// corner sase: if two cells end up on the same row (a.Row + a.RowSpan = b.Row + b.RowSpan),
// bottom edges of their bounding boxes should be at the same level
static void AdjustCellSizes(ICollection <TableCellRenderingCommand> commands, DynamicDictionary <int, float> rowBottomOffsets)
{
foreach (var command in commands)
{
var lastRow = command.Cell.Row + command.Cell.RowSpan - 1;
var height = rowBottomOffsets[lastRow] - command.Offset.Y;
command.Size = new Size(command.Size.Width, height);
command.Offset = new Position(command.Offset.X, rowBottomOffsets[command.Cell.Row - 1]);
}
}
ICollection <TableCellRenderingCommand> GetRenderingCommands()
{
var rowBottomOffsets = new DynamicDictionary <int, float>();
var commands = new List <TableCellRenderingCommand>();
var cellsToTry = Cells.Where(x => x.Row + x.RowSpan - 1 >= CurrentRow);
var currentRow = CurrentRow;
var maxRenderingRow = RowsCount;
foreach (var cell in cellsToTry)
{
// update position of previous row
if (cell.Row > currentRow)
{
rowBottomOffsets[currentRow] = Math.Max(rowBottomOffsets[currentRow], rowBottomOffsets[currentRow - 1]);
if (rowBottomOffsets[currentRow - 1] > availableSpace.Height + Size.Epsilon)
{
break;
}
foreach (var row in Enumerable.Range(cell.Row, cell.Row - currentRow))
{
rowBottomOffsets[row] = Math.Max(rowBottomOffsets[row - 1], rowBottomOffsets[row]);
}
currentRow = cell.Row;
}
// cell visibility optimizations
if (cell.Row > maxRenderingRow)
{
break;
}
// calculate cell position / size
var topOffset = rowBottomOffsets[cell.Row - 1];
var availableWidth = GetCellWidth(cell);
var availableHeight = availableSpace.Height - topOffset;
var availableCellSize = new Size(availableWidth, availableHeight);
var cellSize = cell.Measure(availableCellSize);
// corner case: if cell within the row is not fully rendered, do not attempt to render next row
if (cellSize.Type == SpacePlanType.PartialRender)
{
maxRenderingRow = Math.Min(maxRenderingRow, cell.Row + cell.RowSpan - 1);
}
// corner case: if cell within the row want to wrap to the next page, do not attempt to render this row
if (cellSize.Type == SpacePlanType.Wrap)
{
maxRenderingRow = Math.Min(maxRenderingRow, cell.Row - 1);
continue;
}
// update position of the last row that cell occupies
var bottomRow = cell.Row + cell.RowSpan - 1;
rowBottomOffsets[bottomRow] = Math.Max(rowBottomOffsets[bottomRow], topOffset + cellSize.Height);
// accept cell to be rendered
commands.Add(new TableCellRenderingCommand()
{
Cell = cell,
Measurement = cellSize,
Size = new Size(availableWidth, cellSize.Height),
Offset = new Position(columnOffsets[cell.Column - 1], topOffset)
});
}
if (!commands.Any())
{
return(commands);
}
var maxRow = commands.Select(x => x.Cell).Max(x => x.Row + x.RowSpan);
foreach (var row in Enumerable.Range(CurrentRow, maxRow - CurrentRow))
{
rowBottomOffsets[row] = Math.Max(rowBottomOffsets[row - 1], rowBottomOffsets[row]);
}
AdjustCellSizes(commands, rowBottomOffsets);
// corner case: reject cell if other cells within the same row are rejected
return(commands.Where(x => x.Cell.Row <= maxRenderingRow).ToList());
}
