[truetype] Provide function to apply `HVAR' advance width variation.
* src/truetype/ttgxvar.c (tt_hadvance_adjust): New function. * src/truetype/ttgxvar.h: Updated.
This commit is contained in:
Dave Arnold
Werner Lemberg
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097cd874ee
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aa0c4b4f55
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@ -1,3 +1,11 @@
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2016-12-15 Dave Arnold <darnold@adobe.com>
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Werner Lemberg <wl@gnu.org>
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[truetype] Provide function to apply `HVAR' advance width variation.
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* src/truetype/ttgxvar.c (tt_hadvance_adjust): New function.
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* src/truetype/ttgxvar.h: Updated.
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2016-12-15 Dave Arnold <darnold@adobe.com>
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Werner Lemberg <wl@gnu.org>
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@ -748,6 +748,151 @@
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}
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/*************************************************************************/
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/* */
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/* <Function> */
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/* tt_hadvance_adjust */
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/* */
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/* <Description> */
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/* Apply HVAR advance width adjustment of a given glyph. */
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/* */
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/* <Input> */
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/* gindex :: The glyph index. */
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/* */
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/* <InOut> */
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/* face :: The font face. */
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/* */
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/* adelta :: Points to width value that gets modified. */
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/* */
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FT_LOCAL_DEF( FT_Error )
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tt_hadvance_adjust( TT_Face face,
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FT_UInt gindex,
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FT_Int *avalue )
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{
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FT_Error error = FT_Err_Ok;
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GX_HVarData varData;
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FT_UInt innerIndex, outerIndex;
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FT_UInt master, j;
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FT_Fixed netAdjustment = 0; /* accumulated adjustment */
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FT_Fixed scaledDelta;
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FT_Short* deltaSet;
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FT_Fixed delta;
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if ( !face->blend )
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goto Exit;
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if ( !face->blend->hvar_loaded )
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{
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/* initialize hvar table */
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face->blend->hvar_error = ft_var_load_hvar( face );
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}
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if ( !face->blend->hvar_checked )
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{
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error = face->blend->hvar_error;
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goto Exit;
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}
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if ( gindex >= face->blend->hvar_table->widthMap.mapCount )
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{
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FT_TRACE2(( "gindex %d out of range\n", gindex ));
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error = FT_THROW( Invalid_Argument );
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goto Exit;
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}
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/* trust that HVAR parser has checked indices */
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outerIndex = face->blend->hvar_table->widthMap.outerIndex[gindex];
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innerIndex = face->blend->hvar_table->widthMap.innerIndex[gindex];
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varData = &face->blend->hvar_table->itemStore.varData[outerIndex];
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deltaSet = &varData->deltaSet[varData->regionIdxCount * innerIndex];
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/* See pseudo code from `Font Variations Overview' */
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/* in the OpenType specification. */
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/* outer loop steps through master designs to be blended */
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for ( master = 0; master < varData->regionIdxCount; master++ )
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{
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FT_Fixed scalar = FT_FIXED_ONE;
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FT_UInt regionIndex = varData->regionIndices[master];
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GX_AxisCoords axis = face->blend
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->hvar_table
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->itemStore.varRegionList[regionIndex]
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.axisList;
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/* inner loop steps through axes in this region */
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for ( j = 0;
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j < face->blend->hvar_table->itemStore.axisCount;
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j++, axis++ )
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{
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FT_Fixed axisScalar;
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/* compute the scalar contribution of this axis; */
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/* ignore invalid ranges */
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if ( axis->startCoord > axis->peakCoord ||
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axis->peakCoord > axis->endCoord )
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axisScalar = FT_FIXED_ONE;
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else if ( axis->startCoord < 0 &&
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axis->endCoord > 0 &&
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axis->peakCoord != 0 )
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axisScalar = FT_FIXED_ONE;
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/* peak of 0 means ignore this axis */
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else if ( axis->peakCoord == 0 )
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axisScalar = FT_FIXED_ONE;
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/* ignore this region if coords are out of range */
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else if ( face->blend->normalizedcoords[j] < axis->startCoord ||
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face->blend->normalizedcoords[j] > axis->endCoord )
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axisScalar = 0;
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/* calculate a proportional factor */
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else
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{
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if ( face->blend->normalizedcoords[j] == axis->peakCoord )
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axisScalar = FT_FIXED_ONE;
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else if ( face->blend->normalizedcoords[j] < axis->peakCoord )
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axisScalar =
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FT_DivFix( face->blend->normalizedcoords[j] - axis->startCoord,
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axis->peakCoord - axis->startCoord );
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else
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axisScalar =
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FT_DivFix( axis->endCoord - face->blend->normalizedcoords[j],
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axis->endCoord - axis->peakCoord );
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}
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/* take product of all the axis scalars */
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scalar = FT_MulFix( scalar, axisScalar );
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} /* per-axis loop */
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FT_TRACE4(( ", %f ", scalar / 65536.0 ));
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/* get the scaled delta for this region */
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delta = FT_intToFixed( deltaSet[master] );
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scaledDelta = FT_MulFix( scalar, delta );
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/* accumulate the adjustments from each region */
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netAdjustment = netAdjustment + scaledDelta;
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} /* per-region loop */
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FT_TRACE4(( "]\n" ));
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/* apply the accumulated adjustment to derive the interpolated value */
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*avalue += FT_fixedToInt( netAdjustment );
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Exit:
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return error;
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}
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typedef struct GX_GVar_Head_
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{
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FT_Long version;
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@ -254,6 +254,10 @@ FT_BEGIN_HEADER
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FT_Outline* outline,
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FT_UInt n_points );
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FT_LOCAL( FT_Error )
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tt_hadvance_adjust( TT_Face face,
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FT_UInt gindex,
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FT_Int *adelta );
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FT_LOCAL( FT_Error )
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tt_get_var_blend( TT_Face face,
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