aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/python/fonttools/fontTools/varLib/avar.py
blob: 164a4a805878f0ed8b9615cfaf9fe47ecf7020aa (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
from fontTools.varLib import _add_avar, load_designspace
from fontTools.varLib.models import VariationModel
from fontTools.varLib.varStore import VarStoreInstancer
from fontTools.misc.fixedTools import fixedToFloat as fi2fl
from fontTools.misc.cliTools import makeOutputFileName
from itertools import product
import logging

log = logging.getLogger("fontTools.varLib.avar")


def _denormalize(v, axis):
    if v >= 0:
        return axis.defaultValue + v * (axis.maxValue - axis.defaultValue)
    else:
        return axis.defaultValue + v * (axis.defaultValue - axis.minValue)


def _pruneLocations(locations, poles, axisTags):
    # Now we have all the input locations, find which ones are
    # not needed and remove them.

    # Note: This algorithm is heavily tied to how VariationModel
    # is implemented.  It assumes that input was extracted from
    # VariationModel-generated object, like an ItemVariationStore
    # created by fontmake using varLib.models.VariationModel.
    # Some CoPilot blabbering:
    # I *think* I can prove that this algorithm is correct, but
    # I'm not 100% sure.  It's possible that there are edge cases
    # where this algorithm will fail.  I'm not sure how to prove
    # that it's correct, but I'm also not sure how to prove that
    # it's incorrect.  I'm not sure how to write a test case that
    # would prove that it's incorrect.  I'm not sure how to write
    # a test case that would prove that it's correct.

    model = VariationModel(locations, axisTags)
    modelMapping = model.mapping
    modelSupports = model.supports
    pins = {tuple(k.items()): None for k in poles}
    for location in poles:
        i = locations.index(location)
        i = modelMapping[i]
        support = modelSupports[i]
        supportAxes = set(support.keys())
        for axisTag, (minV, _, maxV) in support.items():
            for v in (minV, maxV):
                if v in (-1, 0, 1):
                    continue
                for pin in pins.keys():
                    pinLocation = dict(pin)
                    pinAxes = set(pinLocation.keys())
                    if pinAxes != supportAxes:
                        continue
                    if axisTag not in pinAxes:
                        continue
                    if pinLocation[axisTag] == v:
                        break
                else:
                    # No pin found. Go through the previous masters
                    # and find a suitable pin.  Going backwards is
                    # better because it can find a pin that is close
                    # to the pole in more dimensions, and reducing
                    # the total number of pins needed.
                    for candidateIdx in range(i - 1, -1, -1):
                        candidate = modelSupports[candidateIdx]
                        candidateAxes = set(candidate.keys())
                        if candidateAxes != supportAxes:
                            continue
                        if axisTag not in candidateAxes:
                            continue
                        candidate = {
                            k: defaultV for k, (_, defaultV, _) in candidate.items()
                        }
                        if candidate[axisTag] == v:
                            pins[tuple(candidate.items())] = None
                            break
                    else:
                        assert False, "No pin found"
    return [dict(t) for t in pins.keys()]


def mappings_from_avar(font, denormalize=True):
    fvarAxes = font["fvar"].axes
    axisMap = {a.axisTag: a for a in fvarAxes}
    axisTags = [a.axisTag for a in fvarAxes]
    axisIndexes = {a.axisTag: i for i, a in enumerate(fvarAxes)}
    if "avar" not in font:
        return {}, {}
    avar = font["avar"]
    axisMaps = {
        tag: seg
        for tag, seg in avar.segments.items()
        if seg and seg != {-1: -1, 0: 0, 1: 1}
    }
    mappings = []

    if getattr(avar, "majorVersion", 1) == 2:
        varStore = avar.table.VarStore
        regions = varStore.VarRegionList.Region

        # Find all the input locations; this finds "poles", that are
        # locations of the peaks, and "corners", that are locations
        # of the corners of the regions.  These two sets of locations
        # together constitute inputLocations to consider.

