如何使用C＃裁剪图像？-Java 学习之路

218

如何编写将在C＃中裁剪图像的应用程序？

14 回答

您可以使用Graphics.DrawImage从位图中将裁剪后的图像绘制到图形对象上 .

Rectangle cropRect = new Rectangle(...);
Bitmap src = Image.FromFile(fileName) as Bitmap;
Bitmap target = new Bitmap(cropRect.Width, cropRect.Height);

using(Graphics g = Graphics.FromImage(target))
{
   g.DrawImage(src, new Rectangle(0, 0, target.Width, target.Height), 
                    cropRect,                        
                    GraphicsUnit.Pixel);
}

回复于 2024-05-06T13:27:20+08:00

6
看看这个链接：http://www.switchonthecode.com/tutorials/csharp-tutorial-image-editing-saving-cropping-and-resizing [<== Link is DEAD]
```
private static Image cropImage(Image img, Rectangle cropArea)
{
   Bitmap bmpImage = new Bitmap(img);
   return bmpImage.Clone(cropArea, bmpImage.PixelFormat);
}
```
回复于 2024-05-06T13:27:20+08:00
2
比接受的答案更简单的是：
```
public static Bitmap cropAtRect(this Bitmap b, Rectangle r)
{
  Bitmap nb = new Bitmap(r.Width, r.Height);
  Graphics g = Graphics.FromImage(nb);
  g.DrawImage(b, -r.X, -r.Y);
  return nb;
}
```
它避免了最简单答案的“ Out of memory ”异常风险 .

EDIT ：我发现 Bitmap.Save 或Paint.exe保存的PNG很好，但是由于例如保存了PNG而失败了 . Paint Shop Pro 6 - 内容被取代 . 添加 GraphicsUnit.Pixel 会产生不同的错误结果 . 也许只是这些失败的PNG是错误的 .
回复于 2024-05-06T13:27:20+08:00

239

使用bmp.SetResolution（image.HorizontalResolution，image .VerticalResolution）;

这可能是必要的，即使你在这里实现最佳答案，特别是如果你的图像真的很棒，分辨率不是96.0

我的测试示例：

static Bitmap LoadImage()
    {
        return (Bitmap)Bitmap.FromFile( @"e:\Tests\d_bigImage.bmp" ); // here is large image 9222x9222 pixels and 95.96 dpi resolutions
    }

    static void TestBigImagePartDrawing()
    {
        using( var absentRectangleImage = LoadImage() )
        {
            using( var currentTile = new Bitmap( 256, 256 ) )
            {
                currentTile.SetResolution(absentRectangleImage.HorizontalResolution, absentRectangleImage.VerticalResolution);

                using( var currentTileGraphics = Graphics.FromImage( currentTile ) )
                {
                    currentTileGraphics.Clear( Color.Black );
                    var absentRectangleArea = new Rectangle( 3, 8963, 256, 256 );
                    currentTileGraphics.DrawImage( absentRectangleImage, 0, 0, absentRectangleArea, GraphicsUnit.Pixel );
                }

                currentTile.Save(@"e:\Tests\Tile.bmp");
            }
        }
    }

回复于 2024-05-06T13:27:20+08:00

42
这很容易：
- 使用裁剪尺寸创建新的 Bitmap 对象 .
- 使用 Graphics.FromImage 为新位图创建 Graphics 对象 .
- 使用 DrawImage 方法将图像绘制到具有负X和Y坐标的位图上 .
回复于 2024-05-06T13:27:20+08:00

如果你正在使用AForge.NET：

using(var croppedBitmap = new Crop(new Rectangle(10, 10, 10, 10)).Apply(bitmap))
{
    // ...
}

回复于 2024-05-06T13:27:20+08:00

这是一个关于裁剪图像的简单示例

public Image Crop(string img, int width, int height, int x, int y)
{
    try
    {
        Image image = Image.FromFile(img);
        Bitmap bmp = new Bitmap(width, height, PixelFormat.Format24bppRgb);
        bmp.SetResolution(80, 60);

        Graphics gfx = Graphics.FromImage(bmp);
        gfx.SmoothingMode = SmoothingMode.AntiAlias;
        gfx.InterpolationMode = InterpolationMode.HighQualityBicubic;
        gfx.PixelOffsetMode = PixelOffsetMode.HighQuality;
        gfx.DrawImage(image, new Rectangle(0, 0, width, height), x, y, width, height, GraphicsUnit.Pixel);
        // Dispose to free up resources
        image.Dispose();
        bmp.Dispose();
        gfx.Dispose();

        return bmp;
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
        return null;
    }            
}

回复于 2024-05-06T13:27:20+08:00

0
有一个C＃包装器，它是开源的，托管在Codeplex上，名为 Web Image Cropping

Register the control

<%@ Register Assembly="CS.Web.UI.CropImage" Namespace="CS.Web.UI" TagPrefix="cs" %>

