Merge pull request #2633 from wkentaro/pure_python_utils_color

Replace color.pyx with color.py for better compatibility

jsk_recognition_utils/python/jsk_recognition_utils/CMakeLists.txt

@@ -12,9 +12,7 @@ endif()
 include_directories(${Numpy_INCLUDE_DIRS})
 cython_add_module(nms nms.pyx)
 set_target_properties(nms PROPERTIES LIBRARY_OUTPUT_DIRECTORY ${CATKIN_DEVEL_PREFIX}/${CATKIN_PACKAGE_PYTHON_DESTINATION})
-cython_add_module(color color.pyx)
-set_target_properties(color PROPERTIES LIBRARY_OUTPUT_DIRECTORY ${CATKIN_DEVEL_PREFIX}/${CATKIN_PACKAGE_PYTHON_DESTINATION})
-install(TARGETS nms color
+install(TARGETS nms
   ARCHIVE DESTINATION ${CATKIN_PACKAGE_PYTHON_DESTINATION}
   LIBRARY DESTINATION ${CATKIN_PACKAGE_PYTHON_DESTINATION}
 )

jsk_recognition_utils/python/jsk_recognition_utils/color.py

@@ -0,0 +1,35 @@
+import numpy as np
+
+
+# Taken from https://github.com/wkentaro/imgviz/blob/master/imgviz/label.py  # NOQA
+def labelcolormap(N=256):
+    """Label colormap.
+    Parameters
+    ----------
+    N: int
+        Number of labels (default: 256).
+
+    Returns
+    -------
+    cmap: numpy.ndarray, (N, 3), numpy.uint8
+        Label id to colormap.
+    """
+
+    def bitget(byteval, idx):
+        shape = byteval.shape + (8,)
+        return np.unpackbits(byteval).reshape(shape)[..., -1 - idx]
+
+    i = np.arange(N, dtype=np.uint8)
+    r = np.full_like(i, 0)
+    g = np.full_like(i, 0)
+    b = np.full_like(i, 0)
+
+    i = np.repeat(i[:, None], 8, axis=1)
+    i = np.right_shift(i, np.arange(0, 24, 3)).astype(np.uint8)
+    j = np.arange(8)[::-1]
+    r = np.bitwise_or.reduce(np.left_shift(bitget(i, 0), j), axis=1)
+    g = np.bitwise_or.reduce(np.left_shift(bitget(i, 1), j), axis=1)
+    b = np.bitwise_or.reduce(np.left_shift(bitget(i, 2), j), axis=1)
+
+    cmap = np.stack((r, g, b), axis=1).astype(np.uint8)
+    return cmap