public IEnumerable <TextLine> DivideTextItemsIntoLines(float availableWidth, float availableHeight)
{
var queue = new Queue <ITextBlockItem>(RenderingQueue);
var currentItemIndex = CurrentElementIndex;
var currentHeight = 0f;
while (queue.Any())
{
var line = GetNextLine();
if (!line.Elements.Any())
{
yield break;
}
if (currentHeight + line.LineHeight > availableHeight + Size.Epsilon)
{
yield break;
}
currentHeight += line.LineHeight;
yield return(line);
}
TextLine GetNextLine()
{
var currentWidth = 0f;
var currentLineElements = new List <TextLineElement>();
while (true)
{
if (!queue.Any())
{
break;
}
var currentElement = queue.Peek();
var measurementRequest = new TextMeasurementRequest
{
Canvas = Canvas,
PageContext = PageContext,
StartIndex = currentItemIndex,
AvailableWidth = availableWidth - currentWidth,
IsFirstElementInBlock = currentElement == Items.First(),
IsFirstElementInLine = !currentLineElements.Any()
};
var measurementResponse = currentElement.Measure(measurementRequest);
if (measurementResponse == null)
{
break;
}
currentLineElements.Add(new TextLineElement
{
Item = currentElement,
Measurement = measurementResponse
});
currentWidth += measurementResponse.Width;
currentItemIndex = measurementResponse.NextIndex;
if (!measurementResponse.IsLast)
{
break;
}
currentItemIndex = 0;
queue.Dequeue();
}
return(TextLine.From(currentLineElements));
}
}