/// <summary>
/// Advances the layout state to the next line of text after inserting a line break character at the end of the current line.
/// </summary>
/// <param name="output">The <see cref="TextLayoutCommandStream"/> which is being populated.</param>
/// <param name="length">The number of characters in the line break.</param>
/// <param name="settings">The current layout settings.</param>
public void AdvanceLayoutToNextLineWithBreak(TextLayoutCommandStream output, Int32 length, ref TextLayoutSettings settings)
{
var lineSpacing = settings.Font.GetFace(SpriteFontStyle.Regular).LineSpacing;
var lineHeightCurrent = lineHeight;
if (lineHeightCurrent == 0)
{
lineHeightCurrent = lineSpacing;
}
output.WriteLineBreak(new TextLayoutLineBreakCommand(length));
AdvanceLineToNextCommand(0, lineHeightCurrent, 1, length, isLineBreak: true);
AdvanceLayoutToNextLine(output, ref settings);
AdvanceLineToNextCommand(0, 0, 0, 0);
lineHeightTentative = lineSpacing;
}
/// <summary>
/// Accumulates sequential text tokens into a single text command.
/// </summary>
private Boolean AccumulateText(TextParserTokenStream input, TextLayoutCommandStream output, SpriteFontFace font, ref Int32 index, ref LayoutState state, ref TextLayoutSettings settings)
{
var hyphenate = (settings.Options & TextLayoutOptions.Hyphenate) == TextLayoutOptions.Hyphenate;
var availableWidth = (settings.Width ?? Int32.MaxValue);
var x = state.PositionX;
var y = state.PositionY;
var width = 0;
var height = 0;
var accumulatedStart = input[index].Text.Start + (state.ParserTokenOffset ?? 0);
var accumulatedLength = 0;
var accumulatedCount = 0;
var lineOverflow = false;
var lineBreakPossible = false;
var tokenText = default(StringSegment);
var tokenNext = default(TextParserToken?);
var tokenSize = default(Size2);
var tokenKerning = 0;
var tokenIsBreakingSpace = false;
while (index < input.Count)
{
var token = input[index];
if (token.TokenType != TextParserTokenType.Text || token.IsNewLine)
{
break;
}
if (!IsSegmentForCurrentSource(token.Text))
{
if (accumulatedCount > 0)
{
break;
}
EmitChangeSourceIfNecessary(input, output, ref token);
}
tokenText = token.Text.Substring(state.ParserTokenOffset ?? 0);
tokenNext = GetNextTextToken(input, index);
tokenSize = MeasureToken(font, token.TokenType, tokenText, tokenNext);
tokenKerning = font.Kerning.Get(tokenText[tokenText.Length - 1], ' ');
// NOTE: We assume in a couple of places that tokens sizes don't exceed Int16.MaxValue, so try to
// avoid accumulating tokens larger than that just in case somebody is doing something dumb
if (width + tokenSize.Width > Int16.MaxValue)
{
break;
}
if (token.IsWhiteSpace && (state.LineBreakCommand == null || !token.IsNonBreakingSpace))
{
lineBreakPossible = true;
state.LineBreakCommand = output.Count;
state.LineBreakOffset = accumulatedLength + token.Text.Length - 1;
tokenIsBreakingSpace = true;
}
else
{
tokenIsBreakingSpace = false;
}
// For most tokens we need to bail out here if there's a line overflow, but
// if it's a breaking space we need to be sure that it's part of the command stream
// so that we can go back and replace it in the line break phase!
var overflowsLine = state.PositionX + tokenSize.Width - tokenKerning > availableWidth;
if (overflowsLine && !tokenIsBreakingSpace)
{
lineOverflow = true;
break;
}
if (tokenText.Start != accumulatedStart + accumulatedLength)
{
break;
}
width = width + tokenSize.Width;
height = Math.Max(height, tokenSize.Height);
accumulatedLength = accumulatedLength + tokenText.Length;
accumulatedCount++;
state.AdvanceLineToNextCommand(tokenSize.Width, tokenSize.Height, 1, tokenText.Length);
state.ParserTokenOffset = 0;
state.LineLengthInCommands--;
index++;
// At this point, we need to bail out even for breaking spaces.
