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C#实现图片缩略图功能的示例详解

作者:芝麻粒儿

这篇文章主要为大家详细介绍了如何利用C#实现图片缩略图的功能,文中的示例代码讲解详细,对我们学习C#有一定的帮助,感兴趣的小伙伴可以跟随小编一起了解一下

实践过程

效果

代码

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

    public Image ResourceImage;
    private int ImageWidth;
    private int ImageHeight;
    public string ErrMessage;

    public bool ThumbnailCallback()
    {
        return false;
    }

    public bool GetReducedImage(double Percent, string targetFilePath)
    {
        try
        {
            Bitmap bt = new Bitmap(120, 120);
            Graphics g = Graphics.FromImage(bt);
            g.Clear(Color.White);
            Image ReducedImage;
            Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);
            ImageWidth = Convert.ToInt32(ResourceImage.Width * Percent);
            ImageHeight = Convert.ToInt32(ResourceImage.Height * Percent);
            ReducedImage = ResourceImage.GetThumbnailImage(ImageWidth, ImageHeight, callb, IntPtr.Zero);
            if (ImageWidth > ImageHeight)
            {
                g.DrawImage(ReducedImage, 0, (int) (120 - ImageHeight) / 2, ImageWidth, ImageHeight);
            }
            else
            {
                g.DrawImage(ReducedImage, (int) (120 - ImageWidth) / 2, 0, ImageWidth, ImageHeight);
            }

            g.DrawRectangle(new Pen(Color.Gainsboro), 0, 0, 119, 119);
            bt.Save(@targetFilePath, ImageFormat.Jpeg);
            bt.Dispose();
            ReducedImage.Dispose();
            return true;
        }
        catch (Exception e)
        {
            ErrMessage = e.Message;
            return false;
        }
    }

    private void button1_Click(object sender, EventArgs e)
    {
        if (openFileDialog1.ShowDialog() == DialogResult.OK)
        {
            pictureBox1.Image = Image.FromFile(openFileDialog1.FileName);
        }
    }

    private void button2_Click(object sender, EventArgs e)
    {
        double percent;
        string imgpath = openFileDialog1.FileName;
        string imgName = imgpath.ToString().Substring(imgpath.ToString().LastIndexOf("\\") + 1,
            imgpath.ToString().Length - 1 - imgpath.ToString().LastIndexOf("\\"));
        imgName = imgName.Remove(imgName.LastIndexOf("."));
        if (openFileDialog1.FileName.Length != 0)
        {
            ResourceImage = Image.FromFile(openFileDialog1.FileName);
            if (ResourceImage.Width < ResourceImage.Height)
            {
                percent = (double) 120 / ResourceImage.Height;
            }
            else
            {
                percent = (double) 120 / ResourceImage.Width;
            }

            GetReducedImage(percent, "c:\\_" + imgName + ".JPG");
            pictureBox2.Image = Image.FromFile("c:\\_" + imgName + ".JPG");
        }
    }
}
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.pictureBox1 = new System.Windows.Forms.PictureBox();
        this.pictureBox2 = new System.Windows.Forms.PictureBox();
        this.button1 = new System.Windows.Forms.Button();
        this.button2 = new System.Windows.Forms.Button();
        this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog();
        ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
        ((System.ComponentModel.ISupportInitialize)(this.pictureBox2)).BeginInit();
        this.SuspendLayout();
        // 
        // pictureBox1
        // 
        this.pictureBox1.Location = new System.Drawing.Point(11, 42);
        this.pictureBox1.Name = "pictureBox1";
        this.pictureBox1.Size = new System.Drawing.Size(262, 232);
        this.pictureBox1.SizeMode = System.Windows.Forms.PictureBoxSizeMode.Zoom;
        this.pictureBox1.TabIndex = 0;
        this.pictureBox1.TabStop = false;
        // 
        // pictureBox2
        // 
        this.pictureBox2.Location = new System.Drawing.Point(305, 80);
        this.pictureBox2.Name = "pictureBox2";
        this.pictureBox2.Size = new System.Drawing.Size(155, 132);
        this.pictureBox2.SizeMode = System.Windows.Forms.PictureBoxSizeMode.Zoom;
        this.pictureBox2.TabIndex = 1;
        this.pictureBox2.TabStop = false;
        // 
        // button1
        // 
        this.button1.Location = new System.Drawing.Point(11, 13);
        this.button1.Name = "button1";
        this.button1.Size = new System.Drawing.Size(75, 23);
        this.button1.TabIndex = 2;
        this.button1.Text = "选择图片";
        this.button1.UseVisualStyleBackColor = true;
        this.button1.Click += new System.EventHandler(this.button1_Click);
        // 
        // button2
        // 
        this.button2.Location = new System.Drawing.Point(93, 12);
        this.button2.Name = "button2";
        this.button2.Size = new System.Drawing.Size(75, 23);
        this.button2.TabIndex = 3;
        this.button2.Text = "显示缩略图";
        this.button2.UseVisualStyleBackColor = true;
        this.button2.Click += new System.EventHandler(this.button2_Click);
        // 
        // openFileDialog1
        // 
        this.openFileDialog1.Filter = "图片文件|*.jpg;*.jpeg;*.bmp;*.png";
        // 
        // Form1
        // 
        this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.ClientSize = new System.Drawing.Size(487, 296);
        this.Controls.Add(this.button2);
        this.Controls.Add(this.button1);
        this.Controls.Add(this.pictureBox2);
        this.Controls.Add(this.pictureBox1);
        this.Name = "Form1";
        this.Text = "Form1";
        ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
        ((System.ComponentModel.ISupportInitialize)(this.pictureBox2)).EndInit();
        this.ResumeLayout(false);

    }

    #endregion

    private System.Windows.Forms.PictureBox pictureBox1;
    private System.Windows.Forms.PictureBox pictureBox2;
    private System.Windows.Forms.Button button1;
    private System.Windows.Forms.Button button2;
    private System.Windows.Forms.OpenFileDialog openFileDialog1;
}

到此这篇关于C#实现图片缩略图功能的示例详解的文章就介绍到这了,更多相关C#图片缩略图内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家!

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