implement QR code scanning

contrib/android/buildozer_qml.spec

@@ -52,7 +52,8 @@ requirements =
     cryptography,
     pyqt5sip,
     pyqt5,
-    pillow
+    pillow,
+    libzbar
 
 # (str) Presplash of the application
 #presplash.filename = %(source.dir)s/gui/kivy/theming/splash.png

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
+                    })
+                }
             }
         }
     }

electrum/gui/qml/qeqr.py

@@ -1,42 +1,54 @@
-from PyQt5.QtCore import pyqtProperty, pyqtSignal, pyqtSlot, QObject, QUrl
-from PyQt5.QtGui import QImage
+from PyQt5.QtCore import pyqtProperty, pyqtSignal, pyqtSlot, QObject, QUrl, QRect, QPoint
+from PyQt5.QtGui import QImage,QColor
 from PyQt5.QtQuick import QQuickImageProvider
 
 from electrum.logging import get_logger
+from electrum.qrreader import get_qr_reader
 
+from electrum.i18n import _
 import qrcode
 #from qrcode.image.styledpil import StyledPilImage
 #from qrcode.image.styles.moduledrawers import *
 
 from PIL import Image, ImageQt
-
 from ctypes import *
+import sys
 
 class QEQR(QObject):
     def __init__(self, text=None, parent=None):
         super().__init__(parent)
         self._text = text
+        self.qrreader = get_qr_reader()
+        if not self.qrreader:
+            raise Exception(_("The platform QR detection library is not available."))
 
     _logger = get_logger(__name__)
 
-    scanReadyChanged = pyqtSignal()
+    busyChanged = pyqtSignal()
+    dataChanged = pyqtSignal()
     imageChanged = pyqtSignal()
 
-    _scanReady = True
+    _busy = False
     _image = None
 
     @pyqtSlot('QImage')
     def scanImage(self, image=None):
-        if not self._scanReady:
-            self._logger.warning("Already processing an image. Check 'ready' property before calling scanImage")
+        if self._busy:
+            self._logger.warning("Already processing an image. Check 'busy' property before calling scanImage")
+            return
+
+        if image == None:
+            self._logger.warning("No image to decode")
             return
-        self._scanReady = False
-        self.scanReadyChanged.emit()
 
-        pilimage = self.convertToPILImage(image)
-        self.parseQR(pilimage)
+        self._busy = True
+        self.busyChanged.emit()
 
-        self._scanReady = True
+        self.logImageStats(image)
+        self._parseQR(image)
+
+        self._busy = False
+        self.busyChanged.emit()
 
     def logImageStats(self, image):
         self._logger.info('width: ' + str(image.width()))
@@ -44,33 +56,63 @@ class QEQR(QObject):
         self._logger.info('depth: ' + str(image.depth()))
         self._logger.info('format: ' + str(image.format()))
 
-    def convertToPILImage(self, image): # -> Image:
-        self.logImageStats(image)
-
-        rawimage = image.constBits()
-        # assumption: pixels are 32 bits ARGB
-        numbytes = image.width() * image.height() * 4
-
-        self._logger.info(type(rawimage))
-        buf = bytearray(numbytes)
-        c_buf = (c_byte * numbytes).from_buffer(buf)
-        memmove(c_buf, c_void_p(rawimage.__int__()), numbytes)
-        buf2 = bytes(buf)
-
-        return Image.frombytes('RGBA', (image.width(), image.height()), buf2, 'raw')
-
-    def parseQR(self, image):
-        # TODO
-        pass
-
-    @pyqtProperty(bool, notify=scanReadyChanged)
-    def scanReady(self):
-        return self._scanReady
+    def _parseQR(self, image):
+        self.w = image.width()
+        self.h = image.height()
+        img_crop_rect = self._get_crop(image, 360)
+        frame_cropped = image.copy(img_crop_rect)
+
+        # Convert to Y800 / GREY FourCC (single 8-bit channel)
+        # This creates a copy, so we don't need to keep the frame around anymore
+        frame_y800 = frame_cropped.convertToFormat(QImage.Format_Grayscale8)
+
+        self.frame_id = 0
+        # Read the QR codes from the frame
+        self.qrreader_res = self.qrreader.read_qr_code(
+            frame_y800.constBits().__int__(), frame_y800.byteCount(),
+            frame_y800.bytesPerLine(),
+            frame_y800.width(),
+            frame_y800.height(), self.frame_id
+            )
+
+        if len(self.qrreader_res) > 0:
+            result = self.qrreader_res[0]
+            self._data = result
+            self.dataChanged.emit()
+
+    def _get_crop(self, image: QImage, scan_size: int) -> QRect:
+        """
+        Returns a QRect that is scan_size x scan_size in the middle of the resolution
+        """
+        self.scan_pos_x = (image.width() - scan_size) // 2
+        self.scan_pos_y = (image.height() - scan_size) // 2
+        return QRect(self.scan_pos_x, self.scan_pos_y, scan_size, scan_size)
+
+    @pyqtProperty(bool, notify=busyChanged)
+    def busy(self):
+        return self._busy
 
     @pyqtProperty('QImage', notify=imageChanged)
     def image(self):
         return self._image
 
+    @pyqtProperty(str, notify=dataChanged)
+    def data(self):
+        return self._data.data
+
+    @pyqtProperty('QPoint', notify=dataChanged)
+    def center(self):
+        (x,y) = self._data.center
+        return QPoint(x+self.scan_pos_x, y+self.scan_pos_y)
+
+    @pyqtProperty('QVariant', notify=dataChanged)
+    def points(self):
+        result = []
+        for item in self._data.points:
+            (x,y) = item
+            result.append(QPoint(x+self.scan_pos_x, y+self.scan_pos_y))
+        return result
+
 class QEQRImageProvider(QQuickImageProvider):
     def __init__(self, parent=None):
         super().__init__(QQuickImageProvider.Image)

electrum/qrreader/zbar.py

@@ -37,8 +37,9 @@ from .abstract_base import AbstractQrCodeReader, QrCodeResult
 
 _logger = get_logger(__name__)
 
-
-if sys.platform == 'darwin':
+if 'ANDROID_DATA' in os.environ:
+    LIBNAME = 'libzbar.so'
+elif sys.platform == 'darwin':
     LIBNAME = 'libzbar.0.dylib'
 elif sys.platform in ('windows', 'win32'):
     LIBNAME = 'libzbar-0.dll'