cf2_blues_init( CF2_Blues blues,
CF2_Font font )
{
/* pointer to parsed font object */
CFF_Decoder* decoder = font->decoder;
CF2_Fixed zoneHeight;
CF2_Fixed maxZoneHeight = 0;
CF2_Fixed csUnitsPerPixel;
size_t numBlueValues;
size_t numOtherBlues;
size_t numFamilyBlues;
size_t numFamilyOtherBlues;
FT_Pos* blueValues;
FT_Pos* otherBlues;
FT_Pos* familyBlues;
FT_Pos* familyOtherBlues;
size_t i;
CF2_Fixed emBoxBottom, emBoxTop;
CF2_Int unitsPerEm = font->unitsPerEm;
if ( unitsPerEm == 0 )
unitsPerEm = 1000;
FT_ZERO( blues );
blues->scale = font->innerTransform.d;
cf2_getBlueMetrics( decoder,
&blues->blueScale,
&blues->blueShift,
&blues->blueFuzz );
cf2_getBlueValues( decoder, &numBlueValues, &blueValues );
cf2_getOtherBlues( decoder, &numOtherBlues, &otherBlues );
cf2_getFamilyBlues( decoder, &numFamilyBlues, &familyBlues );
cf2_getFamilyOtherBlues( decoder, &numFamilyOtherBlues, &familyOtherBlues );
/*
* synthetic em box hint heuristic
*
* Apply this when ideographic dictionary (LanguageGroup 1) has no
* real alignment zones. Adobe tools generate dummy zones at -250 and
* 1100 for a 1000 unit em. Fonts with ICF-based alignment zones
* should not enable the heuristic. When the heuristic is enabled,
* the font's blue zones are ignored.
*
*/
/* get em box from OS/2 typoAscender/Descender */
/* TODO: FreeType does not parse these metrics. Skip them for now. */
#if 0
FCM_getHorizontalLineMetrics( &e,
font->font,
&ascender,
&descender,
&linegap );
if ( ascender - descender == unitsPerEm )
{
emBoxBottom = cf2_intToFixed( descender );
emBoxTop = cf2_intToFixed( ascender );
}
else
#endif
{
emBoxBottom = CF2_ICF_Bottom;
emBoxTop = CF2_ICF_Top;
}
if ( cf2_getLanguageGroup( decoder ) == 1 &&
( numBlueValues == 0 ||
( numBlueValues == 4 &&
cf2_blueToFixed( blueValues[0] ) < emBoxBottom &&
cf2_blueToFixed( blueValues[1] ) < emBoxBottom &&
cf2_blueToFixed( blueValues[2] ) > emBoxTop &&
cf2_blueToFixed( blueValues[3] ) > emBoxTop ) ) )
{
/*
* Construct hint edges suitable for synthetic ghost hints at top
* and bottom of em box. +-CF2_MIN_COUNTER allows for unhinted
* features above or below the last hinted edge. This also gives a
* net 1 pixel boost to the height of ideographic glyphs.
*
* Note: Adjust synthetic hints outward by epsilon (0x.0001) to
* avoid interference. E.g., some fonts have real hints at
* 880 and -120.
*/
blues->emBoxBottomEdge.csCoord = emBoxBottom - CF2_FIXED_EPSILON;
blues->emBoxBottomEdge.dsCoord = cf2_fixedRound(
FT_MulFix(
blues->emBoxBottomEdge.csCoord,
blues->scale ) ) -
CF2_MIN_COUNTER;
blues->emBoxBottomEdge.scale = blues->scale;
blues->emBoxBottomEdge.flags = CF2_GhostBottom |
CF2_Locked |
CF2_Synthetic;
blues->emBoxTopEdge.csCoord = emBoxTop + CF2_FIXED_EPSILON +
2 * font->darkenY;
blues->emBoxTopEdge.dsCoord = cf2_fixedRound(
FT_MulFix(
blues->emBoxTopEdge.csCoord,
blues->scale ) ) +
CF2_MIN_COUNTER;
blues->emBoxTopEdge.scale = blues->scale;
blues->emBoxTopEdge.flags = CF2_GhostTop |
CF2_Locked |
CF2_Synthetic;
blues->doEmBoxHints = TRUE; /* enable the heuristic */
return;
}
/* copy `BlueValues' and `OtherBlues' to a combined array of top and */
/* bottom zones */
for ( i = 0; i < numBlueValues; i += 2 )
{
blues->zone[blues->count].csBottomEdge =
cf2_blueToFixed( blueValues[i] );
blues->zone[blues->count].csTopEdge =
cf2_blueToFixed( blueValues[i + 1] );
zoneHeight = blues->zone[blues->count].csTopEdge -
blues->zone[blues->count].csBottomEdge;
if ( zoneHeight < 0 )
{
FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" ));
continue; /* reject this zone */
}
if ( zoneHeight > maxZoneHeight )
{
/* take maximum before darkening adjustment */
/* so overshoot suppression point doesn't change */
maxZoneHeight = zoneHeight;
}
/* adjust both edges of top zone upward by twice darkening amount */
if ( i != 0 )
{
blues->zone[blues->count].csTopEdge += 2 * font->darkenY;
