Add Radiance .hdr support + unit tests

Also change read() behavior such that an exception is raised if file
parsing fails. Previously, an exception was raised in some cases, while
in others, None was returned. Also, basic file attributes (name, type,
size) are now returned even if the file is not recognized.

Author: toaarnio

README.md

@@ -2,9 +2,9 @@
 
 [![Build Status](https://travis-ci.com/toaarnio/imsize.svg?branch=master)](https://travis-ci.com/github/toaarnio/imsize)
 
-Lightning-fast extraction of image dimensions & bit depth. Tested on Python 3.8 and Ubuntu 20.04.
+Lightning-fast extraction of image dimensions & bit depth. Tested on Python 3.8+ and Ubuntu 22.04.
 
-Supports PGM / PPM / PNM / PFM / PNG / BMP / JPG / TIFF / INSP / EXR / DNG / CR2 / NEF / RAW / NPY.
+Supports PGM / PPM / PNM / PFM / PNG / BMP / JPG / TIFF / INSP / EXR / HDR / DNG / CR2 / NEF / RAW / NPY.
 
 **Installing on Linux:**
 ```

imsize/consoleapp.py

@@ -21,7 +21,7 @@
 
 
 FILETYPES = ["*.png", "*.pnm", "*.pgm", "*.ppm", "*.pfm", "*.bmp",
-             "*.jpeg", "*.jpg", "*.insp", "*.tiff", "*.tif",
+             "*.jpeg", "*.jpg", "*.insp", "*.tiff", "*.tif", "*.hdr",
              "*.exr", "*.dng", "*.cr2", "*.nef", "*.raw", "*.npy"]
 
 

imsize/imsize.py

@@ -44,7 +44,7 @@ class ImageInfo:
 
     Attributes:
       filespec (str): The filespec given to read(), copied verbatim
-      filetype (str): File type: png|pnm|pfm|bmp|jpeg|insp|tiff|exr|dng|cr2|nef|raw|npy
+      filetype (str): File type: png|pnm|pfm|bmp|jpeg|insp|tiff|exr|hdr|dng|cr2|nef|raw|npy|...
       filesize (int): Size of the file on disk in bytes
       header_size (int): Size of .raw file header in bytes
       isfloat (bool): True if the image is in floating-point format
@@ -91,8 +91,10 @@ def read(filespec):
     """
     Parses a lowest common denominator set of metadata from the given
     image, i.e., the dimensions and bit depth. Does not read the entire
-    file but only what's necessary. Returns an ImageInfo with all fields
-    filled in, or None in case of failure.
+    file but only what's necessary. If the file type is recognized and
+    parsing succeeds, returns an ImageInfo with all fields filled in.
+    Otherwise, an exception is raised or only the basic file attributes
+    (name, type, size) are filled in.
 
     Example:
       info = imsize.read("myfile.jpg")
@@ -114,6 +116,7 @@ def read(filespec):
                 "tiff": _read_tiff,
                 "tif": _read_tiff,
                 "exr": _read_exr,
+                "hdr": _read_hdr,
                 "dng": _read_dng,
                 "cr2": _read_cr2,
                 "nef": _read_nef,
@@ -123,7 +126,15 @@ def read(filespec):
         handler = handlers[filetype]
         info = handler(filespec)
         return info
-    return None
+    else:
+        # unrecognized file extension
+        info = ImageInfo()
+        info.filespec = filespec
+        info.filetype = filetype
+        info.filesize = os.path.getsize(filespec)
+        info.nbytes = info.filesize
+        info.uncertain = True
+        return info
 
 
 ######################################################################################
@@ -154,6 +165,7 @@ def _read_png(filespec):
                       6: 4}[ihdr[3]]  # truecolor_alpha => 4 channels
         info = _complete(info)
         return info
+    raise RuntimeError(f"File {filespec} is not a valid PNG file.")
 
 
 def _read_pnm(filespec):
