1 files changed, 58 insertions, 0 deletions
diff --git a/preview_thread.py b/preview_thread.py
new file mode 100644
index 0000000..740f6c6
--- /dev/null
+++ b/preview_thread.py
@@ -0,0 +1,58 @@
+from PyQt4 import QtCore, QtGui, uic
+from PyQt4.QtCore import pyqtSignal, pyqtSlot
+from PIL import Image, ImageDraw, ImageFont
+from PIL.ImageQt import ImageQt
+import core
+import time
+from queue import Queue, Empty
+import numpy
+
+class Worker(QtCore.QObject):
+
+  imageCreated = pyqtSignal(['QImage'])
+
+  def __init__(self, parent=None, queue=None):
+    QtCore.QObject.__init__(self)
+    parent.newTask.connect(self.createPreviewImage)
+    parent.processTask.connect(self.process)
+    self.core = core.Core()
+    self.queue = queue
+
+
+  @pyqtSlot(str, str, QtGui.QFont)
+  def createPreviewImage(self, backgroundImage, titleText, titleFont):
+    # print('worker thread id: {}'.format(QtCore.QThread.currentThreadId()))
+    dic = {
+      "backgroundImage": backgroundImage,
+      "titleText": titleText,
+      "titleFont": titleFont
+    }
+    self.queue.put(dic)
+
+  @pyqtSlot()
+  def process(self):
+    try:
+      nextPreviewInformation = self.queue.get(block=False)
+      while self.queue.qsize() >= 2:
+        try:
+          self.queue.get(block=False)
+        except Empty:
+          continue
+
+      im = self.core.drawBaseImage(
+        nextPreviewInformation["backgroundImage"],
+        nextPreviewInformation["titleText"],
+        nextPreviewInformation["titleFont"])
+
+      spectrum = numpy.fromfunction(lambda x: 0.008*(x-128)**2, (255,), dtype="int16")
+
+      im = self.core.drawBars(spectrum, im)
+
+      self._image = ImageQt(im)
+      self._previewImage = QtGui.QImage(self._image)
+
+      self._scaledPreviewImage = self._previewImage.scaled(320, 180, QtCore.Qt.IgnoreAspectRatio, QtCore.Qt.SmoothTransformation)
+
+      self.imageCreated.emit(self._scaledPreviewImage)
+    except Empty:
+      True