private void ScrollHorizontallyToPoint(MouseTextPosition position)
{
if (position.Horizontal == HorizontalBounds.Inside)
{
return;
}
// If outside to the left then reset the viewport all the way to the start first
if (position.Horizontal == HorizontalBounds.Left)
{
this.textView.ViewportLeft = 0;
}
// Ensure the position is visible, either if we were off the right or if
// we were off to the left and went too far by resetting the viewport left to 0
this.textView.ViewScroller.EnsureSpanVisible(
this.textView.GetTextElementSpan(position.Point));
}
private MouseTextPosition GetMouseTextPosition(MouseEventArgs args)
{
var mousePoint = args?.GetPosition(this.textView.VisualElement) ??
Mouse.GetPosition(this.textView.VisualElement);
var result = new MouseTextPosition {
Horizontal = HorizontalBounds.Inside
};
// Find the line we are interested in based on mouse position
ITextViewLine line;
if (mousePoint.Y <= 0)
{
line = this.textView.TextViewLines.FirstVisibleLine;
result.Vertical = VerticalBounds.Above;
}
else if (mousePoint.Y >= this.textView.ViewportBottom - this.textView.ViewportTop)
{
line = this.textView.TextViewLines.LastVisibleLine;
result.Vertical = VerticalBounds.Below;
}
else
{
// If GetTextViewLineContainingYCoordinate returns null in this situation
// then since we are within the viewport we know we must have scrolled all
// the way to the end of the document and the mosue must be over the viewport
// space showing after the end of the document hence in that case we select the
// last line.
line = this.textView.TextViewLines.GetTextViewLineContainingYCoordinate(
mousePoint.Y + this.textView.ViewportTop)
?? this.textView.TextViewLines.LastVisibleLine;
result.Vertical = VerticalBounds.Inside;
}
var x = mousePoint.X + this.textView.ViewportLeft;
// If the mouse is outside the viewport to right or left then
// select the first or last point on the line
if (x < this.textView.ViewportLeft)
{
result.Point = line.Start;
if (line.TextLeft < this.textView.ViewportLeft)
{
result.Horizontal = HorizontalBounds.Left;
}
else if (line.TextLeft > this.textView.ViewportRight)
{
result.Horizontal = HorizontalBounds.Right;
}
return(result);
}
if (x > this.textView.ViewportRight)
{
result.Point = line.End;
if (line.TextRight > this.textView.ViewportRight)
{
result.Horizontal = HorizontalBounds.Right;
}
else if (line.TextRight < this.textView.ViewportLeft)
{
result.Horizontal = HorizontalBounds.Left;
}
return(result);
}
// Find and adjust the desired point based on x position
var point = line.GetBufferPositionFromXCoordinate(x);
if (point.HasValue)
{
// The point will always be for the charecter that the mouse is over
// however it feels far more natural (and VS selection does this) to
// select a charecter based on the closest start point to the mouse.
// Here we select the next charecter if its start position is closer.
var bounds = line.GetCharacterBounds(point.Value);
if (x > (bounds.Left + (bounds.Width / 2)))
{
result.Point = line.GetBufferPositionFromXCoordinate(x + bounds.Width) ?? point.Value;
return(result);
}
result.Point = point.Value;
return(result);
}
// If we get here the line does not go all the way to the viewport right
// side and we are past the end of the line but inside the viewport
result.Point = line.End;
if (line.TextRight < this.textView.ViewportLeft)
{
result.Horizontal = HorizontalBounds.Left;
}
return(result);
}