@@ -188,6 +200,30 @@ def _read_pfm(filespec):
     return info
 
 
+def _read_hdr(filespec):
+    info = ImageInfo()
+    info.filespec = filespec
+    info.filetype = "hdr"
+    info.filesize = os.path.getsize(filespec)
+    info.isfloat = True
+    info.cfa_raw = False
+    info.nchan = 3
+    info.bitdepth = 32
+    info.bytedepth = 4
+    with open(filespec, "rb") as f:
+        if f.readline() != b"#?RADIANCE\n":
+            raise RuntimeError(f"File {filespec} is not a valid Radiance HDR file.")
+        for line in f:
+            if line == b"\n":
+                dims = f.readline().decode("utf-8")  # '-Y 480 +X 720'
+                dims = dims.split(" ")
+                info.height = int(dims[1])
+                info.width = int(dims[3])
+                info = _complete(info)
+                return info
+    raise RuntimeError(f"File {filespec} is not a valid Radiance HDR file.")
+
+
 def _read_bmp(filespec):
     info = ImageInfo()
     info.filespec = filespec
@@ -211,6 +247,7 @@ def _read_bmp(filespec):
             info.maxval = 255
         info = _complete(info)
         return info
+    raise RuntimeError(f"File {filespec} is not a valid BMP file.")
 
 
 def _read_exr(filespec):
@@ -249,7 +286,8 @@ def _read_jpeg(filespec):
             info.width = sof[2]
             info.nchan = sof[3]
             info = _complete(info)
-    return info
+            return info
+    raise RuntimeError(f"File {filespec} is not a valid JPEG file.")
 
 
 def _read_insp(filespec):
@@ -380,8 +418,6 @@ def _read_raw(filespec):  # reading the whole file ==> SLOW
         minbits = max(minbits, 10)  # 10, 12, 14, 16
         info.bitdepth = int(minbits)  # can underestimate bpp if image is very dark
         info = _complete(info)
-    else:
-        info = None
     return info
 
 
@@ -408,6 +444,7 @@ def _read_npy(filespec):
             info.maxval = 1.0 if info.isfloat else 2 ** info.bitdepth - 1
             info = _complete(info)
             return info
+    raise RuntimeError(f"File {filespec} is not a valid NPY file.")
 
 
 def _complete(info):

imsize/version.py

@@ -1 +1 @@
-__version__ = "1.3.5"
+__version__ = "1.4.0"

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "imsize"
-version = "1.3.5"
+version = "1.4.0"
 description="Lightning-fast extraction of image dimensions & bit depth."
 authors = [{name = "Tomi Aarnio", email = "[email protected]"}]
 readme = "README.md"

test/images/vinesunset.hdr

@@ -92,6 +92,20 @@ def test_npy(self):
             self.assertEqual(info.bytedepth, 2)
             self.assertEqual(info.nbytes, 20 * 10 * 5 * 2)
 
+    def test_hdr(self):
+        hdrs = glob.glob(os.path.join(imagedir, "*.hdr"))
+        self.assertTrue(len(hdrs) > 0)
+        for i, hdr in enumerate(sorted(hdrs)):
+            info = imsize.read(hdr)
+            self.assertEqual(info.filetype, "hdr")
+            self.assertEqual(info.isfloat, True)
+            self.assertEqual(info.width, 720)
+            self.assertEqual(info.height, 480)
+            self.assertEqual(info.nchan, 3)
+            self.assertEqual(info.bitdepth, 32)
+            self.assertEqual(info.bytedepth, 4)
+            self.assertEqual(info.nbytes, info.width * info.height * info.nchan * info.bytedepth)
+
     def test_orientations(self):
         jpegs = sorted(glob.glob(os.path.join(imagedir, "orientations", "*.jpg")))
         tiffs = sorted(glob.glob(os.path.join(imagedir, "orientations", "*.tif")))