/* get scaling and hint flag from GlyphSlot */
static void
cf2_getScaleAndHintFlag( CFF_Decoder* decoder,
CF2_Fixed* x_scale,
CF2_Fixed* y_scale,
FT_Bool* hinted,
FT_Bool* scaled )
{
FT_ASSERT( decoder && decoder->builder.glyph );
/* note: FreeType scale includes a factor of 64 */
*hinted = decoder->builder.glyph->hint;
*scaled = decoder->builder.glyph->scaled;
if ( *hinted )
{
*x_scale = FT_DivFix( decoder->builder.glyph->x_scale,
cf2_intToFixed( 64 ) );
*y_scale = FT_DivFix( decoder->builder.glyph->y_scale,
cf2_intToFixed( 64 ) );
}
else
{
/* for unhinted outlines, `cff_slot_load' does the scaling, */
/* thus render at `unity' scale */
*x_scale = 0x0400; /* 1/64 as 16.16 */
*y_scale = 0x0400;
}
}
cf2_getBlueMetrics( CFF_Decoder* decoder,
CF2_Fixed* blueScale,
CF2_Fixed* blueShift,
CF2_Fixed* blueFuzz )
{
FT_ASSERT( decoder && decoder->current_subfont );
*blueScale = FT_DivFix(
decoder->current_subfont->private_dict.blue_scale,
cf2_intToFixed( 1000 ) );
*blueShift = cf2_intToFixed(
decoder->current_subfont->private_dict.blue_shift );
*blueFuzz = cf2_intToFixed(
decoder->current_subfont->private_dict.blue_fuzz );
}
cf2_getNominalWidthX( CFF_Decoder* decoder )
{
FT_ASSERT( decoder && decoder->current_subfont );
return cf2_intToFixed(
decoder->current_subfont->private_dict.nominal_width );
}
cf2_getDefaultWidthX( CFF_Decoder* decoder )
{
FT_ASSERT( decoder && decoder->current_subfont );
return cf2_intToFixed(
decoder->current_subfont->private_dict.default_width );
}
/*
* This check should avoid most internal overflow cases. Clients should
* generally respond to `Glyph_Too_Big' by getting a glyph outline
* at EM size, scaling it and filling it as a graphics operation.
*
*/
static FT_Error
cf2_checkTransform( const CF2_Matrix* transform,
CF2_Int unitsPerEm )
{
CF2_Fixed maxScale;
FT_ASSERT( unitsPerEm > 0 );
if ( transform->a <= 0 || transform->d <= 0 )
return FT_THROW( Invalid_Size_Handle );
FT_ASSERT( transform->b == 0 && transform->c == 0 );
FT_ASSERT( transform->tx == 0 && transform->ty == 0 );
if ( unitsPerEm > 0x7FFF )
return FT_THROW( Glyph_Too_Big );
maxScale = FT_DivFix( CF2_MAX_SIZE, cf2_intToFixed( unitsPerEm ) );
if ( transform->a > maxScale || transform->d > maxScale )
return FT_THROW( Glyph_Too_Big );
return FT_Err_Ok;
}
cf2_getStdHW( CFF_Decoder* decoder )
{
FT_ASSERT( decoder && decoder->current_subfont );
return cf2_intToFixed(
decoder->current_subfont->private_dict.standard_width );
}
cf2_getPpemY( CFF_Decoder* decoder )
{
FT_ASSERT( decoder &&
decoder->builder.face &&
decoder->builder.face->root.size );
FT_ASSERT( decoder->builder.face->root.size->metrics.y_ppem );
return cf2_intToFixed(
decoder->builder.face->root.size->metrics.y_ppem );
}
cf2_stack_popFixed( CF2_Stack stack )
{
if ( stack->top == &stack->buffer[0] )
{
CF2_SET_ERROR( stack->error, Stack_Underflow );
return cf2_intToFixed( 0 ); /* underflow */
}
--stack->top;
switch ( stack->top->type )
{
case CF2_NumberInt:
return cf2_intToFixed( stack->top->u.i );
case CF2_NumberFrac:
return cf2_fracToFixed( stack->top->u.f );
default:
return stack->top->u.r;
}
}
cf2_stack_getReal( CF2_Stack stack,
CF2_UInt idx )
{
FT_ASSERT( cf2_stack_count( stack ) <= CF2_OPERAND_STACK_SIZE );
