feat(jpeg): add thumbnail functionality to jpeg reader

src/cmake/testing.cmake

@@ -285,6 +285,7 @@ macro (oiio_add_all_tests)
             # These Python tests also need access to oiio-images
             oiio_add_tests (
                 python-imageinput python-imagebufalgo
+                python-thumbnail-jpeg
                 IMAGEDIR oiio-images
                 ENVIRONMENT "${_pybind_tests_pythonpath}"
                 )

src/jpeg.imageio/jpeg_pvt.h

@@ -64,7 +64,8 @@ class JpgInput final : public ImageInput {
     const char* format_name(void) const override { return "jpeg"; }
     int supports(string_view feature) const override
     {
-        return (feature == "exif" || feature == "iptc" || feature == "ioproxy");
+        return (feature == "exif" || feature == "iptc" || feature == "ioproxy"
+                || feature == "thumbnail");
     }
     bool valid_file(Filesystem::IOProxy* ioproxy) const override;
 
@@ -77,6 +78,7 @@ class JpgInput final : public ImageInput {
                                int z, void* data) override;
     bool read_native_scanlines(int subimage, int miplevel, int ybegin, int yend,
                                span<std::byte> data) override;
+    bool get_thumbnail(ImageBuf& thumb, int subimage) override;
     bool close() override;
 
     const std::string& filename() const { return m_filename; }
@@ -108,6 +110,10 @@ class JpgInput final : public ImageInput {
     uhdr_codec_private_t* m_uhdr_dec;
 #endif
 
+    // This will point to an embedded JPEG thumbnail if exists.
+    // This span is only valid until jpeg_destroy_decompress(&m_cinfo) is called.
+    cspan<uint8_t> m_thumbnail_data;
+
     void init()
     {
         m_raw           = false;
@@ -122,6 +128,7 @@ class JpgInput final : public ImageInput {
 #if defined(USE_UHDR)
         m_uhdr_dec = NULL;
 #endif
+        m_thumbnail_data = cspan<uint8_t>();
     }
 
     // Rummage through the JPEG "APP1" marker pointed to by buf, decoding
@@ -139,6 +146,8 @@ class JpgInput final : public ImageInput {
 
     void close_file() { init(); }
 
+    void scan_for_thumbnail(cspan<uint8_t> exif);
+
     friend class JpgOutput;
 };
 

src/jpeg.imageio/jpeginput.cpp

@@ -8,6 +8,7 @@
 
 #include <OpenImageIO/filesystem.h>
 #include <OpenImageIO/fmath.h>
+#include <OpenImageIO/imagebuf.h>
 #include <OpenImageIO/imageio.h>
 #include <OpenImageIO/strutil.h>
 #include <OpenImageIO/tiffutils.h>
@@ -296,13 +297,14 @@ JpgInput::open(const std::string& name, ImageSpec& newspec)
         if (is_exif_marker(m)) {
             // The block starts with "Exif\0\0", so skip 6 bytes to get
             // to the start of the actual Exif data TIFF directory
-            bool ok = decode_exif(string_view((char*)m->data + 6,
-                                              m->data_length - 6),
-                                  m_spec);
+            auto exif = cspan<uint8_t>((uint8_t*)m->data + 6,
+                                       m->data_length - 6);
+            bool ok   = decode_exif(exif, m_spec);
             if (!ok && OIIO::get_int_attribute("imageinput:strict")) {
                 errorfmt("Could not decode Exif");
                 return false;
             }
+            scan_for_thumbnail(exif);
         } else if (m->marker == (JPEG_APP0 + 1) && m->data_length >= 28
                    && !strncmp((const char*)m->data,
                                "http://ns.adobe.com/xap/1.0/", 28)) {  //NOSONAR
@@ -791,4 +793,141 @@ JpgInput::jpeg_decode_iptc(string_view buf)
     return decode_iptc_iim(buf, m_spec);
 }
 
