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[SVG] reuse SVG doc offsets on compile; remove deprecated version-1 support #2430

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merged 4 commits into from Oct 18, 2021
Merged

[SVG] reuse SVG doc offsets on compile; remove deprecated version-1 support #2430

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be8d6e2
SVG: remove old deprecated version1 and embedded colorPalettes
anthrotype Oct 13, 2021
2967f18
SVG: on compile reuse offsets when doc bytes are same
anthrotype Oct 13, 2021
11c98b0
SVG: don't write extra empty newline at beginning of SVG table
anthrotype Oct 13, 2021
e3bc036
Add tests for SVG table
anthrotype Oct 13, 2021
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294 changes: 32 additions & 262 deletions Lib/fontTools/ttLib/tables/S_V_G_.py
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@@ -1,26 +1,6 @@
from fontTools.misc.textTools import bytesjoin, strjoin, tobytes, tostr
from fontTools.misc import sstruct
from . import DefaultTable
try:
import xml.etree.cElementTree as ET
except ImportError:
import xml.etree.ElementTree as ET
from io import BytesIO
import struct
import logging


log = logging.getLogger(__name__)
"""Compiles/decompiles SVG table.


__doc__="""
Compiles/decompiles version 0 and 1 SVG tables from/to XML.

Version 1 is the first SVG definition, implemented in Mozilla before Aug 2013, now deprecated.
This module will decompile this correctly, but will compile a version 1 table
only if you add the secret element "<version1/>" to the SVG element in the TTF file.

Version 0 is the joint Adobe-Mozilla proposal, which supports color palettes.
https://docs.microsoft.com/en-us/typography/opentype/spec/svg

The XML format is:
<SVG>
Expand All @@ -31,53 +11,29 @@
<svgDoc endGlyphID="n" startGlyphID="m">
<![CDATA[ <complete SVG doc> ]]
</svgDoc>

<colorPalettes>
<colorParamUINameID>n</colorParamUINameID>
...
<colorParamUINameID>m</colorParamUINameID>
<colorPalette uiNameID="n">
<colorRecord red="<int>" green="<int>" blue="<int>" alpha="<int>" />
...
<colorRecord red="<int>" green="<int>" blue="<int>" alpha="<int>" />
</colorPalette>
...
<colorPalette uiNameID="m">
<colorRecord red="<int> green="<int>" blue="<int>" alpha="<int>" />
...
<colorRecord red=<int>" green="<int>" blue="<int>" alpha="<int>" />
</colorPalette>
</colorPalettes>
</SVG>
"""

Color values must be less than 256.
from fontTools.misc.textTools import bytesjoin, strjoin, tobytes, tostr
from fontTools.misc import sstruct
from . import DefaultTable
from io import BytesIO
import struct
import logging

The number of color records in each </colorPalette> must be the same as
the number of <colorParamUINameID> elements.

"""
log = logging.getLogger(__name__)

XML = ET.XML
XMLElement = ET.Element
xmlToString = ET.tostring

SVG_format_0 = """
> # big endian
version: H
offsetToSVGDocIndex: L
offsetToColorPalettes: L
reserved: L
"""

SVG_format_0Size = sstruct.calcsize(SVG_format_0)

SVG_format_1 = """
> # big endian
version: H
numIndicies: H
"""

SVG_format_1Size = sstruct.calcsize(SVG_format_1)

doc_index_entry_format_0 = """
> # big endian
startGlyphID: H
Expand All @@ -88,84 +44,26 @@

doc_index_entry_format_0Size = sstruct.calcsize(doc_index_entry_format_0)

colorRecord_format_0 = """
red: B
green: B
blue: B
alpha: B
"""


class table_S_V_G_(DefaultTable.DefaultTable):

def __init__(self, tag=None):
DefaultTable.DefaultTable.__init__(self, tag)
self.colorPalettes = None

def decompile(self, data, ttFont):
self.docList = None
self.colorPalettes = None
pos = 0
self.version = struct.unpack(">H", data[pos:pos+2])[0]

if self.version == 1:
# This is pre-standardization version of the table; and obsolete. But we decompile it for now.
# https://wiki.mozilla.org/SVGOpenTypeFonts
self.decompile_format_1(data, ttFont)
else:
if self.version != 0:
log.warning(
"Unknown SVG table version '%s'. Decompiling as version 0.", self.version)
# This is the standardized version of the table; and current.
# https://www.microsoft.com/typography/otspec/svg.htm
self.decompile_format_0(data, ttFont)

def decompile_format_0(self, data, ttFont):
dummy, data2 = sstruct.unpack2(SVG_format_0, data, self)
self.docList = []
# Version 0 is the standardized version of the table; and current.
# https://www.microsoft.com/typography/otspec/svg.htm
sstruct.unpack(SVG_format_0, data[:SVG_format_0Size], self)
if self.version != 0:
log.warning(
"Unknown SVG table version '%s'. Decompiling as version 0.", self.version)
# read in SVG Documents Index
self.decompileEntryList(data)