if ( idx >= cf2_stack_count( stack ) )
{
CF2_SET_ERROR( stack->error, Stack_Overflow );
return cf2_intToFixed( 0 ); /* bounds error */
}
switch ( stack->buffer[idx].type )
{
case CF2_NumberInt:
return cf2_intToFixed( stack->buffer[idx].u.i );
case CF2_NumberFrac:
return cf2_fracToFixed( stack->buffer[idx].u.f );
default:
return stack->buffer[idx].u.r;
}
}
cf2_getPpemY( CFF_Decoder* decoder )
{
FT_ASSERT( decoder &&
decoder->builder.face &&
decoder->builder.face->root.size );
/*
* Note that `y_ppem' can be zero if there wasn't a call to
* `FT_Set_Char_Size' or something similar. However, this isn't a
* problem since we come to this place in the code only if
* FT_LOAD_NO_SCALE is set (the other case gets caught by
* `cf2_checkTransform'). The ppem value is needed to compute the stem
* darkening, which is disabled for getting the unscaled outline.
*
*/
return cf2_intToFixed(
decoder->builder.face->root.size->metrics.y_ppem );
}
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 );
}
}
cf2_blues_capture( const CF2_Blues blues,
CF2_Hint bottomHintEdge,
CF2_Hint topHintEdge )
{
/* TODO: validate? */
CF2_Fixed csFuzz = blues->blueFuzz;
/* new position of captured edge */
CF2_Fixed dsNew;
/* amount that hint is moved when positioned */
CF2_Fixed dsMove = 0;
FT_Bool captured = FALSE;
CF2_UInt i;
/* assert edge flags are consistent */
FT_ASSERT( !cf2_hint_isTop( bottomHintEdge ) &&
!cf2_hint_isBottom( topHintEdge ) );
/* TODO: search once without blue fuzz for compatibility with coretype? */
for ( i = 0; i < blues->count; i++ )
{
if ( blues->zone[i].bottomZone &&
cf2_hint_isBottom( bottomHintEdge ) )
{
if ( ( blues->zone[i].csBottomEdge - csFuzz ) <=
bottomHintEdge->csCoord &&
bottomHintEdge->csCoord <=
( blues->zone[i].csTopEdge + csFuzz ) )
{
/* bottom edge captured by bottom zone */
if ( blues->suppressOvershoot )
dsNew = blues->zone[i].dsFlatEdge;
else if ( ( blues->zone[i].csTopEdge - bottomHintEdge->csCoord ) >=
blues->blueShift )
{
/* guarantee minimum of 1 pixel overshoot */
dsNew = FT_MIN(
cf2_fixedRound( bottomHintEdge->dsCoord ),
blues->zone[i].dsFlatEdge - cf2_intToFixed( 1 ) );
}
else
{
/* simply round captured edge */
dsNew = cf2_fixedRound( bottomHintEdge->dsCoord );
}
dsMove = dsNew - bottomHintEdge->dsCoord;
captured = TRUE;
break;
}
}
if ( !blues->zone[i].bottomZone && cf2_hint_isTop( topHintEdge ) )
{
if ( ( blues->zone[i].csBottomEdge - csFuzz ) <=
topHintEdge->csCoord &&
topHintEdge->csCoord <=
( blues->zone[i].csTopEdge + csFuzz ) )
{
/* top edge captured by top zone */
if ( blues->suppressOvershoot )
dsNew = blues->zone[i].dsFlatEdge;
else if ( ( topHintEdge->csCoord - blues->zone[i].csBottomEdge ) >=
blues->blueShift )
{
/* guarantee minimum of 1 pixel overshoot */
dsNew = FT_MAX(
cf2_fixedRound( topHintEdge->dsCoord ),
blues->zone[i].dsFlatEdge + cf2_intToFixed( 1 ) );
}
else
{
/* simply round captured edge */
dsNew = cf2_fixedRound( topHintEdge->dsCoord );
}
dsMove = dsNew - topHintEdge->dsCoord;
captured = TRUE;
break;
}
}
}
if ( captured )
{
/* move both edges and flag them `locked' */
if ( cf2_hint_isValid( bottomHintEdge ) )
{
bottomHintEdge->dsCoord += dsMove;
cf2_hint_lock( bottomHintEdge );
