C # jpg thumbnail Function Code

Copy codeThe Code is as follows: // <summary>
/// Generate jpg thumbnail bytes, which are required in my small software. So I made a function and shared it with you.
/// Why do we need to generate bytes instead of files? This is to facilitate subsequent processing ^_^
/// </Summary>
/// <Param name = "originalImagePath"> original path </param>
/// <Param name = "quality"> quality 0-100 </param>
/// <Param name = "width"> width </param>
/// <Param name = "height"> height </param>
/// <Param name = "mode"> mode: HW, W, H, Cut </param>
/// <Returns> </returns>
Public static byte [] MakeJPGThumbnailBytes (string originalImagePath, long quality, int width, int height, string mode)
{
Image originalImage = Image. FromFile (originalImagePath );
MemoryStream s = new MemoryStream ();
Int towidth = width;
Int toheight = height;

Int x = 0;
Int y = 0;
Int ow = originalImage. Width;
Int oh = originalImage. Height;

Switch (mode)
{
Case "HW": // specify high-width Scaling (possibly deformed)
Break;
Case "W": // specify the width, and the height is proportional.
Toheight = originalImage. Height * width/originalImage. Width;
Break;
Case "H": // specify the height. The width is proportional.
Towidth = originalImage. Width * height/originalImage. Height;
Break;
Case "Cut": // specify the height and width (not deformed)
If (double) originalImage. Width/(double) originalImage. Height> (double) towidth/(double) toheight)
{
Oh = originalImage. Height;
Ow = originalImage. Height * towidth/toheight;
Y = 0;
X = (originalImage. Width-ow)/2;
}
Else
{
Ow = originalImage. Width;
Oh = originalImage. Width * height/towidth;
X = 0;
Y = (originalImage. Height-oh)/2;
}
Break;
Default:
Break;
}

// Create a bmp Image
Image bitmap = new System. Drawing. Bitmap (towidth, toheight );

// Create a canvas
Graphics g = System. Drawing. Graphics. FromImage (bitmap );

// Set a high quality Interpolation Method
G. InterpolationMode = System. Drawing. Drawing2D. InterpolationMode. High;

// Set high quality and smooth Low Speed
G. SmoothingMode = System. Drawing. Drawing2D. SmoothingMode. HighQuality;

// Clear the canvas and fill it with a transparent background color
G. Clear (Color. Transparent );

// Draw the specified part of the original image at the specified position and in the specified size
G. DrawImage (originalImage, new Rectangle (0, 0, towidth, toheight ),
New Rectangle (x, y, ow, oh ),
GraphicsUnit. Pixel );

Try
{
// Save the thumbnail in jpg format
EncoderParameters eps = new EncoderParameters (1 );
EncoderParameter ep = new EncoderParameter (Encoder. Quality, quality );
Eps. Param [0] = ep;
Bitmap. Save (s, GetCodecInfo ("image/jpeg"), eps );
Return s. GetBuffer ();
}
Catch (System. Exception e)
{
Throw e;
}
Finally
{
OriginalImage. Dispose ();
Bitmap. Dispose ();
S. Dispose ();
G. Dispose ();
}
}

/**/
/// <Summary>
/// Used to save JPG files
/// </Summary>
/// <Param name = "mimeType"> </param>
/// <Returns> obtain the ImageCodecInfo of the specified mimeType. </returns>
Private static ImageCodecInfo GetCodecInfo (string mimeType)
{
ImageCodecInfo [] CodecInfo = ImageCodecInfo. GetImageEncoders ();
Foreach (ImageCodecInfo ici in CodecInfo)
{
If (ici. MimeType = mimeType) return ici;
}
Return null;
}