public static RectangleF GetTextSize(CTFrame frame)
{
var minY = float.MaxValue;
var maxY = float.MinValue;
float width = 0;
var lines = frame.GetLines();
var origins = new CGPoint[lines.Length];
frame.GetLineOrigins(new NSRange(0, 0), origins);
for (var i = 0; i < lines.Length; i++)
{
var line = lines[i];
var lineWidth = (float)line.GetTypographicBounds(out var ascent, out var descent, out var leading);
if (lineWidth > width)
{
width = lineWidth;
}
var origin = origins[i];
minY = (float)Math.Min(minY, origin.Y - ascent);
maxY = (float)Math.Max(maxY, origin.Y + descent);
lines[i].Dispose();
}
return(new RectangleF(0f, minY, width, Math.Max(0, maxY - minY)));
}
public override Size GetSize(object backend)
{
LayoutInfo li = (LayoutInfo)backend;
using (CTFrame frame = CreateFrame(li)) {
if (frame == null)
{
return(Size.Zero);
}
Size result = Size.Zero;
CTLine [] lines = frame.GetLines();
float lineHeight = li.Font.Ascender - li.Font.Descender + li.Font.Leading;
// try to approximate Pango's layout
foreach (var line in lines)
{
result.Width = Math.Max(result.Width, line.GetTypographicBounds());
result.Height += lineHeight;
// clean up after ourselves as we go
line.Dispose();
}
// CoreText throws away trailing line breaks..
if (li.Text.EndsWith("\n"))
{
result.Height += lineHeight;
}
result.Width = Math.Ceiling(result.Width);
result.Height = Math.Ceiling(result.Height);
return(result);
}
}
void TextChanged ()
{
SetNeedsDisplay ();
ClearPreviousLayoutInformation ();
attributedString = new NSAttributedString (Text, attributes);
framesetter = new CTFramesetter (attributedString);
UIBezierPath path = UIBezierPath.FromRect (Bounds);
frame = framesetter.GetFrame (new NSRange (0, 0), path.CGPath, null);
}
void TextChanged()
{
SetNeedsDisplay();
ClearPreviousLayoutInformation();
attributedString = new NSAttributedString(Text, attributes);
framesetter = new CTFramesetter(attributedString);
UIBezierPath path = UIBezierPath.FromRect(Bounds);
frame = framesetter.GetFrame(new NSRange(0, 0), path.CGPath, null);
}
void ClearPreviousLayoutInformation ()
{
if (framesetter != null) {
framesetter.Dispose ();
framesetter = null;
}
if (frame != null) {
frame.Dispose ();
frame = null;
}
}
public override Size GetSize(object backend)
{
LayoutInfo li = (LayoutInfo)backend;
using (CTFrame frame = CreateFrame(li)) {
if (frame == null)
{
return(Size.Zero);
}
Size result = Size.Zero;
CTLine [] lines = frame.GetLines();
nfloat lineHeight = li.Font.Ascender - li.Font.Descender + li.Font.Leading;
CTLine ellipsis = null;
bool ellipsize = li.Width.HasValue && li.TextTrimming == TextTrimming.WordElipsis;
if (ellipsize)
{
ellipsis = new CTLine(CreateAttributedString(li, "..."));
}
// try to approximate Pango's layout
foreach (var line in lines)
{
var l = line;
if (ellipsize) // we need to create a new CTLine here because the framesetter already truncated the text for the line
{
l = new CTLine(CreateAttributedString(li, li.Text.Substring((int)line.StringRange.Location)))
.GetTruncatedLine(li.Width.Value, CTLineTruncation.End, ellipsis);
line.Dispose();
}
result.Width = Math.Max(result.Width, l.GetTypographicBounds());
result.Height += lineHeight;
// clean up after ourselves as we go
l.Dispose();
}
// CoreText throws away trailing line breaks..
