start experiments with image tracer

examples/imgtracer.py

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+import logging
+import matplotlib.pyplot as plt
+import time
+from threading import Thread
+
+import numpy
+from PIL import Image
+
+
+class Tracer(object):
+    def __init__(self, fname):
+        super(Tracer, self).__init__()
+        self.orig = Image.open(fname)
+        self.conv1 = self.orig.convert("1")
+        self.src = numpy.asarray(self.conv1)
+        self.dst = numpy.copy(self.src)
+
+    def trace(self):
+        width, height = self.dst.shape
+        self.dst.fill(False)
+        mark = numpy.copy(self.dst)
+
+        # start in center
+        posx = width / 2
+        posy = height / 2
+
+        # go circles to find a pixel in src
+
+        # move until we find new pixels
+        # repeat
+
+        for x in range(0, width):
+            for y in range(0, height):
+                time.sleep(0.01)
+                if (x + y) % 2 == 0:
+                    self.dst[x][y] = True
+
+
+class TracerVisualizer(object):
+    def __init__(self, tracer):
+        """
+        :type tracer: Tracer
+        """
+        self.tracer = tracer
+
+    def run(self):
+        tracer = self.tracer
+        thr = Thread(target=tracer.trace)
+        thr.setDaemon(True)
+        thr.start()
+
+        fig, (ax1, ax2, ax3) = plt.subplots(nrows=1, ncols=3)
+        ax1.imshow(tracer.orig)
+        ax2.imshow(tracer.conv1)
+        plt.show(block=False)
+
+        while plt.get_fignums():  # weird trick to react on close
+            ax3.imshow(tracer.dst, cmap='gray')
+            plt.pause(0.01)
+
+
+if __name__ == "__main__":
+    logging.basicConfig(level=logging.DEBUG)
+    trc = Tracer("/tmp/truck.png")
+
+    TracerVisualizer(trc).run()