+void
+JpgInput::scan_for_thumbnail(cspan<uint8_t> exif)
+{
+    try {
+        bool host_little = littleendian();
+        bool file_little = (exif[0] == 0x49 && exif[1] == 0x49);
+        bool swab        = (host_little != file_little);
+
+        const uint8_t* soi_ptr = nullptr;
+        const uint8_t* eoi_ptr = nullptr;
+
+        size_t i = 0;
+        while (i < exif.size() - 1) {
+            if (exif[i] == 0xFF && exif[i + 1] == 0xD8) {
+                soi_ptr = &exif[i];
+                break;
+            }
+            i++;
+        }
+
+        if (!soi_ptr)
+            return;
+
+        // extract image properties along the way
+        uint16_t width  = 0;
+        uint16_t height = 0;
+        int numchan     = 0;
+
+        while (i < exif.size() - 1) {
+            if (exif[i++] == 0xFF) {
+                const auto marker = exif[i];
+                if (marker == 0xD9) {
+                    eoi_ptr = &exif[i] + 1;  // one past (exclusive)
+                    break;
+                } else if (marker == 0xC0 || marker == 0xC2) {
+                    uint16_t length = (exif.at(i + 2) << 8) + exif.at(i + 1);
+                    height          = (exif.at(i + 5) << 8) + exif.at(i + 4);
+                    width           = (exif.at(i + 7) << 8) + exif.at(i + 6);
+                    numchan         = exif[i + 8];
+
+                    if (swab) {
+                        swap_endian(&length);
+                        swap_endian(&height);
+                        swap_endian(&width);
+                    }
+
+                    length -= 2;
+
+                    if (i + length < exif.size() - 1) {
+                        i += length;
+                    }
+                } else if ((marker >= 0xC0 && marker < 0xD0)
+                           || (marker > 0xD9 && marker <= 0xFE)) {
+                    // Skip ahead for markers that have an associated length
+                    uint16_t length = (exif.at(i + 2) << 8) + exif.at(i + 1);
+
+                    if (swab) {
+                        swap_endian(&length);
+                    }
+
+                    length -= 2;
+
+                    if (i + length < exif.size() - 1) {
+                        i += length;
+                    }
+                }
+            }
+        }
+
+        if (eoi_ptr) {
+            m_thumbnail_data = cspan<uint8_t>(soi_ptr, eoi_ptr);
+            m_spec.attribute("thumbnail_width", width);
+            m_spec.attribute("thumbnail_height", height);
+            m_spec.attribute("thumbnail_nchannels", numchan);
+        }
+
+    } catch (const std::exception& e) {
+        errorfmt("ERROR scanning for thumbnail: {}", e.what());
+    }
+}
+
+bool
+JpgInput::get_thumbnail(ImageBuf& thumb, int subimage)
+{
+    if (!m_decomp_create) {
+        errorfmt("ImageInput hasn't been initialised properly");
+        return false;
+    }
+
+    if (m_thumbnail_data.empty()) {
+        errorfmt("No thumbnail found");
+        return false;
+    }
+
+    auto image_input = OIIO::ImageInput::create("jpeg", false);
+    if (image_input == nullptr) {
+        std::string errmsg = OIIO::geterror();
+        errorfmt("{}", errmsg.size() ? errmsg.c_str() : "unknown error");
+        return false;
+    }
+
+    Filesystem::IOMemReader proxy(m_thumbnail_data.data(),
+                                  m_thumbnail_data.size());
+    bool result = image_input->valid_file(&proxy);
+    if (!result) {
+        errorfmt("the thumbnail is not a valid image of type \"jpeg\"");
+        return false;
+    }
+
+    ImageSpec temp_spec, image_spec;
+    Filesystem::IOProxy* pp = &proxy;
+    temp_spec.attribute("oiio:ioproxy", TypeDesc::PTR, &pp);
+
+    result = image_input->open("", image_spec, temp_spec);
+    if (!result) {
+        errorfmt(
+            "failed to initialise an ImageInput object with the thumbnail data");
+        return false;
+    }
+
+    thumb.reset(image_spec);
+
+    result = image_input->read_image(0, 0, 0, image_spec.nchannels,
+                                     image_spec.format, thumb.localpixels());
+
+    if (!result) {
+        errorfmt(
+            "failed to initialise an ImageInput object of type \"jpeg\" with the thumbnail data");
+        image_input->close();
+        return false;
+    }
+
+    image_input->close();
+    return true;
+}
+
+
 OIIO_PLUGIN_NAMESPACE_END

testsuite/gpsread/ref/out.txt

@@ -1,12 +1,15 @@
 Reading ../oiio-images/tahoe-gps.jpg
 ../oiio-images/tahoe-gps.jpg : 2048 x 1536, 3 channel, uint8 jpeg
-    SHA-1: C3B420EF8C20C4771F6F7BF89EA9D9D4002BA016
+    SHA-1: 71EBEC73B8E8B3533780B15147E61D895C80E8B1
     channel list: R, G, B
     Make: "HTC"
     Model: "T-Mobile G1"
     Orientation: 1 (normal)
     ResolutionUnit: "none"
     Software: "title;va"
+    thumbnail_height: 240
+    thumbnail_nchannels: 3
+    thumbnail_width: 320
     XResolution: 72
     YResolution: 72
     Exif:ColorSpace: 1

testsuite/jpeg-corrupt/ref/out-alt2.txt

@@ -4,6 +4,9 @@ src/corrupt-exif.jpg :  256 x  256, 3 channel, uint8 jpeg
     channel list: R, G, B
     Orientation: 1 (normal)
     ResolutionUnit: "in"
+    thumbnail_height: 160
+    thumbnail_nchannels: 3
+    thumbnail_width: 160
     XResolution: 300
     YResolution: 300
     jpeg:subsampling: "4:2:0"

testsuite/jpeg-corrupt/ref/out-alt3.txt

@@ -4,6 +4,9 @@ src/corrupt-exif.jpg :  256 x  256, 3 channel, uint8 jpeg
     channel list: R, G, B
     Orientation: 1 (normal)
     ResolutionUnit: "in"
+    thumbnail_height: 160
+    thumbnail_nchannels: 3
+    thumbnail_width: 160
     XResolution: 300
     YResolution: 300
     jpeg:subsampling: "4:2:0"

