Initial version of webcam importer, with preview display

glue_exp/importers/webcam/__init__.py

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+# This plugin requires OpenCV to be installed, and returns a PIL Image object
+
+
+def setup():
+
+    from glue.logger import logger
+    try:
+        import cv2
+    except ImportError:
+        logger.info("Could not load webcam importer plugin, since OpenCV is required")
+        return
+
+    from glue.config import importer
+    from .qt_widget import QtWebcamImporter
+
+    @importer("Import from webcam")
+    def webcam_importer():
+        wi = QtWebcamImporter()
+        wi.exec_()
+        return wi.data
+
+    logger.info("Loaded webcam importer plugin")

glue_exp/importers/webcam/qt_widget.py

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+import os
+
+from glue.external.qt import QtGui, QtCore
+from glue.qt.qtutil import load_ui
+
+from .webcam_helpers import Webcam, frame_to_data
+
+UI_FILE = os.path.join(os.path.dirname(__file__), 'webcam.ui')
+
+
+class WebcamView(QtGui.QWidget):
+
+    def __init__(self, parent=None):
+
+        super(WebcamView, self).__init__()
+
+        self._frozen = False
+
+        self._webcam = Webcam()
+
+        self._update_image()
+
+        self._timer = QtCore.QTimer(self)
+        self._timer.timeout.connect(self._update_image)
+        self._timer.start(100)
+
+    def freeze(self):
+        self._frozen = True
+
+    def resume(self):
+        self._frozen = False
+
+    def paintEvent(self, event):
+
+        # We need to preserve aspect ratio. Figure out bounding box for
+        # webcam image.
+
+        im_dx = self._image.width()
+        im_dy = self._image.height()
+        im_ratio = im_dx / float(im_dy)
+
+        wi_dx = self.width()
+        wi_dy = self.height()
+        wi_ratio = wi_dx / float(wi_dy)
+
+        if wi_ratio > im_ratio:  # Need to pad on sides
+
+            xmin = wi_dx / 2. - wi_dy / 2. * im_ratio
+            ymin = 0.
+            width = wi_dy * im_ratio
+            height = wi_dy
+
+        else:  # Need to pad on top/bottom
+
+            xmin = 0.
+            ymin = wi_dy / 2. - wi_dx / 2. / float(im_ratio)
+            width = wi_dx
+            height = wi_dx / float(im_ratio)
+
+        painter = QtGui.QPainter(self)
+        painter.drawImage(QtCore.QRect(xmin, ymin, width, height), self._image)
+
+
+    def _update_image(self):
+        if not self._frozen:
+            frame = self._webcam.capture_frame()
+            self._image = QtGui.QImage(frame.tostring(), frame.shape[1], frame.shape[0], QtGui.QImage.Format_RGB888).rgbSwapped()
+            self._data = frame_to_data(frame)
+            self.update()
+
+
+class QtWebcamImporter(QtGui.QDialog):
+
+    def __init__(self):
+        super(QtWebcamImporter, self).__init__()
+        self.pil_image = None
+        self.ui = load_ui(UI_FILE, self)
+        self._webcam_preview = WebcamView()
+        self.image.addWidget(self._webcam_preview)
+        self.capture.clicked.connect(self.flip_capture_button)
+        self.cancel.clicked.connect(self.reject)
+        self.ok.clicked.connect(self.finalize)
+        self.ok.setEnabled(False)
+        self.capture.setDefault(True)
+        self.data = []
+
+    def flip_capture_button(self):
+        if self._webcam_preview._frozen:
+            self._webcam_preview.resume()
+            self.capture.setText("Capture")
+            self.capture.setDefault(True)
+            self.ok.setEnabled(False)
+        else:
+            self._webcam_preview.freeze()
+            self.capture.setText("Try again")
+            self.capture.setDefault(False)
+            self.ok.setEnabled(True)
+            self.ok.setDefault(True)
+
+    def finalize(self):
+        self.data = [self._webcam_preview._data]
+        self.accept()

glue_exp/importers/webcam/webcam.ui

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+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>Dialog</class>
+ <widget class="QDialog" name="Dialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>529</width>
+    <height>506</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Webcam Importer</string>
+  </property>
+  <layout class="QGridLayout" name="gridLayout">
+   <item row="0" column="0">
+    <layout class="QVBoxLayout" name="image"/>
+   </item>
+   <item row="1" column="0">
+    <layout class="QHBoxLayout" name="horizontalLayout_2">
+     <item>
+      <spacer name="horizontalSpacer_2">
+       <property name="orientation">
+        <enum>Qt::Horizontal</enum>
+       </property>
+       <property name="sizeHint" stdset="0">
+        <size>
+         <width>40</width>
+         <height>20</height>
+        </size>
+       </property>
+      </spacer>
+     </item>
+     <item>
+      <widget class="QPushButton" name="capture">
+       <property name="text">
+        <string>Capture</string>
+       </property>
+       <property name="checkable">
+        <bool>false</bool>
+       </property>
+       <property name="default">
+        <bool>false</bool>
+       </property>
+      </widget>
+     </item>
+     <item>
+      <spacer name="horizontalSpacer_3">
+       <property name="orientation">
+        <enum>Qt::Horizontal</enum>
+       </property>
+       <property name="sizeHint" stdset="0">
+        <size>
+         <width>40</width>
+         <height>20</height>
+        </size>
+       </property>
+      </spacer>
+     </item>
+    </layout>
+   </item>
+   <item row="2" column="0">
+    <layout class="QHBoxLayout" name="horizontalLayout">
+     <item>
+      <spacer name="horizontalSpacer">
+       <property name="orientation">
+        <enum>Qt::Horizontal</enum>
+       </property>
+       <property name="sizeHint" stdset="0">
+        <size>
+         <width>40</width>
+         <height>20</height>
+        </size>
+       </property>
+      </spacer>
+     </item>
+     <item>
+      <widget class="QPushButton" name="cancel">
+       <property name="text">
+        <string>Cancel</string>
+       </property>
+      </widget>
+     </item>
+     <item>
+      <widget class="QPushButton" name="ok">
+       <property name="text">
+        <string>OK</string>
+       </property>
+       <property name="checkable">
+        <bool>false</bool>
+       </property>
+       <property name="default">
+        <bool>true</bool>
+       </property>
+      </widget>
+     </item>
+    </layout>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>

glue_exp/importers/webcam/webcam_helpers.py

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+import cv2
+
+from glue.core import Data
+
+class Webcam(object):
+
+    def __init__(self):
+        self._capture = cv2.VideoCapture(0)
+
+    def capture_frame(self):
+        ret, frame = self._capture.read()
+        return frame
+
+
+def frame_to_data(frame):
+    data = Data(red=frame[::-1,::-1,2],
+                 green=frame[::-1,::-1,1],
+                 blue=frame[::-1,::-1,0])
+    data.label = "Webcam Snapshot"
+    return data