Resizing
```
<asp:Image ID="Image1" runat="server" ImageUrl="images/328.jpg" />
<cs:CropImage ID="wci1" runat="server" Image="Image1" 
     X="10" Y="10" X2="50" Y2="50" />
```
Cropping in code behind - 单击按钮时调用裁剪方法;

wci1.Crop(Server.MapPath("images/sample1.jpg"));
回复于 2024-05-06T13:27:20+08:00
3

假设您想要拍摄图像文件（JPEG，BMP，TIFF等）并裁剪它然后将其保存为较小的图像文件，我建议使用具有.NET API的第三方工具 . 以下是我喜欢的一些流行的：

LeadTools
Accusoft Pegasus Snowbound Imaging SDK

回复于 2024-05-06T13:27:20+08:00

在C＃中剪切图像非常容易 . 然而，做这些事情你将如何管理你的图像裁剪将会有点困难 .

以下示例是如何在C＃中裁剪图像的方法 .

var filename = @"c:\personal\images\horizon.png";
var img = Image.FromFile(filename);
var rect = new Rectangle(new Point(0, 0), img.Size);
var cloned = new Bitmap(img).Clone(rect, img.PixelFormat);
var bitmap = new Bitmap(cloned, new Size(50, 50));
cloned.Dispose();

回复于 2024-05-06T13:27:20+08:00

204

只有这个样本工作没有问题：

var crop = new Rectangle(0, y, bitmap.Width, h);
var bmp = new Bitmap(bitmap.Width, h);
var tempfile = Application.StartupPath+"\\"+"TEMP"+"\\"+Path.GetRandomFileName();


using (var gr = Graphics.FromImage(bmp))
{
    try
    {
        var dest = new Rectangle(0, 0, bitmap.Width, h);
        gr.DrawImage(image,dest , crop, GraphicsUnit.Point);
        bmp.Save(tempfile,ImageFormat.Jpeg);
        bmp.Dispose();
    }
    catch (Exception)
    {


    }

}

回复于 2024-05-06T13:27:20+08:00

这是另一种方式 . 就我而言，我有：

2个数字更新控件（称为LeftMargin和TopMargin）
1图片框（pictureBox1）
我调用生成的1个按钮
在C：\ imagenes \ myImage.gif上
1张图片

在按钮内我有这个代码：

Image myImage = Image.FromFile(@"C:\imagenes\myImage.gif");
Bitmap croppedBitmap = new Bitmap(myImage);
croppedBitmap = croppedBitmap.Clone(
            new Rectangle(
                (int)LeftMargin.Value, (int)TopMargin.Value,
                myImage.Width - (int)LeftMargin.Value,
                myImage.Height - (int)TopMargin.Value),
            System.Drawing.Imaging.PixelFormat.DontCare);
pictureBox1.Image = croppedBitmap;

我在使用C＃的Visual Studio 2012中尝试过它 . 我发现了这个解决方案page

回复于 2024-05-06T13:27:20+08:00

这是在github上运行的演示

https://github.com/SystematixIndore/Crop-SaveImageInCSharp

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication1.WebForm1" %>

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
  <title></title>
 <link href="css/jquery.Jcrop.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3/jquery.min.js"></script>
<script type="text/javascript" src="js/jquery.Jcrop.js"></script>
</head>
<body>
  <form id="form2" runat="server">
  <div>
    <asp:Panel ID="pnlUpload" runat="server">
      <asp:FileUpload ID="Upload" runat="server" />
      

      <asp:Button ID="btnUpload" runat="server" OnClick="btnUpload_Click" Text="Upload" />
      <asp:Label ID="lblError" runat="server" Visible="false" />
    </asp:Panel>
    <asp:Panel ID="pnlCrop" runat="server" Visible="false">
      <asp:Image ID="imgCrop" runat="server" />
      

      <asp:HiddenField ID="X" runat="server" />
      <asp:HiddenField ID="Y" runat="server" />
      <asp:HiddenField ID="W" runat="server" />
      <asp:HiddenField ID="H" runat="server" />
      <asp:Button ID="btnCrop" runat="server" Text="Crop" OnClick="btnCrop_Click" />
    </asp:Panel>
    <asp:Panel ID="pnlCropped" runat="server" Visible="false">
      <asp:Image ID="imgCropped" runat="server" />
    </asp:Panel>
  </div>
  </form>
    <script type="text/javascript">
  jQuery(document).ready(function() {
    jQuery('#imgCrop').Jcrop({
      onSelect: storeCoords
    });
  });

  function storeCoords(c) {
    jQuery('#X').val(c.x);
    jQuery('#Y').val(c.y);
    jQuery('#W').val(c.w);
    jQuery('#H').val(c.h);
  };

</script>
</body>
</html>

用于上传和裁剪的C＃代码逻辑 .

