C# 图片处理

目录

 1.按比例调整图片

 2.合成图片

 3.切割图片

 

1.按比例调整图片尺寸

 1 #region 按比例调整图片尺寸
 2 public static Bitmap GetThumbnail(Image bmp, int width, int height)
 3 {
 4     if (width == 0)
 5     {
 6         width = height * bmp.Width / bmp.Height;
 7     }
 8     if (height == 0)
 9     {
10         height = width * bmp.Height / bmp.Width;
11     }
12     Image imgSource = bmp;
13     Bitmap outBmp = new Bitmap(width, height);
14     Graphics g = Graphics.FromImage(outBmp);
15     g.Clear(Color.Transparent);
16     // 设置画布的描绘质量   
17     g.CompositingQuality = CompositingQuality.HighQuality;
18     g.SmoothingMode = SmoothingMode.HighQuality;
19     g.InterpolationMode = InterpolationMode.HighQualityBicubic;
20 
21     g.DrawImage(imgSource, new Rectangle(0, 0, width, height + 1), 0, 0, imgSource.Width, imgSource.Height, GraphicsUnit.Pixel);
22 
23     g.Dispose();
24     imgSource.Dispose();
25     bmp.Dispose();
26     return outBmp;
27 }
28 #endregion
按比例调整图片尺寸

  

2.合成图片

 1 /// <summary>
 2 /// 两种图片合并，类似相册，有个背景图，中间贴自己的目标图片        
 3 /// <param name="sourceImg">粘贴的源图片</param>
 4 /// <param name="destImg">粘贴的目标图片</param>
 5 /// <param name="name">合成图片存储路径</param>
 6 /// </summary>
 7 public void CombinImage(string sourceImg, string destImg, string name)
 8 {
 9     System.Drawing.Image imgBack = System.Drawing.Image.FromFile(sourceImg);     //相框图片 
10     System.Drawing.Image img = System.Drawing.Image.FromFile(destImg);        //照片图片
11 
12     Bitmap bmp = new Bitmap(imgBack.Width, imgBack.Height);
13 
14     Graphics g = Graphics.FromImage(bmp);
15     g.Clear(Color.White);
16     g.DrawImage(imgBack, 0, 0, imgBack.Width, imgBack.Height);
17     //g.FillRectangle(System.Drawing.Brushes.Black, 16, 16, (int)112 + 2, ((int)73 + 2));//相片四周刷一层黑色边框
18 
19     //g.DrawImage(img, 照片与相框的左边距, 照片与相框的上边距, 照片宽, 照片高);
20     g.DrawImage(img, imgBack.Width / 2 - img.Width / 2 + 0, imgBack.Height / 2 - img.Height / 2 + 0, img.Width, img.Height);
21     GC.Collect();
22 
23     //保存指定格式图片
24     bmp.Save(name, ImageFormat.Png);    
25 }
合成图片

 

 

3.切割图片

 

    /// <summary>
        /// 对URL链接图片进行切割操作
        /// </summary>
        /// <param name="ImgUrl">URL链接图片</param>
        /// <param name="Height">需要图片的高</param>
        /// <returns></returns>
        public async Task CardCutImg(string ImgUrl,int Height)
        {
            //这段步骤可根据实际情况跳过
            //传进来的地址可能会进行url编码操作，在这里需要对url进行解码
            string url = HttpUtility.UrlDecode(ImgUrl);
            //这一步是对文件名称进行URL编码(根据实际情况而定，我这里查看的是阿里云上的图)
            var arr = url.Split("/");            
            string enCodeFileName = HttpUtility.UrlEncode(arr[arr.Length - 1]);
            string resultURL = arr.Where(x => !x.Contains(".png")).ToList().Join("/") + "/" + enCodeFileName;

            //将URL转成文件流来进行处理
            Stream stream = await resultURL.GetAsStreamAsync();
            //如下方式也可
            //var wc = new System.Net.WebClient();
            //byte[] imageData = wc.DownloadData(item.CardOssUrl);
            //Stream stream = new MemoryStream(imageData);
            
            //转成Image类型，获取图片的高宽属性
            Image img = Image.FromStream(stream);

            Bitmap bitmap = new Bitmap(stream);
            var bt = new Bitmap(img.Width, Height);

            var grahics = Graphics.FromImage(bt);
            Rectangle resultRectangle = new Rectangle(0, 0, img.Width, Height);//指定在什么位置，绘制多大的图像
            Rectangle sourceRectangle = new Rectangle(0, 0, img.Width, Height);//指定源图像的位置和大小
            grahics.DrawImage(bitmap, resultRectangle, sourceRectangle, GraphicsUnit.Pixel);
            //grahics.DrawString("这是水印", new Font("黑体", 20), new SolidBrush(Color.FromArgb(70, Color.Black)), 60, height / 2);//加水印

            bt.Save("D:\\.jpg");

        }

        //调用
        await CardCutImg("https://keys-resource.oss-cn-shanghai.aliyuncs.com/WrongQuestionBook/13%2B1.png",118);
切割图片

 

posted @ 2021-07-20 17:27  Haoeaoi  阅读(317)  评论(0)  编辑  收藏  举报