blues->zone[blues->count].csBottomEdge += 2 * font->darkenY;
}
/* first `BlueValue' is bottom zone; others are top */
if ( i == 0 )
{
blues->zone[blues->count].bottomZone =
TRUE;
blues->zone[blues->count].csFlatEdge =
blues->zone[blues->count].csTopEdge;
}
else
{
blues->zone[blues->count].bottomZone =
FALSE;
blues->zone[blues->count].csFlatEdge =
blues->zone[blues->count].csBottomEdge;
}
blues->count += 1;
}
for ( i = 0; i < numOtherBlues; i += 2 )
{
blues->zone[blues->count].csBottomEdge =
cf2_blueToFixed( otherBlues[i] );
blues->zone[blues->count].csTopEdge =
cf2_blueToFixed( otherBlues[i + 1] );
zoneHeight = blues->zone[blues->count].csTopEdge -
blues->zone[blues->count].csBottomEdge;
if ( zoneHeight < 0 )
{
FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" ));
continue; /* reject this zone */
}
if ( zoneHeight > maxZoneHeight )
{
/* take maximum before darkening adjustment */
/* so overshoot suppression point doesn't change */
maxZoneHeight = zoneHeight;
}
/* Note: bottom zones are not adjusted for darkening amount */
/* all OtherBlues are bottom zone */
blues->zone[blues->count].bottomZone =
TRUE;
blues->zone[blues->count].csFlatEdge =
blues->zone[blues->count].csTopEdge;
blues->count += 1;
}
/* Adjust for FamilyBlues */
/* Search for the nearest flat edge in `FamilyBlues' or */
/* `FamilyOtherBlues'. According to the Black Book, any matching edge */
/* must be within one device pixel */
csUnitsPerPixel = FT_DivFix( cf2_intToFixed( 1 ), blues->scale );
/* loop on all zones in this font */
for ( i = 0; i < blues->count; i++ )
{
size_t j;
CF2_Fixed minDiff;
CF2_Fixed flatFamilyEdge, diff;
/* value for this font */
CF2_Fixed flatEdge = blues->zone[i].csFlatEdge;
if ( blues->zone[i].bottomZone )
{
/* In a bottom zone, the top edge is the flat edge. */
/* Search `FamilyOtherBlues' for bottom zones; look for closest */
/* Family edge that is within the one pixel threshold. */
minDiff = CF2_FIXED_MAX;
for ( j = 0; j < numFamilyOtherBlues; j += 2 )
{
/* top edge */
flatFamilyEdge = cf2_blueToFixed( familyOtherBlues[j + 1] );
diff = cf2_fixedAbs( flatEdge - flatFamilyEdge );
if ( diff < minDiff && diff < csUnitsPerPixel )
{
blues->zone[i].csFlatEdge = flatFamilyEdge;
minDiff = diff;
if ( diff == 0 )
break;
}
}
/* check the first member of FamilyBlues, which is a bottom zone */
if ( numFamilyBlues >= 2 )
{
/* top edge */
flatFamilyEdge = cf2_blueToFixed( familyBlues[1] );
diff = cf2_fixedAbs( flatEdge - flatFamilyEdge );
if ( diff < minDiff && diff < csUnitsPerPixel )
blues->zone[i].csFlatEdge = flatFamilyEdge;
}
}
else
{
/* In a top zone, the bottom edge is the flat edge. */
/* Search `FamilyBlues' for top zones; skip first zone, which is a */
/* bottom zone; look for closest Family edge that is within the */
/* one pixel threshold */
minDiff = CF2_FIXED_MAX;
for ( j = 2; j < numFamilyBlues; j += 2 )
{
/* bottom edge */
flatFamilyEdge = cf2_blueToFixed( familyBlues[j] );
/* adjust edges of top zone upward by twice darkening amount */
flatFamilyEdge += 2 * font->darkenY; /* bottom edge */
diff = cf2_fixedAbs( flatEdge - flatFamilyEdge );
if ( diff < minDiff && diff < csUnitsPerPixel )
{
blues->zone[i].csFlatEdge = flatFamilyEdge;
minDiff = diff;
if ( diff == 0 )
break;
}
}
}
}
/* TODO: enforce separation of zones, including BlueFuzz */
/* Adjust BlueScale; similar to AdjustBlueScale() in coretype */
/* `bcsetup.c'. */
if ( maxZoneHeight > 0 )
{
if ( blues->blueScale > FT_DivFix( cf2_intToFixed( 1 ),
maxZoneHeight ) )
{
/* clamp at maximum scale */
blues->blueScale = FT_DivFix( cf2_intToFixed( 1 ),
maxZoneHeight );
}
/*
* TODO: Revisit the bug fix for 613448. The minimum scale
* requirement catches a number of library fonts. For
* example, with default BlueScale (.039625) and 0.4 minimum,
* the test below catches any font with maxZoneHeight < 10.1.
