C#实现无损压缩图片的示例详解

目录

• 实践过程
• 效果
• 代码

实践过程

效果

代码

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    FileSystemInfo[] fsi = null;
    string ImgPath = "";
    ArrayList al = new ArrayList();
    string ImgSavePath = "";
    string strSourcePath = "";
    Thread td;
    Image ig = null;
    string strSavePath = "";

    private void Form1_Load(object sender, EventArgs e)
    {
        CheckForIllegalCrossThreadCalls = false;
    }

    /// <summary>
    /// 无损图片缩放
    /// </summary>
    /// <param name="sFile">图片的原始路径</param>
    /// <param name="dFile">缩放后图片的保存路径</param>
    /// <param name="dHeight">缩放后图片的高度</param>
    /// <param name="dWidth">缩放后图片的宽度</param>
    /// <returns></returns>
    public static bool GetPicThumbnail(string sFile, string dFile, int dHeight, int dWidth)
    {
        Image iSource = Image.FromFile(sFile);
        ImageFormat tFormat = iSource.RawFormat;
        int sW = 0, sH = 0;
        // 按比例缩放
        Size tem_size = new Size(iSource.Width, iSource.Height);
        if (tem_size.Height > dHeight || tem_size.Width > dWidth)
        {
            if ((tem_size.Width * dHeight) > (tem_size.Height * dWidth))
            {
                sW = dWidth;
                sH = (dWidth * tem_size.Height) / tem_size.Width;
            }
            else
            {
                sH = dHeight;
                sW = (tem_size.Width * dHeight) / tem_size.Height;
            }
        }
        else
        {
            sW = tem_size.Width;
            sH = tem_size.Height;
        }

        Bitmap oB = new Bitmap(dWidth, dHeight);
        Graphics g = Graphics.FromImage(oB);
        g.Clear(Color.WhiteSmoke);
        // 设置画布的描绘质量
        g.CompositingQuality = CompositingQuality.HighQuality;
        g.SmoothingMode = SmoothingMode.HighQuality;
        g.InterpolationMode = InterpolationMode.HighQualityBicubic;
        g.DrawImage(iSource, new Rectangle((dWidth - sW) / 2, (dHeight - sH) / 2, sW, sH), 0, 0, iSource.Width, iSource.Height, GraphicsUnit.Pixel);
        g.Dispose();
        // 以下代码为保存图片时，设置压缩质量
        EncoderParameters eP = new EncoderParameters();
        long[] qy = new long[1];
        qy[0] = 100;
        EncoderParameter eParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qy);
        eP.Param[0] = eParam;
        try
        {
            //获得包含有关内置图像编码解码器的信息的ImageCodecInfo对象。
            ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders();
            ImageCodecInfo jpegICIinfo = null;
            for (int x = 0; x < arrayICI.Length; x++)
            {
                if (arrayICI[x].FormatDescription.Equals("JPEG"))
                {
                    jpegICIinfo = arrayICI[x]; //设置JPEG编码
                    break;
                }
            }

            if (jpegICIinfo != null)
            {
                oB.Save(dFile, jpegICIinfo, eP);
            }
            else
            {
                oB.Save(dFile, tFormat);
            }

            return true;
        }
        catch
        {
            return false;
        }
        finally
        {
            iSource.Dispose();
            oB.Dispose();
        }
    }

    private void pictureBox1_Click(object sender, EventArgs e)
    {
        if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
        {
            fsi = null;
            al.Clear();
            txtPicPath.Text = folderBrowserDialog1.SelectedPath;
            ImgPath = txtPicPath.Text.Trim();
            DirectoryInfo di = new DirectoryInfo(txtPicPath.Text);
            fsi = di.GetFileSystemInfos();
            for (int i = 0; i < fsi.Length; i++)
            {
                string ofile = fsi[i].ToString();
                string fileType = ofile.Substring(ofile.LastIndexOf(".") + 1, ofile.Length - ofile.LastIndexOf(".") - 1);
                fileType = fileType.ToLower();
                if (fileType == "jpeg" || fileType == "jpg" || fileType == "bmp" || fileType == "png")
                {
                    al.Add(ofile);
                }
            }

            lblPicNum.Text = al.Count.ToString();
        }
    }

    private void pictureBox2_Click(object sender, EventArgs e)
    {
        if (folderBrowserDialog2.ShowDialog() == DialogResult.OK)
        {
            txtSavePath.Text = folderBrowserDialog2.SelectedPath;
            ImgSavePath = txtSavePath.Text.Trim();
        }
    }

