c# - 如何在 .NET 中一步裁剪和调整图像大小

Question

我有一个图像文件，我想使用 System.Drawing 类同时裁剪和调整大小

我正在尝试以本文中的想法为基础:http://www.schnieds.com/2011/07/image-upload-crop-and-resize-with.html

我可以分别裁剪和调整大小，但是当我尝试组合这个过程时，我得到了一些奇怪的输出。

这是我一直在尝试的

using (System.Drawing.Bitmap _bitmap = new System.Drawing.Bitmap(w, h))
{
    _bitmap.SetResolution(img.HorizontalResolution, img.VerticalResolution);
    using (Graphics _graphic = Graphics.FromImage(_bitmap))
    {
        _graphic.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
        _graphic.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
        _graphic.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;
        _graphic.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;

        //Code used to crop
        _graphic.DrawImage(img, 0, 0, w, h);
        _graphic.DrawImage(img, new Rectangle(0, 0, w, h), x, y, w, h, GraphicsUnit.Pixel);

        //Code I used to resize
        _graphic.DrawImage(img, 0, 0, img.Width, img.Height);
        _graphic.DrawImage(img, new Rectangle(0, 0, W_FixedSize, H_FixedSize), 0, 0, img.Width, img.Height, GraphicsUnit.Pixel);



       //continued...
    }
}

在上面的代码中...有两个部分被注释...一个用于裁剪，一个用于调整大小。

对于裁剪，我将图像的适当坐标和宽度/高度部分传递给裁剪(x、y、w、h)。

我想根据我的参数裁剪并根据 W_FixedSize 和 H_Fixed 大小参数绘制图像。

Answer 1

我正在使用我写的这个类:

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;

namespace Studio.Utilities
{
    public class ImageResizer
    {
        public void ResizeImage(string origFileLocation, string newFileLocation, string origFileName, string newFileName, int newWidth, int maxHeight, bool resizeIfWider)
        {
            System.Drawing.Image FullSizeImage = System.Drawing.Image.FromFile(origFileLocation + origFileName);
            // Ensure the generated thumbnail is not being used by rotating it 360 degrees
            FullSizeImage.RotateFlip(System.Drawing.RotateFlipType.Rotate180FlipNone);
            FullSizeImage.RotateFlip(System.Drawing.RotateFlipType.Rotate180FlipNone);

            if (resizeIfWider)
            {
                if (FullSizeImage.Width <= newWidth)
                {
                    //newWidth = FullSizeImage.Width;
                }
            }

            int newHeight = FullSizeImage.Height * newWidth / FullSizeImage.Width;
            if (newHeight > maxHeight) // Height resize if necessary
            {
                //newWidth = FullSizeImage.Width * maxHeight / FullSizeImage.Height;
                newHeight = maxHeight;
            }
            newHeight = maxHeight;
            // Create the new image with the sizes we've calculated
            System.Drawing.Image NewImage = FullSizeImage.GetThumbnailImage(newWidth, newHeight, null, IntPtr.Zero);
            FullSizeImage.Dispose();
            NewImage.Save(newFileLocation + newFileName);
        }
        public void ResizeImageAndRatio(string origFileLocation, string newFileLocation, string origFileName, string newFileName, int newWidth, int newHeight, bool resizeIfWider)
        {

            System.Drawing.Image initImage = System.Drawing.Image.FromFile(origFileLocation + origFileName);
            int templateWidth = newWidth;
            int templateHeight = newHeight;
                double templateRate = double.Parse(templateWidth.ToString()) / templateHeight;
                double initRate = double.Parse(initImage.Width.ToString()) / initImage.Height;
                if (templateRate == initRate)
                {

                    System.Drawing.Image templateImage = new System.Drawing.Bitmap(templateWidth, templateHeight);
                    System.Drawing.Graphics templateG = System.Drawing.Graphics.FromImage(templateImage);
                    templateG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                    templateG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                    templateG.Clear(Color.White);
                    templateG.DrawImage(initImage, new System.Drawing.Rectangle(0, 0, templateWidth, templateHeight), new System.Drawing.Rectangle(0, 0, initImage.Width, initImage.Height), System.Drawing.GraphicsUnit.Pixel);
                    templateImage.Save(newFileLocation + newFileName, System.Drawing.Imaging.ImageFormat.Jpeg);
                }

                else
                {

                    System.Drawing.Image pickedImage = null;
                    System.Drawing.Graphics pickedG = null;


                    Rectangle fromR = new Rectangle(0, 0, 0, 0);
                    Rectangle toR = new Rectangle(0, 0, 0, 0);


                    if (templateRate > initRate)
                    {

                        pickedImage = new System.Drawing.Bitmap(initImage.Width, int.Parse(Math.Floor(initImage.Width / templateRate).ToString()));
                        pickedG = System.Drawing.Graphics.FromImage(pickedImage);


                        fromR.X = 0;
                        fromR.Y = int.Parse(Math.Floor((initImage.Height - initImage.Width / templateRate) / 2).ToString());
                        fromR.Width = initImage.Width;
                        fromR.Height = int.Parse(Math.Floor(initImage.Width / templateRate).ToString());


                        toR.X = 0;
                        toR.Y = 0;
                        toR.Width = initImage.Width;
                        toR.Height = int.Parse(Math.Floor(initImage.Width / templateRate).ToString());
                    }

                    else
                    {
                        pickedImage = new System.Drawing.Bitmap(int.Parse(Math.Floor(initImage.Height * templateRate).ToString()), initImage.Height);
                        pickedG = System.Drawing.Graphics.FromImage(pickedImage);

                        fromR.X = int.Parse(Math.Floor((initImage.Width - initImage.Height * templateRate) / 2).ToString());
                        fromR.Y = 0;
                        fromR.Width = int.Parse(Math.Floor(initImage.Height * templateRate).ToString());
                        fromR.Height = initImage.Height;

                        toR.X = 0;
                        toR.Y = 0;
                        toR.Width = int.Parse(Math.Floor(initImage.Height * templateRate).ToString());
                        toR.Height = initImage.Height;
                    }


                    pickedG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                    pickedG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;


                    pickedG.DrawImage(initImage, toR, fromR, System.Drawing.GraphicsUnit.Pixel);


                    System.Drawing.Image templateImage = new System.Drawing.Bitmap(templateWidth, templateHeight);
                    System.Drawing.Graphics templateG = System.Drawing.Graphics.FromImage(templateImage);
                    templateG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                    templateG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                    templateG.Clear(Color.White);
                    templateG.DrawImage(pickedImage, new System.Drawing.Rectangle(0, 0, templateWidth, templateHeight), new System.Drawing.Rectangle(0, 0, pickedImage.Width, pickedImage.Height), System.Drawing.GraphicsUnit.Pixel);
                    templateImage.Save(newFileLocation + newFileName, System.Drawing.Imaging.ImageFormat.Jpeg);


                    templateG.Dispose();
                    templateImage.Dispose();

                    pickedG.Dispose();
                    pickedImage.Dispose();
                }
                initImage.Dispose();
            }

    }
}