* There are library fonts ranging from 2 to 10 that get
* caught, including e.g., Eurostile LT Std Medium with
* maxZoneHeight of 6.
*
*/
#if 0
if ( blueScale < .4 / maxZoneHeight )
{
tetraphilia_assert( 0 );
/* clamp at minimum scale, per bug 0613448 fix */
blueScale = .4 / maxZoneHeight;
}
#endif
}
/*
* Suppress overshoot and boost blue zones at small sizes. Boost
* amount varies linearly from 0.5 pixel near 0 to 0 pixel at
* blueScale cutoff.
* Note: This boost amount is different from the coretype heuristic.
*
*/
if ( blues->scale < blues->blueScale )
{
blues->suppressOvershoot = TRUE;
/* Change rounding threshold for `dsFlatEdge'. */
/* Note: constant changed from 0.5 to 0.6 to avoid a problem with */
/* 10ppem Arial */
blues->boost = FT_MulFix(
cf2_floatToFixed( .6 ),
( cf2_intToFixed( 1 ) -
FT_DivFix( blues->scale,
blues->blueScale ) ) );
if ( blues->boost > 0x7FFF )
{
/* boost must remain less than 0.5, or baseline could go negative */
blues->boost = 0x7FFF;
}
}
/* boost and darkening have similar effects; don't do both */
if ( font->stemDarkened )
blues->boost = 0;
/* set device space alignment for each zone; */
/* apply boost amount before rounding flat edge */
for ( i = 0; i < blues->count; i++ )
{
if ( blues->zone[i].bottomZone )
blues->zone[i].dsFlatEdge = cf2_fixedRound(
FT_MulFix(
blues->zone[i].csFlatEdge,
blues->scale ) -
blues->boost );
else
blues->zone[i].dsFlatEdge = cf2_fixedRound(
FT_MulFix(
blues->zone[i].csFlatEdge,
blues->scale ) +
blues->boost );
}
}
static void
cf2_doFlex( CF2_Stack opStack,
CF2_Fixed* curX,
CF2_Fixed* curY,
CF2_GlyphPath glyphPath,
const FT_Bool* readFromStack,
FT_Bool doConditionalLastRead )
{
CF2_Fixed vals[14];
CF2_UInt index;
FT_Bool isHFlex;
CF2_Int top, i, j;
vals[0] = *curX;
vals[1] = *curY;
index = 0;
isHFlex = readFromStack[9] == FALSE;
top = isHFlex ? 9 : 10;
for ( i = 0; i < top; i++ )
{
vals[i + 2] = vals[i];
if ( readFromStack[i] )
vals[i + 2] += cf2_stack_getReal( opStack, index++ );
}
if ( isHFlex )
vals[9 + 2] = *curY;
if ( doConditionalLastRead )
{
FT_Bool lastIsX = (FT_Bool)( cf2_fixedAbs( vals[10] - *curX ) >
cf2_fixedAbs( vals[11] - *curY ) );
CF2_Fixed lastVal = cf2_stack_getReal( opStack, index );
if ( lastIsX )
{
vals[12] = vals[10] + lastVal;
vals[13] = *curY;
}
else
{
vals[12] = *curX;
vals[13] = vals[11] + lastVal;
}
}
else
{
if ( readFromStack[10] )
vals[12] = vals[10] + cf2_stack_getReal( opStack, index++ );
else
vals[12] = *curX;
if ( readFromStack[11] )
vals[13] = vals[11] + cf2_stack_getReal( opStack, index );
else
vals[13] = *curY;
}
for ( j = 0; j < 2; j++ )
cf2_glyphpath_curveTo( glyphPath, vals[j * 6 + 2],
vals[j * 6 + 3],
vals[j * 6 + 4],
vals[j * 6 + 5],
vals[j * 6 + 6],
vals[j * 6 + 7] );
cf2_stack_clear( opStack );
*curX = vals[12];
*curY = vals[13];
}