documentation update

Author: JorjMcKie

docs/font.rst

@@ -261,15 +261,15 @@ A Font object also contains useful general information, like the font bbox, the
 
       *(New in v1.18.0)*
 
-      The ascender value of the font, see `here <https://en.wikipedia.org/wiki/Ascender_(typography)>`_ for details.
+      The ascender value of the font, see `here <https://en.wikipedia.org/wiki/Ascender_(typography)>`_ for details. Please note that there is a difference to the strict definition: our value includes everything above the baseline -- not just the height difference between upper case "A" and and lower case "a".
 
       :rtype: float
 
    .. attribute:: descender
 
       *(New in v1.18.0)*
 
-      The descender value of the font, see `here <https://en.wikipedia.org/wiki/Descender>`_ for details.
+      The descender value of the font, see `here <https://en.wikipedia.org/wiki/Descender>`_ for details. This value always is negative and is the portion that some glyphs descend below the base line, for example "g" or "y". As a consequence, the value ``ascender - descender`` is the total height, that every glyph of the font fits into. This is true at least for most fonts -- as always, there are exceptions, especially for calligraphic fonts, etc.
 
       :rtype: float
 

docs/textpage.rst

@@ -237,7 +237,7 @@ Spans contain the actual text. A line contains **more than one span only**, if i
 **Key**             **Value**
 =============== =====================================================================
 bbox            span rectangle, formatted as *tuple(fitz.Rect)*
-origin          *tuple* coordinates of the first character's bottom left point
+origin          *tuple* coordinates of the first character's origin
 font            font name *(str)*
 ascender        ascender of the font *(float)*
 descender       descender of the font *(float)*
@@ -296,13 +296,13 @@ We are currently providing the bbox in :data:`rect_like` format. In a future ver
    :align: top
    :scale: 66
 
-=============== =========================================================
+=============== ===========================================================
 **Key**             **Value**
-=============== =========================================================
-origin          *tuple* coordinates of the character's bottom left point
+=============== ===========================================================
+origin          *tuple* coordinates of the character's left baseline point
 bbox            character rectangle, formatted as *tuple(fitz.Rect)*
 c               the character (unicode)
-=============== =========================================================
+=============== ===========================================================
 
 .. rubric:: Footnotes