我正在一个销售手工制作的珠宝的网站上工作,我正在完成图像编辑器,但它的行为不太正确。
基本上,用户上传的图像将被保存为源,然后它会被调整大小以适应用户的屏幕并保存为临时文件。然后,用户将转到允许他们裁剪图像并将其保存为最终版本的屏幕。
除了最终版本有 3 个错误外,所有这些都工作正常。首先是图像底部的一些黑色水平线。其次是沿着边缘的各种轮廓。我以为这是因为我降低了质量,但即使是 100%,它仍然会出现……最后,我注意到裁剪后的图像总是比我指定的低几个像素……
无论如何,我希望有使用 C# 编辑图像经验的人可以看看代码,看看我在哪里可能偏离了正确的道路。
哦,顺便说一句,这是在 ASP.NET MVC 应用程序中。
代码如下:
public class ImageProvider {
private readonly ProductProvider ProductProvider = null;
private readonly EncoderParameters HighQualityEncoder = new EncoderParameters();
private readonly ImageCodecInfo JpegCodecInfo = ImageCodecInfo.GetImageEncoders().Single(
c => (c.MimeType == "image/jpeg"));
private readonly string Path = HttpContext.Current.Server.MapPath("~/Resources/Images/Products");
private readonly short[][] Dimensions = new short[3][] {
new short[2] { 640, 480 },
new short[2] { 240, 0 },
new short[2] { 80, 60 }
}
public ImageProvider(ProductProvider ProductProvider) {
this.ProductProvider = ProductProvider;
HighQualityEncoder.Param[0] = new EncoderParameter(Encoder.Quality, 100L);
}
public void Crop(string FileName, Image Image, Crop Crop) {
using (Bitmap Source = new Bitmap(Image)) {
using (Bitmap Target = new Bitmap(Crop.Width, Crop.Height)) {
using (Graphics Graphics = Graphics.FromImage(Target)) {
Graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
Graphics.SmoothingMode = SmoothingMode.HighQuality;
Graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
Graphics.CompositingQuality = CompositingQuality.HighQuality;
Graphics.DrawImage(Source, new Rectangle(0, 0, Target.Width, Target.Height), new Rectangle(Crop.Left, Crop.Top, Crop.Width, Crop.Height), GraphicsUnit.Pixel);
}
Target.Save(FileName, JpegCodecInfo, HighQualityEncoder);
}
}
}
public void CropAndResize(Product Product, Crop Crop) {
using (Image Source = Image.FromFile(String.Format("{0}/{1}.source", Path, Product.ProductId))) {
using (Image Temp = Image.FromFile(String.Format("{0}/{1}.temp", Path, Product.ProductId))) {
float Percent = ((float)Source.Width / (float)Temp.Width);
short Width = (short)(Temp.Width * Percent);
short Height = (short)(Temp.Height * Percent);
Crop.Height = (short)(Crop.Height * Percent);
Crop.Left = (short)(Crop.Left * Percent);
Crop.Top = (short)(Crop.Top * Percent);
Crop.Width = (short)(Crop.Width * Percent);
Img Img = new Img();
this.ProductProvider.AddImageAndSave(Product, Img);
this.Crop(String.Format("{0}/{1}.cropped", Path, Img.ImageId), Source, Crop);
using (Image Cropped = Image.FromFile(String.Format("{0}/{1}.cropped", Path, Img.ImageId))) {
this.Resize(this.Dimensions[0], String.Format("{0}/{1}-L.jpg", Path, Img.ImageId), Cropped, HighQualityEncoder);
this.Resize(this.Dimensions[1], String.Format("{0}/{1}-T.jpg", Path, Img.ImageId), Cropped, HighQualityEncoder);
this.Resize(this.Dimensions[2], String.Format("{0}/{1}-S.jpg", Path, Img.ImageId), Cropped, HighQualityEncoder);
}
}
}
this.Purge(Product);
}
public void QueueFor( Product Product, HttpPostedFileBase PostedFile) {
using (Image Image = Image.FromStream(PostedFile.InputStream)) {
this.Resize(new short[2] {
1152,
0
}, String.Format("{0}/{1}.temp", Path, Product.ProductId), Image, HighQualityEncoder);
}
PostedFile.SaveAs(String.Format("{0}/{1}.source", Path, Product.ProductId));
}
private void Purge(Product Product) {
string Source = String.Format("{0}/{1}.source", Path, Product.ProductId);
string Temp = String.Format("{0}/{1}.temp", Path, Product.ProductId);
if (File.Exists(Source)) {
File.Delete(Source);
}
if (File.Exists(Temp)) {
File.Delete(Temp);
}
foreach (Img Img in Product.Imgs) {
string Cropped = String.Format("{0}/{1}.cropped", Path, Img.ImageId);
if (File.Exists(Cropped)) {
File.Delete(Cropped);
}
}
}
public void Resize( short[] Dimensions, string FileName, Image Image, EncoderParameters EncoderParameters) {
