/// <summary>
/// Populates text measures. If you use a shared textShaper, call this before GetSpans, or GetLines.
/// </summary>
public void LoadMeasures(TextShaper textShaper = null)
{
if (textShaper == null)
{
textShaper = new TextShaper(false);
}
if (GlyphSpan == null)
{
GlyphSpan = textShaper.GetGlyphSpan(Font, Text);
var fontMetrics = GlyphSpan.Paints[0].FontMetrics;
FontHeight = fontMetrics.CapHeight;
if (Font.LineHeight.HasValue)
{
LineHeight = Font.LineHeight.Value;
}
else
{
LineHeight = (fontMetrics.Descent - fontMetrics.Ascent + fontMetrics.Leading) * LineSpacing;
}
MarginY = (LineHeight - FontHeight) / 2;
}
if (LineBreakMode == LineBreakMode.MiddleTruncation)
{
if (EllipsisGlyphSpan == null)
{
EllipsisGlyphSpan = textShaper.GetGlyphSpan(Font, " … ");
}
}
}
/// <summary>
/// Measure this text block, given supplied maximum width
/// </summary>
/// <param name="textShaper">Text Shaper (measurement cache) to use, or null if measurements shouldn't be cached in memory</param>
public SKSize Measure(float maxwidth, TextShaper textShaper = null)
{
float width = 0;
LoadMeasures(textShaper);
if (LineBreakMode == LineBreakMode.MiddleTruncation)
{
var spans = GetSpans(maxwidth);
foreach (var span in spans)
{
width += span.width;
}
return(new SKSize(width, LineHeight));
}
else
{
var lines = GetLines(maxwidth);
foreach (var line in lines)
{
if (width < line.width)
{
width = line.width;
}
}
return(new SKSize(width, lines.Count * LineHeight));
}
}
private SKRect Layout(SKCanvas canvas, SKRect rect, FlowDirection flowDirection, TextShaper textShaper)
{
var width = rect.Width;
var line = new List <(RichTextSpan span, MeasuredSpan wordspan)>();
var linewidth = 0.0f;
var linefontheight = 0f;
var linemarginy = 0f;
var maxlinewidth = 0.0f;
var y = rect.Top;
if (Spans != null)
{
// calculate maximum font dimensions
foreach (var span in Spans)
{
if (span != null)
{
var(fontheight, marginy) = span.GetMeasures(textShaper);
if (linefontheight < fontheight)
{
linefontheight = fontheight;
}
if (linemarginy < marginy)
{
linemarginy = marginy;
}
}
}
y += linefontheight + linemarginy;
// draw all text blocks in succession
foreach (var span in Spans)
{
if (span != null)
{
var childlines = span.GetLines(width, linewidth, false);
if (childlines != null)
{
var childlinecount = childlines.Count;
for (var i = 0; i < childlinecount; i++)
{
var wordspan = childlines[i];
line.Add((span, wordspan));
linewidth += wordspan.width;
if (maxlinewidth < linewidth)
{
maxlinewidth = linewidth;
}
if (i != childlinecount - 1)
{
LayoutLine();
}
}
}
}
}
if (line.Count > 0)
{
LayoutLine();
}
y -= linefontheight + linemarginy;
}
if (flowDirection == FlowDirection.Unknown || flowDirection == FlowDirection.LeftToRight)
{
return(new SKRect(rect.Left, rect.Top, rect.Left + maxlinewidth + floatroundingmargin, y));
}
else
{
return(new SKRect(rect.Right - maxlinewidth - floatroundingmargin, rect.Top, rect.Right, y));
}
void LayoutLine()
{
if (canvas != null)
{
if (flowDirection == FlowDirection.LeftToRight)
{
var x = rect.Left;
foreach (var chunk in line)
{
if (PixelRounding)
{
x = (float)Math.Round(x);
}
var span = chunk.span;
var spanwidth = chunk.wordspan.width;
// draw the span
span.DrawMeasuredSpan(canvas, x, y, linefontheight, linemarginy, chunk.wordspan, false);
#if DEBUGCONTAINER
var paintrect = new SKRect(x + t.X, y - text.FontHeight - text.MarginY + t.Y, x + spanwidth + t.X, y + text.MarginY + t.Y);
using (var borderpaint = new SKPaint()
{
Color = SKColors.Orange.WithAlpha(64), IsStroke = true
})
canvas.DrawRect(paintrect, borderpaint);
#endif
x += spanwidth;
}
}
else
{
var x = rect.Right;
foreach (var chunk in line)
{
var span = chunk.span;
var spanwidth = chunk.wordspan.width;
if (PixelRounding)
{
x = (float)Math.Round(x);
}
x -= spanwidth;
// draw the span
span.DrawMeasuredSpan(canvas, x, y, linefontheight, linemarginy, chunk.wordspan, true);
#if DEBUGCONTAINER
var paintrect = new SKRect(x - t.X, y - text.FontHeight - text.MarginY + t.Y, x + spanwidth - t.X, y + text.MarginY + t.Y);
using (var borderpaint = new SKPaint()
{
Color = SKColors.Orange.WithAlpha(64), IsStroke = true
})
