.fill: vo
+    }
+
+    SequentialAnimation {
+        id: foundAnimation
+        PropertyAction { target: scanner; property: '_pointsVisible'; value: true}
+        PauseAnimation { duration: 80 }
+        PropertyAction { target: scanner; property: '_pointsVisible'; value: false}
+        PauseAnimation { duration: 80 }
+        PropertyAction { target: scanner; property: '_pointsVisible'; value: true}
+        PauseAnimation { duration: 80 }
+        PropertyAction { target: scanner; property: '_pointsVisible'; value: false}
+        PauseAnimation { duration: 80 }
+        PropertyAction { target: scanner; property: '_pointsVisible'; value: true}
+        PauseAnimation { duration: 80 }
+        PropertyAction { target: scanner; property: '_pointsVisible'; value: false}
+        PauseAnimation { duration: 80 }
+        PropertyAction { target: scanner; property: '_pointsVisible'; value: true}
+        onFinished: found()
+    }
+
+    Component {
+        id: r
+        Rectangle {
+            property int cx
+            property int cy
+            width: 15
+            height: 15
+            x: cx - width/2
+            y: cy - height/2
+            radius: 5
+            visible: scanner._pointsVisible
+        }
+    }
+
+    Connections {
+        target: QR
+        function onDataChanged() {
+            console.log(QR.data)
+            scanner.active = false
+            scanner.scanData = QR.data
+            still.source = scanner.url
+
+            var sx = still.width/still.sourceSize.width
+            var sy = still.height/still.sourceSize.height
+            r.createObject(scanner, {cx: QR.points[0].x * sx, cy: QR.points[0].y * sy, color: 'yellow'})
+            r.createObject(scanner, {cx: QR.points[1].x * sx, cy: QR.points[1].y * sy, color: 'yellow'})
+            r.createObject(scanner, {cx: QR.points[2].x * sx, cy: QR.points[2].y * sy, color: 'yellow'})
+            r.createObject(scanner, {cx: QR.points[3].x * sx, cy: QR.points[3].y * sy, color: 'yellow'})
+
+            foundAnimation.start()
         }
     }
 
@@ -28,6 +94,12 @@ Item {
         deviceId: QtMultimedia.defaultCamera.deviceId
         viewfinder.resolution: "640x480"
 
+        focus {
+            focusMode: Camera.FocusContinuous
+            focusPointMode: Camera.FocusPointCustom
+            customFocusPoint: Qt.point(0.5, 0.5)
+        }
+
         function dumpstats() {
             console.log(camera.viewfinder.resolution)
             console.log(camera.viewfinder.minimumFrameRate)
@@ -36,6 +108,49 @@ Item {
             resolutions.forEach(function(item, i) {
                 console.log('' + item.width + 'x' + item.height)
             })
+            // TODO
+            // pick a suitable resolution from the available resolutions
+            // problem: some cameras have no supportedViewfinderResolutions
+            // but still error out when an invalid resolution is set.
+            // 640x480 seems to be universally available, but this needs to
+            // be checked across a range of phone models.
         }
     }
+
+    Timer {
+        id: scanTimer
+        interval: 200
+        repeat: true
+        running: scanner.active
+        onTriggered: {
+            if (QR.busy)
+                return
+            vo.grabToImage(function(result) {
+                if (result.image !== undefined) {
+                    scanner.url = result.url
+                    QR.scanImage(result.image)
+                } else {
+                    console.log('image grab returned null')
+                }
+            })
+        }
+    }
+
+    Component.onCompleted: {
+        console.log('Scan page initialized')
+        QtMultimedia.availableCameras.forEach(function(item) {
+            console.log('cam found')
+            console.log(item.deviceId)
+            console.log(item.displayName)
+            console.log(item.position)
+            console.log(item.orientation)
+            if (QtMultimedia.defaultCamera.deviceId == item.deviceId) {
+                vo.orientation = item.orientation
+            }
+
+            camera.dumpstats()
+        })
+
+        active = true
+    }
 }

electrum/gui/qml/components/Scan.qml

@@ -2,13 +2,25 @@ import QtQuick 2.6
 import QtQuick.Controls 2.0
 
 Item {
+    id: scanPage
+    property string title: qsTr('Scan')
 
     property bool toolbar: false
 
+    property string scanData
+
+    signal found
+
     QRScan {
         anchors.top: parent.top
         anchors.bottom: parent.bottom
         width: parent.width
+
+        onFound: {
+            scanPage.scanData = scanData
+            scanPage.found()
+            app.stack.pop()
+        }
     }
 
     Button {

electrum/gui/qml/components/Send.qml

@@ -80,7 +80,13 @@ Pane {
 
             Button {
                 text: qsTr('Scan QR Code')
-                onClicked: app.stack.push(Qt.resolvedUrl('Scan.qml'))
+                onClicked: {
+                    var page = app.stack.push(Qt.resolvedUrl('Scan.qml'))
+                    page.onFound.connect(function() {
+                        console.log('got ' + page.scanData)
+                        address.text = page.scanData
+                    })
+                }
             }
         }
     }