}
if ( cf2_hint_isValid( topHintEdge ) )
{
topHintEdge->dsCoord += dsMove;
cf2_hint_lock( topHintEdge );
}
}
return captured;
}
/* Compute a stem darkening amount in character space. */
static void
cf2_computeDarkening( CF2_Fixed emRatio,
CF2_Fixed ppem,
CF2_Fixed stemWidth,
CF2_Fixed* darkenAmount,
CF2_Fixed boldenAmount,
FT_Bool stemDarkened )
{
/* Internal calculations are done in units per thousand for */
/* convenience. */
CF2_Fixed stemWidthPer1000, scaledStem;
*darkenAmount = 0;
if ( boldenAmount == 0 && !stemDarkened )
return;
/* protect against range problems and divide by zero */
if ( emRatio < cf2_floatToFixed( .01 ) )
return;
if ( stemDarkened )
{
/* convert from true character space to 1000 unit character space; */
/* add synthetic emboldening effect */
/* we have to assure that the computation of `scaledStem' */
/* and `stemWidthPer1000' don't overflow */
stemWidthPer1000 = FT_MulFix( stemWidth + boldenAmount, emRatio );
if ( emRatio > CF2_FIXED_ONE &&
stemWidthPer1000 <= ( stemWidth + boldenAmount ) )
{
stemWidthPer1000 = 0; /* to pacify compiler */
scaledStem = cf2_intToFixed( 2333 );
}
else
{
scaledStem = FT_MulFix( stemWidthPer1000, ppem );
if ( ppem > CF2_FIXED_ONE &&
scaledStem <= stemWidthPer1000 )
scaledStem = cf2_intToFixed( 2333 );
}
/*
* Total darkening amount is computed in 1000 unit character space
* using the modified 5 part curve as Avalon rasterizer.
* The darkening amount is smaller for thicker stems.
* It becomes zero when the stem is thicker than 2.333 pixels.
*
* In Avalon rasterizer,
*
* darkenAmount = 0.5 pixels if scaledStem <= 0.5 pixels,
* darkenAmount = 0.333 pixels if 1 <= scaledStem <= 1.667 pixels,
* darkenAmount = 0 pixel if scaledStem >= 2.333 pixels,
*
* and piecewise linear in-between.
*
*/
if ( scaledStem < cf2_intToFixed( 500 ) )
*darkenAmount = FT_DivFix( cf2_intToFixed( 400 ), ppem );
else if ( scaledStem < cf2_intToFixed( 1000 ) )
*darkenAmount = FT_DivFix( cf2_intToFixed( 525 ), ppem ) -
FT_MulFix( stemWidthPer1000,
cf2_floatToFixed( .25 ) );
else if ( scaledStem < cf2_intToFixed( 1667 ) )
*darkenAmount = FT_DivFix( cf2_intToFixed( 275 ), ppem );
else if ( scaledStem < cf2_intToFixed( 2333 ) )
*darkenAmount = FT_DivFix( cf2_intToFixed( 963 ), ppem ) -
FT_MulFix( stemWidthPer1000,
cf2_floatToFixed( .413 ) );
/* use half the amount on each side and convert back to true */
/* character space */
*darkenAmount = FT_DivFix( *darkenAmount, 2 * emRatio );
}
/* add synthetic emboldening effect in character space */
*darkenAmount += boldenAmount / 2;
}
/* caller's transform is adjusted for subpixel positioning */
static void
cf2_font_setup( CF2_Font font,
const CF2_Matrix* transform )
{
/* pointer to parsed font object */
CFF_Decoder* decoder = font->decoder;
FT_Bool needExtraSetup = FALSE;
/* character space units */
CF2_Fixed boldenX = font->syntheticEmboldeningAmountX;
CF2_Fixed boldenY = font->syntheticEmboldeningAmountY;
CF2_Fixed ppem;
/* clear previous error */
font->error = FT_Err_Ok;
/* if a CID fontDict has changed, we need to recompute some cached */
/* data */
needExtraSetup = font->lastSubfont != cf2_getSubfont( decoder );
/* if ppem has changed, we need to recompute some cached data */
