internal UIImage RenderImage(IFontImageSource imageSource, float scale)
{
var font = FontManager.GetFont(imageSource.Font);
var color = (imageSource.Color ?? Colors.White).ToPlatform();
var glyph = (NSString)imageSource.Glyph;
var attString = new NSAttributedString(glyph, font, color);
var imagesize = glyph.GetSizeUsingAttributes(attString.GetUIKitAttributes(0, out _));
UIGraphics.BeginImageContextWithOptions(imagesize, false, scale);
var ctx = new NSStringDrawingContext();
var boundingRect = attString.GetBoundingRect(imagesize, 0, ctx);
attString.DrawString(new CGRect(
imagesize.Width / 2 - boundingRect.Size.Width / 2,
imagesize.Height / 2 - boundingRect.Size.Height / 2,
imagesize.Width,
imagesize.Height));
var image = UIGraphics.GetImageFromCurrentImageContext();
UIGraphics.EndImageContext();
return(image.ImageWithRenderingMode(UIImageRenderingMode.AlwaysOriginal));
}
public Task <IImageSourceServiceResult <UIImage>?> GetImageAsync(IFontImageSource imageSource, float scale = 1, CancellationToken cancellationToken = default)
{
if (imageSource.IsEmpty)
{
return(FromResult(null));
}
try
{
// TODO: use a cached way
var image = RenderImage(imageSource, scale);
if (image == null)
{
throw new InvalidOperationException("Unable to generate font image.");
}
var result = new ImageSourceServiceResult(image, true, () => image.Dispose());
return(FromResult(result));
}
catch (Exception ex)
{
Logger?.LogWarning(ex, "Unable to generate font image '{Glyph}'.", imageSource.Glyph);
throw;
}
}
public async Task <IImageSourceServiceResult <Drawable>?> GetDrawableAsync(IFontImageSource imageSource, Context context, CancellationToken cancellationToken = default)
{
if (imageSource.IsEmpty)
{
return(null);
}
var glyph = imageSource.Glyph;
var size = FontManager.GetFontSize(imageSource.Font);
var textSize = TypedValue.ApplyDimension(size.Unit, size.Value, context.Resources?.DisplayMetrics);
var typeface = FontManager.GetTypeface(imageSource.Font);
var color = (imageSource.Color ?? Graphics.Colors.White).ToPlatform();
try
{
var result = await Glide
.With(context)
.Load(new FontImageSourceModel(glyph, textSize, typeface, color))
.SubmitAsync(context, cancellationToken)
.ConfigureAwait(false);
if (result == null)
{
throw new InvalidOperationException("Unable to generate font image.");
}
return(result);
}
catch (Exception ex)
{
Logger?.LogWarning(ex, "Unable to generate font image '{Glyph}'.", glyph);
throw;
}
}
public async Task <IImageSourceServiceResult <Image>?> GetImageAsync(IFontImageSource imageSource, Image image, CancellationToken cancellationToken = default)
{
if (imageSource.IsEmpty)
{
return(null);
}
try
{
//TODO : Fix me correctly later.
var isLoadComplated = await image.LoadAsync(string.Empty, cancellationToken);
if (!isLoadComplated)
{
throw new InvalidOperationException("Unable to load image file.");
}
var result = new ImageSourceServiceResult(image);
return(result);
}
catch (Exception ex)
{
Logger?.LogWarning(ex, "Unable to generate font image '{Glyph}'.", imageSource.Glyph);
throw;
}
}
string GetFontSource(IFontImageSource imageSource)
{
if (imageSource == null)
{
return(string.Empty);
}
var fontFamily = FontManager.GetFontFamily(imageSource.Font);
var fontSource = fontFamily.Source;
var allFamilies = fontFamily.Source.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
if (allFamilies.Length > 1)
{
// There's really no perfect solution to handle font families with fallbacks (comma-separated)
// So if the font family has fallbacks, only one is taken, because CanvasTextFormat
// only supports one font family
var source = imageSource.Font.Family ?? String.Empty;
foreach (var family in allFamilies)
{
if (family.Contains(source, StringComparison.Ordinal))
{
fontSource = family;
break;
}
}
}
return(fontSource);
}
internal CanvasImageSource RenderImageSource(IFontImageSource imageSource, float scale)
{
// TODO: The DPI not working as the view is not respecting the
// value, so just reset to 1 to keep the correct size.
scale = 1;
var dpi = scale * DeviceDisplay.BaseLogicalDpi;
var fontFamily = GetFontSource(imageSource);
var fontSize = (float)imageSource.Font.Size;
var color = (imageSource.Color ?? Colors.White).ToWindowsColor();
var textFormat = new CanvasTextFormat
{
FontFamily = fontFamily,
FontSize = fontSize,
HorizontalAlignment = CanvasHorizontalAlignment.Center,
VerticalAlignment = CanvasVerticalAlignment.Center,
Options = CanvasDrawTextOptions.Default
};
var device = CanvasDevice.GetSharedDevice();
using var layout = new CanvasTextLayout(device, imageSource.Glyph, textFormat, 0, 0);
// add a 1px padding all around
var canvasWidth = (float)layout.DrawBounds.Width + 2;
var canvasHeight = (float)layout.DrawBounds.Height + 2;
var canvasImageSource = new CanvasImageSource(device, canvasWidth, canvasHeight, dpi);
using (var ds = canvasImageSource.CreateDrawingSession(UI.Colors.Transparent))
{
// offset by 1px as we added a 1px padding
var x = (layout.DrawBounds.X * -1) + 1;
var y = (layout.DrawBounds.Y * -1) + 1;
ds.DrawTextLayout(layout, (float)x, (float)y, color);
}
return(canvasImageSource);
}
