// Parses font's offset table and alters OffsetTable object appropriately.
public OffsetTable ParseOffsetTable(byte[] fontContent)
{
OffsetTable offsetTable = new OffsetTable();
uint offset = 0;
offsetTable.tag = ReadDataAndIncreaseIndex(fontContent, ref offset, TagLength);
offsetTable.numTables = ReadDataAndIncreaseIndex <ushort>(fontContent, ref offset, sizeof(ushort));
offsetTable.searchRange = ReadDataAndIncreaseIndex <ushort>(fontContent, ref offset, sizeof(ushort));
offsetTable.entrySelector = ReadDataAndIncreaseIndex <ushort>(fontContent, ref offset, sizeof(ushort));
offsetTable.rangeShift = ReadDataAndIncreaseIndex <ushort>(fontContent, ref offset, sizeof(ushort));
start = offset;
return(offsetTable);
}
// Updates OffsetTable object and the offset table in font to reflect a table being added.
public OffsetTable UpdateOffsetTable(OffsetTable offsetTable, ref byte[] source)
{
OffsetTable newOffsetTable = offsetTable;
newOffsetTable.numTables += 1;
byte[] newNumTables = GetBytesBigEndian(offsetTable.numTables);
int offsetTableNumTablesOffset = TagLength; // Advance past the initial tag of the offset table.
Array.Copy(newNumTables, 0, source, offsetTableNumTablesOffset, sizeof(ushort)); // Overwrite numTables with numTables + 1.
// Calculate searchRange, entrySelector and rangeShift as outlined in the Offset Table section of the OpenType spec.
ushort searchRange = 1, entrySelector = 0;
while ((searchRange << 1) < offsetTable.numTables)
{
searchRange <<= 1;
entrySelector++;
}
searchRange <<= 4; // multiply by 16
newOffsetTable.searchRange = searchRange;
newOffsetTable.entrySelector = entrySelector;
newOffsetTable.rangeShift = (ushort)((offsetTable.numTables * 16) - offsetTable.searchRange);
byte[] newSearchRange = GetBytesBigEndian(offsetTable.searchRange);
byte[] newEntrySelector = GetBytesBigEndian(offsetTable.entrySelector);
byte[] newRangeShift = GetBytesBigEndian(offsetTable.rangeShift);
// Write the newly calculated values of searchRange, entrySelector and rangeShift to source.
int sourceIndex = sizeof(uint) + sizeof(ushort);
Array.Copy(newSearchRange, 0, source, sourceIndex, sizeof(ushort));
sourceIndex += sizeof(ushort);
Array.Copy(newEntrySelector, 0, source, sourceIndex, sizeof(ushort));
sourceIndex += sizeof(ushort);
Array.Copy(newRangeShift, 0, source, sourceIndex, sizeof(ushort));
return(newOffsetTable);
}
public async Task LoadDataAsync(StorageFile file)
{
parser.Start = 0;
parser.Current = 0;
FontFileName = file.Name;
// Read contents of file and return a buffer.
IBuffer buffer = await FileIO.ReadBufferAsync(file);
source = new byte[buffer.Length];
// Put buffer byte info into source.
using (DataReader reader = DataReader.FromBuffer(buffer))
{
reader.ReadBytes(source);
}
offsetTable = parser.ParseOffsetTable(source);
TableRecords = new TableRecord[offsetTable.numTables];
for (int i = 0; i < TableRecords.Length; i++)
{
TableRecords[i] = parser.ReadTableRecord(source);
}
// Create a temporary list to contain the updated GlyphModel objects.
List <GlyphModel> tempList = new List <GlyphModel>();
foreach (TableRecord record in TableRecords)
{
if (record.tag == "cmap")
{
// Only supports cmap tables of format 0 or format 4.
foreach (GlyphModel currentGlyph in parser.ParseCMap(record, source))
{
// If codepoint matches known whitespace, do not append to preview list.
uint codepoint = currentGlyph.CodePoint;
if (0x0 <= codepoint && codepoint <= 0x001F || 0x7F <= codepoint && codepoint <= 0xA0 || 0x2000 <= codepoint && codepoint <= 0x200F ||
codepoint == 0x202F || codepoint == 0x205F || codepoint == 0x3000 || codepoint == 0xFEFF || codepoint == 0x20)
{
continue;
}
else
{
tempList.Add(currentGlyph);
}
}
}
else if (record.tag == "name")
{
FamilyName = parser.GetFamilyName(record, source);
// If no FamilyName is found, do not load the font.
if (FamilyName == null)
{
return;
}
}
}
// Create local font saved in temp folder.
LocalFont = "ms-appdata:///temp/" + FontFileName + "#" + FamilyName;
// Assign local font to each GlyphModel.
foreach (GlyphModel glyph in tempList)
{
glyph.FontFamily = LocalFont;
}
// Repopulate the list of all GlyphModel objects.
AllGlyphs.Clear();
foreach (GlyphModel glyph in tempList)
{
AllGlyphs.Add(glyph);
}
}
public async Task AddSvgAsync(ushort glyphID, StorageFile svgFile)
{
// Add SVG data into a buffer.
IBuffer buffer = await FileIO.ReadBufferAsync(svgFile);
byte[] svgContent = new byte[buffer.Length];
// Read buffer into bytes in svgContent.
using (DataReader reader = DataReader.FromBuffer(buffer))
{
reader.ReadBytes(svgContent);
}
// Tweak the SVG: Add glyph ID and adjust the X/Y origin in accordance with OpenType spec.
