c# 在保持纵横比的同时将图像调整为不同的大小 [英] c# Image resizing to different size while preserving aspect ratio

问题描述

我正在尝试调整图像大小，同时保留原始图像的纵横比，以免新图像看起来被压扁.

I'm trying to resize an image while preserving the aspect ratio from the original image so the new image doesn't look squashed.

例如:

将 150*100 的图像转换为 150*150 的图像.
高度的额外50像素需要用白色背景色填充.

Convert a 150*100 image into a 150*150 image.
The extra 50 pixels of the height need to be padded with a white background color.

这是我正在使用的当前代码.

This is the current code I am using.

它适用于调整大小，但更改原始图像的纵横比会挤压新图像.

It works well for resizing but changing the aspect ratio of the original image squashes the new image.

private void resizeImage(string path, string originalFilename, 
                         int width, int height)
    {
        Image image = Image.FromFile(path + originalFilename);

        System.Drawing.Image thumbnail = new Bitmap(width, height);
        System.Drawing.Graphics graphic = 
                     System.Drawing.Graphics.FromImage(thumbnail);

        graphic.InterpolationMode = InterpolationMode.HighQualityBicubic;
        graphic.SmoothingMode = SmoothingMode.HighQuality;
        graphic.PixelOffsetMode = PixelOffsetMode.HighQuality;
        graphic.CompositingQuality = CompositingQuality.HighQuality;

        graphic.DrawImage(image, 0, 0, width, height);

        System.Drawing.Imaging.ImageCodecInfo[] info =
                         ImageCodecInfo.GetImageEncoders();
        EncoderParameters encoderParameters;
        encoderParameters = new EncoderParameters(1);
        encoderParameters.Param[0] = new EncoderParameter(Encoder.Quality,
                         100L);            
        thumbnail.Save(path + width + "." + originalFilename, info[1], 
                         encoderParameters);
    }

我想填充图像而不是裁剪图像

I'd like to have the image padded instead of cropped

推荐答案

通过学习这个这篇 CodeProject 文章.

static Image FixedSize(Image imgPhoto, int Width, int Height)
    {
        int sourceWidth = imgPhoto.Width;
        int sourceHeight = imgPhoto.Height;
        int sourceX = 0;
        int sourceY = 0;
        int destX = 0;
        int destY = 0;

        float nPercent = 0;
        float nPercentW = 0;
        float nPercentH = 0;

        nPercentW = ((float)Width / (float)sourceWidth);
        nPercentH = ((float)Height / (float)sourceHeight);
        if (nPercentH < nPercentW)
        {
            nPercent = nPercentH;
            destX = System.Convert.ToInt16((Width -
                          (sourceWidth * nPercent)) / 2);
        }
        else
        {
            nPercent = nPercentW;
            destY = System.Convert.ToInt16((Height -
                          (sourceHeight * nPercent)) / 2);
        }

        int destWidth = (int)(sourceWidth * nPercent);
        int destHeight = (int)(sourceHeight * nPercent);

        Bitmap bmPhoto = new Bitmap(Width, Height,
                          PixelFormat.Format24bppRgb);
        bmPhoto.SetResolution(imgPhoto.HorizontalResolution,
                         imgPhoto.VerticalResolution);

        Graphics grPhoto = Graphics.FromImage(bmPhoto);
        grPhoto.Clear(Color.Red);
        grPhoto.InterpolationMode =
                InterpolationMode.HighQualityBicubic;

        grPhoto.DrawImage(imgPhoto,
            new Rectangle(destX, destY, destWidth, destHeight),
            new Rectangle(sourceX, sourceY, sourceWidth, sourceHeight),
            GraphicsUnit.Pixel);

        grPhoto.Dispose();
        return bmPhoto;
    }

这篇关于c# 在保持纵横比的同时将图像调整为不同的大小的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！