path: root/Lib/fontTools/ttLib/scaleUpem.py

"""Change the units-per-EM of a font.

AAT and Graphite tables are not supported. CFF/CFF2 fonts
are de-subroutinized."""


from fontTools.ttLib.ttVisitor import TTVisitor
import fontTools.ttLib as ttLib
import fontTools.ttLib.tables.otBase as otBase
import fontTools.ttLib.tables.otTables as otTables
from fontTools.cffLib import VarStoreData
import fontTools.cffLib.specializer as cffSpecializer
from fontTools.misc.fixedTools import otRound


__all__ = ["scale_upem", "ScalerVisitor"]


class ScalerVisitor(TTVisitor):
    def __init__(self, scaleFactor):
        self.scaleFactor = scaleFactor

    def scale(self, v):
        return otRound(v * self.scaleFactor)


@ScalerVisitor.register_attrs(
    (
        (ttLib.getTableClass("head"), ("unitsPerEm", "xMin", "yMin", "xMax", "yMax")),
        (ttLib.getTableClass("post"), ("underlinePosition", "underlineThickness")),
        (ttLib.getTableClass("VORG"), ("defaultVertOriginY")),
        (
            ttLib.getTableClass("hhea"),
            (
                "ascent",
                "descent",
                "lineGap",
                "advanceWidthMax",
                "minLeftSideBearing",
                "minRightSideBearing",
                "xMaxExtent",
                "caretOffset",
            ),
        ),
        (
            ttLib.getTableClass("vhea"),
            (
                "ascent",
                "descent",
                "lineGap",
                "advanceHeightMax",
                "minTopSideBearing",
                "minBottomSideBearing",
                "yMaxExtent",
                "caretOffset",
            ),
        ),
        (
            ttLib.getTableClass("OS/2"),
            (
                "xAvgCharWidth",
                "ySubscriptXSize",
                "ySubscriptYSize",
                "ySubscriptXOffset",
                "ySubscriptYOffset",
                "ySuperscriptXSize",
                "ySuperscriptYSize",
                "ySuperscriptXOffset",
                "ySuperscriptYOffset",
                "yStrikeoutSize",
                "yStrikeoutPosition",
                "sTypoAscender",
                "sTypoDescender",
                "sTypoLineGap",
                "usWinAscent",
                "usWinDescent",
                "sxHeight",
                "sCapHeight",
            ),
        ),
        (
            otTables.ValueRecord,
            ("XAdvance", "YAdvance", "XPlacement", "YPlacement"),
        ),  # GPOS
        (otTables.Anchor, ("XCoordinate", "YCoordinate")),  # GPOS
        (otTables.CaretValue, ("Coordinate")),  # GDEF
        (otTables.BaseCoord, ("Coordinate")),  # BASE
        (otTables.MathValueRecord, ("Value")),  # MATH
        (otTables.ClipBox, ("xMin", "yMin", "xMax", "yMax")),  # COLR
    )
)
def visit(visitor, obj, attr, value):
    setattr(obj, attr, visitor.scale(value))


@ScalerVisitor.register_attr(
    (ttLib.getTableClass("hmtx"), ttLib.getTableClass("vmtx")), "metrics"
)
def visit(visitor, obj, attr, metrics):
    for g in metrics:
        advance, lsb = metrics[g]
        metrics[g] = visitor.scale(advance), visitor.scale(lsb)


@ScalerVisitor.register_attr(ttLib.getTableClass("VMTX"), "VOriginRecords")
def visit(visitor, obj, attr, VOriginRecords):
    for g in VOriginRecords:
        VOriginRecords[g] = visitor.scale(VOriginRecords[g])


@ScalerVisitor.register_attr(ttLib.getTableClass("glyf"), "glyphs")
def visit(visitor, obj, attr, glyphs):
    for g in glyphs.values():
        if g.isComposite():
            for component in g.components:
                component.x = visitor.scale(component.x)
                component.y = visitor.scale(component.y)
        else:
            for attr in ("xMin", "xMax", "yMin", "yMax"):
                v = getattr(g, attr, None)
                if v is not None:
                    setattr(g, attr, visitor.scale(v))

        glyf = visitor.font["glyf"]
        coordinates = g.getCoordinates(glyf)[0]
        for i, (x, y) in enumerate(coordinates):
            coordinates[i] = visitor.scale(x), visitor.scale(y)


@ScalerVisitor.register_attr(ttLib.getTableClass("gvar"), "variations")
def visit(visitor, obj, attr, variations):
    for varlist in variations.values():
        for var in varlist:
            coordinates = var.coordinates
            for i, xy in enumerate(coordinates):
                if xy is None:
                    continue
                coordinates[i] = visitor.scale(xy[0]), visitor.scale(xy[1])


@ScalerVisitor.register_attr(ttLib.getTableClass("kern"), "kernTables")
def visit(visitor, obj, attr, kernTables):
    for table in kernTables:
        kernTable = table.kernTable
        for k in kernTable.keys():
            kernTable[k] = visitor.scale(kernTable[k])


def _cff_scale(visitor, args):
    for i, arg in enumerate(args):
        if not isinstance(arg, list):
            args[i] = visitor.scale(arg)
        else:
            num_blends = arg[-1]
            _cff_scale(visitor, arg)
            arg[-1] = num_blends