# read in colorPalettes table.
self.colorPalettes = colorPalettes = ColorPalettes()
pos = self.offsetToColorPalettes
if pos > 0:
colorPalettes.numColorParams = numColorParams = struct.unpack(">H", data[pos:pos+2])[0]
if numColorParams > 0:
colorPalettes.colorParamUINameIDs = colorParamUINameIDs = []
pos = pos + 2
for i in range(numColorParams):
nameID = struct.unpack(">H", data[pos:pos+2])[0]
colorParamUINameIDs.append(nameID)
pos = pos + 2

colorPalettes.numColorPalettes = numColorPalettes = struct.unpack(">H", data[pos:pos+2])[0]
pos = pos + 2
if numColorPalettes > 0:
colorPalettes.colorPaletteList = colorPaletteList = []
for i in range(numColorPalettes):
colorPalette = ColorPalette()
colorPaletteList.append(colorPalette)
colorPalette.uiNameID = struct.unpack(">H", data[pos:pos+2])[0]
pos = pos + 2
colorPalette.paletteColors = paletteColors = []
for j in range(numColorParams):
colorRecord, colorPaletteData = sstruct.unpack2(colorRecord_format_0, data[pos:], ColorRecord())
paletteColors.append(colorRecord)
pos += 4

def decompile_format_1(self, data, ttFont):
self.offsetToSVGDocIndex = 2
self.decompileEntryList(data)

def decompileEntryList(self, data):
# data starts with the first entry of the entry list.
pos = subTableStart = self.offsetToSVGDocIndex
self.numEntries = numEntries = struct.unpack(">H", data[pos:pos+2])[0]
self.numEntries = struct.unpack(">H", data[pos:pos+2])[0]
pos += 2
if self.numEntries > 0:
data2 = data[pos:]
self.docList = []
self.entries = entries = []
entries = []
for i in range(self.numEntries):
docIndexEntry, data2 = sstruct.unpack2(doc_index_entry_format_0, data2, DocumentIndexEntry())
entries.append(docIndexEntry)
Expand All @@ -185,13 +83,6 @@ def decompileEntryList(self, data):
self.docList.append( [doc, entry.startGlyphID, entry.endGlyphID] )

def compile(self, ttFont):
if hasattr(self, "version1"):
data = self.compileFormat1(ttFont)
else:
data = self.compileFormat0(ttFont)
return data

def compileFormat0(self, ttFont):
version = 0
offsetToSVGDocIndex = SVG_format_0Size # I start the SVGDocIndex right after the header.
# get SGVDoc info.
Expand All @@ -201,8 +92,8 @@ def compileFormat0(self, ttFont):
datum = struct.pack(">H",numEntries)
entryList.append(datum)
curOffset = len(datum) + doc_index_entry_format_0Size*numEntries
seenDocs = {}
for doc, startGlyphID, endGlyphID in self.docList:
docOffset = curOffset
docBytes = tobytes(doc, encoding="utf_8")
if getattr(self, "compressed", False) and not docBytes.startswith(b"\x1f\x8b"):
import gzip
Expand All @@ -214,63 +105,25 @@ def compileFormat0(self, ttFont):
docBytes = gzipped
del gzipped, bytesIO
docLength = len(docBytes)
curOffset += docLength
if docBytes in seenDocs:
docOffset = seenDocs[docBytes]
else:
docOffset = curOffset
curOffset += docLength
seenDocs[docBytes] = docOffset
docList.append(docBytes)
entry = struct.pack(">HHLL", startGlyphID, endGlyphID, docOffset, docLength)
entryList.append(entry)
docList.append(docBytes)
entryList.extend(docList)
svgDocData = bytesjoin(entryList)

# get colorpalette info.
if self.colorPalettes is None:
offsetToColorPalettes = 0
palettesData = ""
else:
offsetToColorPalettes = SVG_format_0Size + len(svgDocData)
dataList = []
numColorParams = len(self.colorPalettes.colorParamUINameIDs)
datum = struct.pack(">H", numColorParams)
dataList.append(datum)
for uiNameId in self.colorPalettes.colorParamUINameIDs:
datum = struct.pack(">H", uiNameId)
dataList.append(datum)
numColorPalettes = len(self.colorPalettes.colorPaletteList)
datum = struct.pack(">H", numColorPalettes)
dataList.append(datum)
for colorPalette in self.colorPalettes.colorPaletteList:
datum = struct.pack(">H", colorPalette.uiNameID)
dataList.append(datum)
for colorRecord in colorPalette.paletteColors:
data = struct.pack(">BBBB", colorRecord.red, colorRecord.green, colorRecord.blue, colorRecord.alpha)
dataList.append(data)
palettesData = bytesjoin(dataList)

header = struct.pack(">HLL", version, offsetToSVGDocIndex, offsetToColorPalettes)
data = [header, svgDocData, palettesData]
reserved = 0
header = struct.pack(">HLL", version, offsetToSVGDocIndex, reserved)
data = [header, svgDocData]
data = bytesjoin(data)
return data