/* note: because of CID font matrix concatenation, ppem and transform */
/* do not necessarily track. */
ppem = cf2_getPpemY( decoder );
if ( font->ppem != ppem )
{
font->ppem = ppem;
needExtraSetup = TRUE;
}
/* copy hinted flag on each call */
font->hinted = font->renderingFlags & CF2_FlagsHinted;
/* determine if transform has changed; */
/* include Fontmatrix but ignore translation */
if ( ft_memcmp( transform,
&font->currentTransform,
4 * sizeof ( CF2_Fixed ) ) != 0 )
{
/* save `key' information for `cache of one' matrix data; */
/* save client transform, without the translation */
font->currentTransform = *transform;
font->currentTransform.tx =
font->currentTransform.ty = cf2_intToFixed( 0 );
/* TODO: FreeType transform is simple scalar; for now, use identity */
/* for outer */
font->innerTransform = *transform;
font->outerTransform.a =
font->outerTransform.d = cf2_intToFixed( 1 );
font->outerTransform.b =
font->outerTransform.c = cf2_intToFixed( 0 );
needExtraSetup = TRUE;
}
/*
* font->darkened is set to true if there is a stem darkening request or
* the font is synthetic emboldened.
* font->darkened controls whether to adjust blue zones, winding order,
* and hinting.
*
*/
if ( font->stemDarkened != ( font->renderingFlags & CF2_FlagsDarkened ) )
{
font->stemDarkened = font->renderingFlags & CF2_FlagsDarkened;
/* blue zones depend on darkened flag */
needExtraSetup = TRUE;
}
/* recompute variables that are dependent on transform or FontDict or */
/* darken flag */
if ( needExtraSetup )
{
/* StdVW is found in the private dictionary; */
/* recompute darkening amounts whenever private dictionary or */
/* transform change */
/* Note: a rendering flag turns darkening on or off, so we want to */
/* store the `on' amounts; */
/* darkening amount is computed in character space */
/* TODO: testing size-dependent darkening here; */
/* what to do for rotations? */
CF2_Fixed emRatio;
CF2_Fixed stdHW;
CF2_Int unitsPerEm = font->unitsPerEm;
if ( unitsPerEm == 0 )
unitsPerEm = 1000;
ppem = FT_MAX( cf2_intToFixed( 4 ),
font->ppem ); /* use minimum ppem of 4 */
#if 0
/* since vstem is measured in the x-direction, we use the `a' member */
/* of the fontMatrix */
emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->a );
#endif
/* Freetype does not preserve the fontMatrix when parsing; use */
/* unitsPerEm instead. */
/* TODO: check precision of this */
emRatio = cf2_intToFixed( 1000 ) / unitsPerEm;
font->stdVW = cf2_getStdVW( decoder );
if ( font->stdVW <= 0 )
font->stdVW = FT_DivFix( cf2_intToFixed( 75 ), emRatio );
if ( boldenX > 0 )
{
/* Ensure that boldenX is at least 1 pixel for synthetic bold font */
/* (similar to what Avalon does) */
boldenX = FT_MAX( boldenX,
FT_DivFix( cf2_intToFixed( unitsPerEm ), ppem ) );
/* Synthetic emboldening adds at least 1 pixel to darkenX, while */
/* stem darkening adds at most half pixel. Since the purpose of */
/* stem darkening (readability at small sizes) is met with */
/* synthetic emboldening, no need to add stem darkening for a */
/* synthetic bold font. */
cf2_computeDarkening( emRatio,
ppem,
font->stdVW,
&font->darkenX,
boldenX,
FALSE );
}
else
cf2_computeDarkening( emRatio,
