This helper extension class will let you resize image with option for fixed aspect ratio. This also adjust the image to its correct orientation.
Extension Methods
| Method | Description |
| ConvertToImageByteArray(optionalMaxHeight, optionalFixWidth) | Resize and correct image orientation. Returns image as byte array. |
| SaveAsJpegFile(filePath, optionalMaxHeight, optionalFixWidth) | Resize and correct image orientation and save in JPEG file format. Returns the filename of the saved image. |
| ConvertByteArrayToImage() | Convert and returns image as Bitmap |
Usage
var fileDialog = new OpenFileDialog();
fileDialog.Filter = "Image File|*.jpg;*.jpeg;*.png;*gif";
fileDialog.ShowDialog();
// the original image
byte[] imgDataFromFile = System.IO.File.ReadAllBytes(fileDialog.FileName);
// the optimized image which you can save to the database
byte[] imgDataResized = imgDataFromFile.ConvertToImageByteArray(256);
// converts image byte array to Bitmap for use in ImageList
Bitmap pic = imgDataResized.ConvertByteArrayToImage();
// export the image in JPEG file format
string fileName = imgDataResized.SaveAsJpegFile(@"C:\mypics\pic.jpg", 400, 300);
Example
imageList1.ImageSize = new Size(256, 256);
imageList1.ColorDepth = ColorDepth.Depth32Bit;
imageList1.Images.Add(pic);
listView1.LargeImageList = imageList1;
ListViewItem item = new ListViewItem();
item.ImageIndex = imageList1.Images.Count - 1;
item.Text = "Sample Caption " + item.ImageIndex;
listView1.Items.Add(item);
ImageUploadExtension.cs
Simply include this code in your project.
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.IO;
public static class ImageUploadExtension
{
private const int MAX_HEIGHT = 600; // default height in pixel
private const bool QUALITY = true; // true = high quality, false = fast performance
public static byte[] ConvertToImageByteArray(this byte[] imgData, int maxHeight = MAX_HEIGHT, int? fixWidth = null)
{
try
{
using (Image newImage = Image.FromStream(new MemoryStream(imgData)))
{ }
}
catch (OutOfMemoryException ex)
{
//The file does not have a valid image format.
//-or- GDI+ does not support the pixel format of the file
return null;
}
try
{
return Resize(imgData, maxHeight, fixWidth); // Resize and store as Jpeg
}
catch { }
return null;
}
public static string SaveAsJpegFile(this byte[] imgData, string filePath, int maxHeight = MAX_HEIGHT, int? fixWidth = null)
{
try
{
var arrImageBytes = ConvertToImageByteArray(imgData, maxHeight, fixWidth);
string filename = Path.GetFileNameWithoutExtension(filePath) + ".jpg";
System.IO.Directory.CreateDirectory(Path.GetDirectoryName(filePath));
System.IO.File.WriteAllBytes(filename, arrImageBytes);
return filename;
}
catch
{
return string.Empty;
}
}
public static Bitmap ConvertByteArrayToImage(this byte[] blob)
{
MemoryStream mStream = new MemoryStream();
byte[] pData = blob;
mStream.Write(pData, 0, Convert.ToInt32(pData.Length));
Bitmap bm = new Bitmap(mStream, false);
mStream.Dispose();
return bm;
}
#region Methods
public static byte[] Resize(this byte[] image, int maxHeight, int? fixedWidth = null)
{
if (image != null)
{
MemoryStream stream = new MemoryStream(image);
Image img = Image.FromStream(stream);
foreach (var prop in img.PropertyItems)
{
//if ((prop.Id == 0x0112 || prop.Id == 5029 || prop.Id == 274))
if (Array.IndexOf(img.PropertyIdList, 274) > -1)
{
var orientation = (int)img.GetPropertyItem(274).Value[0];
img = OrientImage(img, orientation);
}
if(fixedWidth == null)
{
img = ScaleImage(img, maxHeight, QUALITY);
}
else
{
img = FixedSize(img, fixedWidth.Value, maxHeight, true);
}
var ms = new MemoryStream();
img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
image = ms.ToArray();
}
return image;
}
else
{
return null;
}
}
private static Image OrientImage(Image img, int orientation)
{
switch (orientation)
{
case 1:
// No rotation required.
