internal LsErr CreateLine(
int cpFirst,
int lineLength,
int maxWidth,
LineFlags lineFlags,
IntPtr previousLineBreakRecord,
out IntPtr ploline,
out LsLInfo plslineInfo,
out int maxDepth,
out LsLineWidths lineWidths
)
{
Invariant.Assert(_ploc.Value != System.IntPtr.Zero);
return(UnsafeNativeMethods.LoCreateLine(
_ploc.Value,
cpFirst,
lineLength,
maxWidth,
(uint)lineFlags, // line flags
previousLineBreakRecord,
out plslineInfo,
out ploline,
out maxDepth,
out lineWidths
));
}
private FullTextBreakpoint(
FullTextState fullText,
int firstCharIndex,
int maxLineWidth,
ref LsBreaks lsbreaks,
int breakIndex
) : this()
{
// According to antons: PTS only uses the width of a feasible break to avoid
// clipping in subpage. At the moment, there is no good solution as of how
// PTS client would be able to compute this width efficiently using LS.
// The work around - although could be conceived would simply be too slow.
// The width should therefore be set to the paragraph width for the time being.
//
// Client of text formatter would simply pass the value of TextBreakpoint.Width
// back to PTS pfnFormatLineVariants call.
LsLineWidths lineWidths = new LsLineWidths();
lineWidths.upLimLine = maxLineWidth;
lineWidths.upStartMainText = fullText.TextStore.Settings.TextIndent;
lineWidths.upStartMarker = lineWidths.upStartMainText;
lineWidths.upStartTrailing = lineWidths.upLimLine;
lineWidths.upMinStartTrailing = lineWidths.upStartTrailing;
// construct the correspondent text metrics
unsafe
{
_metrics.Compute(
fullText,
firstCharIndex,
maxLineWidth,
null, // collapsingSymbol
ref lineWidths,
&lsbreaks.plslinfoArray[breakIndex]
);
_ploline = new SecurityCriticalDataForSet <IntPtr>(lsbreaks.pplolineArray[breakIndex]);
// keep the line penalty handle
_penaltyResource = new SecurityCriticalDataForSet <IntPtr>(lsbreaks.plinepenaltyArray[breakIndex]);
if (lsbreaks.plslinfoArray[breakIndex].fForcedBreak != 0)
{
_isLineTruncated = true;
}
}
}
private double _pixelsPerDip; // PixelsPerDip
/// <summary>
/// Construct text metrics from full text info
/// </summary>
/// <remarks>
///
/// When the application formats a line of text. It starts from the leading edge of the paragraph - the reference position
/// called "Paragraph Start". It gives the width of the paragraph or "Paragraph Width" to TextFormatter as one of the main
/// parameters to TextFormatter.FormatLine method. It may also provide additional info about how it wants the line to look
/// like. The following are all of such info and how the formatting process is carried on inside TextFormatter.
///
///
/// *** Indent/Paragraph Indent ***
/// The application may specify "Indent" - the distance from the beginning of the line to the beginning of the text in that
/// line. The value is sent to TextFormatter via [TextParagraphProperties.Indent]. It may also specify "Paragraph Indent"
/// - the distance from the beginning of the paragraph to the beginning of the line [TextParagraphProperties.ParagraphIndent].
/// The usage of paragraph indent is to offset the beginning of the line relative to the paragraph starting point, while
/// indent is to offset the beginning of text realtive to the line starting point. Paragraph indent is not included as part
/// of the line width while indent is.
///
///
/// *** Text Alignment ***
/// "Text Alignment" [TextParagraphProperties.TextAlignment] may be specified to align the leading, center or trailing edge
/// of the line to the leading, center or trailing edge of the paragraph excluding paragraph indent.
///
///
/// *** Bullet/Auto-numbering ***
/// The application may also specify "bullet" (or "marker") for the line. Marker does not affect the layout measurement of the
/// line. Line with marker has the same line width with the line that has not. The presence of marker however affects the
/// pixel-wise black width of the line. The application specifies the distance from the beginning of the line to the trailing
/// edge of the marker symbol via the property [TextMarkerProperties.Offset]. The application can create the visual effect of
/// having marker embedded inside the body of paragraph text (so-called "marker inside") by specifying a positive indent so
/// that the text starts after the beginning of the line and a positive smaller amount of marker offset to place the marker
/// symbol at between the beginning of the line and the beginning of the text. The "marker outside" visual effect can
/// also be achieved in a similar manner by specifying zero or positive indent value with negative marker offset value.
