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Linearly interpolate weight values 

Rest of Part of https://bugs.freedesktop.org/show_bug.cgi?id=81453

Adds new API:

	FcWeightFromOpenType()
	FcWeightToOpenType()
This commit is contained in:
Behdad Esfahbod 2014-07-25 17:59:26 -04:00
parent bf9df5ada7
commit ffda7c0e81
6 changed files with 141 additions and 26 deletions
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1
doc/Makefile.am
View File

@ -85,6 +85,7 @@ DOC_FUNCS_FNCS = \
fcstring.fncs \
fcstrset.fncs \
fcvalue.fncs \
fcweight.fncs \
$(NULL)
SGML_FILES = \
fontconfig-user.sgml \

47
doc/fcweight.fncs Normal file
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@ -0,0 +1,47 @@
/*
* fontconfig/doc/fcweight.fncs
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation, and that the name of the author(s) not be used in
* advertising or publicity pertaining to distribution of the software without
* specific, written prior permission. The authors make no
* representations about the suitability of this software for any purpose. It
* is provided "as is" without express or implied warranty.
*
* THE AUTHOR(S) DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
@RET@ int
@FUNC@ FcWeightFromOpenType
@TYPE1@ int @ARG1@ ot_weight
@PURPOSE@ Convert from OpenType weight values to fontconfig ones
@DESC@
<function>FcWeightFromOpenType</function> returns an integer value
to use with FC_WEIGHT, from an integer in the 1..1000 range, resembling
the numbers from OpenType specification's OS/2 usWeight numbers, which
are also similar to CSS font-weight numbers. If input is negative,
zero, or greater than 1000, returns -1. This function linearly interpolates
between various FC_WEIGHT_* constants. As such, the returned value does not
necessarily match any of the predefined constants.
@SINCE@ 2.11.91
@@
@RET@ int
@FUNC@ FcWeightToOpenType
@TYPE1@ int @ARG1@ ot_weight
@PURPOSE@ Convert from fontconfig weight values to OpenType ones
@DESC@
<function>FcWeightToOpenType</function> is the inverse of
<function>FcWeightFromOpenType</function>. If the input is less than
FC_WEIGHT_THIN or greater than FC_WEIGHT_EXTRABLACK, returns -1. Otherwise
returns a number in the range 1 to 1000.
@SINCE@ 2.11.91
@@

7
fontconfig/fontconfig.h
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@ -908,6 +908,13 @@ FcRangeDestroy (FcRange *range);
FcPublic FcRange *
FcRangeCopy (const FcRange *r);
/* fcweight.c */
FcPublic int
FcWeightFromOpenType (int ot_weight);
FcPublic int
FcWeightToOpenType (int fc_weight);
/* fcstr.c */

1
src/Makefile.am
View File

@ -154,6 +154,7 @@ libfontconfig_la_SOURCES = \
fcserialize.c \
fcstat.c \
fcstr.c \
fcweight.c \
fcwindows.h \
fcxml.c \
ftglue.h \

27
src/fcfreetype.c
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@ -1628,32 +1628,7 @@ FcFreeTypeQueryFace (const FT_Face face,
if (os2 && os2->version != 0xffff)
{
if (os2->usWeightClass == 0)
;
else if (os2->usWeightClass < 150)
weight = FC_WEIGHT_THIN;
else if (os2->usWeightClass < 250)
weight = FC_WEIGHT_EXTRALIGHT;
else if (os2->usWeightClass < 325)
weight = FC_WEIGHT_LIGHT;
else if (os2->usWeightClass < 365)
weight = FC_WEIGHT_SEMILIGHT;
else if (os2->usWeightClass < 390)
weight = FC_WEIGHT_BOOK;
else if (os2->usWeightClass < 450)
weight = FC_WEIGHT_REGULAR;
else if (os2->usWeightClass < 550)
weight = FC_WEIGHT_MEDIUM;
else if (os2->usWeightClass < 650)
weight = FC_WEIGHT_SEMIBOLD;
else if (os2->usWeightClass < 750)
weight = FC_WEIGHT_BOLD;
else if (os2->usWeightClass < 850)
weight = FC_WEIGHT_EXTRABOLD;
else if (os2->usWeightClass < 925)
weight = FC_WEIGHT_BLACK;
else if (os2->usWeightClass < 1000)
weight = FC_WEIGHT_EXTRABLACK;
weight = FcWeightFromOpenType (os2->usWeightClass);
if ((FcDebug() & FC_DBG_SCANV) && weight != -1)
printf ("\tos2 weight class %d maps to weight %d\n",
os2->usWeightClass, weight);

84
src/fcweight.c Normal file
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@ -0,0 +1,84 @@
/*
* fontconfig/src/fcweight.c
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation, and that the name of the author(s) not be used in
* advertising or publicity pertaining to distribution of the software without
* specific, written prior permission. The authors make no
* representations about the suitability of this software for any purpose. It
* is provided "as is" without express or implied warranty.
*
* THE AUTHOR(S) DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
#include "fcint.h"
static const struct {
int ot;
int fc;
} map[] = {
{ 0, FC_WEIGHT_THIN },
{ 100, FC_WEIGHT_THIN },
{ 200, FC_WEIGHT_EXTRALIGHT },
{ 350, FC_WEIGHT_DEMILIGHT },
{ 300, FC_WEIGHT_LIGHT },
{ 380, FC_WEIGHT_BOOK },
{ 400, FC_WEIGHT_REGULAR },
{ 500, FC_WEIGHT_MEDIUM },
{ 600, FC_WEIGHT_DEMIBOLD },
{ 700, FC_WEIGHT_BOLD },
{ 800, FC_WEIGHT_EXTRABOLD },
{ 900, FC_WEIGHT_BLACK },
{1000, FC_WEIGHT_EXTRABLACK },
};
static int lerp(int x, int x1, int x2, int y1, int y2)
{
int dx = x2 - x1;
int dy = y2 - y1;
assert (dx > 0 && dy > 0 && x1 <= x && x <= x2);
return y1 + (dy*(x-x1) + dx/2) / dx;
}
FcPublic int
FcWeightFromOpenType (int ot_weight)
{
int i;
if (ot_weight <= 0 || ot_weight > 1000)
return -1;
for (i = 1; ot_weight > map[i].ot; i++)
;
if (ot_weight == map[i].ot)
return map[i].fc;
/* Interpolate between two items. */
return lerp (ot_weight, map[i-1].ot, map[i].ot, map[i-1].fc, map[i].fc);
}
FcPublic int
FcWeightToOpenType (int fc_weight)
{
int i;
if (fc_weight < 0 || fc_weight > FC_WEIGHT_EXTRABLACK)
return -1;
for (i = 1; fc_weight > map[i].fc; i++)
;
if (fc_weight == map[i].fc)
return map[i].ot;
/* Interpolate between two items. */
return lerp (fc_weight, map[i-1].fc, map[i].fc, map[i-1].ot, map[i].ot);
}