[Go] [C #] Resolve generated thumbnail blur issues

First, the problem scenario

Generates thumbnails of 48pxx48px for a square picture and saves them as picture files, but finds that the generated thumbnails are blurry.

The resulting blurred thumbnails are as follows:

Original picture (300pxx300px, PNG format):

System.Drawing.Image is called in the code. Getthumbnailimage () method, the main implementation code is as follows:

1 Private voidSavethumbnail (Bitmap Bitmap,intWidthintHeightstringDirectorystringFileNamestringextension)2 {3     varPhysicalPath = directory + filename +extension;4     using(varthumbnail = bitmap. Getthumbnailimage (width, height, () = {return true;}, IntPtr.Zero))5     {6         using(varEncoderParameters =NewEncoderParameters (1))7         {8encoderparameters.param[0] =NewEncoderparameter (Encoder.quality,100L);9 thumbnail. Save (PhysicalPath,Ten imagecodecinfo.getimageencoders () One. Where (x =x.filenameextension.contains (extension. Toupperinvariant ())) A                             . FirstOrDefault (), - encoderparameters); -         } the     }            -}

Second, the solution

Instead, call the System.Drawing.Graphics.DrawImage () method, and the main implementation code is as follows:

1 Private voidSavethumbnail (Bitmap Originbitmap,intWidthintHeightstringDirectorystringFileNamestringextension)2 {3     varPhysicalPath = directory + filename +extension;4             5     using(varNewImage =NewBitmap (width, height))6     {7         using(varGraphic =getgraphic (Originbitmap, newimage))8         {9Graphic. DrawImage (Originbitmap,0,0, width, height);Ten             using(varEncoderParameters =NewEncoderParameters (1)) One             { Aencoderparameters.param[0] =NewEncoderparameter (Encoder.quality,100L); - Newimage.save (PhysicalPath, - imagecodecinfo.getimageencoders () the. Where (x =x.filenameextension.contains (extension. Toupperinvariant ())) -                                 . FirstOrDefault (), - encoderparameters); -             } +         } -     }             + } A  at PrivateGraphics getgraphic (Image originimage, Bitmap newimage) - { - newimage.setresolution (originimage.horizontalresolution, originimage.verticalresolution); -     varGraphic =graphics.fromimage (newimage); -Graphic. Interpolationmode =System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic; -Graphic. SmoothingMode =System.Drawing.Drawing2D.SmoothingMode.HighQuality; inGraphic. Pixeloffsetmode =System.Drawing.Drawing2D.PixelOffsetMode.HighQuality; -Graphic.compositingquality =System.Drawing.Drawing2D.CompositingQuality.HighQuality; to     returngraphic; +}

The resulting thumbnail effect is as follows:

Iii. references

Cropping image using JQuery, Jcrop and ASP

Resizing an Image without losing any quality

[Go] [C #] Resolve generated thumbnail blur issues