if (overflowsLine && tokenIsBreakingSpace)
{
lineOverflow = true;
break;
}
}
if (lineBreakPossible)
{
var preLineBreakTextStart = accumulatedStart;
var preLineBreakTextLength = state.LineBreakOffset.Value;
var preLineBreakText = CreateStringSegmentFromCurrentSource(preLineBreakTextStart, preLineBreakTextLength);
var preLineBreakSize = (preLineBreakText.Length == 0) ? Size2.Zero :
MeasureToken(font, TextParserTokenType.Text, preLineBreakText);
state.BrokenTextSizeBeforeBreak = preLineBreakSize;
var postLineBreakStart = accumulatedStart + (state.LineBreakOffset.Value + 1);
var postLineBreakLength = accumulatedLength - (state.LineBreakOffset.Value + 1);
var postLineBreakText = CreateStringSegmentFromCurrentSource(postLineBreakStart, postLineBreakLength);
var postLineBreakSize = (postLineBreakText.Length == 0) ? Size2.Zero :
MeasureToken(font, TextParserTokenType.Text, postLineBreakText, GetNextTextToken(input, index - 1));
state.BrokenTextSizeAfterBreak = postLineBreakSize;
}
var bounds = new Rectangle(x, y, width, height);
EmitTextIfNecessary(output, accumulatedStart, accumulatedLength, ref bounds, ref state);
if (lineOverflow && !state.ReplaceLastBreakingSpaceWithLineBreak(output, ref settings))
{
var overflowingToken = input[index];
if (overflowingToken.IsWhiteSpace && !overflowingToken.IsNonBreakingSpace)
{
output.WriteLineBreak(new TextLayoutLineBreakCommand(1));
state.AdvanceLineToNextCommand(0, 0, 1, 1, isLineBreak: true);
state.AdvanceLayoutToNextLine(output, ref settings);
if (overflowingToken.Text.Length > 1)
{
state.ParserTokenOffset = 1;
}
else
{
index++;
}
return(true);
}
if (!GetFittedSubstring(font, availableWidth, ref tokenText, ref tokenSize, ref state, hyphenate) && state.LineWidth == 0)
{
return(false);
}
var overflowingTokenBounds = (tokenText.Length == 0) ? Rectangle.Empty :
new Rectangle(state.PositionX, state.PositionY, tokenSize.Width, tokenSize.Height);
var overflowingTextEmitted = EmitTextIfNecessary(output, tokenText.Start, tokenText.Length, ref overflowingTokenBounds, ref state);
if (overflowingTextEmitted)
{
state.AdvanceLineToNextCommand(tokenSize.Width, tokenSize.Height, 0, tokenText.Length);
if (hyphenate)
{
output.WriteHyphen();
state.AdvanceLineToNextCommand(0, 0, 1, 0);
}
}
state.ParserTokenOffset = (state.ParserTokenOffset ?? 0) + tokenText.Length;
state.AdvanceLayoutToNextLine(output, ref settings);
}
return(true);
}
/// <summary>
/// Accumulates sequential text tokens into a single text command.
/// </summary>
private Boolean AccumulateText(TextParserTokenStream input, TextLayoutCommandStream output, SpriteFontFace font, ref Int32 index, ref LayoutState state, ref TextLayoutSettings settings)
{
var hyphenate = (settings.Options & TextLayoutOptions.Hyphenate) == TextLayoutOptions.Hyphenate;
var availableWidth = (settings.Width ?? Int32.MaxValue);
var x = state.PositionX;
var y = state.PositionY;
var width = 0;
var height = 0;
var accumulatedStart = input[index].Text.Start + (state.ParserTokenOffset ?? 0);
var accumulatedLength = 0;
var accumulatedCount = 0;
var lineOverflow = false;
var lineBreakPossible = false;
var tokenText = default(StringSegment);
var tokenNext = default(TextParserToken?);
var tokenSize = default(Size2);
while (index < input.Count)
{
var token = input[index];
if (token.TokenType != TextParserTokenType.Text || token.IsNewLine)
break;
if (!IsSegmentForCurrentSource(token.Text))
{
if (accumulatedCount > 0)
break;
EmitChangeSourceIfNecessary(input, output, ref token);
}
tokenText = token.Text.Substring(state.ParserTokenOffset ?? 0);
tokenNext = GetNextTextToken(input, index);
tokenSize = MeasureToken(font, token.TokenType, tokenText, tokenNext);
// NOTE: We assume in a couple of places that tokens sizes don't exceed Int16.MaxValue, so try to
// avoid accumulating tokens larger than that just in case somebody is doing something dumb
if (width + tokenSize.Width > Int16.MaxValue)
break;
var overflowsLine = state.PositionX + tokenSize.Width > availableWidth;