@ScalerVisitor.register_attr(
    (ttLib.getTableClass("CFF "), ttLib.getTableClass("CFF2")), "cff"
)
def visit(visitor, obj, attr, cff):
    cff.desubroutinize()
    topDict = cff.topDictIndex[0]
    varStore = getattr(topDict, "VarStore", None)
    getNumRegions = varStore.getNumRegions if varStore is not None else None
    privates = set()
    for fontname in cff.keys():
        font = cff[fontname]
        cs = font.CharStrings
        for g in font.charset:
            c, _ = cs.getItemAndSelector(g)
            privates.add(c.private)

            commands = cffSpecializer.programToCommands(
                c.program, getNumRegions=getNumRegions
            )
            for op, args in commands:
                _cff_scale(visitor, args)
            c.program[:] = cffSpecializer.commandsToProgram(commands)

        # Annoying business of scaling numbers that do not matter whatsoever

        for attr in (
            "UnderlinePosition",
            "UnderlineThickness",
            "FontBBox",
            "StrokeWidth",
        ):
            value = getattr(topDict, attr, None)
            if value is None:
                continue
            if isinstance(value, list):
                _cff_scale(visitor, value)
            else:
                setattr(topDict, attr, visitor.scale(value))

        for i in range(6):
            topDict.FontMatrix[i] /= visitor.scaleFactor

        for private in privates:
            for attr in (
                "BlueValues",
                "OtherBlues",
                "FamilyBlues",
                "FamilyOtherBlues",
                # "BlueScale",
                # "BlueShift",
                # "BlueFuzz",
                "StdHW",
                "StdVW",
                "StemSnapH",
                "StemSnapV",
                "defaultWidthX",
                "nominalWidthX",
            ):
                value = getattr(private, attr, None)
                if value is None:
                    continue
                if isinstance(value, list):
                    _cff_scale(visitor, value)
                else:
                    setattr(private, attr, visitor.scale(value))


# ItemVariationStore


@ScalerVisitor.register(otTables.VarData)
def visit(visitor, varData):
    for item in varData.Item:
        for i, v in enumerate(item):
            item[i] = visitor.scale(v)


# COLRv1


def _setup_scale_paint(paint, scale):
    if -2 <= scale <= 2 - (1 >> 14):
        paint.Format = otTables.PaintFormat.PaintScaleUniform
        paint.scale = scale
        return

    transform = otTables.Affine2x3()
    transform.populateDefaults()
    transform.xy = transform.yx = transform.dx = transform.dy = 0
    transform.xx = transform.yy = scale

    paint.Format = otTables.PaintFormat.PaintTransform
    paint.Transform = transform


@ScalerVisitor.register(otTables.BaseGlyphPaintRecord)
def visit(visitor, record):
    oldPaint = record.Paint

    scale = otTables.Paint()
    _setup_scale_paint(scale, visitor.scaleFactor)
    scale.Paint = oldPaint

    record.Paint = scale

    return True


@ScalerVisitor.register(otTables.Paint)
def visit(visitor, paint):
    if paint.Format != otTables.PaintFormat.PaintGlyph:
        return True

    newPaint = otTables.Paint()
    newPaint.Format = paint.Format
    newPaint.Paint = paint.Paint
    newPaint.Glyph = paint.Glyph
    del paint.Paint
    del paint.Glyph

    _setup_scale_paint(paint, 1 / visitor.scaleFactor)
    paint.Paint = newPaint

    visitor.visit(newPaint.Paint)

    return False


def scale_upem(font, new_upem):
    """Change the units-per-EM of font to the new value."""
    upem = font["head"].unitsPerEm
    visitor = ScalerVisitor(new_upem / upem)
    visitor.visit(font)


def main(args=None):
    """Change the units-per-EM of fonts"""

    if args is None:
        import sys

        args = sys.argv[1:]

    from fontTools.ttLib import TTFont
    from fontTools.misc.cliTools import makeOutputFileName
    import argparse

    parser = argparse.ArgumentParser(
        "fonttools ttLib.scaleUpem", description="Change the units-per-EM of fonts"
    )
    parser.add_argument("font", metavar="font", help="Font file.")
    parser.add_argument(
        "new_upem", metavar="new-upem", help="New units-per-EM integer value."
    )
    parser.add_argument(
        "--output-file", metavar="path", default=None, help="Output file."
    )

    options = parser.parse_args(args)

    font = TTFont(options.font)
    new_upem = int(options.new_upem)
    output_file = (
        options.output_file
        if options.output_file is not None
        else makeOutputFileName(options.font, overWrite=True, suffix="-scaled")
    )

    scale_upem(font, new_upem)

    print("Writing %s" % output_file)
    font.save(output_file)


if __name__ == "__main__":
    import sys

    sys.exit(main())