From 0249bcb9dec85b582b7af69a7922dd22242bb16b Mon Sep 17 00:00:00 2001
From: Davis King <davis@dlib.net>
Date: Sun, 27 May 2018 11:05:20 -0400
Subject: [PATCH] Added get_histogram() to the python API.  Also added more
 overloads of label_connected_blobs().

---
 tools/python/src/image.cpp  | 15 ++++++++++++---
 tools/python/src/image2.cpp | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/tools/python/src/image.cpp b/tools/python/src/image.cpp
index 1e10f30e7..927639f80 100644
--- a/tools/python/src/image.cpp
+++ b/tools/python/src/image.cpp
@@ -820,9 +820,18 @@ ensures \n\
             - blob labels are contiguous, therefore, the number returned by this function is
               the number of blobs in the image (including the background blob).
     !*/
-    m.def("label_connected_blobs", py_label_connected_blobs<unsigned char>, py::arg("img"),py::arg("zero_pixels_are_background")=true,py::arg("neighborhood_connectivity")=8,py::arg("connected_if_both_not_zero")=false);
-    m.def("label_connected_blobs", py_label_connected_blobs<uint16_t>, py::arg("img"),py::arg("zero_pixels_are_background")=true,py::arg("neighborhood_connectivity")=8,py::arg("connected_if_both_not_zero")=false);
-    m.def("label_connected_blobs", py_label_connected_blobs<uint32_t>, docs, py::arg("img"),py::arg("zero_pixels_are_background")=true,py::arg("neighborhood_connectivity")=8,py::arg("connected_if_both_not_zero")=false);
+    m.def("label_connected_blobs", py_label_connected_blobs<unsigned char>, 
+        py::arg("img"),py::arg("zero_pixels_are_background")=true,py::arg("neighborhood_connectivity")=8,py::arg("connected_if_both_not_zero")=false);
+    m.def("label_connected_blobs", py_label_connected_blobs<uint16_t>, 
+        py::arg("img"),py::arg("zero_pixels_are_background")=true,py::arg("neighborhood_connectivity")=8,py::arg("connected_if_both_not_zero")=false);
+    m.def("label_connected_blobs", py_label_connected_blobs<uint32_t>,  
+        py::arg("img"),py::arg("zero_pixels_are_background")=true,py::arg("neighborhood_connectivity")=8,py::arg("connected_if_both_not_zero")=false);
+    m.def("label_connected_blobs", py_label_connected_blobs<uint64_t>,  
+        py::arg("img"),py::arg("zero_pixels_are_background")=true,py::arg("neighborhood_connectivity")=8,py::arg("connected_if_both_not_zero")=false);
+    m.def("label_connected_blobs", py_label_connected_blobs<float>,  
+        py::arg("img"),py::arg("zero_pixels_are_background")=true,py::arg("neighborhood_connectivity")=8,py::arg("connected_if_both_not_zero")=false);
+    m.def("label_connected_blobs", py_label_connected_blobs<double>, docs, 
+        py::arg("img"),py::arg("zero_pixels_are_background")=true,py::arg("neighborhood_connectivity")=8,py::arg("connected_if_both_not_zero")=false);
 
 
     docs =
diff --git a/tools/python/src/image2.cpp b/tools/python/src/image2.cpp
index 2cb53820b..a65666dd5 100644
--- a/tools/python/src/image2.cpp
+++ b/tools/python/src/image2.cpp
@@ -940,6 +940,20 @@ py::array py_tile_images (
 
 // ----------------------------------------------------------------------------------------
 
+template <typename T>
+py::array_t<unsigned long> py_get_histogram (
+    const numpy_image<T>& img,
+    size_t hist_size
+)
+{
+    matrix<unsigned long,1> hist;
+    get_histogram(img,hist,hist_size);
+
+    return numpy_image<unsigned long>(std::move(hist)).squeeze();
+}
+
+// ----------------------------------------------------------------------------------------
+
 void bind_image_classes2(py::module& m)
 {
 
@@ -960,6 +974,27 @@ void bind_image_classes2(py::module& m)
 
     register_extract_image_chip(m);
 
+    m.def("get_histogram", &py_get_histogram<uint8_t>, py::arg("img"), py::arg("hist_size"));
+    m.def("get_histogram", &py_get_histogram<uint16_t>, py::arg("img"), py::arg("hist_size"));
+    m.def("get_histogram", &py_get_histogram<uint32_t>, py::arg("img"), py::arg("hist_size"));
+    m.def("get_histogram", &py_get_histogram<uint64_t>, py::arg("img"), py::arg("hist_size"),
+"ensures \n\
+    - Returns a numpy array, HIST, that contains a histogram of the pixels in img. \n\
+      In particular, we will have: \n\
+        - len(HIST) == hist_size \n\
+        - for all valid i:  \n\
+            - HIST[i] == the number of times a pixel with intensity i appears in img." 
+    /*!
+        ensures
+            - Returns a numpy array, HIST, that contains a histogram of the pixels in img.
+              In particular, we will have:
+                - len(HIST) == hist_size
+                - for all valid i: 
+                    - HIST[i] == the number of times a pixel with intensity i appears in img.
+    !*/
+        );
+
+
     m.def("tile_images", py_tile_images, py::arg("images"),
 "requires \n\
     - images is a list of numpy arrays that can be interpreted as images.  They \n\