canvas.DrawRect(paintrect, borderpaint);
#endif
}
}
}
linewidth = 0;
y += linefontheight + linemarginy * 2;
line.Clear();
}
}
/// <summary>
/// Paint's the rich text in the provided rectangle
/// </summary>
/// <returns>a rect containing the actual bottom of painted text</returns>
public SKRect Paint(SKCanvas canvas, SKRect rect, FlowDirection flowDirection = FlowDirection.LeftToRight, TextShaper textShaper = null)
{
return(Layout(canvas, rect, flowDirection, textShaper));
}
/// <summary>
/// Measures the Rich Text, given the maximum width
/// </summary>
/// <param name="maxWidth"></param>
/// <param name="textShaper"></param>
/// <returns></returns>
public SKSize Measure(float maxWidth, TextShaper textShaper = null)
{
var calculated = Layout(null, new SKRect(0, 0, maxWidth, float.MaxValue), FlowDirection.LeftToRight, textShaper ?? new TextShaper(false));
return(new SKSize(calculated.Width, calculated.Height));
}
public SKRect Draw(SKCanvas canvas, SKRect rect, TextShaper textShaper = null, FlowDirection flowDirection = FlowDirection.LeftToRight)
{
LoadMeasures(textShaper);
var y = rect.Top + FontHeight + MarginY;
if (LineBreakMode == LineBreakMode.MiddleTruncation)
{
var spans = GetSpans(rect.Width);
if (flowDirection == FlowDirection.LeftToRight)
{
var x = rect.Left;
if (spans.Count > 0)
{
canvas.DrawGlyphSpan(GlyphSpan, x, y, Color, spans[0]);
x += spans[0].width;
}
if (spans.Count > 1)
{
canvas.DrawGlyphSpan(EllipsisGlyphSpan, x, y, Color, spans[1]);
x += spans[1].width;
}
if (spans.Count > 2)
{
canvas.DrawGlyphSpan(GlyphSpan, x, y, Color, spans[2]);
}
}
else
{
var x = rect.Right;
if (spans.Count > 0)
{
x -= spans[0].width;
canvas.DrawGlyphSpan(GlyphSpan, x, y, Color, spans[0]);
}
if (spans.Count > 1)
{
x -= spans[1].width;
canvas.DrawGlyphSpan(EllipsisGlyphSpan, x, y, Color, spans[1]);
}
if (spans.Count > 2)
{
x -= spans[2].width;
canvas.DrawGlyphSpan(GlyphSpan, x, y, Color, spans[2]);
}
}
y += LineHeight;
}
else
{
var lines = GetLines(rect.Width);
var i = 0;
foreach (var line in lines)
{
if (GetLineColor != null)
{
Color = GetLineColor(i++, lines.Count);
}
if (LineBreakMode == LineBreakMode.WordWrap)
{
float x;
if (flowDirection == FlowDirection.LeftToRight)
{
x = rect.Left;
}
else
{
x = rect.Right - line.width;
}
canvas.DrawGlyphSpan(GlyphSpan, x, y, Color, line, GlyphAnimation);
}
else if (LineBreakMode == LineBreakMode.Center)
{
var x = rect.Left + (rect.Width - line.width) / 2;
canvas.DrawGlyphSpan(GlyphSpan, x, y, Color, line, GlyphAnimation);
}
y += LineHeight;
}
}
var paintrect = new SKRect(rect.Left, rect.Top, rect.Right, y - LineHeight + MarginY);
#if DEBUGCONTAINER
if (canvas != null)
{
using (var borderpaint = new SKPaint()
{
Color = SKColors.Red.WithAlpha(64), IsStroke = true
})
canvas.DrawRect(paintrect, borderpaint);
}
#endif
return(paintrect);
}
/// <summary>
/// Draw a block of text on the canvas.
/// </summary>
/// <returns>The bounds of the painted text. Note that the returned rectangle's Width is equal to the input (IE only bottom is calculated). Use TextBlock.Measure to get text bounds</returns>
public static SKRect DrawRichTextBlock(this SKCanvas canvas, RichTextBlock text, SKRect rect, TextShaper textShaper = null, FlowDirection flowDirection = FlowDirection.LeftToRight)
{
return(text.Paint(canvas, rect, flowDirection, textShaper));
}
/// <summary>
/// Draw a block of text on the canvas.
/// </summary>
/// <returns>The bounds of the painted text. Note that the returned rectangle's Width is equal to the input (IE only bottom is calculated). Use TextBlock.Measure to get text bounds</returns>
public static SKRect DrawTextBlock(this SKCanvas canvas, TextBlock text, SKRect rect, TextShaper textShaper = null, FlowDirection flowDirection = FlowDirection.LeftToRight)
{
return(text.Draw(canvas, rect, textShaper, flowDirection));
}
/// <summary>
/// Draw a text block
/// </summary>
public static SKRect DrawTextBlock(this SKCanvas canvas, string text, SKRect rect, Font font, SKColor color, TextShaper textShaper = null)
{
var textblock = new TextBlock(font, color, text);
return(DrawTextBlock(canvas, textblock, rect, textShaper));
}