/// <summary>
/// Calculate index of the location
/// where the caret should move to after pressing "up" key.
/// </summary>
public static int Calc_Up(IViewInternal view)
{
Point pt;
int newIndex;
Document doc = view.Document;
// get screen location of the caret
pt = view.GetVirPosFromIndex(doc.CaretIndex);
// calculate next location
pt.X = view.GetDesiredColumn();
pt.Y -= view.LineSpacing;
newIndex = view.GetIndexFromVirPos(pt);
if (newIndex < 0)
{
return(doc.CaretIndex); // don't move
}
// In line selection mode,
// moving caret across the line which contains the anchor position
// should select the line and a line above.
// To select a line above, calculate index of the char at one more line above.
if (doc.SelectionMode == TextDataType.Line &&
newIndex == doc.AnchorIndex &&
view.IsLineHeadIndex(newIndex))
{
pt.Y -= view.LineSpacing;
if (0 <= pt.Y)
{
newIndex = view.GetIndexFromVirPos(pt);
}
}
return(newIndex);
}
/// <summary>
/// Calculate index of the location
/// where the caret should move to after pressing "down" key.
/// </summary>
public static int Calc_Down(IViewInternal view)
{
Point pt;
int newIndex;
Document doc = view.Document;
// get screen location of the caret
pt = view.GetVirPosFromIndex(doc.CaretIndex);
// calculate next location
pt.X = view.GetDesiredColumn();
pt.Y += view.LineSpacing;
/* NOT NEEDED because View.GetIndexFromVirPos handles this case.
* if( view.Height - view.LineSpacing < pt.Y )
* {
* return doc.CaretIndex; // no lines below. don't move.
* }*/
newIndex = view.GetIndexFromVirPos(pt);
// In line selection mode,
// moving caret across the line which contains the anchor position
// should select the line and a line below.
// To select a line below, calculate index of the char at one more line below.
if (doc.SelectionMode == TextDataType.Line &&
view.IsLineHeadIndex(newIndex))
{
Point pt2 = new Point(pt.X, pt.Y + view.LineSpacing);
int skippedNewIndex = view.GetIndexFromVirPos(pt2);
if (skippedNewIndex == doc.AnchorIndex)
{
newIndex = skippedNewIndex;
}
}
return(newIndex);
}