diff options
Diffstat (limited to 'source/blender/blenlib/intern/freetypefont.c')
| -rw-r--r-- | source/blender/blenlib/intern/freetypefont.c | 174 |
1 files changed, 87 insertions, 87 deletions
diff --git a/source/blender/blenlib/intern/freetypefont.c b/source/blender/blenlib/intern/freetypefont.c index a0e72af8131..eb2070bce76 100644 --- a/source/blender/blenlib/intern/freetypefont.c +++ b/source/blender/blenlib/intern/freetypefont.c @@ -545,90 +545,90 @@ typedef struct FT_Outline_ #endif -/***//* -from: http://www.freetype.org/freetype2/docs/glyphs/glyphs-6.html#section-1 - -Vectorial representation of Freetype glyphs - -The source format of outlines is a collection of closed paths called "contours". Each contour is -made of a series of line segments and bezier arcs. Depending on the file format, these can be -second-order or third-order polynomials. The former are also called quadratic or conic arcs, and -they come from the TrueType format. The latter are called cubic arcs and mostly come from the -Type1 format. - -Each arc is described through a series of start, end and control points. Each point of the outline -has a specific tag which indicates wether it is used to describe a line segment or an arc. - - -The following rules are applied to decompose the contour's points into segments and arcs : - -# two successive "on" points indicate a line segment joining them. - -# one conic "off" point amidst two "on" points indicates a conic bezier arc, the "off" point being - the control point, and the "on" ones the start and end points. - -# Two successive cubic "off" points amidst two "on" points indicate a cubic bezier arc. There must - be exactly two cubic control points and two on points for each cubic arc (using a single cubic - "off" point between two "on" points is forbidden, for example). - -# finally, two successive conic "off" points forces the rasterizer to create (during the scan-line - conversion process exclusively) a virtual "on" point amidst them, at their exact middle. This - greatly facilitates the definition of successive conic bezier arcs. Moreover, it's the way - outlines are described in the TrueType specification. - -Note that it is possible to mix conic and cubic arcs in a single contour, even though no current -font driver produces such outlines. - - * # on - * off - __---__ - #-__ _-- -_ - --__ _- - - --__ # \ - --__ # - -# - Two "on" points - Two "on" points and one "conic" point - between them - - - - * - # __ Two "on" points with two "conic" - \ - - points between them. The point - \ / \ marked '0' is the middle of the - - 0 \ "off" points, and is a 'virtual' - -_ _- # "on" point where the curve passes. - -- It does not appear in the point - list. - * - - - - - * # on - * * off - __---__ - _-- -_ - _- - - # \ - # - - Two "on" points - and two "cubic" point - between them - - -Each glyph's original outline points are located on a grid of indivisible units. The points are stored -in the font file as 16-bit integer grid coordinates, with the grid origin's being at (0, 0); they thus -range from -16384 to 16383. - -Convert conic to bezier arcs: -Conic P0 P1 P2 -Bezier B0 B1 B2 B3 -B0=P0 -B1=(P0+2*P1)/3 -B2=(P2+2*P1)/3 -B3=P2 - -*//****/ +/* + * from: http://www.freetype.org/freetype2/docs/glyphs/glyphs-6.html#section-1 + * + * Vectorial representation of Freetype glyphs + * + * The source format of outlines is a collection of closed paths called "contours". Each contour is + * made of a series of line segments and bezier arcs. Depending on the file format, these can be + * second-order or third-order polynomials. The former are also called quadratic or conic arcs, and + * they come from the TrueType format. The latter are called cubic arcs and mostly come from the + * Type1 format. + * + * Each arc is described through a series of start, end and control points. Each point of the outline + * has a specific tag which indicates wether it is used to describe a line segment or an arc. + * + * + * The following rules are applied to decompose the contour's points into segments and arcs : + * + * # two successive "on" points indicate a line segment joining them. + * + * # one conic "off" point amidst two "on" points indicates a conic bezier arc, the "off" point being + * the control point, and the "on" ones the start and end points. + * + * # Two successive cubic "off" points amidst two "on" points indicate a cubic bezier arc. There must + * be exactly two cubic control points and two on points for each cubic arc (using a single cubic + * "off" point between two "on" points is forbidden, for example). + * + * # finally, two successive conic "off" points forces the rasterizer to create (during the scan-line + * conversion process exclusively) a virtual "on" point amidst them, at their exact middle. This + * greatly facilitates the definition of successive conic bezier arcs. Moreover, it's the way + * outlines are described in the TrueType specification. + * + * Note that it is possible to mix conic and cubic arcs in a single contour, even though no current + * font driver produces such outlines. + * + * * # on + * * off + * __---__ + * #-__ _-- -_ + * --__ _- - + * --__ # \ + * --__ # + * -# + * Two "on" points + * Two "on" points and one "conic" point + * between them + * + * + * + * * + * # __ Two "on" points with two "conic" + * \ - - points between them. The point + * \ / \ marked '0' is the middle of the + * - 0 \ "off" points, and is a 'virtual' + * -_ _- # "on" point where the curve passes. + * -- It does not appear in the point + * list. + * * + * + * + * + * + * * # on + * * * off + * __---__ + * _-- -_ + * _- - + * # \ + * # + * + * Two "on" points + * and two "cubic" point + * between them + * + * + * Each glyph's original outline points are located on a grid of indivisible units. The points are stored + * in the font file as 16-bit integer grid coordinates, with the grid origin's being at (0, 0); they thus + * range from -16384 to 16383. + * + * Convert conic to bezier arcs: + * Conic P0 P1 P2 + * Bezier B0 B1 B2 B3 + * B0=P0 + * B1=(P0+2*P1)/3 + * B2=(P2+2*P1)/3 + * B3=P2 + * + */ |