Miniature di immagine ASP.NET

Question

Sto cercando di generare anteprime da file di immagini archiviati in una cartella sotto la radice del sito Web, sto attualmente usando le Capebilite integrate in .NET per generare dinamicamente le anteprime ma la qualità peggiora e dal momento che è un webshop questo è tutto un vero problema, la mia domanda è se ci sono dei buoni framework (open source?) che possono aiutarmi a creare e rielaborare la miniatura dell'anteprima dell'immagine e possibile aiuto con la compressione della dimensione del file immagine durante il caricamento?

Ho guardato ma non hai ancora trovato?

Grazie in anticipo.

Answer 1

Ho scritto del codice che potresti usare. Per favore, non venderlo;)

Questo è il codice:

/*
 *  Software Developed by Filip Ekberg ( Filip@SmartIT.se )
 * 
 *  For Questions regarding this software, please send me an E-mail
 * 
 */

#region Usings
using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
#endregion

namespace ImageResizer
{
    class ImageProcessor
    {
        #region Members
        private int m_imgWidht,
                    m_imgHeight,
                    m_oImgWidht,
                    m_oImgHeight;

        private float m_vertRes,
                      m_horiRes;

        private double m_size = 0.25;

        private Bitmap m_Bitmap;
        private Graphics m_Graphics;
        private Image m_currentImage;

        private PixelFormat m_pxlFormat = PixelFormat.Format32bppRgb;
        private InterpolationMode m_interpolationMode = InterpolationMode.HighQualityBilinear;
        private CompositingQuality m_compositingQuality = CompositingQuality.HighQuality;
        private SmoothingMode m_smoothingMode = SmoothingMode.None;
        #endregion

        #region Access Methods

        public int ImageWidth 
        {
            get { return m_imgWidht; }
        }
        public int ImageHeight 
       {
            get { return m_imgHeight; }
        }
        public float VerticalResolution
        {
            get { return m_vertRes; }
            set { m_vertRes = value; }
        }
        public float HorizonalResolution
        {
            get { return m_horiRes; }
            set { m_horiRes = value; }
        }

        /// <summary>
        /// Use ImageSize struct for setting this.
        /// </summary>
        public double Size
        {
            get { return m_size; }
            set { m_size = value; }
        }
        public Image ProcessImage
        {
            get { return m_currentImage; }
            set { m_currentImage = value; }
        }
        public PixelFormat ImagePixelFormat 
        {
            get { return m_pxlFormat; }
            set { m_pxlFormat = value; }
        }
        public InterpolationMode ImageInterpolationMode
        {
            get { return m_interpolationMode; }
            set { m_interpolationMode = value; }
        }
        public CompositingQuality ImageCompositingQuality
        {
            get { return m_compositingQuality; }
            set { m_compositingQuality = value; }
        }
        public SmoothingMode ImageSmoothingMode
        {
            get { return m_smoothingMode; }
            set { m_smoothingMode = value; }
        }

        #endregion

        #region Process Image
        public Bitmap BeginProcess()
        {
            if ( m_currentImage == null )
                return null;

            m_oImgWidht = m_currentImage.Width;
            m_oImgHeight = m_currentImage.Height;

            m_vertRes = m_currentImage.VerticalResolution;
            m_horiRes = m_currentImage.HorizontalResolution;

            m_imgWidht = (int)(m_oImgWidht * (double)m_size);
            m_imgHeight = (int)(m_oImgHeight * (double)m_size);


            m_Bitmap = new Bitmap(m_imgWidht, m_imgHeight, m_pxlFormat);

            m_Bitmap.SetResolution(m_vertRes, m_horiRes);

            m_Graphics = Graphics.FromImage(m_Bitmap);

            m_Graphics.InterpolationMode = m_interpolationMode;

            m_Graphics.CompositingQuality = m_compositingQuality;

            m_Graphics.SmoothingMode = m_smoothingMode;

            // m_Graphics.DrawImage(m_currentImage, new Rectangle(0, 0, m_imgWidht, m_imgHeight), new Rectangle(0, 0, m_oImgWidht, m_oImgHeight), GraphicsUnit.Pixel);

            Rectangle rectDestination = new Rectangle(0, 0, m_imgWidht, m_imgHeight);
           // m_Graphics.DrawImage(m_currentImage,
           //     new Rectangle(-1, -1, m_oImgWidht + 2, m_oImgHeight + 2),
            //    new Rectangle(m_oImgWidht, m_oImgHeight, m_imgWidht, m_oImgHeight),
            //    GraphicsUnit.Pixel);
            ImageAttributes ia = new ImageAttributes();
            ia.SetWrapMode(WrapMode.TileFlipXY);
            m_Graphics.DrawImage(m_currentImage, rectDestination, 0, 0, m_oImgWidht, m_oImgHeight, GraphicsUnit.Pixel, ia); 

            // m_Graphics.Dispose();

            return m_Bitmap;
        }
        #endregion
    }
}

Ecco come potresti usarlo:

private ImageProcessor m_processor = new ImageProcessor();


m_currentImage = new Bitmap(currentFile.FullName);

                // Display a Thumbnail of it
                pictureBox1.Image = m_currentImage.GetThumbnailImage(pictureBox1.Width, pictureBox1.Height, null, IntPtr.Zero);

                // Update the Label with Filename and what file is currently processed
                delegate_lblControl(currentFile.Name + "\n" + m_currentProcessedImage + " / " + m_fileList.Length);

                // Increase the value on the ProcessBar
                delegate_imageProcessValue(1);

                // Process the Image
                m_processor.ProcessImage = m_currentImage;

                m_processor.Size = m_size;

                m_finalProcessedImage = m_processor.BeginProcess();

                ImageCodecInfo jgpEncoder = GetEncoder(ImageFormat.Jpeg);
                System.Drawing.Imaging.Encoder myEncoder =
                    System.Drawing.Imaging.Encoder.Quality;

                EncoderParameters myEncoderParameters = new EncoderParameters(1);
                EncoderParameter myEncoderParameter = new EncoderParameter(myEncoder, m_jpegQuality);
                myEncoderParameters.Param[0] = myEncoderParameter;


                // Save the Image to the Output folder
                m_finalProcessedImage.Save(fldOutput.SelectedPath + "\\" + currentFile.Name, jgpEncoder, myEncoderParameters);

                // Dispose the Images
                m_finalProcessedImage.Dispose();

                m_currentImage.Dispose();

Ciò che il codice che ho scritto può effettivamente fare è ridimensionare le tue immagini a una percentuale specifica.