C# 改变图片尺寸(压缩)，Image Resize

最新推荐文章于 2025-05-22 12:03:02 发布

转载最新推荐文章于 2025-05-22 12:03:02 发布 · 1.1k 阅读

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CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/miralce/p/5147697.html

文章标签：

#c# #游戏 #人工智能

本文介绍了一种图像处理算法，能够将指定目录中的图片按照指定的高度和宽度进行缩放，同时保持原始图片的比例，或者将图片按照比例放到中心位置。此算法适用于不同需求的图像缩放场景。

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/// <summary>
    /// Resize image with a directory as source
    /// </summary>
    /// <param name="OriginalFileLocation">Image location</param>
    /// <param name="heigth">new height</param>
    /// <param name="width">new width</param>
    /// <param name="keepAspectRatio">keep the aspect ratio</param>
    /// <param name="getCenter">return the center bit of the image</param>
    /// <returns>image with new dimentions</returns>
    public Image resizeImageFromFile(String OriginalFileLocation, int heigth, int width, Boolean keepAspectRatio, Boolean getCenter)
    {
        int newheigth = heigth;
        System.Drawing.Image FullsizeImage = System.Drawing.Image.FromFile(OriginalFileLocation);

        // Prevent using images internal thumbnail
        FullsizeImage.RotateFlip(System.Drawing.RotateFlipType.Rotate180FlipNone);
        FullsizeImage.RotateFlip(System.Drawing.RotateFlipType.Rotate180FlipNone);

        if (keepAspectRatio || getCenter)
        {
            int bmpY = 0;
            double resize = (double)FullsizeImage.Width / (double)width;//get the resize vector
            if (getCenter)
            {
                bmpY = (int)((FullsizeImage.Height - (heigth * resize)) / 2);// gives the Y value of the part that will be cut off, to show only the part in the center
                Rectangle section = new Rectangle(new Point(0, bmpY), new Size(FullsizeImage.Width, (int)(heigth * resize)));// create the section to cut of the original image
                //System.Console.WriteLine("the section that will be cut off: " + section.Size.ToString() + " the Y value is minimized by: " + bmpY);
                Bitmap orImg = new Bitmap((Bitmap)FullsizeImage);//for the correct effect convert image to bitmap.
                FullsizeImage.Dispose();//clear the original image
                using (Bitmap tempImg = new Bitmap(section.Width, section.Height))
                {
                    Graphics cutImg = Graphics.FromImage(tempImg);//              set the file to save the new image to.
                    cutImg.DrawImage(orImg, 0, 0, section, GraphicsUnit.Pixel);// cut the image and save it to tempImg
                    FullsizeImage = tempImg;//save the tempImg as FullsizeImage for resizing later
                    orImg.Dispose();
                    cutImg.Dispose();
                    return FullsizeImage.GetThumbnailImage(width, heigth, null, IntPtr.Zero);
                }
            }
            else newheigth = (int)(FullsizeImage.Height / resize);//  set the new heigth of the current image
        }//return the image resized to the given heigth and width
        return FullsizeImage.GetThumbnailImage(width, newheigth, null, IntPtr.Zero);
    }


     /// <summary>
    /// Resize image with a directory as source
    /// </summary>
    /// <param name="OriginalFileLocation">Image location</param>
    /// <param name="heigth">new height</param>
    /// <param name="width">new width</param>
    /// <returns>image with new dimentions</returns>
    public Image resizeImageFromFile(String OriginalFileLocation, int heigth, int width)
    {
        return resizeImageFromFile(OriginalFileLocation, heigth, width, false, false);
    }

    /// <summary>
    /// Resize image with a directory as source
    /// </summary>
    /// <param name="OriginalFileLocation">Image location</param>
    /// <param name="heigth">new height</param>
    /// <param name="width">new width</param>
    /// <param name="keepAspectRatio">keep the aspect ratio</param>
    /// <returns>image with new dimentions</returns>
    public Image resizeImageFromFile(String OriginalFileLocation, int heigth, int width, Boolean keepAspectRatio)
    {
        return resizeImageFromFile(OriginalFileLocation, heigth, width, keepAspectRatio, false);
    }