    private void button2_Click(object sender, EventArgs e)
    {
        Application.Exit();
    }

    private void rbPercent_Enter(object sender, EventArgs e)
    {
        groupBox1.Focus();
    }

    private void rbResolving_Enter(object sender, EventArgs e)
    {
        groupBox1.Focus();
    }

    private void CompleteIMG()
    {
        progressBar1.Maximum = al.Count;
        progressBar1.Minimum = 1;
        if (ImgPath.Length == 3)
            strSourcePath = ImgPath;
        else
            strSourcePath = ImgPath + "\\";

        if (ImgSavePath.Length == 3)
            strSavePath = ImgSavePath;
        else
            strSavePath = ImgSavePath + "\\";
        for (int i = 0; i < al.Count; i++)
        {
            ig = Image.FromFile(strSourcePath + al[i].ToString());
            if (rbPercent.Checked)
            {
                GetPicThumbnail(strSourcePath + al[i].ToString(), strSavePath + al[i].ToString(), Convert.ToInt32(ig.Width * (numericUpDown1.Value / 100)),
                    Convert.ToInt32(ig.Height * (numericUpDown1.Value / 100)));
            }

            ig.Dispose();
            progressBar1.Value = i + 1;
            lblComplete.Text = Convert.ToString(i + 1);
        }

        if (lblComplete.Text == al.Count.ToString())
        {
            MessageBox.Show("压缩成功", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
            progressBar1.Value = 1;
            pictureBox1.Enabled = true;
            pictureBox2.Enabled = true;
            rbPercent.Enabled = true;
            lblPicNum.Text = "0";
            lblComplete.Text = "0";
        }
    }

    private void button1_Click(object sender, EventArgs e)
    {
        if (txtPicPath.Text.Trim() != "" && txtSavePath.Text.Trim() != "" && lblPicNum.Text != "0")
        {
            pictureBox1.Enabled = false;
            pictureBox2.Enabled = false;
            rbPercent.Enabled = false;
            td = new Thread(new ThreadStart(this.CompleteIMG));
            td.Start();
        }
        else
        {
            if (txtPicPath.Text.Trim() == "" && txtSavePath.Text.Trim() == "")
            {
                MessageBox.Show("警告：请选择待处理的图片目录及保存位置", "警告", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
            else
            {
                if (txtPicPath.Text.Trim() == "")
                    MessageBox.Show("警告：请选择待处理的图片", "警告", MessageBoxButtons.OK, MessageBoxIcon.Error);
                if (txtSavePath.Text.Trim() == "")
                    MessageBox.Show("警告：请选择保存路径", "警告", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }
    }

    private void Form1_FormClosed(object sender, FormClosedEventArgs e)
    {
        if (td != null)
        {
            td.Abort();
        }
    }
}

 partial class Form1
    {
        /// <summary>
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// 清理所有正在使用的资源。
        /// </summary>
        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows 窗体设计器生成的代码