if (li.Text.EndsWith("\n"))
{
result.Height += lineHeight;
}
result.Width = Math.Ceiling(result.Width);
result.Height = Math.Ceiling(result.Height);
return(result);
}
}
void ClearPreviousLayoutInformation()
{
if (framesetter != null)
{
framesetter.Dispose();
framesetter = null;
}
if (frame != null)
{
frame.Dispose();
frame = null;
}
}
internal static void Draw(CGContext ctx, object layout, double x, double y)
{
LayoutInfo li = (LayoutInfo)layout;
using (CTFrame frame = CreateFrame(li)) {
if (frame == null)
{
return;
}
CTLine ellipsis = null;
bool ellipsize = li.Width.HasValue && li.TextTrimming == TextTrimming.WordElipsis;
if (ellipsize)
{
ellipsis = new CTLine(CreateAttributedString(li, "..."));
}
nfloat lineHeight = li.Font.Ascender - li.Font.Descender + li.Font.Leading;
ctx.SaveState();
ctx.TextMatrix = CGAffineTransform.MakeScale(1f, -1f);
ctx.TranslateCTM((float)x, (float)y + li.Font.Ascender);
foreach (var line in frame.GetLines())
{
ctx.TextPosition = CGPoint.Empty;
// Determine final line
var ln = line;
if (ellipsize)
{
// we need to create a new CTLine here because the framesetter already truncated the text for the line
ln = new CTLine(CreateAttributedString(li, li.Text.Substring((int)line.StringRange.Location)))
.GetTruncatedLine(li.Width.Value, CTLineTruncation.End, ellipsis);
line.Dispose();
}
else if (li.Width.HasValue && li.TextAlignment != Alignment.Start)
{
var tx = li.Width.Value - GetLineWidth(ln);
if (li.TextAlignment == Alignment.Center)
{
tx /= 2d;
}
ctx.TextPosition = new CGPoint((nfloat)tx, 0);
}
ln.Draw(ctx);
ctx.TranslateCTM(0, lineHeight);
ln.Dispose();
}
ctx.RestoreState();
}
}
void drawLabel(CGContext ctx, CGRect rect, nfloat yCoord, nfloat xCoord, UITextAlignment alignment, string label, bool flipContext = true, bool centerVertical = false)
{
// Draw light the sunrise and Sunset labels at the ends of the light box
using (UIColor fontColor = UIColor.White, shadowColor = UIColor.Black.ColorWithAlpha(0.1f)) {
var fontAttributes = new UIFontAttributes(new UIFontFeature(CTFontFeatureNumberSpacing.Selector.ProportionalNumbers));
using (var desc = UIFont.SystemFontOfSize(fontSize).FontDescriptor.CreateWithAttributes(fontAttributes)) {
using (UIFont font = UIFont.FromDescriptor(desc, fontSize)) {
// calculating the range of our attributed string
var range = new NSRange(0, label.Length);
// set justification for text block
using (var alignStyle = new NSMutableParagraphStyle {
Alignment = alignment
}) {
// add stylistic attributes to out attributed string
var stringAttributes = new UIStringAttributes {
ForegroundColor = fontColor,
Font = font,
ParagraphStyle = alignStyle
};
var target = new CGSize(float.MaxValue, float.MaxValue);
NSRange fit;
using (NSMutableAttributedString attrString = new NSMutableAttributedString(label, stringAttributes)) {
//creating a container for out attributed string
using (CTFramesetter framesetter = new CTFramesetter(attrString)) {
CGSize frameSize = framesetter.SuggestFrameSize(range, null, target, out fit);
if (alignment == UITextAlignment.Center)
{
xCoord -= (frameSize.Width / 2);
}
if (alignment == UITextAlignment.Right)
{
xCoord -= frameSize.Width;
}
// subtract the frameSize so the flipped context behaves as expected
yCoord -= frameSize.Height;
if (centerVertical)
{
yCoord += (frameSize.Height / 2);
}
var textRect = new CGRect(xCoord, yCoord, frameSize.Width, frameSize.Height);
using (CGPath path = new CGPath()) {
path.AddRect(textRect);
ctx.SetShadow(new CGSize(0.0f, 1.0f), 0.0f, shadowColor.CGColor);
using (CTFrame frame = framesetter.GetFrame(range, path, null)) {
if (flipContext)
{
ctx.SaveState();
ctx.TranslateCTM(0, rect.Height);
ctx.ScaleCTM(1, -1);
frame.Draw(ctx);
ctx.RestoreState();
}
else
{
frame.Draw(ctx);
}
}
}
}
}
}
}
}
}
}