public static int GetStringAvailableIndex(MeasureFontRequest req)
{
if (string.IsNullOrEmpty(req.Input))
{
return(-1);
}
var cloneReq = req.Clone();
var availableSize = req.AvailableSize.Width * req.AvailableSize.Height;
var maxCharNum = req.Input.Length;
//判断宽高是否为一个可读数
int availableSizeInt;
if (Int32.TryParse(availableSize.ToString(), out availableSizeInt))
{
//一个字符的宽高
cloneReq.Input = "a";
cloneReq.AvailableSize = new Size(Double.PositiveInfinity, Double.PositiveInfinity);
var charSize = MeasureStringSize(cloneReq);
maxCharNum = (int)(availableSize / charSize.Width / charSize.Height + req.AvailableSize.Width / charSize.Width);
}
if (req.IsNext)
{
cloneReq.Input = maxCharNum >= req.Input.Length ? req.Input : req.Input.Substring(0, maxCharNum);
}
else
{
cloneReq.Input = maxCharNum >= req.Input.Length ? req.Input : req.Input.Substring(req.Input.Length - maxCharNum, maxCharNum);
}
cloneReq.AvailableSize = req.AvailableSize;
var size = MeasureStringSize(cloneReq);
if (size.Height > req.AvailableSize.Height)
{
if (cloneReq.Input.Length - 1 == 0)
{
return(0);
}
if (req.IsNext)
{
cloneReq.Input = cloneReq.Input.Substring(0, cloneReq.Input.Length - 1);
}
else
{
cloneReq.Input = cloneReq.Input.Substring(1, cloneReq.Input.Length - 1);
}
return(GetStringAvailableIndex(cloneReq));
}
else
{
return(cloneReq.Input.Length);
}
}
public MeasureFontRequest Clone()
{
var clone = new MeasureFontRequest()
{
Input = Input,
FontFamily = FontFamily,
FontSize = FontSize,
AvailableSize = AvailableSize,
IsNext = IsNext,
};
return(clone);
}
public static Size MeasureStringSize(MeasureFontRequest req)
{
var tb = new TextBlock();
tb.MaxLines = req.MaxLines;
tb.TextWrapping = TextWrapping.Wrap;
tb.Text = req.Input;
tb.FontFamily = req.FontFamily;
tb.FontSize = req.FontSize;
tb.Measure(req.AvailableSize);
Size actualSize = new Size();
actualSize.Width = tb.ActualWidth;
actualSize.Height = tb.ActualHeight;
return(actualSize);
}