        /// <summary>
        /// 设计器支持所需的方法 - 不要
        /// 使用代码编辑器修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            this.groupBox1 = new System.Windows.Forms.GroupBox();
            this.panel2 = new System.Windows.Forms.Panel();
            this.pictureBox2 = new System.Windows.Forms.PictureBox();
            this.txtSavePath = new System.Windows.Forms.TextBox();
            this.panel1 = new System.Windows.Forms.Panel();
            this.pictureBox1 = new System.Windows.Forms.PictureBox();
            this.txtPicPath = new System.Windows.Forms.TextBox();
            this.label2 = new System.Windows.Forms.Label();
            this.label1 = new System.Windows.Forms.Label();
            this.groupBox2 = new System.Windows.Forms.GroupBox();
            this.numericUpDown1 = new System.Windows.Forms.NumericUpDown();
            this.label4 = new System.Windows.Forms.Label();
            this.label3 = new System.Windows.Forms.Label();
            this.rbPercent = new System.Windows.Forms.RadioButton();
            this.groupBox3 = new System.Windows.Forms.GroupBox();
            this.progressBar1 = new System.Windows.Forms.ProgressBar();
            this.label13 = new System.Windows.Forms.Label();
            this.lblComplete = new System.Windows.Forms.Label();
            this.lblPicNum = new System.Windows.Forms.Label();
            this.label8 = new System.Windows.Forms.Label();
            this.label7 = new System.Windows.Forms.Label();
            this.button1 = new System.Windows.Forms.Button();
            this.button2 = new System.Windows.Forms.Button();
            this.folderBrowserDialog1 = new System.Windows.Forms.FolderBrowserDialog();
            this.folderBrowserDialog2 = new System.Windows.Forms.FolderBrowserDialog();
            this.groupBox1.SuspendLayout();
            this.panel2.SuspendLayout();
            ((System.ComponentModel.ISupportInitialize)(this.pictureBox2)).BeginInit();
            this.panel1.SuspendLayout();
            ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
            this.groupBox2.SuspendLayout();
            ((System.ComponentModel.ISupportInitialize)(this.numericUpDown1)).BeginInit();
            this.groupBox3.SuspendLayout();
            this.SuspendLayout();
            //
            // groupBox1
            //
            this.groupBox1.Controls.Add(this.panel2);
            this.groupBox1.Controls.Add(this.panel1);
            this.groupBox1.Controls.Add(this.label2);
            this.groupBox1.Controls.Add(this.label1);
            this.groupBox1.Location = new System.Drawing.Point(3, 1);
            this.groupBox1.Name = "groupBox1";
            this.groupBox1.Size = new System.Drawing.Size(458, 81);
            this.groupBox1.TabIndex = 0;
            this.groupBox1.TabStop = false;
            this.groupBox1.Text = "常规";
            //
            // panel2
            //
            this.panel2.BackColor = System.Drawing.Color.White;
            this.panel2.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
            this.panel2.Controls.Add(this.pictureBox2);
            this.panel2.Controls.Add(this.txtSavePath);
            this.panel2.Location = new System.Drawing.Point(130, 53);
            this.panel2.Name = "panel2";
            this.panel2.Size = new System.Drawing.Size(322, 21);
            this.panel2.TabIndex = 5;
            //
            // pictureBox2
            //
            this.pictureBox2.Cursor = System.Windows.Forms.Cursors.PanSE;
            this.pictureBox2.Image = global::CompressImg.Properties.Resources.文件夹打开;
            this.pictureBox2.Location = new System.Drawing.Point(300, 0);
            this.pictureBox2.Name = "pictureBox2";
            this.pictureBox2.Size = new System.Drawing.Size(19, 18);
            this.pictureBox2.TabIndex = 8;
            this.pictureBox2.TabStop = false;
            this.pictureBox2.Click += new System.EventHandler(this.pictureBox2_Click);
            //
            // txtSavePath
            //
            this.txtSavePath.BackColor = System.Drawing.Color.White;
            this.txtSavePath.BorderStyle = System.Windows.Forms.BorderStyle.None;
            this.txtSavePath.Location = new System.Drawing.Point(0, 1);
            this.txtSavePath.Name = "txtSavePath";
            this.txtSavePath.ReadOnly = true;
            this.txtSavePath.Size = new System.Drawing.Size(302, 14);
            this.txtSavePath.TabIndex = 1;
            //
            // panel1
            //
            this.panel1.BackColor = System.Drawing.Color.White;
            this.panel1.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
            this.panel1.Controls.Add(this.pictureBox1);
            this.panel1.Controls.Add(this.txtPicPath);
            this.panel1.Location = new System.Drawing.Point(130, 23);
            this.panel1.Name = "panel1";
            this.panel1.Size = new System.Drawing.Size(322, 21);
            this.panel1.TabIndex = 4;
            //
            // pictureBox1
            //
            this.pictureBox1.Cursor = System.Windows.Forms.Cursors.PanSE;
            this.pictureBox1.Image = global::CompressImg.Properties.Resources.文件夹打开;
            this.pictureBox1.Location = new System.Drawing.Point(300, 0);
            this.pictureBox1.Name = "pictureBox1";
            this.pictureBox1.Size = new System.Drawing.Size(19, 18);
            this.pictureBox1.TabIndex = 8;
            this.pictureBox1.TabStop = false;
            this.pictureBox1.Click += new System.EventHandler(this.pictureBox1_Click);
            //
            // txtPicPath
            //
            this.txtPicPath.BackColor = System.Drawing.Color.White;
            this.txtPicPath.BorderStyle = System.Windows.Forms.BorderStyle.None;
            this.txtPicPath.Location = new System.Drawing.Point(0, 1);
            this.txtPicPath.Name = "txtPicPath";
            this.txtPicPath.ReadOnly = true;
            this.txtPicPath.Size = new System.Drawing.Size(302, 14);
            this.txtPicPath.TabIndex = 1;
            //
            // label2
            //
            this.label2.AutoSize = true;
            this.label2.Location = new System.Drawing.Point(7, 57);
            this.label2.Name = "label2";
            this.label2.Size = new System.Drawing.Size(125, 12);
            this.label2.TabIndex = 2;
            this.label2.Text = "处理后的图片保存至：";
            //
            // label1
            //
            this.label1.AutoSize = true;
            this.label1.Location = new System.Drawing.Point(8, 28);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(125, 12);
            this.label1.TabIndex = 0;
            this.label1.Text = "等待处理的图片位置：";
            //
            // groupBox2
            //
            this.groupBox2.Controls.Add(this.numericUpDown1);
            this.groupBox2.Controls.Add(this.label4);
            this.groupBox2.Controls.Add(this.label3);
            this.groupBox2.Controls.Add(this.rbPercent);
            this.groupBox2.Location = new System.Drawing.Point(3, 86);
            this.groupBox2.Name = "groupBox2";
            this.groupBox2.Size = new System.Drawing.Size(458, 47);
            this.groupBox2.TabIndex = 1;
            this.groupBox2.TabStop = false;
