// Public method to create a rect for a given range in the text contents
// Called by our EditableTextRange to implement the required
// UITextInput:firstRectForRange method
public CGRect FirstRect(NSRange range)
{
int index = (int)range.Location;
// Iterate over our CTLines, looking for the line that encompasses the given range
var lines = frame.GetLines();
for (int i = 0; i < lines.Length; i++)
{
CTLine line = lines [i];
NSRange lineRange = line.StringRange;
int localIndex = index - (int)lineRange.Location;
if (localIndex >= 0 && localIndex < lineRange.Length)
{
// For this sample, we use just the first line that intersects range
int finalIndex = (int)Math.Min(lineRange.Location + lineRange.Length, range.Location + range.Length);
// Create a rect for the given range within this line
nfloat xStart = line.GetOffsetForStringIndex(index);
nfloat xEnd = line.GetOffsetForStringIndex(finalIndex);
var origins = new CGPoint [lines.Length];
frame.GetLineOrigins(new NSRange(i, 0), origins);
nfloat ascent, descent, leading;
line.GetTypographicBounds(out ascent, out descent, out leading);
return(new CGRect(xStart, origins [0].Y - descent, xEnd - xStart, ascent + descent));
}
}
return(CGRect.Empty);
}
// Helper method for drawing the current selection range (as a simple filled rect)
void DrawRangeAsSelection(NSRange selectionRange)
{
// If not in editing mode, we do not draw selection rects
if (!IsEditing)
{
return;
}
// If selection range empty, do not draw
if (selectionRange.Length == 0 || selectionRange.Location == NSRange.NotFound)
{
return;
}
// set the fill color to the selection color
SelectionColor.SetFill();
// Iterate over the lines in our CTFrame, looking for lines that intersect
// with the given selection range, and draw a selection rect for each intersection
var lines = frame.GetLines();
for (int i = 0; i < lines.Length; i++)
{
CTLine line = lines [i];
NSRange lineRange = line.StringRange;
NSRange range = new NSRange(lineRange.Location, lineRange.Length);
NSRange intersection = RangeIntersection(range, selectionRange);
if (intersection.Location != NSRange.NotFound && intersection.Length > 0)
{
// The text range for this line intersects our selection range
nfloat xStart = line.GetOffsetForStringIndex(intersection.Location);
nfloat xEnd = line.GetOffsetForStringIndex(intersection.Location + intersection.Length);
var origin = new CGPoint [lines.Length];
// Get coordinate and bounds information for the intersection text range
frame.GetLineOrigins(new NSRange(i, 0), origin);
nfloat ascent, descent, leading;
line.GetTypographicBounds(out ascent, out descent, out leading);
// Create a rect for the intersection and draw it with selection color
CGRect selectionRect = new CGRect(xStart, origin [0].Y - descent, xEnd - xStart, ascent + descent);
UIGraphics.RectFill(selectionRect);
}
}
}
// Public method to determine the CGRect for the insertion point or selection, used
// when creating or updating our SimpleCaretView instance
public CGRect CaretRect(int index)
{
var lines = frame.GetLines();
// Special case, no text
if (text.Length == 0)
{
CGPoint origin = new CGPoint(Bounds.GetMinX(), Bounds.GetMinY() - font.Leading);
// Note: using fabs() for typically negative descender from fonts
return(new CGRect(origin.X, origin.Y - (nfloat)Math.Abs(font.Descender), 3, font.Ascender + (nfloat)Math.Abs(font.Descender)));
}
// Special case, insertion point at final position in text after newline
if (index == text.Length && text.EndsWith("\n"))
{
CTLine line = lines [lines.Length - 1];
NSRange range = line.StringRange;
nfloat xPos = line.GetOffsetForStringIndex(range.Location);
var origins = new CGPoint [lines.Length];
nfloat ascent, descent, leading;
line.GetTypographicBounds(out ascent, out descent, out leading);
frame.GetLineOrigins(new NSRange(lines.Length - 1, 0), origins);
// Place point after last line, including any font leading spacing if applicable
origins[0].Y -= font.Leading;
return(new CGRect(xPos, origins [0].Y - descent, 3, ascent + descent));
}
// Regular case, caret somewhere within our text content range
for (int i = 0; i < lines.Length; i++)
{
CTLine line = lines [i];
NSRange range = line.StringRange;
int localIndex = index - (int)range.Location;
if (localIndex >= 0 && localIndex <= range.Length)
{
// index is in the range for this line
nfloat xPos = line.GetOffsetForStringIndex(index);
var origins = new CGPoint [lines.Length];
nfloat ascent, descent, leading;
line.GetTypographicBounds(out ascent, out descent, out leading);
frame.GetLineOrigins(new NSRange(i, 0), origins);
// Make a small "caret" rect at the index position
return(new CGRect(xPos, origins [0].Y - descent, 3, ascent + descent));
}
}
return(CGRect.Empty);
}
