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利用C#实现修改图片透明度功能

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#实现修改图片透明度功能,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了解一下

实践过程

效果

代码

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }
    Image new_img;
    private void ChangeAlpha()
    {
        pictureBox1.Refresh();
        Bitmap source = new Bitmap(pictureBox1.Image);
        Bitmap effect = new Bitmap(pictureBox1.Image.Width,pictureBox1.Image.Height);
        Graphics _effect = Graphics.FromImage(effect);
        float[][] matrixItems ={new float[]{1,0,0,0,0},
                                  new float [] {0,1,0,0,0},
                                  new float []{0,0,1,0,0},
                                  new float []{0,0,0,0,0},
                                  new float[]{0,0,0,trackBar1.Value/255f,1}};
        ColorMatrix imgMatrix = new ColorMatrix(matrixItems);
        ImageAttributes imgEffect = new ImageAttributes();
        imgEffect.SetColorMatrix(imgMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);
        if (source.Width <= 368)
        {
            _effect.DrawImage(source, new Rectangle(0, 0, pictureBox1.Image.Width, pictureBox1.Image.Height), 0, 0, pictureBox1.Image.Width, pictureBox1.Image.Height, GraphicsUnit.Pixel, imgEffect);
        }
        else
        {
            _effect.DrawImage(pictureBox1.Image, new Rectangle(0, 0, pictureBox1.Image.Width, pictureBox1.Image.Height), 0, 0, pictureBox1.Image.Width, pictureBox1.Image.Height, GraphicsUnit.Pixel, imgEffect);
        }
        pictureBox1.Image = effect;
    }
    private void Form1_Load(object sender, EventArgs e)
    {

    }

    private void trackBar1_ValueChanged(object sender, EventArgs e)
    {
        ChangeAlpha();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        if (openFileDialog1.ShowDialog() == DialogResult.OK)
        {
            pictureBox1.Image = Image.FromFile(openFileDialog1.FileName);
        }
    }
}
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.trackBar1 = new System.Windows.Forms.TrackBar();
        this.button1 = new System.Windows.Forms.Button();
        this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog();
        ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
        ((System.ComponentModel.ISupportInitialize)(this.trackBar1)).BeginInit();
        this.SuspendLayout();
        // 
        // pictureBox1
        // 
        this.pictureBox1.Location = new System.Drawing.Point(12, 80);
        this.pictureBox1.Name = "pictureBox1";
        this.pictureBox1.Size = new System.Drawing.Size(424, 258);
        this.pictureBox1.SizeMode = System.Windows.Forms.PictureBoxSizeMode.Zoom;
        this.pictureBox1.TabIndex = 0;
        this.pictureBox1.TabStop = false;
        // 
        // trackBar1
        // 
        this.trackBar1.Location = new System.Drawing.Point(12, 41);
        this.trackBar1.Maximum = 100;
        this.trackBar1.Minimum = 1;
        this.trackBar1.Name = "trackBar1";
        this.trackBar1.Size = new System.Drawing.Size(424, 45);
        this.trackBar1.TabIndex = 1;
        this.trackBar1.TickStyle = System.Windows.Forms.TickStyle.None;
        this.trackBar1.Value = 100;
        this.trackBar1.ValueChanged += new System.EventHandler(this.trackBar1_ValueChanged);
        // 
        // button1
        // 
        this.button1.Location = new System.Drawing.Point(12, 12);
        this.button1.Name = "button1";
        this.button1.Size = new System.Drawing.Size(75, 23);
        this.button1.TabIndex = 2;
        this.button1.Text = "打开图片";
        this.button1.UseVisualStyleBackColor = true;
        this.button1.Click += new System.EventHandler(this.button1_Click);
        // 
        // openFileDialog1
        // 
        this.openFileDialog1.Filter = "图片文件|*.jpg;*.jpeg;*.png;*.bmp";
        // 
        // Form1
        // 
        this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.ClientSize = new System.Drawing.Size(447, 350);
        this.Controls.Add(this.pictureBox1);
        this.Controls.Add(this.button1);
        this.Controls.Add(this.trackBar1);
        this.Name = "Form1";
        this.Text = "Form1";
        this.Load += new System.EventHandler(this.Form1_Load);
        ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
        ((System.ComponentModel.ISupportInitialize)(this.trackBar1)).EndInit();
        this.ResumeLayout(false);
        this.PerformLayout();

    }

    #endregion

    private System.Windows.Forms.PictureBox pictureBox1;
    private System.Windows.Forms.TrackBar trackBar1;
    private System.Windows.Forms.Button button1;
    private System.Windows.Forms.OpenFileDialog openFileDialog1;
}

到此这篇关于利用C#实现修改图片透明度功能的文章就介绍到这了,更多相关C#修改图片透明度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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