            this.groupBox2.Text = "改变大小";
            //
            // numericUpDown1
            //
            this.numericUpDown1.Location = new System.Drawing.Point(188, 17);
            this.numericUpDown1.Maximum = new decimal(new int[] {
            200,
            0,
            0,
            0});
            this.numericUpDown1.Minimum = new decimal(new int[] {
            1,
            0,
            0,
            0});
            this.numericUpDown1.Name = "numericUpDown1";
            this.numericUpDown1.Size = new System.Drawing.Size(40, 21);
            this.numericUpDown1.TabIndex = 8;
            this.numericUpDown1.Value = new decimal(new int[] {
            50,
            0,
            0,
            0});
            //
            // label4
            //
            this.label4.AutoSize = true;
            this.label4.Location = new System.Drawing.Point(234, 22);
            this.label4.Name = "label4";
            this.label4.Size = new System.Drawing.Size(11, 12);
            this.label4.TabIndex = 4;
            this.label4.Text = "%";
            //
            // label3
            //
            this.label3.AutoSize = true;
            this.label3.Location = new System.Drawing.Point(92, 22);
            this.label3.Name = "label3";
            this.label3.Size = new System.Drawing.Size(89, 12);
            this.label3.TabIndex = 2;
            this.label3.Text = "改成原图大小的";
            //
            // rbPercent
            //
            this.rbPercent.AutoSize = true;
            this.rbPercent.Checked = true;
            this.rbPercent.Location = new System.Drawing.Point(10, 20);
            this.rbPercent.Name = "rbPercent";
            this.rbPercent.Size = new System.Drawing.Size(71, 16);
            this.rbPercent.TabIndex = 0;
            this.rbPercent.TabStop = true;
            this.rbPercent.Text = "按百分比";
            this.rbPercent.UseVisualStyleBackColor = true;
            this.rbPercent.Enter += new System.EventHandler(this.rbPercent_Enter);
            //
            // groupBox3
            //
            this.groupBox3.Controls.Add(this.progressBar1);
            this.groupBox3.Controls.Add(this.label13);
            this.groupBox3.Controls.Add(this.lblComplete);
            this.groupBox3.Controls.Add(this.lblPicNum);
            this.groupBox3.Controls.Add(this.label8);
            this.groupBox3.Controls.Add(this.label7);
            this.groupBox3.Location = new System.Drawing.Point(3, 139);
            this.groupBox3.Name = "groupBox3";
            this.groupBox3.Size = new System.Drawing.Size(458, 85);
            this.groupBox3.TabIndex = 9;
            this.groupBox3.TabStop = false;
            this.groupBox3.Text = "操作显示";
            //
            // progressBar1
            //
            this.progressBar1.Location = new System.Drawing.Point(107, 54);
            this.progressBar1.Name = "progressBar1";
            this.progressBar1.Size = new System.Drawing.Size(302, 18);
            this.progressBar1.Step = 1;
            this.progressBar1.TabIndex = 16;
            //
            // label13
            //
            this.label13.AutoSize = true;
            this.label13.Location = new System.Drawing.Point(42, 57);
            this.label13.Name = "label13";
            this.label13.Size = new System.Drawing.Size(53, 12);
            this.label13.TabIndex = 15;
            this.label13.Text = "处理进度";
            //
            // lblComplete
            //
            this.lblComplete.AutoSize = true;
            this.lblComplete.Location = new System.Drawing.Point(339, 25);
            this.lblComplete.Name = "lblComplete";
            this.lblComplete.Size = new System.Drawing.Size(11, 12);
            this.lblComplete.TabIndex = 12;
            this.lblComplete.Text = "0";
            //
            // lblPicNum
            //
            this.lblPicNum.AutoSize = true;
            this.lblPicNum.Location = new System.Drawing.Point(149, 26);
            this.lblPicNum.Name = "lblPicNum";
            this.lblPicNum.Size = new System.Drawing.Size(11, 12);
            this.lblPicNum.TabIndex = 11;
            this.lblPicNum.Text = "0";
            //
            // label8
            //
            this.label8.AutoSize = true;
            this.label8.Location = new System.Drawing.Point(255, 26);
            this.label8.Name = "label8";
            this.label8.Size = new System.Drawing.Size(77, 12);
            this.label8.TabIndex = 10;
            this.label8.Text = "已经处理成功";
            //
            // label7
            //
            this.label7.AutoSize = true;
            this.label7.Location = new System.Drawing.Point(42, 26);
            this.label7.Name = "label7";
            this.label7.Size = new System.Drawing.Size(101, 12);
            this.label7.TabIndex = 9;
            this.label7.Text = "待处理的图片共有";
            //
            // button1
            //
            this.button1.Location = new System.Drawing.Point(305, 230);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(75, 23);
            this.button1.TabIndex = 10;
            this.button1.Text = "开始压缩";
            this.button1.UseVisualStyleBackColor = true;
            this.button1.Click += new System.EventHandler(this.button1_Click);
            //
            // button2
            //
            this.button2.Location = new System.Drawing.Point(386, 230);
            this.button2.Name = "button2";
            this.button2.Size = new System.Drawing.Size(75, 23);
            this.button2.TabIndex = 11;
            this.button2.Text = "取消";
            this.button2.UseVisualStyleBackColor = true;
            this.button2.Click += new System.EventHandler(this.button2_Click);
            //
            // Form1
            //
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(463, 261);
            this.Controls.Add(this.button2);
            this.Controls.Add(this.button1);
            this.Controls.Add(this.groupBox3);
            this.Controls.Add(this.groupBox2);
            this.Controls.Add(this.groupBox1);
            this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle;
            this.MaximizeBox = false;
            this.MinimizeBox = false;
            this.Name = "Form1";
            this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
            this.Text = "无损压缩图片";
            this.Load += new System.EventHandler(this.Form1_Load);
            this.FormClosed += new System.Windows.Forms.FormClosedEventHandler(this.Form1_FormClosed);
            this.groupBox1.ResumeLayout(false);
            this.groupBox1.PerformLayout();
            this.panel2.ResumeLayout(false);
            this.panel2.PerformLayout();
            ((System.ComponentModel.ISupportInitialize)(this.pictureBox2)).EndInit();
            this.panel1.ResumeLayout(false);
            this.panel1.PerformLayout();
            ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
            this.groupBox2.ResumeLayout(false);
            this.groupBox2.PerformLayout();
            ((System.ComponentModel.ISupportInitialize)(this.numericUpDown1)).EndInit();
            this.groupBox3.ResumeLayout(false);
            this.groupBox3.PerformLayout();
            this.ResumeLayout(false);

