Implement Image.create_from_file and update the object_detector_test.py file accordingly.

PiperOrigin-RevId: 477682930

mediapipe/python/BUILD

@@ -48,6 +48,8 @@ pybind_extension(
         "//mediapipe/python/pybind:timestamp",
         "//mediapipe/python/pybind:validated_graph_config",
         "//mediapipe/tasks/python/core/pybind:task_runner",
+        "@com_google_absl//absl/strings:str_format",
+        "@stblib//:stb_image",
         # Type registration.
         "//mediapipe/framework:basic_types_registration",
         "//mediapipe/framework/formats:classification_registration",

mediapipe/python/image_test.py

@@ -15,6 +15,7 @@
 """Tests for mediapipe.python._framework_bindings.image."""
 
 import gc
+import os
 import random
 import sys
 
@@ -23,6 +24,7 @@ import cv2
 import numpy as np
 import PIL.Image
 
+# resources dependency
 from mediapipe.python._framework_bindings import image
 from mediapipe.python._framework_bindings import image_frame
 
@@ -185,6 +187,16 @@ class ImageTest(absltest.TestCase):
     gc.collect()
     self.assertEqual(sys.getrefcount(rgb_image), initial_ref_count)
 
+  def test_image_create_from_file(self):
+    image_path = os.path.join(
+        resources.GetRunfilesDir(),
+        'mediapipe/tasks/testdata/vision/cat.jpg')
+    loaded_image = Image.create_from_file(image_path)
+    self.assertEqual(loaded_image.width, 600)
+    self.assertEqual(loaded_image.height, 400)
+    self.assertEqual(loaded_image.channels, 3)
+    self.assertEqual(loaded_image.image_format, ImageFormat.SRGB)
+
 
 if __name__ == '__main__':
   absltest.main()

mediapipe/python/pybind/BUILD

@@ -45,6 +45,8 @@ pybind_library(
         ":util",
         "//mediapipe/framework:type_map",
         "//mediapipe/framework/formats:image",
+        "@com_google_absl//absl/strings:str_format",
+        "@stblib//:stb_image",
     ],
 )
 

mediapipe/python/pybind/image.cc

@@ -16,9 +16,11 @@
 
 #include <memory>
 
+#include "absl/strings/str_format.h"
 #include "mediapipe/python/pybind/image_frame_util.h"
 #include "mediapipe/python/pybind/util.h"
 #include "pybind11/stl.h"
+#include "stb_image.h"
 
 namespace mediapipe {
 namespace python {
@@ -225,6 +227,62 @@ void ImageSubmodule(pybind11::module* module) {
     image.is_aligned(16)
 )doc");
 
+  image.def_static(
+      "create_from_file",
+      [](const std::string& file_name) {
+        int width;
+        int height;
+        int channels;
+        auto* image_data =
+            stbi_load(file_name.c_str(), &width, &height, &channels,
+                      /*desired_channels=*/0);
+        if (image_data == nullptr) {
+          throw RaisePyError(PyExc_RuntimeError,
+                             absl::StrFormat("Image decoding failed (%s): %s",
+                                             stbi_failure_reason(), file_name)
+                                 .c_str());
+        }
+        ImageFrameSharedPtr image_frame;
+        switch (channels) {
+          case 1:
+            image_frame = std::make_shared<ImageFrame>(
+                ImageFormat::GRAY8, width, height, width, image_data,
+                stbi_image_free);
+            break;
+          case 3:
+            image_frame = std::make_shared<ImageFrame>(
+                ImageFormat::SRGB, width, height, 3 * width, image_data,
+                stbi_image_free);
+            break;
+          case 4:
+            image_frame = std::make_shared<ImageFrame>(
+                ImageFormat::SRGBA, width, height, 4 * width, image_data,
+                stbi_image_free);
+            break;
+          default:
+            throw RaisePyError(
+                PyExc_RuntimeError,
+                absl::StrFormat(
+                    "Expected image with 1 (grayscale), 3 (RGB) or 4 "
+                    "(RGBA) channels, found %d channels.",
+                    channels)
+                    .c_str());
+        }
+        return Image(std::move(image_frame));
+      },
+      R"doc(Creates `Image` object from the image file.
+
+Args:
+  file_name: Image file name.
+
+Returns:
+  `Image` object.
+
+Raises:
+  RuntimeError if the image file can't be decoded.
+  )doc",
+      py::arg("file_name"));
+
   image.def_property_readonly("width", &Image::width)
       .def_property_readonly("height", &Image::height)
       .def_property_readonly("channels", &Image::channels)