internal void Draw(SKCanvas canvas, SKPoint origin)
{
SKPaint paint = Paint;
/* TODO: This originated from Native code, it might be useful for debugging character positions as
* we improve the FormattedText support. Will need to port this to C# obviously. Rmove when
* not needed anymore.
*
* SkPaint dpaint;
* ctx->Canvas->save();
* ctx->Canvas->translate(origin.fX, origin.fY);
* for (int c = 0; c < Lines.size(); c++)
* {
* dpaint.setARGB(255, 0, 0, 0);
* SkRect rc;
* rc.fLeft = 0;
* rc.fTop = Lines[c].Top;
* rc.fRight = Lines[c].Width;
* rc.fBottom = rc.fTop + LineOffset;
* ctx->Canvas->drawRect(rc, dpaint);
* }
* for (int c = 0; c < Length; c++)
* {
* dpaint.setARGB(255, c % 10 * 125 / 10 + 125, (c * 7) % 10 * 250 / 10, (c * 13) % 10 * 250 / 10);
* dpaint.setStyle(SkPaint::kFill_Style);
* ctx->Canvas->drawRect(Rects[c], dpaint);
* }
* ctx->Canvas->restore();
*/
for (int c = 0; c < _skiaLines.Count; c++)
{
PerspexFormattedTextLine line = _skiaLines[c];
var subString = _text.Substring(line.Start, line.Length);
canvas.DrawText(subString, origin.X, origin.Y + line.Top + LineOffset, paint);
}
}
void Rebuild()
{
var length = _text.Length;
_lines.Clear();
_skiaRects = new SKRect[length];
_skiaLines = new List <PerspexFormattedTextLine>();
int curOff = 0;
float curY = 0;
var metrics = Paint.FontMetrics;
var mTop = metrics.Top; // The greatest distance above the baseline for any glyph (will be <= 0).
var mBottom = metrics.Bottom; // The greatest distance below the baseline for any glyph (will be >= 0).
var mLeading = metrics.Leading; // The recommended distance to add between lines of text (will be >= 0).
// This seems like the best measure of full vertical extent
float lineHeight = mBottom - mTop;
// Rendering is relative to baseline
LineOffset = -metrics.Top;
string subString;
byte[] bytes;
GCHandle pinnedArray;
IntPtr pointer;
for (int c = 0; curOff < length; c++)
{
float lineWidth = -1;
int measured;
int extraSkip = 0;
if (WidthConstraint <= 0)
{
measured = length;
}
else
{
float constraint = WidthConstraint;
if (constraint > MAX_LINE_WIDTH)
{
constraint = MAX_LINE_WIDTH;
}
subString = _text.Substring(curOff);
// TODO: This method is not linking into SkiaSharp so we must use the RAW buffer version for now
//measured = (int)Paint.BreakText(subString, constraint, out lineWidth) / 2;
bytes = Encoding.UTF8.GetBytes(subString);
pinnedArray = GCHandle.Alloc(bytes, GCHandleType.Pinned);
pointer = pinnedArray.AddrOfPinnedObject();
// for some reason I have to pass nBytes * 2. I assume under the hood it expects Unicode/WChar??
measured = (int)Paint.BreakText(pointer, (IntPtr)(bytes.Length * 2), constraint, out lineWidth) / 2;
pinnedArray.Free();
if (measured == 0)
{
measured = 1;
lineWidth = -1;
}
char nextChar = ' ';
if (curOff + measured < length)
{
nextChar = _text[curOff + measured];
}
if (nextChar != ' ')
{
// Perform scan for the last space and end the line there
for (int si = curOff + measured - 1; si > curOff; si--)
{
if (_text[si] == ' ')
{
measured = si - curOff;
extraSkip = 1;
break;
}
}
}
}
PerspexFormattedTextLine line = new PerspexFormattedTextLine();
line.Start = curOff;
line.Length = measured;
line.Width = lineWidth;
line.Height = lineHeight;
line.Top = curY;
if (line.Width < 0)
{
line.Width = _skiaRects[line.Start + line.Length - 1].Right;
}
// Build character rects
for (int i = line.Start; i < line.Start + line.Length; i++)
{
float prevRight = 0;
if (i != line.Start)
{
prevRight = _skiaRects[i - 1].Right;
}
subString = _text.Substring(line.Start, i - line.Start + 1);
float w = Paint.MeasureText(subString);
SKRect rc;
rc.Left = prevRight;
rc.Right = w;
rc.Top = line.Top;
rc.Bottom = line.Top + line.Height;
_skiaRects[i] = rc;
}
subString = _text.Substring(line.Start, line.Length);
line.Width = Paint.MeasureText(subString);
_skiaLines.Add(line);
curY += lineHeight;
// TODO: We may want to consider adding Leading to the vertical line spacing but for now
// it appears to make no difference. Revisit as part of FormattedText improvements.
//
//curY += mLeading;
curOff += measured + extraSkip;
}
// Now convert to Perspex data formats
_lines.Clear();
_rects.Clear();
float maxX = 0;
for (var c = 0; c < _skiaLines.Count; c++)
{
var w = _skiaLines[c].Width;
if (maxX < w)
{
maxX = w;
}
_lines.Add(new FormattedTextLine(_skiaLines[c].Length, _skiaLines[c].Height));
}
for (var c = 0; c < _text.Length; c++)
{
_rects.Add(_skiaRects[c].ToPerspexRect());
}
if (_skiaLines.Count == 0)
{
_size = new Size();
}
else
{
var lastLine = _skiaLines[_skiaLines.Count - 1];
_size = new Size(maxX, lastLine.Top + lastLine.Height);
}
}
