/// <summary>
/// Measures the size of the provided string at the specified font size (starting at a specific offset),
/// stopping when the available space is full and returning the number of characters fitted.
/// </summary>
/// <param name="encoding">The encoding to use to map the characters</param>
/// <param name="s">The string to measure the size of</param>
/// <param name="startOffset">The starting (zero based) offset in that string to start measuring from</param>
/// <param name="emsize">The M size in font units</param>
/// <param name="availablePts">The max width allowed for this string</param>
/// <param name="wordspace">The spacing between words in font units. Default 0</param>
/// <param name="charspace">The spacing between characters in font units. Default 0</param>
/// <param name="hscale">The horizontal scaling of all characters. Default 100</param>
/// <param name="vertical">If true then this is vertical writing</param>
/// <param name="wordboundary">If True the measuring will stop at a boundary to a word rather than character.</param>
/// <param name="charsfitted">Set to the number of characters that can be renered at this size within the width.</param>
/// <returns></returns>
public LineSize MeasureString(CMapEncoding encoding, string s, int startOffset, double emsize, double availablePts, double?wordspacePts, double charspacePts, double hscale, bool vertical, bool wordboundary, out int charsfitted, FontUnitType useUnits = FontUnitType.UseFontPreference)
{
HorizontalMetrics table = this.Directories["hmtx"].Table as HorizontalMetrics;
CMAPTable cmap = this.Directories["cmap"].Table as CMAPTable;
OS2Table os2 = this.Directories["OS/2"].Table as OS2Table;
CMAPSubTable mac = cmap.GetOffsetTable(encoding);
if (mac == null)
{
mac = cmap.GetOffsetTable(CMapEncoding.MacRoman);
}
HorizontalHeader hhead = this.Directories["hhea"].Table as HorizontalHeader;
FontHeader head = this.Directories["head"].Table as FontHeader;
double availableFU = availablePts * ((double)head.UnitsPerEm / emsize);
double charspaceFU = NoCharacterSpace;
if (charspacePts != NoCharacterSpace)
{
charspaceFU = charspacePts * ((double)head.UnitsPerEm / emsize);
}
double wordspaceFU = NoWordSpace;
if (wordspacePts.HasValue)
{
wordspaceFU = (wordspacePts.Value * ((double)head.UnitsPerEm / emsize));
}
else if (charspacePts != NoCharacterSpace)
{
//If we dont have explicit wordspacing then we use the character spacing
wordspaceFU = charspaceFU;
}
double len = 0.0;
double lastwordlen = 0.0;
int lastwordcount = 0;
charsfitted = 0;
for (int i = startOffset; i < s.Length; i++)
{
char c = s[i];
if (char.IsWhiteSpace(c))
{
lastwordlen = len;
lastwordcount = charsfitted;
}
int moffset = (int)mac.GetCharacterGlyphOffset(c);
if (moffset >= table.HMetrics.Count)
{
moffset = table.HMetrics.Count - 1;
}
Scryber.OpenType.SubTables.HMetric metric;
metric = table.HMetrics[moffset];
double w = metric.AdvanceWidth;
if (i == 0)
{
w -= metric.LeftSideBearing;
}
if (c == ' ')
{
if (wordspaceFU != NoWordSpace)
{
w += wordspaceFU;
}
}
else if (charspaceFU != NoCharacterSpace)
{
w += charspaceFU;
}
if (hscale != NoHorizontalScale)
{
w *= hscale;
}
len += w;
//check if we can fit more
if (len > availableFU)
{
len -= w;
break;
}
charsfitted++;
}
bool isboundary = false;
if ((charsfitted + startOffset < s.Length) && wordboundary && lastwordlen > 0)
{
len = lastwordlen;
charsfitted = lastwordcount;
isboundary = true;
}
len = len * emsize;
len = len / (double)head.UnitsPerEm;
double h = GetLineHeight(useUnits, os2, hhead, head, emsize);
return(new LineSize(len, h, charsfitted, startOffset, isboundary));
}
public LineSize MeasureString(CMapEncoding encoding, string s, int startOffset, double emsize, double available, bool wordboundary, out int charsfitted, FontUnitType useUnits = FontUnitType.UseFontPreference)
{
HorizontalMetrics table = this.Directories["hmtx"].Table as HorizontalMetrics;
CMAPTable cmap = this.Directories["cmap"].Table as CMAPTable;
OS2Table os2 = this.Directories["OS/2"].Table as OS2Table;
CMAPSubTable mac = cmap.GetOffsetTable(encoding);
if (mac == null)
{
mac = cmap.GetOffsetTable(CMapEncoding.MacRoman);
}
HorizontalHeader hhead = this.Directories["hhea"].Table as HorizontalHeader;
FontHeader head = this.Directories["head"].Table as FontHeader;
available = (available * head.UnitsPerEm) / emsize;
double len = 0.0;
double lastwordlen = 0.0;
int lastwordcount = 0;
charsfitted = 0;
for (int i = startOffset; i < s.Length; i++)
{
char c = s[i];
if (char.IsWhiteSpace(c))
{
lastwordlen = len;
lastwordcount = charsfitted;
}
int moffset = (int)mac.GetCharacterGlyphOffset(c);
//System.Diagnostics.Debug.WriteLine("Character '" + chars[i].ToString() + "' (" + ((byte)chars[i]).ToString() + ") has offset '" + moffset.ToString() + "' in mac encoding and '" + woffset + "' in windows encoding");
if (moffset >= table.HMetrics.Count)
{
moffset = table.HMetrics.Count - 1;
}
Scryber.OpenType.SubTables.HMetric metric;
metric = table.HMetrics[moffset];
if (i == 0)
{
len = -metric.LeftSideBearing;
}
len += metric.AdvanceWidth;
//check if we can fit more
if (len > available)
{
len -= metric.AdvanceWidth;
break;
}
charsfitted++;
}
bool isboundary = false;
if ((charsfitted + startOffset < s.Length) && wordboundary && lastwordlen > 0)
{
len = lastwordlen;
charsfitted = lastwordcount;
isboundary = true;
}
len = len / (double)head.UnitsPerEm;
len = len * emsize;
double h = GetLineHeight(useUnits, os2, hhead, head, emsize);
return(new LineSize((float)len, (float)h, charsfitted, startOffset, isboundary));
}
public double MeasureChars(string chars, int startOffset, double emsize, double available, bool wordboundary, out int fitted)
{
int totalUnits = (int)Math.Floor((available * this.FUnitsPerEm) / emsize);
int measured = 0;
int count = 0;
int lastWordLen = 0;
int lastWordCount = 0;
for (int i = startOffset; i < chars.Length; i++)
{
char c = chars[i];
if (char.IsWhiteSpace(c))
{
lastWordLen = measured;
lastWordCount = count;
}
HMetric metric;
if (_lookup.TryGetValue(c, out metric) == false)
{
int moffset = _offsets.GetCharacterGlyphOffset(c);
if (moffset >= _metrics.Count)
{
moffset = _metrics.Count - 1;
}
metric = _metrics[moffset];
_lookup.Add(c, metric);
}
if (i == 0)
{
measured -= metric.LeftSideBearing;
}
measured += metric.AdvanceWidth;
if (measured > totalUnits)
{
measured -= metric.AdvanceWidth;
break;
}
else
{
count++;
}
}
if (count + startOffset < chars.Length)
{
if (wordboundary && lastWordLen > 0)
{
//Not everything fitted so go bask to the last full word
//(if there was one).
measured = lastWordLen;
count = lastWordCount;
}
}
double w = (measured * emsize) / (double)_unitsPerEm;
fitted = count;
return(w);
}