// NOTE: This could be changed to return a TransformGroup which would allow a
// combination of transforms to be performed on the image
private Transform GetTransform(BitmapSource source)
{
Debug.Assert(source != null);
var width = _size.Width;
var height = _size.Height;
if (_size.Mode == Mode.Scale)
{
// Automatically fill in blank with/height values
if (width == 0)
{
width = height * source.PixelWidth / source.PixelHeight;
}
else if (height == 0)
{
height = width * source.PixelHeight / source.PixelWidth;
}
else if (_ignoreRotations)
{
if ((width > height) != (source.PixelWidth > source.PixelHeight))
{
var temp = width;
width = height;
height = temp;
}
}
}
var scaleX = UnitHelper.ConvertToScale(width, _size.Unit, source.PixelWidth, source.DpiX);
var scaleY = UnitHelper.ConvertToScale(height, _size.Unit, source.PixelHeight, source.DpiY);
if (_size.Mode == Mode.Scale)
{
var minScale = Math.Min(scaleX, scaleY);
scaleX = minScale;
scaleY = minScale;
}
else if (_size.Mode != Mode.Stretch)
{
throw new NotSupportedException(String.Format(CultureInfo.InvariantCulture, "The mode '{0}' is not yet supported.", _size.Mode));
}
if (_shrinkOnly)
{
var maxScale = Math.Max(scaleX, scaleY);
if (maxScale > 1.0)
{
scaleX = 1.0;
scaleY = 1.0;
}
}
return(new ScaleTransform(scaleX, scaleY));
}