ChangeSvgOriginID(ref svgContent, glyphID);
for (int i = 0; i < TableRecords.Length; i++)
{
if (TableRecords[i].tag == "SVG ")
{
parser.AssembleSvgContent(ref TableRecords[i], ref source, svgContent, glyphID, this);
break;
}
// Checks if SVG table is not present
else if (String.Compare(TableRecords[i].tag, "SVG ", StringComparison.Ordinal) > 0)
{
// Changes offset table to reflect the addition of a new table
offsetTable = parser.UpdateOffsetTable(offsetTable, ref source);
// Changes the offsets contained in all of the table records in order to reflect the addition of a table record
parser.ChangeTableRecOffsets(TableRecords, ref source, ((sizeof(uint) * 4) * -1), 0);
byte[] newSource = new byte[source.Length + (sizeof(uint) * 6) + (sizeof(ushort) * 2)];
// Copies from the beginning of the source array to the end of the table record preceeding the location of the new SVG table record
Array.Copy(source, 0, newSource, 0, (int)(TableRecords[i].offsetOfOffset - (sizeof(uint) * 2)));
string tag = "SVG ";
byte[] svgTag = Encoding.ASCII.GetBytes((string)tag);
// Adds SVG tag for the table record
Array.Copy(svgTag, 0, newSource, (int)(TableRecords[i].offsetOfOffset - (sizeof(uint) * 2)), sizeof(uint));
byte[] checksum = BitConverter.GetBytes((uint)0);
Array.Reverse(checksum);
// Adds the checksum for the table record
Array.Copy(checksum, 0, newSource, (int)(TableRecords[i].offsetOfOffset - sizeof(uint)), sizeof(uint));
byte[] offset = BitConverter.GetBytes((uint)(source.Length + (sizeof(uint) * 4)));
Array.Reverse(offset);
// Adds the offset for the table record
Array.Copy(offset, 0, newSource, (int)(TableRecords[i].offsetOfOffset), sizeof(uint));
byte[] length = BitConverter.GetBytes((uint)((sizeof(ushort) + sizeof(uint)) * 2));
Array.Reverse(length);
// Adds the length for the table record
Array.Copy(length, 0, newSource, (int)(TableRecords[i].offsetOfOffset + sizeof(uint)), sizeof(uint));
// Copies from the beginning of the table record following the new SVG table record in the source array to the end of the source array
Array.Copy(source, (int)(TableRecords[i].offsetOfOffset - (sizeof(uint) * 2)), newSource, (int)(TableRecords[i].offsetOfOffset + (sizeof(uint) * 2)), (int)(source.Length - (TableRecords[i].offsetOfOffset - (sizeof(uint) * 2))));
byte[] version = BitConverter.GetBytes((ushort)0);
Array.Reverse(version);
// Adds the SVG table at the very end of the font file
// Copies the version number to the newSource array (0)
Array.Copy(version, 0, newSource, (int)(source.Length + (sizeof(uint) * 4)), sizeof(ushort));
byte[] svgDocIndexOffset = BitConverter.GetBytes((uint)(sizeof(ushort) + (sizeof(uint) * 2)));
Array.Reverse(svgDocIndexOffset);
// Copies the SVG Document Index Offset to the newSource array
Array.Copy(svgDocIndexOffset, 0, newSource, (int)(source.Length + (sizeof(uint) * 4) + sizeof(ushort)), sizeof(uint));
byte[] reserved = BitConverter.GetBytes((uint)0);
Array.Reverse(reserved);
// Copies reserved to th enewSource array
Array.Copy(reserved, 0, newSource, (int)(source.Length + (sizeof(uint) * 5) + sizeof(ushort)), sizeof(uint));
byte[] numEntries = BitConverter.GetBytes((ushort)0);
Array.Reverse(numEntries);
// Copies the number of SVG Document Index Entries to the newSource array (in this case just 0 because it is a new table)
Array.Copy(numEntries, 0, newSource, (int)(source.Length + (sizeof(uint) * 6) + sizeof(ushort)), sizeof(ushort));
TableRecord svg = new TableRecord();
svg.tag = "SVG ";
svg.checksum = 0;
svg.offsetOfOffset = TableRecords[i].offsetOfOffset;
svg.offset = (uint)(source.Length + (sizeof(uint) * 4));
svg.length = (uint)((sizeof(ushort) + sizeof(uint)) * 2);
source = newSource;
parser.Start = 12; // Start is 12 because the offset table is always before the table records and is always 12 bytes in length
parser.Current = 12;
TableRecords = new TableRecord[offsetTable.numTables];
for (int j = 0; j < TableRecords.Length; j++)
{
TableRecords[j] = parser.ReadTableRecord(source);
}
parser.AssembleSvgContent(ref svg, ref source, svgContent, glyphID, this);
break;
}
}
// Create an updated font file in temp folder.
StorageFolder tempFolder = ApplicationData.Current.TemporaryFolder;
StorageFile newFontFile = await tempFolder.CreateFileAsync(FontFileName, CreationCollisionOption.GenerateUniqueName);
await FileIO.WriteBytesAsync(newFontFile, source);
// Hang on to the new font file.
temporaryFontFile = newFontFile;
}
