This section describes the way scalable representation of glyph images, +
This section describes the way scalable representations of glyph images, called outlines, are used by FreeType as well as client applications.
@@ -94,7 +94,7 @@ points, rather than device-specific pixels. Points are a simple physical unit, where 1 point = 1/72th of an inch, in digital typography. As an example, most Roman books are - printed with a body text which size is chosen between 10 and + printed with a body text whose size is somewhere between 10 and 14 points.It is thus possible to compute the size of text in pixels from the @@ -148,7 +148,7 @@
In creating the glyph outlines, a type designer uses an imaginary square called the EM square. Typically, the EM square can be - thought of as a tablet on which the character are drawn. The square's + thought of as a tablet on which the characters are drawn. The square's size, i.e., the number of grid units on its sides, is very important for two reasons:
@@ -218,7 +218,7 @@As a consequence, proper glyph rendering needs the scaled points to be aligned along the target device pixel grid, through an operation - called grid-fitting, and often hinting. One of its + called grid-fitting (often called hinting). One of its main purposes is to ensure that important widths and heights are respected throughout the whole font (for example, it is very often desirable that the "I" and the "T" have their central vertical line of @@ -255,7 +255,7 @@
automatic grid-fitting
Some formats simply include no control information with each - glyph outline, apart metrics like the advance width and height. It + glyph outline, apart from metrics like the advance width and height. It is then up to the renderer to "guess" the more interesting features of the outline in order to perform some decent grid-fitting.
@@ -306,7 +306,7 @@Size. Glyph programs can be long.
-Technicity. +
Technical difficulty. It is extremely difficult to write good hinting programs. Very few tools available.