///
///
/// *** Formatted Line Properties ***
/// Once the line formatting process is completed and a line is returned to the application. The application determines the
/// distance from the paragraph starting point to the actual beginning of the line by looking at the "Line Start" property of
/// the text line [TextLine.Start]. The "Width" of the line can be determined, naturally, from the property [TextLine.Width].
/// The property value [TextLine.OverhangLeading] represents the distance from the beginning of the line, or the line's alignment
/// point, to the first leading pixel of that line so-called the "Black Start". The property [TextLine.OverhangTrailing]
/// is the distance from the last trailing pixel of the line to the trailing edge alignment point of the line. The application
/// uses these "overhang" or "overshoot" values to ensure proper positioning of text that avoids pixel clipping of the
/// glyph image. A less sophisticated application may provide reasonable leading and trailing margin around the text line
/// and ignores these properties altogether.
///
///
/// *** Hit-Testing ***
/// The application may also perform hit-testing by calling methods on TextLine. All the distances involved in hit-testing
/// operations are distances from the paragraph start, not from the line start. Marker symbol on its own is not hit-testable.
///
///
/// *** Tabs ***
/// The application may specify tab stops - an array of positions to where text aligns. Each tab stop may have different
/// "Tab Alignment". The left, center and right tab alignment aligns the tab stop position to the leading, center and the
/// trailing edge of the text following the tab character. "Tab Leader" may also be specified to fill the distance occupied
/// by the presence of tab character with the symbol of choice. Tab stops is specified thru the property [TextParagraph.Tabs].
/// In the absence of tab stops, the application may assume an automatic tab stop - so called "Incremental Tab" specified by
/// the property [TextParagraphProperties.DefaultIncrementalTab]. The property could be overridden, by default the value
/// is set by TextFormatter to 4 em of the paragraph's default font.
///
///
/// *** Line Services Properties ***
/// TextFormatter relies on LS to calculate the distance from the beginning of the line to the beginning of text or "Text Start"
/// and keep it in the private property [this._textStart]. This value is non-zero when 1) the line starts with indentation or
/// 2) the line starts with marker - either bullet or auto-numbering symbol.
///
/// In case of the line with marker, LS also produces the distance from the beginning of the line to the beginning of the marker
/// symbol, but TextFormatter does not retain that distance because marker is outside the line. The application is assumed
/// responsibility to make sure the marker symbol is not going to be clipped out. The application achieves that by manipulating
/// the indent value along with the marker offset value.
///
/// TextFormatter also retains the total "Text Width" value computed by LS in the private property [this._textWidth]. This
/// is the distance from the beginning of the text to the end including all trailing whitespaces at the end of the line. The
/// similar value but with trailing whitespaces excluded is kept in the private property [this._textWidthAtTrailing].
///
/// TextFormatter starts formatting a LS line by assuming the beginning of the line being at an imaginary origin. It then
/// places the starting point of the content depending on whether the line has either marker symbol or indent. The actual
/// mechanism for the placement is in FetchLineProps callback where the value [LsLineProps.durLeft] represents the distance
/// relative to the line's origin where actual content begins. The distances can either be positive or negative. Negative
/// distance runs in the reverse direction from the direction of text flow. When a negative indent or marker offset is
/// specified, durLeft is set to negative distance relative to line start.
///
/// TextFormatter however does not rely on LS for the whole line's text alignment. It always formats LS as if the line is
/// left-aligned. Once the distances of the line are received, it aligns the whole line according to the text alignment setting
/// specified by the application, outside the LS call. The result of this aligning process is a distance from the beginning of
/// the paragraph to the beginning of text and is kept in a private property [this._paragraphToText].
///
/// </remarks>
internal unsafe void Compute(
FullTextState fullText,
int firstCharIndex,
int paragraphWidth,
FormattedTextSymbols collapsingSymbol,
ref LsLineWidths lineWidths,
LsLInfo *plsLineInfo
)
{
_formatter = fullText.Formatter;
TextStore store = fullText.TextStore;
_pixelsPerDip = store.Settings.TextSource.PixelsPerDip;
// obtain position of important distances
_textStart = lineWidths.upStartMainText;
_textWidthAtTrailing = lineWidths.upStartTrailing;
_textWidth = lineWidths.upLimLine;
// append line end collapsing symbol if any
if (collapsingSymbol != null)
{
AppendCollapsingSymbolWidth(TextFormatterImp.RealToIdeal(collapsingSymbol.Width));
}
// make all widths relative to text start
_textWidth -= _textStart;
_textWidthAtTrailing -= _textStart;
// keep the newline character count if any
_cchNewline = store.CchEol;
// count text and dependant characters
_lscpLim = plsLineInfo->cpLimToContinue;
_lastRun = fullText.CountText(_lscpLim, firstCharIndex, out _cchLength);
Debug.Assert(_cchLength > 0);
if (plsLineInfo->endr != LsEndRes.endrEndPara &&
plsLineInfo->endr != LsEndRes.endrSoftCR)
{
// endrEndPara denotes that the line ends at paragraph end. It is a result of submitting Paragraph Separator to LS.