if (overflowsLine)
{
lineOverflow = true;
break;
}
if (tokenText.Start != accumulatedStart + accumulatedLength)
break;
if (token.IsWhiteSpace && (state.LineBreakCommand == null || !token.IsNonBreakingSpace))
{
lineBreakPossible = true;
state.LineBreakCommand = output.Count;
state.LineBreakOffset = accumulatedLength + token.Text.Length - 1;
}
width = width + tokenSize.Width;
height = Math.Max(height, tokenSize.Height);
accumulatedLength = accumulatedLength + tokenText.Length;
accumulatedCount++;
state.AdvanceLineToNextCommand(tokenSize.Width, tokenSize.Height, 1, tokenText.Length);
state.ParserTokenOffset = 0;
state.LineLengthInCommands--;
index++;
}
if (lineBreakPossible)
{
var preLineBreakTextStart = accumulatedStart;
var preLineBreakTextLength = state.LineBreakOffset.Value;
var preLineBreakText = CreateStringSegmentFromCurrentSource(preLineBreakTextStart, preLineBreakTextLength);
var preLineBreakSize = (preLineBreakText.Length == 0) ? Size2.Zero :
MeasureToken(font, TextParserTokenType.Text, preLineBreakText);
state.BrokenTextSizeBeforeBreak = preLineBreakSize;
var postLineBreakStart = accumulatedStart + (state.LineBreakOffset.Value + 1);
var postLineBreakLength = accumulatedLength - (state.LineBreakOffset.Value + 1);
var postLineBreakText = CreateStringSegmentFromCurrentSource(postLineBreakStart, postLineBreakLength);
var postLineBreakSize = (postLineBreakText.Length == 0) ? Size2.Zero :
MeasureToken(font, TextParserTokenType.Text, postLineBreakText, GetNextTextToken(input, index - 1));
state.BrokenTextSizeAfterBreak = postLineBreakSize;
}
var bounds = new Rectangle(x, y, width, height);
EmitTextIfNecessary(output, accumulatedStart, accumulatedLength, ref bounds, ref state);
if (lineOverflow && !state.ReplaceLastBreakingSpaceWithLineBreak(output, ref settings))
{
var overflowingToken = input[index];
if (overflowingToken.IsWhiteSpace && !overflowingToken.IsNonBreakingSpace)
{
output.WriteLineBreak(new TextLayoutLineBreakCommand(1));
state.AdvanceLineToNextCommand(0, 0, 1, 1, isLineBreak: true);
state.AdvanceLayoutToNextLine(output, ref settings);
if (overflowingToken.Text.Length > 1)
{
state.ParserTokenOffset = 1;
}
else
{
index++;
}
return true;
}
if (!GetFittedSubstring(font, availableWidth, ref tokenText, ref tokenSize, ref state, hyphenate) && state.LineWidth == 0)
return false;
var overflowingTokenBounds = (tokenText.Length == 0) ? Rectangle.Empty :
new Rectangle(state.PositionX, state.PositionY, tokenSize.Width, tokenSize.Height);
var overflowingTextEmitted = EmitTextIfNecessary(output, tokenText.Start, tokenText.Length, ref overflowingTokenBounds, ref state);
if (overflowingTextEmitted)
{
state.AdvanceLineToNextCommand(tokenSize.Width, tokenSize.Height, 0, tokenText.Length);
if (hyphenate)
{
output.WriteHyphen();
state.AdvanceLineToNextCommand(0, 0, 1, 0);
}
}
state.ParserTokenOffset = (state.ParserTokenOffset ?? 0) + tokenText.Length;
state.AdvanceLayoutToNextLine(output, ref settings);
}
return true;
}
/// <summary>
/// Advances the layout state to the next line of text after inserting a line break character at the end of the current line.
/// </summary>
/// <param name="output">The <see cref="TextLayoutCommandStream"/> which is being populated.</param>
/// <param name="length">The number of characters in the line break.</param>
/// <param name="settings">The current layout settings.</param>
public void AdvanceLayoutToNextLineWithBreak(TextLayoutCommandStream output, Int32 length, ref TextLayoutSettings settings)
{
var lineSpacing = settings.Font.GetFace(SpriteFontStyle.Regular).LineSpacing;
var lineHeightCurrent = lineHeight;
if (lineHeightCurrent == 0)
lineHeightCurrent = lineSpacing;
output.WriteLineBreak(new TextLayoutLineBreakCommand(length));
AdvanceLineToNextCommand(0, lineHeightCurrent, 1, length, isLineBreak: true);
AdvanceLayoutToNextLine(output, ref settings);
AdvanceLineToNextCommand(0, 0, 0, 0);
lineHeightTentative = lineSpacing;
}