ppem,
font->stdVW,
&font->darkenX,
0,
font->stemDarkened );
#if 0
/* since hstem is measured in the y-direction, we use the `d' member */
/* of the fontMatrix */
/* TODO: use the same units per em as above; check this */
emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->d );
#endif
/* set the default stem width, because it must be the same for all */
/* family members; */
/* choose a constant for StdHW that depends on font contrast */
stdHW = cf2_getStdHW( decoder );
if ( stdHW > 0 && font->stdVW > 2 * stdHW )
font->stdHW = FT_DivFix( cf2_intToFixed( 75 ), emRatio );
else
{
/* low contrast font gets less hstem darkening */
font->stdHW = FT_DivFix( cf2_intToFixed( 110 ), emRatio );
}
cf2_computeDarkening( emRatio,
ppem,
font->stdHW,
&font->darkenY,
boldenY,
font->stemDarkened );
if ( font->darkenX != 0 || font->darkenY != 0 )
font->darkened = TRUE;
else
font->darkened = FALSE;
font->reverseWinding = FALSE; /* initial expectation is CCW */
/* compute blue zones for this instance */
cf2_blues_init( &font->blues, font );
}
}
/* Compute a stem darkening amount in character space. */
static void
cf2_computeDarkening( CF2_Fixed emRatio,
CF2_Fixed ppem,
CF2_Fixed stemWidth,
CF2_Fixed* darkenAmount,
CF2_Fixed boldenAmount,
FT_Bool stemDarkened,
FT_Int* darkenParams )
{
/*
* Total darkening amount is computed in 1000 unit character space
* using the modified 5 part curve as Adobe's Avalon rasterizer.
* The darkening amount is smaller for thicker stems.
* It becomes zero when the stem is thicker than 2.333 pixels.
*
* By default, we use
*
* darkenAmount = 0.4 pixels if scaledStem <= 0.5 pixels,
* darkenAmount = 0.275 pixels if 1 <= scaledStem <= 1.667 pixels,
* darkenAmount = 0 pixel if scaledStem >= 2.333 pixels,
*
* and piecewise linear in-between:
*
*
* darkening
* ^
* |
* | (x1,y1)
* |--------+
* | \
* | \
* | \ (x3,y3)
* | +----------+
* | (x2,y2) \
* | \
* | \
* | +-----------------
* | (x4,y4)
* +---------------------------------------------> stem
* thickness
*
*
* This corresponds to the following values for the
* `darkening-parameters' property:
*
* (x1, y1) = (500, 400)
* (x2, y2) = (1000, 275)
* (x3, y3) = (1667, 275)
* (x4, y4) = (2333, 0)
*
*/
/* Internal calculations are done in units per thousand for */
/* convenience. The x axis is scaled stem width in */
/* thousandths of a pixel. That is, 1000 is 1 pixel. */
/* The y axis is darkening amount in thousandths of a pixel.*/
/* In the code, below, dividing by ppem and */
/* adjusting for emRatio converts darkenAmount to character */
/* space (font units). */
CF2_Fixed stemWidthPer1000, scaledStem;
*darkenAmount = 0;
if ( boldenAmount == 0 && !stemDarkened )
return;
/* protect against range problems and divide by zero */
if ( emRatio < cf2_floatToFixed( .01 ) )
return;
if ( stemDarkened )
{
FT_Int x1 = darkenParams[0];
FT_Int y1 = darkenParams[1];
FT_Int x2 = darkenParams[2];
FT_Int y2 = darkenParams[3];
FT_Int x3 = darkenParams[4];
FT_Int y3 = darkenParams[5];
FT_Int x4 = darkenParams[6];
FT_Int y4 = darkenParams[7];
/* convert from true character space to 1000 unit character space; */
/* add synthetic emboldening effect */
/* we have to assure that the computation of `scaledStem' */
