Robust image I/O (#6765)

- Use file signatures (beginning bytes) instead of filename extension (png/jpg) to select decoder. jpg files with png extension and vice versa are read correctly.
- Catch libjpeg errors and report as normal Open3D exceptions. Change Open3D warnings to errors (exceptions) on jpeg I/O error.
- Simplify demo_scene example
- Clear image on read error
- Fix for github release macOS bug.

.github/workflows/documentation.yml

@@ -92,7 +92,7 @@ jobs:
           tar_file="open3d-${GITHUB_SHA}-docs.tar.gz"
           rm -rf ${tar_file}
           # Docs in docs/_out/html
-          tar -C docs/_out -czf ${tar_file} html
+          tar -C docs/_out -cvzf ${tar_file} html
 
           echo "Waiting for other release assets..."
           this_sha=$(echo ${GITHUB_SHA} | cut -c 1-6)
@@ -110,7 +110,6 @@ jobs:
           echo "\nAll assets ready. Removing release assets except from last 3 commits: ${last_shas[@]}"
           release_assets=($(gh release view main-devel --json assets --jq '.assets[] | .name'))
           last_shas=($(git log --pretty=format:%h --abbrev-commit -n 3))
-          echo "Waiting for all assets to be ready..."
           for relass in "${release_assets[@]}"; do
               found=false
               for last_sha in "${last_shas[@]}"; do

.github/workflows/macos.yml

@@ -168,8 +168,6 @@ jobs:
           path: open3d-*-app-macosx-10_15-universal2.zip
           if-no-files-found: error
 
-      - name: Checkout source code
-        uses: actions/checkout@v4
       - name: Update viewer devel release
         if: ${{ github.ref == 'refs/heads/main' }}
         env:

cpp/open3d/io/ImageIO.cpp

@@ -7,24 +7,25 @@
 
 #include "open3d/io/ImageIO.h"
 
+#include <array>
+#include <fstream>
 #include <unordered_map>
 
 #include "open3d/utility/FileSystem.h"
 #include "open3d/utility/Logging.h"
 
 namespace open3d {
+namespace io {
 
 namespace {
-using namespace io;
 
-static const std::unordered_map<
-        std::string,
-        std::function<bool(const std::string &, geometry::Image &)>>
-        file_extension_to_image_read_function{
-                {"png", ReadImageFromPNG},
-                {"jpg", ReadImageFromJPG},
-                {"jpeg", ReadImageFromJPG},
-        };
+using signature_decoder_t =
+        std::pair<std::string,
+                  std::function<bool(const std::string &, geometry::Image &)>>;
+static const std::array<signature_decoder_t, 2> signature_decoder_list{
+        {{"\x89\x50\x4e\x47\xd\xa\x1a\xa", ReadImageFromPNG},
+         {"\xFF\xD8\xFF", ReadImageFromJPG}}};
+static constexpr uint8_t MAX_SIGNATURE_LEN = 8;
 
 static const std::unordered_map<
         std::string,
@@ -34,11 +35,8 @@ static const std::unordered_map<
                 {"jpg", WriteImageToJPG},
                 {"jpeg", WriteImageToJPG},
         };
-
 }  // unnamed namespace
 
-namespace io {
-
 std::shared_ptr<geometry::Image> CreateImageFromFile(
         const std::string &filename) {
     auto image = std::make_shared<geometry::Image>();
@@ -47,21 +45,27 @@ std::shared_ptr<geometry::Image> CreateImageFromFile(
 }
 
 bool ReadImage(const std::string &filename, geometry::Image &image) {
-    std::string filename_ext =
-            utility::filesystem::GetFileExtensionInLowerCase(filename);
-    if (filename_ext.empty()) {
-        utility::LogWarning(
-                "Read geometry::Image failed: missing file extension.");
-        return false;
-    }
-    auto map_itr = file_extension_to_image_read_function.find(filename_ext);
-    if (map_itr == file_extension_to_image_read_function.end()) {
-        utility::LogWarning(
-                "Read geometry::Image failed: file extension {} unknown",
-                filename_ext);
-        return false;
+    std::string signature_buffer(MAX_SIGNATURE_LEN, 0);
+    std::ifstream file(filename, std::ios::binary);
+    file.read(&signature_buffer[0], MAX_SIGNATURE_LEN);
+    std::string err_msg;
+    if (!file) {
+        err_msg = "Read geometry::Image failed for file {}. I/O error.";
+    } else {
+        file.close();
+        for (const auto &signature_decoder : signature_decoder_list) {
+            if (signature_buffer.compare(0, signature_decoder.first.size(),
+                                         signature_decoder.first) == 0) {
+                return signature_decoder.second(filename, image);
+            }
+        }
+        err_msg =
+                "Read geometry::Image failed for file {}. Unknown file "
+                "signature, only PNG and JPG are supported.";
     }
-    return map_itr->second(filename, image);
+    image.Clear();
+    utility::LogWarning(err_msg.c_str(), filename);
+    return false;
 }
 
 bool WriteImage(const std::string &filename,

cpp/open3d/io/ImageIO.h

@@ -69,11 +69,18 @@ bool WriteImageToJPG(const std::string &filename,
                      const geometry::Image &image,
                      int quality = kOpen3DImageIODefaultQuality);
 
-/// The general entrance for reading an Image from memory
+/// Read a PNG image from memory.
+/// \param image_data_ptr the pointer to image data in memory.
+/// \param image_data_size the size of image data in memory.
+/// \return return true if the read function is successful, false otherwise.
 bool ReadPNGFromMemory(const unsigned char *image_data_ptr,
                        size_t image_data_size,
                        geometry::Image &image);
 
+/// Read a JPG image from memory.
+/// \param image_data_ptr the pointer to image data in memory.
+/// \param image_data_size the size of image data in memory.
+/// \return return true if the read function is successful, false otherwise.
 bool ReadJPGFromMemory(const unsigned char *image_data_ptr,
                        size_t image_data_size,
                        geometry::Image &image);