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using SD = System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;

namespace WebApplication1
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        String path = HttpContext.Current.Request.PhysicalApplicationPath + "images\\";
        protected void Page_Load(object sender, EventArgs e)
        {

        }
        protected void btnUpload_Click(object sender, EventArgs e)
        {
            Boolean FileOK = false;
            Boolean FileSaved = false;

            if (Upload.HasFile)
            {
                Session["WorkingImage"] = Upload.FileName;
                String FileExtension = Path.GetExtension(Session["WorkingImage"].ToString()).ToLower();
                String[] allowedExtensions = { ".png", ".jpeg", ".jpg", ".gif" };
                for (int i = 0; i < allowedExtensions.Length; i++)
                {
                    if (FileExtension == allowedExtensions[i])
                    {
                        FileOK = true;
                    }
                }
            }

            if (FileOK)
            {
                try
                {
                    Upload.PostedFile.SaveAs(path + Session["WorkingImage"]);
                    FileSaved = true;
                }
                catch (Exception ex)
                {
                    lblError.Text = "File could not be uploaded." + ex.Message.ToString();
                    lblError.Visible = true;
                    FileSaved = false;
                }
            }
            else
            {
                lblError.Text = "Cannot accept files of this type.";
                lblError.Visible = true;
            }

            if (FileSaved)
            {
                pnlUpload.Visible = false;
                pnlCrop.Visible = true;
                imgCrop.ImageUrl = "images/" + Session["WorkingImage"].ToString();
            }
        }

        protected void btnCrop_Click(object sender, EventArgs e)
        {
            string ImageName = Session["WorkingImage"].ToString();
            int w = Convert.ToInt32(W.Value);
            int h = Convert.ToInt32(H.Value);
            int x = Convert.ToInt32(X.Value);
            int y = Convert.ToInt32(Y.Value);

            byte[] CropImage = Crop(path + ImageName, w, h, x, y);
            using (MemoryStream ms = new MemoryStream(CropImage, 0, CropImage.Length))
            {
                ms.Write(CropImage, 0, CropImage.Length);
                using (SD.Image CroppedImage = SD.Image.FromStream(ms, true))
                {
                    string SaveTo = path + "crop" + ImageName;
                    CroppedImage.Save(SaveTo, CroppedImage.RawFormat);
                    pnlCrop.Visible = false;
                    pnlCropped.Visible = true;
                    imgCropped.ImageUrl = "images/crop" + ImageName;
                }
            }
        }

        static byte[] Crop(string Img, int Width, int Height, int X, int Y)
        {
            try
            {
                using (SD.Image OriginalImage = SD.Image.FromFile(Img))
                {
                    using (SD.Bitmap bmp = new SD.Bitmap(Width, Height))
                    {
                        bmp.SetResolution(OriginalImage.HorizontalResolution, OriginalImage.VerticalResolution);
                        using (SD.Graphics Graphic = SD.Graphics.FromImage(bmp))
                        {
                            Graphic.SmoothingMode = SmoothingMode.AntiAlias;
                            Graphic.InterpolationMode = InterpolationMode.HighQualityBicubic;
                            Graphic.PixelOffsetMode = PixelOffsetMode.HighQuality;
                            Graphic.DrawImage(OriginalImage, new SD.Rectangle(0, 0, Width, Height), X, Y, Width, Height, SD.GraphicsUnit.Pixel);
                            MemoryStream ms = new MemoryStream();
                            bmp.Save(ms, OriginalImage.RawFormat);
                            return ms.GetBuffer();
                        }
                    }
                }
            }
            catch (Exception Ex)
            {
                throw (Ex);
            }
        }
    }
}

回复于 2024-05-06T13:27:20+08:00

我正在寻找一个简单而快速的功能，没有额外的库来完成这项工作 . 我试过了Nicks solution，但我需要29,4秒到"extract" 1195张 Map 集文件的图像 . 所以后来我以这种方式管理，需要2,43秒来完成同样的工作 . 也许这会有所帮助 .

// content of the Texture class
public class Texture
{
    //name of the texture
    public string name { get; set; }
    //x position of the texture in the atlas image
    public int x { get; set; }
    //y position of the texture in the atlas image
    public int y { get; set; }
    //width of the texture in the atlas image
    public int width { get; set; }
    //height of the texture in the atlas image
    public int height { get; set; }
}

Bitmap atlasImage = new Bitmap(@"C:\somepicture.png");
PixelFormat pixelFormat = atlasImage.PixelFormat;

foreach (Texture t in textureList)
{
     try
     {
           CroppedImage = new Bitmap(t.width, t.height, pixelFormat);
           // copy pixels over to avoid antialiasing or any other side effects of drawing
           // the subimages to the output image using Graphics
           for (int x = 0; x < t.width; x++)
               for (int y = 0; y < t.height; y++)
                   CroppedImage.SetPixel(x, y, atlasImage.GetPixel(t.x + x, t.y + y));
           CroppedImage.Save(Path.Combine(workingFolder, t.name + ".png"), ImageFormat.Png);
     }
     catch (Exception ex)
     {
          // handle the exception
     }
}

回复于 2024-05-06T13:27:20+08:00

如何使用C＃裁剪图像？

14 回答

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