/// <summary>
/// Gets the possible lines that may be formed from the given items.
/// </summary>
/// <param name="Start">The item to start the lines on.</param>
/// <param name="Prefered">The prefered size of a line.</param>
/// <param name="Max">The maximum size of a line.</param>
private static IEnumerable<_PlannedLine> _GetPossibleLines(List<FlowItem> Items, int Start, double Prefered, double Max, FlowBlockStyle Style)
{
int cur = Start;
int size = 0;
double len = 0.0;
bool hasline = false;
while (cur < Items.Count)
{
// Insure line does not exceed size limit
if (len - Layout.ErrorThreshold > Prefered && hasline)
{
yield break;
}
if (len - Layout.ErrorThreshold > Max)
{
yield break;
}
// Examine current item
FlowItem item = Items[cur];
// Break item
if (item == BreakFlowItem.Instance)
{
yield return new _PlannedLine
{
Length = len,
Next = cur + 1,
Size = size,
Cut = false
};
hasline = true;
cur++;
size++;
continue;
}
// Cut item
if (item == CutFlowItem.Instance)
{
yield return new _PlannedLine
{
Length = len,
Next = cur + 1,
Size = size,
Cut = true
};
yield break;
}
// Character item
CharacterFlowItem cfi = item as CharacterFlowItem;
if (cfi != null)
{
len += cfi.Font.GetSize(cfi.Name)[Style.MinorAxis];
cur++;
size++;
continue;
}
// Space item
SpaceFlowItem sfi = item as SpaceFlowItem;
if (sfi != null)
{
if (sfi.Breaking)
{
yield return new _PlannedLine
{
Length = len,
Next = cur + 1,
Size = size,
Cut = false
};
hasline = true;
}
len += sfi.Length;
cur++;
size++;
continue;
}
}
// End of items can act as a valid break
yield return new _PlannedLine
{
Length = len,
Next = Items.Count,
Size = size,
Cut = false
};
}
/// <summary>
/// Greedily creates a list of lines for a sequence of items, or returns null if not possible.
/// </summary>
/// <param name="Prefered">The prefered size of a line.</param>
/// <param name="Max">The maximum size of a line.</param>
private static List<_PlannedLine> _GetLinesGreedy(List<FlowItem> Items, double Prefered, double Max, FlowBlockStyle Style)
{
int cur = 0;
List<_PlannedLine> lines = new List<_PlannedLine>();
while (cur < Items.Count)
{
bool hasline = false;
_PlannedLine last = new _PlannedLine();
foreach(_PlannedLine line in _GetPossibleLines(Items, cur, Prefered, Max, Style))
{
hasline = true;
last = line;
}
// Exit if no lines are found.
if (!hasline)
{
return null;
}
cur = last.Next;
lines.Add(last);
}
return lines;
}
/// <summary>
/// Builds the layout lines for a list of planned lines.
/// </summary>
private static List<_Layout.Line> _BuildLayout(
List<_PlannedLine> Lines, List<FlowItem> Items, FlowBlockStyle Style,
double MinorSize, double MinMajorSize, out double MajorSize)
{
List<_Layout.Line> lines = new List<_Layout.Line>(Lines.Count);
int cur = 0;
double majoroff = 0.0;
MajorSize = 0.0;
// Build lines
foreach (_PlannedLine pl in Lines)
{
_Layout.Line line = _BuildLayoutLine(cur, pl.Size, pl.Length, pl.Cut, Items, Style, MinorSize);
lines.Add(line);
cur = pl.Next;
line.MajorOffset = majoroff;
MajorSize = majoroff + line.MajorSize;
majoroff = MajorSize + Style.LineSpacing;
}
MajorSize = Math.Max(MajorSize, MinMajorSize);
// Reverse line direction if needed
if ((int)Style.Direction % 2 > 0)
{
majoroff = MajorSize;
foreach (_Layout.Line line in lines)
{
line.MajorOffset = majoroff - line.MajorSize;
majoroff = line.MajorOffset - Style.LineSpacing;
}
}
return lines;
}
/// <summary>
/// Builds a layout line for a given subset of a list of items. The major offset of the line will not be set.
/// </summary>
/// <param name="Length">The known minimum length of the line.</param>
private static _Layout.Line _BuildLayoutLine(int Start, int Size, double Length, bool Cut, List<FlowItem> Items, FlowBlockStyle Style, double MinorSize)
{
Axis minoraxis = Style.MinorAxis;
double majorsize = Style.LineSize;
_Layout.Item[] items = new _Layout.Item[Size];
// Add visible items while determining their sizes
double totalspace = 0.0;
for (int t = 0; t < items.Length; t++)
{
FlowItem item = Items[Start++];
// Character item
CharacterFlowItem cfi = item as CharacterFlowItem;
if (cfi != null)
{
Point size = cfi.Font.GetSize(cfi.Name).Shift(Style.MinorAxis);
majorsize = Math.Max(majorsize, size.Y);
items[t] = new _Layout.Item
{
MinorSize = size.X,
Source = cfi
};
}
// Space item
SpaceFlowItem sfi = item as SpaceFlowItem;
if (sfi != null)
{
totalspace += sfi.Length;
items[t] = new _Layout.Item
{
MinorSize = sfi.Length,
Source = sfi
};
}
}
// If the flow is justified, adjust the sizes of spaces
if (Style.Justification == FlowJustification.Justify && !Cut)
{
double spacemult = (MinorSize - Length + totalspace) / totalspace;
for (int t = 0; t < items.Length; t++)
{
if (items[t].Source is SpaceFlowItem)
{
items[t].MinorSize *= spacemult;
}
}
}
// Set item offsets
if ((int)Style.Direction % 4 < 2)
{
double off = Style.Justification == FlowJustification.Center ? MinorSize * 0.5 - Length * 0.5 : 0.0;
for (int t = 0; t < items.Length; t++)
{
items[t].MinorOffset = off;
off += items[t].MinorSize;
}
}
else
{
double off = Style.Justification == FlowJustification.Center ? MinorSize * 0.5 + Length * 0.5 : MinorSize;
for (int t = 0; t < items.Length; t++)
{
off -= items[t].MinorSize;
items[t].MinorOffset = off;
}
}
return new _Layout.Line
{
MajorSize = majorsize,
Items = items
};
}
public FlowBlock(List<FlowItem> Items, FlowFit Fit, FlowBlockStyle Style)
{
this.Style = Style;
this.Fit = Fit;
this.Items = Items;
}