        poles = {(): None}  # Just using it as an ordered set
        inputLocations = set({()})
        for varData in varStore.VarData:
            regionIndices = varData.VarRegionIndex
            for regionIndex in regionIndices:
                peakLocation = []
                corners = []
                region = regions[regionIndex]
                for axisIndex, axis in enumerate(region.VarRegionAxis):
                    if axis.PeakCoord == 0:
                        continue
                    axisTag = axisTags[axisIndex]
                    peakLocation.append((axisTag, axis.PeakCoord))
                    corner = []
                    if axis.StartCoord != 0:
                        corner.append((axisTag, axis.StartCoord))
                    if axis.EndCoord != 0:
                        corner.append((axisTag, axis.EndCoord))
                    corners.append(corner)
                corners = set(product(*corners))
                peakLocation = tuple(peakLocation)
                poles[peakLocation] = None
                inputLocations.add(peakLocation)
                inputLocations.update(corners)

        # Sort them by number of axes, then by axis order
        inputLocations = [
            dict(t)
            for t in sorted(
                inputLocations,
                key=lambda t: (len(t), tuple(axisIndexes[tag] for tag, _ in t)),
            )
        ]
        poles = [dict(t) for t in poles.keys()]
        inputLocations = _pruneLocations(inputLocations, list(poles), axisTags)

        # Find the output locations, at input locations
        varIdxMap = avar.table.VarIdxMap
        instancer = VarStoreInstancer(varStore, fvarAxes)
        for location in inputLocations:
            instancer.setLocation(location)
            outputLocation = {}
            for axisIndex, axisTag in enumerate(axisTags):
                varIdx = axisIndex
                if varIdxMap is not None:
                    varIdx = varIdxMap[varIdx]
                delta = instancer[varIdx]
                if delta != 0:
                    v = location.get(axisTag, 0)
                    v = v + fi2fl(delta, 14)
                    # See https://github.com/fonttools/fonttools/pull/3598#issuecomment-2266082009
                    # v = max(-1, min(1, v))
                    outputLocation[axisTag] = v
            mappings.append((location, outputLocation))

        # Remove base master we added, if it maps to the default location
        assert mappings[0][0] == {}
        if mappings[0][1] == {}:
            mappings.pop(0)

    if denormalize:
        for tag, seg in axisMaps.items():
            if tag not in axisMap:
                raise ValueError(f"Unknown axis tag {tag}")
            denorm = lambda v: _denormalize(v, axisMap[tag])
            axisMaps[tag] = {denorm(k): denorm(v) for k, v in seg.items()}

        for i, (inputLoc, outputLoc) in enumerate(mappings):
            inputLoc = {
                tag: _denormalize(val, axisMap[tag]) for tag, val in inputLoc.items()
            }
            outputLoc = {
                tag: _denormalize(val, axisMap[tag]) for tag, val in outputLoc.items()
            }
            mappings[i] = (inputLoc, outputLoc)

    return axisMaps, mappings


def main(args=None):
    """Add `avar` table from designspace file to variable font."""

    if args is None:
        import sys

        args = sys.argv[1:]

    from fontTools import configLogger
    from fontTools.ttLib import TTFont
    from fontTools.designspaceLib import DesignSpaceDocument
    import argparse

    parser = argparse.ArgumentParser(
        "fonttools varLib.avar",
        description="Add `avar` table from designspace file to variable font.",
    )
    parser.add_argument("font", metavar="varfont.ttf", help="Variable-font file.")
    parser.add_argument(
        "designspace",
        metavar="family.designspace",
        help="Designspace file.",
        nargs="?",
        default=None,
    )
    parser.add_argument(
        "-o",
        "--output-file",
        type=str,
        help="Output font file name.",
    )
    parser.add_argument(
        "-v", "--verbose", action="store_true", help="Run more verbosely."
    )

    options = parser.parse_args(args)

    configLogger(level=("INFO" if options.verbose else "WARNING"))

    font = TTFont(options.font)
    if not "fvar" in font:
        log.error("Not a variable font.")
        return 1

    if options.designspace is None:
        from pprint import pprint

        segments, mappings = mappings_from_avar(font)
        pprint(segments)
        pprint(mappings)
        print(len(mappings), "mappings")
        return

    axisTags = [a.axisTag for a in font["fvar"].axes]

    ds = load_designspace(options.designspace, require_sources=False)

    if "avar" in font:
        log.warning("avar table already present, overwriting.")
        del font["avar"]

    _add_avar(font, ds.axes, ds.axisMappings, axisTags)

    if options.output_file is None:
        outfile = makeOutputFileName(options.font, overWrite=True, suffix=".avar")
    else:
        outfile = options.output_file
    if outfile:
        log.info("Saving %s", outfile)
        font.save(outfile)


if __name__ == "__main__":
    import sys

    sys.exit(main())