break;
case 2:
img.RotateFlip(RotateFlipType.RotateNoneFlipX);
break;
case 3:
img.RotateFlip(RotateFlipType.Rotate180FlipNone);
break;
case 4:
img.RotateFlip(RotateFlipType.Rotate180FlipX);
break;
case 5:
img.RotateFlip(RotateFlipType.Rotate90FlipX);
break;
case 6:
img.RotateFlip(RotateFlipType.Rotate90FlipNone);
break;
case 7:
img.RotateFlip(RotateFlipType.Rotate270FlipX);
break;
case 8:
img.RotateFlip(RotateFlipType.Rotate270FlipNone);
break;
}
// This EXIF data is now invalid and should be removed.
img.RemovePropertyItem(274);
return img;
}
private static Image ScaleImage(Image image, int maxHeight = MAX_HEIGHT, bool highQuality = QUALITY)
{
var ratio = (double)maxHeight / image.Height;
var newWidth = (int)(image.Width * ratio);
var newHeight = (int)(image.Height * ratio);
var newImage = new Bitmap(newWidth, newHeight);
using (var g = Graphics.FromImage(newImage))
{
if (highQuality)
{
g.CompositingQuality = CompositingQuality.HighQuality;
g.SmoothingMode = SmoothingMode.HighQuality;
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
}
g.DrawImage(image, 0, 0, newWidth, newHeight);
}
return newImage;
}
private static Image FixedSize(Image image, int Width, int Height, bool needToFill)
{
#region calculations
int sourceWidth = image.Width;
int sourceHeight = image.Height;
int sourceX = 0;
int sourceY = 0;
double destX = 0;
double destY = 0;
double nScale = 0;
double nScaleW = 0;
double nScaleH = 0;
nScaleW = ((double)Width / (double)sourceWidth);
nScaleH = ((double)Height / (double)sourceHeight);
if (!needToFill)
{
nScale = Math.Min(nScaleH, nScaleW);
}
else
{
nScale = Math.Max(nScaleH, nScaleW);
destY = (Height - sourceHeight * nScale) / 2;
destX = (Width - sourceWidth * nScale) / 2;
}
if (nScale > 1)
nScale = 1;
int destWidth = (int)Math.Round(sourceWidth * nScale);
int destHeight = (int)Math.Round(sourceHeight * nScale);
#endregion
Bitmap bmPhoto = null;
try
{
bmPhoto = new Bitmap(destWidth + (int)Math.Round(2 * destX), destHeight + (int)Math.Round(2 * destY));
}
catch (Exception ex)
{
throw new ApplicationException(string.Format("destWidth:{0}, destX:{1}, destHeight:{2}, desxtY:{3}, Width:{4}, Height:{5}",
destWidth, destX, destHeight, destY, Width, Height), ex);
}
using (Graphics grPhoto = Graphics.FromImage(bmPhoto))
{
if (QUALITY == true)
{
grPhoto.InterpolationMode = InterpolationMode.HighQualityBicubic;
grPhoto.CompositingQuality = CompositingQuality.HighQuality;
grPhoto.SmoothingMode = SmoothingMode.HighQuality;
}
Rectangle to = new Rectangle((int)Math.Round(destX), (int)Math.Round(destY), destWidth, destHeight);
Rectangle from = new Rectangle(sourceX, sourceY, sourceWidth, sourceHeight);
grPhoto.DrawImage(image, to, from, GraphicsUnit.Pixel);
return bmPhoto;
}
}
#endregion
}