/* and `stemWidthPer1000' don't overflow */
stemWidthPer1000 = FT_MulFix( stemWidth + boldenAmount, emRatio );
if ( emRatio > CF2_FIXED_ONE &&
stemWidthPer1000 <= ( stemWidth + boldenAmount ) )
{
stemWidthPer1000 = 0; /* to pacify compiler */
scaledStem = cf2_intToFixed( x4 );
}
else
{
scaledStem = FT_MulFix( stemWidthPer1000, ppem );
if ( ppem > CF2_FIXED_ONE &&
scaledStem <= stemWidthPer1000 )
scaledStem = cf2_intToFixed( x4 );
}
/* now apply the darkening parameters */
if ( scaledStem < cf2_intToFixed( x1 ) )
*darkenAmount = FT_DivFix( cf2_intToFixed( y1 ), ppem );
else if ( scaledStem < cf2_intToFixed( x2 ) )
{
FT_Int xdelta = x2 - x1;
FT_Int ydelta = y2 - y1;
FT_Int x = stemWidthPer1000 -
FT_DivFix( cf2_intToFixed( x1 ), ppem );
if ( !xdelta )
goto Try_x3;
*darkenAmount = FT_MulFix( x, FT_DivFix( ydelta, xdelta ) ) +
FT_DivFix( cf2_intToFixed( y1 ), ppem );
}
else if ( scaledStem < cf2_intToFixed( x3 ) )
{
Try_x3:
{
FT_Int xdelta = x3 - x2;
FT_Int ydelta = y3 - y2;
FT_Int x = stemWidthPer1000 -
FT_DivFix( cf2_intToFixed( x2 ), ppem );
if ( !xdelta )
goto Try_x4;
*darkenAmount = FT_MulFix( x, FT_DivFix( ydelta, xdelta ) ) +
FT_DivFix( cf2_intToFixed( y2 ), ppem );
}
}
else if ( scaledStem < cf2_intToFixed( x4 ) )
{
Try_x4:
{
FT_Int xdelta = x4 - x3;
FT_Int ydelta = y4 - y3;
FT_Int x = stemWidthPer1000 -
FT_DivFix( cf2_intToFixed( x3 ), ppem );
if ( !xdelta )
goto Use_y4;
*darkenAmount = FT_MulFix( x, FT_DivFix( ydelta, xdelta ) ) +
FT_DivFix( cf2_intToFixed( y3 ), ppem );
}
}
else
{
Use_y4:
*darkenAmount = FT_DivFix( cf2_intToFixed( y4 ), ppem );
}
/* use half the amount on each side and convert back to true */
/* character space */
*darkenAmount = FT_DivFix( *darkenAmount, 2 * emRatio );
}
/* add synthetic emboldening effect in character space */
*darkenAmount += boldenAmount / 2;
}
/* Compute a stem darkening amount in character space. */
static void
cf2_computeDarkening( CF2_Fixed emRatio,
CF2_Fixed ppem,
CF2_Fixed stemWidth,
CF2_Fixed* darkenAmount,
CF2_Fixed boldenAmount,
FT_Bool stemDarkened,
FT_Int* darkenParams )
{
/*
* Total darkening amount is computed in 1000 unit character space
* using the modified 5 part curve as Adobe's Avalon rasterizer.
* The darkening amount is smaller for thicker stems.
* It becomes zero when the stem is thicker than 2.333 pixels.
*
* By default, we use
*
* darkenAmount = 0.4 pixels if scaledStem <= 0.5 pixels,
* darkenAmount = 0.275 pixels if 1 <= scaledStem <= 1.667 pixels,
* darkenAmount = 0 pixel if scaledStem >= 2.333 pixels,
*
* and piecewise linear in-between:
*
*
* darkening
* ^
* |
* | (x1,y1)
* |--------+
* | \
* | \
* | \ (x3,y3)
* | +----------+
* | (x2,y2) \
* | \
* | \
* | +-----------------
* | (x4,y4)
* +---------------------------------------------> stem
* thickness
*
*
* This corresponds to the following values for the
* `darkening-parameters' property:
*
* (x1, y1) = (500, 400)
* (x2, y2) = (1000, 275)
* (x3, y3) = (1667, 275)
* (x4, y4) = (2333, 0)
*
*/
/* Internal calculations are done in units per thousand for */
/* convenience. The x axis is scaled stem width in */
/* thousandths of a pixel. That is, 1000 is 1 pixel. */
