fixes #344

fastcore/_nbdev.py

@@ -161,6 +161,7 @@
          "Path.readlines": "03_xtras.ipynb",
          "Path.read_json": "03_xtras.ipynb",
          "Path.mk_write": "03_xtras.ipynb",
+         "Path.relpath": "03_xtras.ipynb",
          "Path.ls": "03_xtras.ipynb",
          "Path.__repr__": "03_xtras.ipynb",
          "Path.delete": "03_xtras.ipynb",

fastcore/xtras.py

@@ -105,6 +105,25 @@ def maybe_open(f, mode='r', **kwargs):
         with open(f, mode, **kwargs) as f: yield f
     else: yield f
 
+# Cell
+def _jpg_size(f):
+        size,ftype = 2,0
+        while not 0xc0 <= ftype <= 0xcf:
+            f.seek(size, 1)
+            byte = f.read(1)
+            while ord(byte) == 0xff: byte = f.read(1)
+            ftype = ord(byte)
+            size = struct.unpack('>H', f.read(2))[0] - 2
+        f.seek(1, 1)  # `precision'
+        h,w = struct.unpack('>HH', f.read(4))
+        return w,h
+
+def _gif_size(f): return struct.unpack('<HH', head[6:10])
+
+def _png_size(f):
+    assert struct.unpack('>i', head[4:8])[0]==0x0d0a1a0a
+    return struct.unpack('>ii', head[16:24])
+
 # Cell
 def image_size(fn):
     "Tuple of (w,h) for png, gif, or jpg; `None` otherwise"
@@ -239,6 +258,12 @@ def mk_write(self:Path, data, encoding=None, errors=None, mode=511):
     self.parent.mkdir(exist_ok=True, parents=True, mode=mode)
     self.write_text(data, encoding=encoding, errors=errors)
 
+# Cell
+@patch
+def relpath(self:Path, start=None):
+    "Same as `os.path.relpath`, but returns a `Path`, and resolves symlinks"
+    return Path(os.path.relpath(self.resolve(), Path(start).resolve()))
+
 # Cell
 @patch
 def ls(self:Path, n_max=None, file_type=None, file_exts=None):

nbs/03_xtras.ipynb

@@ -618,7 +618,7 @@
     {
      "data": {
       "text/plain": [
-       "['b', 'a', 'g', 'h', 'f', 'e', 'c', 'd']"
+       "['e', 'd', 'c', 'h', 'f', 'a', 'b', 'g']"
       ]
      },
      "execution_count": null,
@@ -848,6 +848,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "#export\n",
     "def _jpg_size(f):\n",
     "        size,ftype = 2,0\n",
     "        while not 0xc0 <= ftype <= 0xcf:\n",
@@ -1353,6 +1354,60 @@
     "    self.write_text(data, encoding=encoding, errors=errors)"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "#export\n",
+    "@patch\n",
+    "def relpath(self:Path, start=None):\n",
+    "    \"Same as `os.path.relpath`, but returns a `Path`, and resolves symlinks\"\n",
+    "    return Path(os.path.relpath(self.resolve(), Path(start).resolve()))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "Path('/home/jhoward/git/fastcore/fastcore')"
+      ]
+     },
+     "execution_count": null,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "Path('../fastcore/').resolve()\n",
+    "p"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "Path('../fastcore')"
+      ]
+     },
+     "execution_count": null,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "p.relpath(Path('.'))"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -2127,6 +2182,7 @@
       "Converted 03b_net.ipynb.\n",
       "Converted 04_dispatch.ipynb.\n",
       "Converted 05_transform.ipynb.\n",
+      "Converted 06_docments.ipynb.\n",
       "Converted 07_meta.ipynb.\n",
       "Converted 08_script.ipynb.\n",
       "Converted index.ipynb.\n",