Added coordinate system links in documentation

docs/handbook/concepts.rst

@@ -58,6 +58,8 @@ You can read the image size through the :py:attr:`~PIL.Image.Image.size`
 attribute. This is a 2-tuple, containing the horizontal and vertical size in
 pixels.
 
+.. _coordinate-system:
+
 Coordinate System
 -----------------
 

src/PIL/Image.py

@@ -1066,7 +1066,7 @@ class Image(object):
         """
         Returns a rectangular region from this image. The box is a
         4-tuple defining the left, upper, right, and lower pixel
-        coordinate.
+        coordinate. See :ref:`coordinate-system`.
 
         Note: Prior to Pillow 3.4.0, this was a lazy operation.
 
@@ -1173,8 +1173,9 @@ class Image(object):
         image.
 
         :returns: The bounding box is returned as a 4-tuple defining the
-           left, upper, right, and lower pixel coordinate. If the image
+           left, upper, right, and lower pixel coordinate. See
-           is completely empty, this method returns None.
+           :ref:`coordinate-system`. If the image is completely empty, this
+           method returns None.
 
         """
 
@@ -1275,7 +1276,8 @@ class Image(object):
         """
         Returns the pixel value at a given position.
 
-        :param xy: The coordinate, given as (x, y).
+        :param xy: The coordinate, given as (x, y). See
+           :ref:`coordinate-system`.
         :returns: The pixel value.  If the image is a multi-layer image,
            this method returns a tuple.
         """
@@ -1335,8 +1337,8 @@ class Image(object):
         Pastes another image into this image. The box argument is either
         a 2-tuple giving the upper left corner, a 4-tuple defining the
         left, upper, right, and lower pixel coordinate, or None (same as
-        (0, 0)).  If a 4-tuple is given, the size of the pasted image
+        (0, 0)). See :ref:`coordinate-system`. If a 4-tuple is given, the size
-        must match the size of the region.
+        of the pasted image must match the size of the region.
 
         If the modes don't match, the pasted image is converted to the mode of
         this image (see the :py:meth:`~PIL.Image.Image.convert` method for
@@ -1616,7 +1618,8 @@ class Image(object):
         * :py:meth:`~PIL.Image.Image.putdata`
         * :py:mod:`~PIL.ImageDraw`
 
-        :param xy: The pixel coordinate, given as (x, y).
+        :param xy: The pixel coordinate, given as (x, y). See
+           :ref:`coordinate-system`.
         :param value: The pixel value.
         """
 

src/PIL/ImageDraw.py

@@ -327,7 +327,8 @@ def floodfill(image, xy, value, border=None, thresh=0):
     (experimental) Fills a bounded region with a given color.
 
     :param image: Target image.
-    :param xy: Seed position (a 2-item coordinate tuple).
+    :param xy: Seed position (a 2-item coordinate tuple). See
+        :ref:`coordinate-system`.
     :param value: Fill color.
     :param border: Optional border value.  If given, the region consists of
         pixels with a color different from the border color.  If not given,

src/PIL/ImageMorph.py

@@ -211,7 +211,7 @@ class MorphOp(object):
         an image.
 
         Returns a list of tuples of (x,y) coordinates
-        of all matching pixels."""
+        of all matching pixels. See :ref:`coordinate-system`."""
         if self.lut is None:
             raise Exception('No operator loaded')
 
@@ -223,7 +223,7 @@ class MorphOp(object):
         """Get a list of all turned on pixels in a binary image
 
         Returns a list of tuples of (x,y) coordinates
-        of all matching pixels."""
+        of all matching pixels. See :ref:`coordinate-system`."""
 
         if image.mode != 'L':
             raise Exception('Image must be binary, meaning it must use mode L')

src/PIL/ImageTk.py

@@ -169,8 +169,8 @@ class PhotoImage(object):
                    mode does not match, the image is converted to the mode of
                    the bitmap image.
         :param box: A 4-tuple defining the left, upper, right, and lower pixel
-                    coordinate.  If None is given instead of a tuple, all of
+                    coordinate. See :ref:`coordinate-system`. If None is given
-                    the image is assumed.
+                    instead of a tuple, all of the image is assumed.
         """
 
         # convert to blittable

src/PIL/ImageTransform.py

@@ -65,7 +65,7 @@ class ExtentTransform(Transform):
     See :py:meth:`~PIL.Image.Image.transform`
 
     :param bbox: A 4-tuple (x0, y0, x1, y1) which specifies two points in the
-        input image's coordinate system.
+        input image's coordinate system. See :ref:`coordinate-system`.
     """
     method = Image.EXTENT
 

src/PIL/ImageWin.py

@@ -154,8 +154,9 @@ class Dib(object):
                    If the mode does not match, the image is converted to the
                    mode of the bitmap image.
         :param box: A 4-tuple defining the left, upper, right, and
-                    lower pixel coordinate.  If None is given instead of a
+                    lower pixel coordinate.  See :ref:`coordinate-system`. If
-                    tuple, all of the image is assumed.
+                    None is given instead of a tuple, all of the image is
+                    assumed.
         """
         im.load()
         if self.mode != im.mode:

src/PIL/PyAccess.py

@@ -68,7 +68,8 @@ class PyAccess(object):
         numerical value for single band images, and a tuple for
         multi-band images
 
-        :param xy: The pixel coordinate, given as (x, y).
+        :param xy: The pixel coordinate, given as (x, y). See
+           :ref:`coordinate-system`.
         :param color: The pixel value.
         """
         if self.readonly:
@@ -82,7 +83,8 @@ class PyAccess(object):
         value for single band images or a tuple for multiple band
         images
 
-        :param xy: The pixel coordinate, given as (x, y).
+        :param xy: The pixel coordinate, given as (x, y). See
+          :ref:`coordinate-system`.
         :returns: a pixel value for single band images, a tuple of
           pixel values for multiband images.
         """