/// <summary>
/// Resize a source image to the target dimensions, based on the resize mode
/// </summary>
/// <param name="fileName">Full path to the Image to Resize</param>
/// <param name="width">Target desired Width</param>
/// <param name="height">Target desired Height</param>
/// <param name="mode">Resize Mode</param>
/// <returns>Resized Image</returns>
public static Bitmap ResizeImage(string fileName, int width, int height, Enums.ResizeMode mode)
{
if (string.IsNullOrWhiteSpace(fileName))
{
throw new ArgumentNullException(nameof(fileName));
}
if (!System.IO.File.Exists(fileName))
{
throw new ArgumentException("File does not exist", nameof(fileName));
}
Image srcImage;
try
{
srcImage = Image.FromFile(fileName);
}
catch (OutOfMemoryException)
{
//Image.FromFile throws OutOfMemoryException when the file is invalid or unsupported
throw new ArgumentException("File type is not supported", nameof(fileName));
}
return(ResizeImage(srcImage, width, height, mode));
}
/// <summary>
/// Resize a source image to the target dimensions, based on the resize mode
/// </summary>
/// <param name="srcImage">Image to Resize</param>
/// <param name="width">Target desired Width</param>
/// <param name="height">Target desired Height</param>
/// <param name="mode">Resize Mode</param>
/// <returns>Resized Image</returns>
public static Bitmap ResizeImage(Image srcImage, int width, int height, Enums.ResizeMode mode)
{
if (srcImage == null)
{
throw new ArgumentNullException(nameof(srcImage));
}
if (width <= 0)
{
throw new ArgumentException("Width must be Greater than Zero", nameof(width));
}
if (height <= 0)
{
throw new ArgumentException("Height must be Greater than Zero", nameof(height));
}
Rectangle destRect;
Bitmap destImage;
int xPos = 0;
int yPos = 0;
int cropHeight = srcImage.Height;
int cropWidth = srcImage.Width;
var widthRatio = (double)width / srcImage.Width;
var heightRatio = (double)height / srcImage.Height;
double ratio;
switch (mode)
{
//Resize image with no regard for life or limb
case Enums.ResizeMode.Stretch:
destRect = new Rectangle(0, 0, width, height);
destImage = new Bitmap(width, height);
break;
//Resize the image as large as possible while maintaining aspect ratio and not exceeding the bounds
case Enums.ResizeMode.Contain:
ratio = widthRatio < heightRatio ? widthRatio : heightRatio;
destRect = new Rectangle(0, 0, (int)(srcImage.Width * ratio), (int)(srcImage.Height * ratio));
destImage = new Bitmap((int)(srcImage.Width * ratio), (int)(srcImage.Height * ratio));
break;
//Completely cover the canvas, while maintaining aspect ratio
case Enums.ResizeMode.Cover:
ratio = widthRatio > heightRatio ? widthRatio : heightRatio;
//Destination image is exactly requested dimensions
destRect = new Rectangle(0, 0, width, height);
destImage = new Bitmap(width, height);
//Scale the source image so completely covers the requested dimensions
var scaledX = Convert.ToInt32(srcImage.Width * ratio);
var scaledY = Convert.ToInt32(srcImage.Height * ratio);
//Set the start coordinates, centering the source image in the target
xPos = (int)((double)(scaledX - destRect.Width) / 2 / ratio);
yPos = (int)((double)(scaledY - destRect.Height) / 2 / ratio);
//Set the dimensions to grab from the original image
cropHeight = srcImage.Height - Convert.ToInt32((scaledY - height) / ratio);
cropWidth = srcImage.Width - Convert.ToInt32((scaledX - width) / ratio);
break;
default:
throw new ArgumentException("Invalid Resize Mode", nameof(mode));
}
using (var graphics = Graphics.FromImage(destImage))
{
graphics.CompositingMode = CompositingMode.SourceCopy;
graphics.CompositingQuality = CompositingQuality.HighQuality;
graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
graphics.SmoothingMode = SmoothingMode.AntiAlias;
graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
using (var wrapMode = new ImageAttributes())
{
wrapMode.SetWrapMode(WrapMode.TileFlipXY);
graphics.DrawImage(srcImage, destRect, xPos, yPos, cropWidth, cropHeight, GraphicsUnit.Pixel, wrapMode);
}
}
return(destImage);
}
