public void DrawText(string text, float x, float y, TextPresenter textPresenter, bool multiline)
{
bool renderCaret = textPresenter.ShowCaret && textPresenter.RenderCaret;
int selectionStart = Math.Min(textPresenter.SelectionStart, textPresenter.SelectionEnd);
int selectionEnd = Math.Max(textPresenter.SelectionStart, textPresenter.SelectionEnd);
var textToRender = multiline ? text : text.Replace("\n", string.Empty);
var lines = textToRender.Split("\n", StringSplitOptions.RemoveEmptyEntries);
var caretPosition = textPresenter.GetRealPosition(textToRender, textPresenter.CaretPosition, textPresenter.Foreground);
var selectionStartPosition = textPresenter.GetRealPosition(textToRender, selectionStart, textPresenter.Foreground);
var selectionEndPosition = textPresenter.GetRealPosition(textToRender, selectionEnd, textPresenter.Foreground);
SKPaint caretPaint = new SKPaint
{
Color = textPresenter.SelectionEnd != textPresenter.SelectionEnd ? Color.Win10GreyDark : Color.Black,
StrokeWidth = 1
};
if (renderCaret)
{
Canvas.DrawLine(new SKPoint((caretPosition.XOffset + x) * Scale, (y + 2) * Scale),
new SKPoint((caretPosition.XOffset + x) * Scale, (y - textPresenter.Foreground.TextSize - 2) * Scale),
ScalePaint(caretPaint));
}
SKPaint currentForegroundPaint = textPresenter.Foreground;
SKPaint currentBackgroundPaint = textPresenter.Background;
string preSelection = string.Empty;
string selection = string.Empty;
string postSelection = string.Empty;
bool inSelection = false;
for (int i = 0; i < lines.Length; i++)
{
var line = lines[i];
if (selectionStartPosition.Line == i)
{
int selectionLimit = selectionEndPosition.Line == i ? selectionEndPosition.Column : line.Length;
selection = line.Substring(selectionStartPosition.Column, selectionLimit - selectionStartPosition.Column);
preSelection = line.Substring(0, selectionStartPosition.Column);
if (preSelection.Length > 0)
{
Canvas.DrawText(preSelection, x * Scale, (y + selectionStartPosition.YOffset) * Scale, ScalePaint(currentForegroundPaint));
}
currentForegroundPaint = textPresenter.SelectionForeground;
currentBackgroundPaint = textPresenter.SelectionBackground;
if (selection.Length > 0)
{
float selectionWidth = currentForegroundPaint.MeasureText(selection);
Canvas.DrawRect((x + selectionStartPosition.XOffset) * Scale, (y + selectionStartPosition.YOffset) * Scale,
selectionWidth * Scale, -currentForegroundPaint.TextSize * Scale, ScalePaint(currentBackgroundPaint));
Canvas.DrawText(selection, (x + selectionStartPosition.XOffset) * Scale,
(y + selectionStartPosition.YOffset) * Scale, currentForegroundPaint);
}
inSelection = true;
}
if (selectionEndPosition.Line == i)
{
int selectionLimit = selectionStartPosition.Line == i ? selectionStartPosition.Column : 0;
selection = line.Substring(selectionLimit, selectionEndPosition.Column - selectionLimit);
postSelection = line.Substring(selectionEndPosition.Column, line.Length - selectionEndPosition.Column);
if (selection.Length > 0 && selectionStartPosition.Line != i)
{
float selectionWidth = currentForegroundPaint.MeasureText(selection);
Canvas.DrawRect((x + selectionEndPosition.XOffset - selectionWidth) * Scale, (y + selectionEndPosition.YOffset) * Scale,
selectionWidth * Scale, -currentForegroundPaint.TextSize * Scale, ScalePaint(currentBackgroundPaint));
Canvas.DrawText(selection, (x + selectionEndPosition.XOffset - selectionWidth) * Scale,
(y + selectionEndPosition.YOffset) * Scale, ScalePaint(currentForegroundPaint));
}
currentForegroundPaint = textPresenter.Foreground;
currentBackgroundPaint = textPresenter.Background;
if (postSelection.Length > 0)
{
Canvas.DrawText(postSelection, (x + selectionEndPosition.XOffset) * Scale,
(y + selectionEndPosition.YOffset) * Scale, ScalePaint(currentForegroundPaint));
}
inSelection = false;
}
else
{
if (selectionStartPosition.Line != i && selectionEndPosition.Line != i)
{
float yOffset = i * currentForegroundPaint.TextSize;
float lineLength = currentForegroundPaint.MeasureText(line);
if (inSelection)
{
Canvas.DrawRect(x * Scale, (y + yOffset) * Scale, lineLength * Scale, -currentForegroundPaint.TextSize * Scale,
ScalePaint(currentBackgroundPaint));
}
Canvas.DrawText(line, x * Scale, (y + yOffset) * Scale, ScalePaint(currentForegroundPaint));
}
}
}
}