private static void DrawImageAtNewResolution(GDI.Graphics graphics, ImageResolution resolution, GDI.Image gdiImage)
{
graphics.SmoothingMode = SmoothingMode.HighQuality;
graphics.InterpolationMode = InterpolationMode.Bicubic;
graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
graphics.DrawImage(gdiImage, 0, 0, resolution.Width, resolution.Height);
}
public Image ApplyTransforms(Image image, string newResolution = null, string backgroundColour = null,
string watermarkText = null, string imageType = null)
{
if (image == null)
{
throw new ArgumentNullException(nameof(image));
}
if (image.ToGdiImage() == null)
{
throw new ArgumentException("image must contain a GDI image object");
}
if (!TransformsSupplied(newResolution, backgroundColour, watermarkText, imageType))
{
return(image);
}
var resolution = ImageResolution.Parse(newResolution);
var backColour = BackgroundColour.Parse(backgroundColour);
var imgType = ImageType.Parse(imageType);
using var oldImage = image;
var gdiImage = oldImage.ToGdiImage();
var newGdiImage = CreateTransformBitmap(resolution, gdiImage);
using var graphics = GDI.Graphics.FromImage(newGdiImage);
ApplyBackgroundColour(graphics, backColour, newGdiImage);
if (resolution != ImageResolution.None)
{
DrawImageAtNewResolution(graphics, resolution, gdiImage);
}
else
{
DrawImageAtOriginalResolution(graphics, gdiImage);
}
if (!string.IsNullOrWhiteSpace(watermarkText))
{
AddWatermark(graphics, watermarkText);
}
if (imgType == ImageType.None)
{
imgType = ImageType.Parse(gdiImage.RawFormat.ToString());
}
if (!newGdiImage.RawFormat.Equals(imgType.ImageFormat))
{
newGdiImage = SetNewGdiImageFormat(newGdiImage, imgType.ImageFormat);
}
return(new Image(image.Name, newGdiImage));
}
private static GDI.Bitmap CreateTransformBitmap(ImageResolution resolution, GDI.Image gdiImage)
{
return(resolution != ImageResolution.None
? new GDI.Bitmap(resolution.Width, resolution.Height)
: new GDI.Bitmap(gdiImage.Width, gdiImage.Height));
}