ref: aa0c4b4f55f88a489cf5f766c26ba0c285ac738a
parent: 097cd874ee26ef254e6782b528c460a6f9b7d812
author: Dave Arnold <[email protected]>
date: Thu Dec 15 09:04:51 EST 2016
[truetype] Provide function to apply `HVAR' advance width variation. * src/truetype/ttgxvar.c (tt_hadvance_adjust): New function. * src/truetype/ttgxvar.h: Updated.
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,14 @@
2016-12-15 Dave Arnold <[email protected]>
Werner Lemberg <[email protected]>
+ [truetype] Provide function to apply `HVAR' advance width variation.
+
+ * src/truetype/ttgxvar.c (tt_hadvance_adjust): New function.
+ * src/truetype/ttgxvar.h: Updated.
+
+2016-12-15 Dave Arnold <[email protected]>
+ Werner Lemberg <[email protected]>
+
[truetype] Add `HVAR' table parsing.
Note that this is not complete yet; it only handles advance width
--- a/src/truetype/ttgxvar.c
+++ b/src/truetype/ttgxvar.c
@@ -748,6 +748,151 @@
}
+ /*************************************************************************/
+ /* */
+ /* <Function> */
+ /* tt_hadvance_adjust */
+ /* */
+ /* <Description> */
+ /* Apply HVAR advance width adjustment of a given glyph. */
+ /* */
+ /* <Input> */
+ /* gindex :: The glyph index. */
+ /* */
+ /* <InOut> */
+ /* face :: The font face. */
+ /* */
+ /* adelta :: Points to width value that gets modified. */
+ /* */
+ FT_LOCAL_DEF( FT_Error )
+ tt_hadvance_adjust( TT_Face face,
+ FT_UInt gindex,
+ FT_Int *avalue )
+ {+ FT_Error error = FT_Err_Ok;
+
+ GX_HVarData varData;
+
+ FT_UInt innerIndex, outerIndex;
+ FT_UInt master, j;
+ FT_Fixed netAdjustment = 0; /* accumulated adjustment */
+ FT_Fixed scaledDelta;
+ FT_Short* deltaSet;
+ FT_Fixed delta;
+
+
+ if ( !face->blend )
+ goto Exit;
+
+ if ( !face->blend->hvar_loaded )
+ {+ /* initialize hvar table */
+ face->blend->hvar_error = ft_var_load_hvar( face );
+ }
+
+ if ( !face->blend->hvar_checked )
+ {+ error = face->blend->hvar_error;
+ goto Exit;
+ }
+
+ if ( gindex >= face->blend->hvar_table->widthMap.mapCount )
+ {+ FT_TRACE2(( "gindex %d out of range\n", gindex ));
+ error = FT_THROW( Invalid_Argument );
+ goto Exit;
+ }
+
+ /* trust that HVAR parser has checked indices */
+ outerIndex = face->blend->hvar_table->widthMap.outerIndex[gindex];
+ innerIndex = face->blend->hvar_table->widthMap.innerIndex[gindex];
+ varData = &face->blend->hvar_table->itemStore.varData[outerIndex];
+ deltaSet = &varData->deltaSet[varData->regionIdxCount * innerIndex];
+
+ /* See pseudo code from `Font Variations Overview' */
+ /* in the OpenType specification. */
+
+ /* outer loop steps through master designs to be blended */
+ for ( master = 0; master < varData->regionIdxCount; master++ )
+ {+ FT_Fixed scalar = FT_FIXED_ONE;
+ FT_UInt regionIndex = varData->regionIndices[master];
+
+ GX_AxisCoords axis = face->blend
+ ->hvar_table
+ ->itemStore.varRegionList[regionIndex]
+ .axisList;
+
+
+ /* inner loop steps through axes in this region */
+ for ( j = 0;
+ j < face->blend->hvar_table->itemStore.axisCount;
+ j++, axis++ )
+ {+ FT_Fixed axisScalar;
+
+
+ /* compute the scalar contribution of this axis; */
+ /* ignore invalid ranges */
+ if ( axis->startCoord > axis->peakCoord ||
+ axis->peakCoord > axis->endCoord )
+ axisScalar = FT_FIXED_ONE;
+
+ else if ( axis->startCoord < 0 &&
+ axis->endCoord > 0 &&
+ axis->peakCoord != 0 )
+ axisScalar = FT_FIXED_ONE;
+
+ /* peak of 0 means ignore this axis */
+ else if ( axis->peakCoord == 0 )
+ axisScalar = FT_FIXED_ONE;
+
+ /* ignore this region if coords are out of range */
+ else if ( face->blend->normalizedcoords[j] < axis->startCoord ||
+ face->blend->normalizedcoords[j] > axis->endCoord )
+ axisScalar = 0;
+
+ /* calculate a proportional factor */
+ else
+ {+ if ( face->blend->normalizedcoords[j] == axis->peakCoord )
+ axisScalar = FT_FIXED_ONE;
+ else if ( face->blend->normalizedcoords[j] < axis->peakCoord )
+ axisScalar =
+ FT_DivFix( face->blend->normalizedcoords[j] - axis->startCoord,
+ axis->peakCoord - axis->startCoord );
+ else
+ axisScalar =
+ FT_DivFix( axis->endCoord - face->blend->normalizedcoords[j],
+ axis->endCoord - axis->peakCoord );
+ }
+
+ /* take product of all the axis scalars */
+ scalar = FT_MulFix( scalar, axisScalar );
+
+ } /* per-axis loop */
+
+ FT_TRACE4(( ", %f ", scalar / 65536.0 ));
+
+ /* get the scaled delta for this region */
+ delta = FT_intToFixed( deltaSet[master] );
+ scaledDelta = FT_MulFix( scalar, delta );
+
+ /* accumulate the adjustments from each region */
+ netAdjustment = netAdjustment + scaledDelta;
+
+ } /* per-region loop */
+
+ FT_TRACE4(( "]\n" ));
+
+ /* apply the accumulated adjustment to derive the interpolated value */
+ *avalue += FT_fixedToInt( netAdjustment );
+
+ Exit:
+ return error;
+ }
+
+
typedef struct GX_GVar_Head_
{FT_Long version;
--- a/src/truetype/ttgxvar.h
+++ b/src/truetype/ttgxvar.h
@@ -254,6 +254,10 @@
FT_Outline* outline,
FT_UInt n_points );
+ FT_LOCAL( FT_Error )
+ tt_hadvance_adjust( TT_Face face,
+ FT_UInt gindex,
+ FT_Int *adelta );
FT_LOCAL( FT_Error )
tt_get_var_blend( TT_Face face,