From 636ad68f5e4a6f66d3d8987a7565b756c65e3c5e Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Wed, 6 Mar 2019 10:28:45 +1100
Subject: [PATCH] Read Photoshop resolution data

---
 Tests/test_file_jpeg.py    |  9 +++++++++
 src/PIL/IptcImagePlugin.py | 32 +++-----------------------------
 src/PIL/JpegImagePlugin.py | 35 ++++++++++++++++++++++++++++++++++-
 3 files changed, 46 insertions(+), 30 deletions(-)

diff --git a/Tests/test_file_jpeg.py b/Tests/test_file_jpeg.py
index cbe894f34..712a36cd5 100644
--- a/Tests/test_file_jpeg.py
+++ b/Tests/test_file_jpeg.py
@@ -590,6 +590,15 @@ class TestFileJpeg(PillowTestCase):
         # Act / Assert
         self.assertEqual(im._getexif()[306], '2017:03:13 23:03:09')
 
+    def test_photoshop(self):
+        im = Image.open("Tests/images/photoshop-200dpi.jpg")
+        self.assertEqual(im.info["photoshop"][0x03ed], {
+            'XResolution': 200.0,
+            'DisplayedUnitsX': 1,
+            'YResolution': 200.0,
+            'DisplayedUnitsY': 1,
+        })
+
 
 @unittest.skipUnless(sys.platform.startswith('win32'), "Windows only")
 class TestFileCloseW32(PillowTestCase):
diff --git a/src/PIL/IptcImagePlugin.py b/src/PIL/IptcImagePlugin.py
index 5055d2a00..371bb3acf 100644
--- a/src/PIL/IptcImagePlugin.py
+++ b/src/PIL/IptcImagePlugin.py
@@ -198,35 +198,9 @@ def getiptcinfo(im):
 
     elif isinstance(im, JpegImagePlugin.JpegImageFile):
         # extract the IPTC/NAA resource
-        try:
-            app = im.app["APP13"]
-            if app[:14] == b"Photoshop 3.0\x00":
-                app = app[14:]
-                # parse the image resource block
-                offset = 0
-                while app[offset:offset+4] == b"8BIM":
-                    offset += 4
-                    # resource code
-                    code = i16(app, offset)
-                    offset += 2
-                    # resource name (usually empty)
-                    name_len = i8(app[offset])
-                    # name = app[offset+1:offset+1+name_len]
-                    offset = 1 + offset + name_len
-                    if offset & 1:
-                        offset += 1
-                    # resource data block
-                    size = i32(app, offset)
-                    offset += 4
-                    if code == 0x0404:
-                        # 0x0404 contains IPTC/NAA data
-                        data = app[offset:offset+size]
-                        break
-                    offset = offset + size
-                    if offset & 1:
-                        offset += 1
-        except (AttributeError, KeyError):
-            pass
+        photoshop = im.info.get("photoshop")
+        if photoshop:
+            data = photoshop.get(0x0404)
 
     elif isinstance(im, TiffImagePlugin.TiffImageFile):
         # get raw data from the IPTC/NAA tag (PhotoShop tags the data
diff --git a/src/PIL/JpegImagePlugin.py b/src/PIL/JpegImagePlugin.py
index 2f76e9675..d51e0a831 100644
--- a/src/PIL/JpegImagePlugin.py
+++ b/src/PIL/JpegImagePlugin.py
@@ -39,7 +39,7 @@ import struct
 import io
 import warnings
 from . import Image, ImageFile, TiffImagePlugin
-from ._binary import i8, o8, i16be as i16
+from ._binary import i8, o8, i16be as i16, i32be as i32
 from .JpegPresets import presets
 from ._util import isStringType
 
@@ -104,6 +104,39 @@ def APP(self, marker):
         # reassemble the profile, rather than assuming that the APP2
         # markers appear in the correct sequence.
         self.icclist.append(s)
+    elif marker == 0xFFED:
+        if s[:14] == b"Photoshop 3.0\x00":
+            blocks = s[14:]
+            # parse the image resource block
+            offset = 0
+            photoshop = {}
+            while blocks[offset:offset+4] == b"8BIM":
+                offset += 4
+                # resource code
+                code = i16(blocks, offset)
+                offset += 2
+                # resource name (usually empty)
+                name_len = i8(blocks[offset])
+                # name = blocks[offset+1:offset+1+name_len]
+                offset = 1 + offset + name_len
+                if offset & 1:
+                    offset += 1
+                # resource data block
+                size = i32(blocks, offset)
+                offset += 4
+                data = blocks[offset:offset+size]
+                if code == 0x03ED:  # ResolutionInfo
+                    data = {
+                        'XResolution': i32(data[:4]) / 65536,
+                        'DisplayedUnitsX': i16(data[4:8]),
+                        'YResolution': i32(data[8:12]) / 65536,
+                        'DisplayedUnitsY': i16(data[12:]),
+                    }
+                photoshop[code] = data
+                offset = offset + size
+                if offset & 1:
+                    offset += 1
+        self.info["photoshop"] = photoshop
     elif marker == 0xFFEE and s[:5] == b"Adobe":
         self.info["adobe"] = i16(s, 5)
         # extract Adobe custom properties