def compileFormat1(self, ttFont):
version = 1
numEntries = len(self.docList)
header = struct.pack(">HH", version, numEntries)
dataList = [header]
docList = []
curOffset = SVG_format_1Size + doc_index_entry_format_0Size*numEntries
for doc, startGlyphID, endGlyphID in self.docList:
docOffset = curOffset
docBytes = tobytes(doc, encoding="utf_8")
docLength = len(docBytes)
curOffset += docLength
entry = struct.pack(">HHLL", startGlyphID, endGlyphID, docOffset, docLength)
dataList.append(entry)
docList.append(docBytes)
dataList.extend(docList)
data = bytesjoin(dataList)
return data

def toXML(self, writer, ttFont):
writer.newline()
for doc, startGID, endGID in self.docList:
writer.begintag("svgDoc", startGlyphID=startGID, endGlyphID=endGID)
writer.newline()
Expand All @@ -279,33 +132,6 @@ def toXML(self, writer, ttFont):
writer.endtag("svgDoc")
writer.newline()

if (self.colorPalettes is not None) and (self.colorPalettes.numColorParams is not None):
writer.begintag("colorPalettes")
writer.newline()
for uiNameID in self.colorPalettes.colorParamUINameIDs:
writer.begintag("colorParamUINameID")
writer._writeraw(str(uiNameID))
writer.endtag("colorParamUINameID")
writer.newline()
for colorPalette in self.colorPalettes.colorPaletteList:
writer.begintag("colorPalette", [("uiNameID", str(colorPalette.uiNameID))])
writer.newline()
for colorRecord in colorPalette.paletteColors:
colorAttributes = [
("red", hex(colorRecord.red)),
("green", hex(colorRecord.green)),
("blue", hex(colorRecord.blue)),
("alpha", hex(colorRecord.alpha)),
]
writer.begintag("colorRecord", colorAttributes)
writer.endtag("colorRecord")
writer.newline()
writer.endtag("colorPalette")
writer.newline()

writer.endtag("colorPalettes")
writer.newline()

def fromXML(self, name, attrs, content, ttFont):
if name == "svgDoc":
if not hasattr(self, "docList"):
Expand All @@ -315,14 +141,10 @@ def fromXML(self, name, attrs, content, ttFont):
startGID = int(attrs["startGlyphID"])
endGID = int(attrs["endGlyphID"])
self.docList.append( [doc, startGID, endGID] )
elif name == "colorPalettes":
self.colorPalettes = ColorPalettes()
self.colorPalettes.fromXML(name, attrs, content, ttFont)
if self.colorPalettes.numColorParams == 0:
self.colorPalettes = None
else:
log.warning("Unknown %s %s", name, content)


class DocumentIndexEntry(object):
def __init__(self):
self.startGlyphID = None # USHORT
Expand All @@ -332,55 +154,3 @@ def __init__(self):

def __repr__(self):
return "startGlyphID: %s, endGlyphID: %s, svgDocOffset: %s, svgDocLength: %s" % (self.startGlyphID, self.endGlyphID, self.svgDocOffset, self.svgDocLength)

class ColorPalettes(object):
def __init__(self):
self.numColorParams = None # USHORT
self.colorParamUINameIDs = [] # list of name table name ID values that provide UI description of each color palette.
self.numColorPalettes = None # USHORT
self.colorPaletteList = [] # list of ColorPalette records

def fromXML(self, name, attrs, content, ttFont):
for element in content:
if not isinstance(element, tuple):
continue
name, attrib, content = element
if name == "colorParamUINameID":
uiNameID = int(content[0])
self.colorParamUINameIDs.append(uiNameID)
elif name == "colorPalette":
colorPalette = ColorPalette()
self.colorPaletteList.append(colorPalette)
colorPalette.fromXML(name, attrib, content, ttFont)

self.numColorParams = len(self.colorParamUINameIDs)
self.numColorPalettes = len(self.colorPaletteList)
for colorPalette in self.colorPaletteList:
if len(colorPalette.paletteColors) != self.numColorParams:
raise ValueError("Number of color records in a colorPalette ('%s') does not match the number of colorParamUINameIDs elements ('%s')." % (len(colorPalette.paletteColors), self.numColorParams))

class ColorPalette(object):
def __init__(self):
self.uiNameID = None # USHORT. name table ID that describes user interface strings associated with this color palette.
self.paletteColors = [] # list of ColorRecords

def fromXML(self, name, attrs, content, ttFont):
self.uiNameID = int(attrs["uiNameID"])
for element in content:
if isinstance(element, type("")):
continue
name, attrib, content = element
if name == "colorRecord":
colorRecord = ColorRecord()
self.paletteColors.append(colorRecord)
colorRecord.red = eval(attrib["red"])
colorRecord.green = eval(attrib["green"])
colorRecord.blue = eval(attrib["blue"])
colorRecord.alpha = eval(attrib["alpha"])

class ColorRecord(object):
def __init__(self):
self.red = 255 # all are one byte values.
self.green = 255
self.blue = 255
self.alpha = 255