        }

        #endregion

        private System.Windows.Forms.GroupBox groupBox1;
        private System.Windows.Forms.TextBox txtPicPath;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Label label2;
        private System.Windows.Forms.GroupBox groupBox2;
        private System.Windows.Forms.Label label4;
        private System.Windows.Forms.Label label3;
        private System.Windows.Forms.RadioButton rbPercent;
        private System.Windows.Forms.GroupBox groupBox3;
        private System.Windows.Forms.Label label13;
        private System.Windows.Forms.Label lblComplete;
        private System.Windows.Forms.Label lblPicNum;
        private System.Windows.Forms.Label label8;
        private System.Windows.Forms.Label label7;
        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.Button button2;
        private System.Windows.Forms.Panel panel1;
        private System.Windows.Forms.PictureBox pictureBox1;
        private System.Windows.Forms.Panel panel2;
        private System.Windows.Forms.PictureBox pictureBox2;
        private System.Windows.Forms.TextBox txtSavePath;
        private System.Windows.Forms.ProgressBar progressBar1;
        private System.Windows.Forms.FolderBrowserDialog folderBrowserDialog1;
        private System.Windows.Forms.FolderBrowserDialog folderBrowserDialog2;
        private System.Windows.Forms.NumericUpDown numericUpDown1;
    }

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