testsuite/jpeg-corrupt/ref/out-alt4.txt

@@ -4,6 +4,9 @@ src/corrupt-exif.jpg :  256 x  256, 3 channel, uint8 jpeg
     channel list: R, G, B
     Orientation: 1 (normal)
     ResolutionUnit: "in"
+    thumbnail_height: 160
+    thumbnail_nchannels: 3
+    thumbnail_width: 160
     XResolution: 300
     YResolution: 300
     jpeg:subsampling: "4:2:0"

testsuite/jpeg-corrupt/ref/out-alt5.txt

@@ -4,6 +4,9 @@ src/corrupt-exif.jpg :  256 x  256, 3 channel, uint8 jpeg
     channel list: R, G, B
     Orientation: 1 (normal)
     ResolutionUnit: "in"
+    thumbnail_height: 160
+    thumbnail_nchannels: 3
+    thumbnail_width: 160
     XResolution: 300
     YResolution: 300
     jpeg:subsampling: "4:2:0"

testsuite/jpeg-corrupt/ref/out.txt

@@ -4,6 +4,9 @@ src/corrupt-exif.jpg :  256 x  256, 3 channel, uint8 jpeg
     channel list: R, G, B
     Orientation: 1 (normal)
     ResolutionUnit: "in"
+    thumbnail_height: 160
+    thumbnail_nchannels: 3
+    thumbnail_width: 160
     XResolution: 300
     YResolution: 300
     jpeg:subsampling: "4:2:0"

testsuite/python-imageinput/ref/out-python3-win.txt

@@ -36,6 +36,9 @@ Opened "D:/a/OpenImageIO/OpenImageIO/build/testsuite/oiio-images/tahoe-gps.jpg"
   GPS:TimeStamp = (17.0, 56.0, 33.0)
   GPS:MapDatum = "WGS-84"
   GPS:DateStamp = "1915:08:08"
+  thumbnail_width = 320
+  thumbnail_height = 240
+  thumbnail_nchannels = 3
 
 Opened "grid.tx" as a tiff
   resolution 1024x1024+0+0
@@ -230,7 +233,7 @@ Testing read_native_deep_image:
 
 Testing get_thumbnail:
   get_thumbnail returns ImageBuf: True
-  thumbnail initialized: False
+  thumbnail initialized: True
 
 Testing has_error/geterror:
   scanline on tiled None: True

testsuite/python-imageinput/ref/out.txt

@@ -36,6 +36,9 @@ Opened "../oiio-images/tahoe-gps.jpg" as a jpeg
   GPS:TimeStamp = (17.0, 56.0, 33.0)
   GPS:MapDatum = "WGS-84"
   GPS:DateStamp = "1915:08:08"
+  thumbnail_width = 320
+  thumbnail_height = 240
+  thumbnail_nchannels = 3
 
 Opened "grid.tx" as a tiff
   resolution 1024x1024+0+0
@@ -230,7 +233,7 @@ Testing read_native_deep_image:
 
 Testing get_thumbnail:
   get_thumbnail returns ImageBuf: True
-  thumbnail initialized: False
+  thumbnail initialized: True
 
 Testing has_error/geterror:
   scanline on tiled None: True

testsuite/python-thumbnail-jpeg/ref/out.txt

@@ -0,0 +1 @@
+Done.

testsuite/python-thumbnail-jpeg/run.py

@@ -0,0 +1,10 @@
+#!/usr/bin/env python
+
+# Copyright Contributors to the OpenImageIO project.
+# SPDX-License-Identifier: Apache-2.0
+# https://github.com/AcademySoftwareFoundation/OpenImageIO
+
+
+import os
+
+command += pythonbin + " src/test_jpeg_thumbnail.py >> out.txt 2>&1"

testsuite/python-thumbnail-jpeg/src/test_jpeg_thumbnail.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python
+
+# Copyright Contributors to the OpenImageIO project.
+# SPDX-License-Identifier: Apache-2.0
+# https://github.com/AcademySoftwareFoundation/OpenImageIO
+
+from __future__ import annotations
+
+import OpenImageIO as oiio
+
+import os
+
+OIIO_TESTSUITE_IMAGEDIR = os.getenv('OIIO_TESTSUITE_IMAGEDIR',
+                                    '../oiio-images')
+
+######################################################################
+# main test starts here
+
+try:
+    input = oiio.ImageInput.open (OIIO_TESTSUITE_IMAGEDIR + "/tahoe-gps.jpg")
+    thumbnail = input.get_thumbnail()
+    assert thumbnail is not None
+    assert thumbnail.spec().width == 320
+    assert thumbnail.spec().height == 240
+    assert thumbnail.spec().nchannels == 3
+    print ("Done.")
+except Exception as detail:
+    print ("Unknown exception:", detail)