qt: add qr reading from file to ScanQRTextEdit and SendTab

electrum/gui/qt/paytoedit.py

@@ -161,6 +161,13 @@ def line_edit_changed():
             show_error=self.send_tab.show_error,
             setText=self.try_payment_identifier,
         )
+        self.on_qr_from_file_input_btn = partial(
+            self.input_qr_from_file,
+            allow_multi=False,
+            config=self.config,
+            show_error=self.send_tab.show_error,
+            setText=self.try_payment_identifier,
+        )
         self.on_input_file = partial(
             self.input_file,
             config=self.config,

electrum/gui/qt/qrreader/__init__.py

@@ -25,7 +25,8 @@
 from typing import Callable, Optional, TYPE_CHECKING, Mapping, Sequence
 
 from PyQt6.QtWidgets import QMessageBox, QWidget
-from PyQt6.QtGui import QImage
+from PyQt6.QtGui import QImage, QPainter, QColor
+from PyQt6.QtCore import QRect
 
 from electrum.i18n import _
 from electrum.util import UserFacingException
@@ -59,16 +60,34 @@ def scan_qrcode(
 def scan_qr_from_image(image: QImage) -> Sequence[QrCodeResult]:
     """Might raise exception: MissingQrDetectionLib."""
     qr_reader = get_qr_reader()
-    image_y800 = image.convertToFormat(QImage.Format.Format_Grayscale8)
-    res = qr_reader.read_qr_code(
-        image_y800.constBits().__int__(),
-        image_y800.sizeInBytes(),
-        image_y800.bytesPerLine(),
-        image_y800.width(),
-        image_y800.height(),
-    )
+
+    for attempt in range(4):
+        image_y800 = image.convertToFormat(QImage.Format.Format_Grayscale8)
+        res = qr_reader.read_qr_code(
+            image_y800.constBits().__int__(),
+            image_y800.sizeInBytes(),
+            image_y800.bytesPerLine(),
+            image_y800.width(),
+            image_y800.height(),
+        )
+        if res:
+            break
+        # zbar doesn't like qr codes that are too large in relation to the whole image
+        image = _reduce_qr_code_density(image)
     return res
 
+def _reduce_qr_code_density(image: QImage) -> QImage:
+    """ Reduces the size of the qr code relative to the whole image. """
+    new_image = QImage(image.width(), image.height(), QImage.Format.Format_RGB32)
+    new_image.fill(QColor(255, 255, 255))  # Fill white
+
+    painter = QPainter(new_image)
+    source_rect = QRect(0, 0, image.width(), image.height())
+    target_rect = QRect(0, 0, int(image.width() * 0.75), int(image.height() * 0.75))
+    painter.drawImage(target_rect, image, source_rect)
+    painter.end()
+
+    return new_image
 
 def find_system_cameras() -> Mapping[str, str]:
     """Returns a camera_description -> camera_path map."""

electrum/gui/qt/qrtextedit.py

@@ -47,6 +47,13 @@ def __init__(
             show_error=self.show_error,
             setText=setText,
         )
+        self.on_qr_from_file_input_btn = partial(
+            self.input_qr_from_file,
+            allow_multi=allow_multi,
+            config=config,
+            show_error=self.show_error,
+            setText=setText,
+        )
         self.on_input_file = partial(
             self.input_file,
             config=config,
@@ -62,7 +69,8 @@ def add_input_buttons(self, config, allow_multi, setText):
         self.add_menu_button(
             options=[
                 ("picture_in_picture.png", _("Read QR code from screen"), self.on_qr_from_screenshot_input_btn),
-                ("file.png",               _("Read file"),                self.on_input_file),
+                ("qr_file.png",            _("Read QR code from file"),   self.on_qr_from_file_input_btn),
+                ("file.png",               _("Read text from file"),      self.on_input_file),
             ],
         )
         self.add_qr_input_from_camera_button(config=config, show_error=self.show_error, allow_multi=allow_multi, setText=setText)
@@ -72,7 +80,8 @@ def contextMenuEvent(self, e):
         m.addSeparator()
         m.addAction(get_icon_camera(), _("Read QR code with camera"), self.on_qr_from_camera_input_btn)
         m.addAction(read_QIcon("picture_in_picture.png"), _("Read QR code from screen"), self.on_qr_from_screenshot_input_btn)
-        m.addAction(read_QIcon("file.png"), _("Read file"), self.on_input_file)
+        m.addAction(read_QIcon("qr_file.png"), _("Read QR code from file"), self.on_qr_from_file_input_btn)
+        m.addAction(read_QIcon("file.png"), _("Read text from file"), self.on_input_file)
         m.exec(e.globalPos())
 
 

electrum/gui/qt/send_tab.py

@@ -180,6 +180,7 @@ def reset_max(text):
 
         menu.addAction(get_icon_camera(),    _("Read QR code with camera"), self.payto_e.on_qr_from_camera_input_btn)
         menu.addAction(read_QIcon("picture_in_picture.png"), _("Read QR code from screen"), self.payto_e.on_qr_from_screenshot_input_btn)
+        menu.addAction(read_QIcon("qr_file.png"), _("Read QR code from file"), self.payto_e.on_qr_from_file_input_btn)
         menu.addAction(read_QIcon("file.png"), _("Read invoice from file"), self.payto_e.on_input_file)
         self.paytomany_menu = menu.addToggle(_("&Pay to many"), self.toggle_paytomany)
         menu.addSeparator()

electrum/gui/qt/util.py

@@ -832,6 +832,8 @@ def input_file(
         fileName = getOpenFileName(
             parent=None,
             title='select file',
+            # trying to open non-text things like pdfs makes electrum freeze
+            filter="Text files (*.txt *.csv);;All files (*)",
             config=config,
         )
         if not fileName:
@@ -852,6 +854,52 @@ def input_file(
             except Exception as e:
                 show_error(_('Invalid payment identifier in file') + ':\n' + repr(e))
 
+    def input_qr_from_file(
+        self,
+        *,
+        allow_multi: bool = False,
+        config: 'SimpleConfig',
+        show_error: Callable[[str], None],
+        setText: Callable[[str], None] = None,
+    ):
+        from .qrreader import scan_qr_from_image
+        if setText is None:
+            setText = self.setText
+
+        file_name = getOpenFileName(
+            parent=None,
+            title=_("Select image file"),
+            config=config,
+            filter="Image files (*.png *.jpg *.jpeg *.bmp);;",
+        )
+        if not file_name:
+            return
+        image = QImage(file_name)
+        if image.isNull():
+            show_error(_("Failed to open image file."))
+            return
+        try:
+            scan_result: Sequence[QrCodeResult] = scan_qr_from_image(image)
+        except MissingQrDetectionLib as e:
+            show_error(_("Unable to scan image.") + "\n" + repr(e))
+            return
+        if len(scan_result) < 1:
+            show_error(_("No QR code was found in the image."))
+            return
+        if len(scan_result) > 1 and not allow_multi:
+            show_error(_("More than one QR code was found in the image."))
+            return
+
+        if len(scan_result) > 1:
+            result_text = "\n".join([r.data for r in scan_result])
+        else:
+            result_text = scan_result[0].data
+
+        try:
+            setText(result_text)
+        except Exception as e:
+            show_error(_("Couldn't set result") + ':\n' + repr(e))
+
     def input_paste_from_clipboard(
             self,
             *,