/* The y axis is darkening amount in thousandths of a pixel.*/
/* In the code, below, dividing by ppem and */
/* adjusting for emRatio converts darkenAmount to character */
/* space (font units). */
CF2_Fixed stemWidthPer1000, scaledStem;
FT_Int logBase2;
*darkenAmount = 0;
if ( boldenAmount == 0 && !stemDarkened )
return;
/* protect against range problems and divide by zero */
if ( emRatio < cf2_floatToFixed( .01 ) )
return;
if ( stemDarkened )
{
FT_Int x1 = darkenParams[0];
FT_Int y1 = darkenParams[1];
FT_Int x2 = darkenParams[2];
FT_Int y2 = darkenParams[3];
FT_Int x3 = darkenParams[4];
FT_Int y3 = darkenParams[5];
FT_Int x4 = darkenParams[6];
FT_Int y4 = darkenParams[7];
/* convert from true character space to 1000 unit character space; */
/* add synthetic emboldening effect */
/* `stemWidthPer1000' will not overflow for a legitimate font */
stemWidthPer1000 = FT_MulFix( stemWidth + boldenAmount, emRatio );
/* `scaledStem' can easily overflow, so we must clamp its maximum */
/* value; the test doesn't need to be precise, but must be */
/* conservative. The clamp value (default 2333) where */
/* `darkenAmount' is zero is well below the overflow value of */
/* 32767. */
/* */
/* FT_MSB computes the integer part of the base 2 logarithm. The */
/* number of bits for the product is 1 or 2 more than the sum of */
/* logarithms; remembering that the 16 lowest bits of the fraction */
/* are dropped this is correct to within a factor of almost 4. */
/* For example, 0x80.0000 * 0x80.0000 = 0x4000.0000 is 23+23 and */
/* is flagged as possible overflow because 0xFF.FFFF * 0xFF.FFFF = */
/* 0xFFFF.FE00 is also 23+23. */
logBase2 = FT_MSB( (FT_UInt32)stemWidthPer1000 ) +
FT_MSB( (FT_UInt32)ppem );
if ( logBase2 >= 46 )
/* possible overflow */
scaledStem = cf2_intToFixed( x4 );
else
scaledStem = FT_MulFix( stemWidthPer1000, ppem );
/* now apply the darkening parameters */
if ( scaledStem < cf2_intToFixed( x1 ) )
*darkenAmount = FT_DivFix( cf2_intToFixed( y1 ), ppem );
else if ( scaledStem < cf2_intToFixed( x2 ) )
{
FT_Int xdelta = x2 - x1;
FT_Int ydelta = y2 - y1;
FT_Int x = stemWidthPer1000 -
FT_DivFix( cf2_intToFixed( x1 ), ppem );
if ( !xdelta )
goto Try_x3;
*darkenAmount = FT_MulDiv( x, ydelta, xdelta ) +
FT_DivFix( cf2_intToFixed( y1 ), ppem );
}
else if ( scaledStem < cf2_intToFixed( x3 ) )
{
Try_x3:
{
FT_Int xdelta = x3 - x2;
FT_Int ydelta = y3 - y2;
FT_Int x = stemWidthPer1000 -
FT_DivFix( cf2_intToFixed( x2 ), ppem );
if ( !xdelta )
goto Try_x4;
*darkenAmount = FT_MulDiv( x, ydelta, xdelta ) +
FT_DivFix( cf2_intToFixed( y2 ), ppem );
}
}
else if ( scaledStem < cf2_intToFixed( x4 ) )
{
Try_x4:
{
FT_Int xdelta = x4 - x3;
FT_Int ydelta = y4 - y3;
FT_Int x = stemWidthPer1000 -
FT_DivFix( cf2_intToFixed( x3 ), ppem );
if ( !xdelta )
goto Use_y4;
*darkenAmount = FT_MulDiv( x, ydelta, xdelta ) +
FT_DivFix( cf2_intToFixed( y3 ), ppem );
}
}
else
{
Use_y4:
*darkenAmount = FT_DivFix( cf2_intToFixed( y4 ), ppem );
}
/* use half the amount on each side and convert back to true */
/* character space */
*darkenAmount = FT_DivFix( *darkenAmount, 2 * emRatio );
}
/* add synthetic emboldening effect in character space */
*darkenAmount += boldenAmount / 2;
}