// endrSoftCR denotes end of line but not end of paragraph. This is a result of submitting Line Separator to LS.
_cchNewline = 0;
if (plsLineInfo->dcpDepend >= 0)
{
// According to SergeyGe [2/16/2006], dcpDepend reported from LS cannot made precise when considering
// the line ending with hyphenation - this is because LS does not have the knowledge about the amount
// of text, after the hyphenation point, being examined by its client during the process of finding
// the right place to hyphenate. LS client must therefore take into account the number of lookahead
// LSCP examined by hyphenator when computing the correct dcpDepend for the line. In our implementation
// it would just mean we take the max of the two values.
int lscpFirstIndependence = Math.Max(
plsLineInfo->cpLimToContinue + plsLineInfo->dcpDepend,
fullText.LscpHyphenationLookAhead
);
fullText.CountText(lscpFirstIndependence, firstCharIndex, out _cchDepend);
_cchDepend -= _cchLength;
}
}
ParaProp pap = store.Pap;
if (_height <= 0)
{
// if height has not been settled,
// calculate line height and baseline offset
if (pap.LineHeight > 0)
{
// Host specifies line height, honor it.
_height = pap.LineHeight;
_baselineOffset = (int)Math.Round(
_height
* pap.DefaultTypeface.Baseline(pap.EmSize, Constants.DefaultIdealToReal, _pixelsPerDip, fullText.TextFormattingMode)
/ pap.DefaultTypeface.LineSpacing(pap.EmSize, Constants.DefaultIdealToReal, _pixelsPerDip, fullText.TextFormattingMode)
);
}
if (plsLineInfo->dvrMultiLineHeight == int.MaxValue)
{
// Line is empty so text height and text baseline are based on the default typeface;
// it doesn't make sense even for an emtpy line to have zero text height
_textAscent = (int)Math.Round(pap.DefaultTypeface.Baseline(pap.EmSize, Constants.DefaultIdealToReal, _pixelsPerDip, fullText.TextFormattingMode));
_textHeight = (int)Math.Round(pap.DefaultTypeface.LineSpacing(pap.EmSize, Constants.DefaultIdealToReal, _pixelsPerDip, fullText.TextFormattingMode));
}
else
{
_textAscent = plsLineInfo->dvrAscent;
_textHeight = _textAscent + plsLineInfo->dvrDescent;
if (fullText.VerticalAdjust)
{
// Line requires vertical repositioning of text runs
store.AdjustRunsVerticalOffset(
plsLineInfo->cpLimToContinue - firstCharIndex,
_height,
_baselineOffset,
out _textHeight,
out _textAscent
);
}
}
// if the client hasn't specified a line height then the line height and baseline
// are the same as the text height and text baseline
if (_height <= 0)
{
_height = _textHeight;
_baselineOffset = _textAscent;
}
}
// Text alignment aligns the line to correspondent paragraph alignment start edge
switch (pap.Align)
{
case TextAlignment.Right:
// alignment rule:
// "The sum of paragraph start to line start and line width is equal to paragraph width"
//
// PTL + LW = PW
// (PTT - LTT) + (LTT + TW) = PW
// (thus) PTT = PW - TW
_paragraphToText = paragraphWidth - _textWidthAtTrailing;
break;
case TextAlignment.Center:
// alignment rule:
// "The sum of paragraph start to line start and half the line width is equal to half the paragraph width"
//
// PTL + 0.5*LW = 0.5*PW
// (PTT - LTT) + 0.5*(LTT + TW) = 0.5*PW
// (thus) PTT = 0.5 * (PW + LTT - TW)
_paragraphToText = (int)Math.Round((paragraphWidth + _textStart - _textWidthAtTrailing) * 0.5);
break;
default:
// alignment rule:
// "Paragraph start to line start is paragraph indent"
//
// PTL = PI
// PTT - LTT = PI
// (thus) PTT = PI + LTT
_paragraphToText = pap.ParagraphIndent + _textStart;
break;
}
}