if (Dimensions[1] == 0) {
Dimensions[1] = (short)(Image.Height / ((float)Image.Width / (float)Dimensions[0]));
}
using (Bitmap Bitmap = new Bitmap(Dimensions[0], Dimensions[1])) {
using (Graphics Graphics = Graphics.FromImage(Bitmap)) {
Graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
Graphics.SmoothingMode = SmoothingMode.HighQuality;
Graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
Graphics.CompositingQuality = CompositingQuality.HighQuality;
Graphics.DrawImage(Image, 0, 0, Dimensions[0], Dimensions[1]);
};
Bitmap.Save(FileName, JpegCodecInfo, EncoderParameters);
}
}
}
这是其中一张图片:
更新
因此,我在发布后坐下来通读 MSDN 大约 2 个小时,验证了我的代码。据我所知,我在执行操作时使用了尽可能高的质量设置。
无论哪种方式,我最终都稍微清理并简化了代码。我考虑了对源文件的需求并决定删除它,因为它需要我做额外的工作来确定基于临时文件的裁剪尺寸。所以,它不见了。
此外,在流线型的某个地方,黑线消失了,所以我只能假设长宽比问题应该已经按照@StefanE 所述得到了纠正。
此外,正如@VinayC 所说,重新调整器生成的高度值为 479(我仍然不知道如何生成,但无论如何......),但当我切换时,这似乎已得到纠正一直使用 System.Drawing.Size 和 System.Drawing.Rectangle 类,而不是使用我自己的类,它们基本上做同样的事情。
所以,这是更新后的代码。剩下的 两个错误 错误仍然存在,所以我在图像周围一直有一个“重影”轮廓(见第二个附件),我可以缩小到调整大小,因为它出现在第一个重新- 未发生裁剪的大小。 第二个错误是裁剪后的版本在 y 轴上的位置始终低于我作为裁剪器传入的版本。我估计它比我告诉它的低 5%-8%,所以不确定那个(位置不应该改变......除非我从 jQuery 传递一个错误的数字,要检查在那...)。
(我的第二个错误最终导致我一开始就发送了错误的值,裁剪 div 正在根据主内容 div 而不是图像容器 div 获取其相对位置。现在全部修复。)
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Web;
namespace Website.Models.Providers {
public class ImageProvider {
private readonly ProductProvider ProductProvider = null;
private readonly EncoderParameters DefaultQualityEncoder = new EncoderParameters();
private readonly EncoderParameters HighQualityEncoder = new EncoderParameters();
private readonly ImageCodecInfo JpegCodecInfo = ImageCodecInfo.GetImageEncoders().Single(
c =>
(c.MimeType == "image/jpeg"));
private readonly Size[] Sizes = new Size[3] {
new Size(640, 0),
new Size(240, 0),
new Size(80, 0)
};
private readonly string Path = HttpContext.Current.Server.MapPath("~/Resources/Images/Products");
public ImageProvider(
ProductProvider ProductProvider) {
this.ProductProvider = ProductProvider;
this.DefaultQualityEncoder.Param[0] = new EncoderParameter(Encoder.Quality, 80L);
this.HighQualityEncoder.Param[0] = new EncoderParameter(Encoder.Quality, 100L);
}
public void Crop(
string FileName,
Image Image,
Crop Crop) {
using (Bitmap Source = new Bitmap(Image)) {
using (Bitmap Target = new Bitmap(Crop.Width, Crop.Height)) {
using (Graphics Graphics = Graphics.FromImage(Target)) {
Graphics.CompositingMode = CompositingMode.SourceCopy;
Graphics.CompositingQuality = CompositingQuality.HighQuality;
Graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
Graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
Graphics.SmoothingMode = SmoothingMode.HighQuality;
Graphics.DrawImage(Source, new Rectangle(0, 0, Target.Width, Target.Height), new Rectangle(Crop.Left, Crop.Top, Crop.Width, Crop.Height), GraphicsUnit.Pixel);
};
Target.Save(FileName, JpegCodecInfo, HighQualityEncoder);
};
};
}
public void CropAndResize(
Product Product,
Crop Crop) {
using (Image Temp = Image.FromFile(String.Format("{0}/{1}.temp", Path, Product.ProductId))) {
Img Img = new Img();
this.ProductProvider.AddImageAndSave(Product, Img);
this.Crop(String.Format("{0}/{1}.cropped", Path, Img.ImageId), Temp, Crop);
using (Image Cropped = Image.FromFile(String.Format("{0}/{1}.cropped", Path, Img.ImageId))) {
this.Resize(String.Format("{0}/{1}-L.jpg", Path, Img.ImageId), this.Sizes[0], Cropped, HighQualityEncoder);
this.Resize(String.Format("{0}/{1}-T.jpg", Path, Img.ImageId), this.Sizes[1], Cropped, HighQualityEncoder);
this.Resize(String.Format("{0}/{1}-S.jpg", Path, Img.ImageId), this.Sizes[2], Cropped, HighQualityEncoder);
};
};
this.Purge(Product);
}
public void QueueFor(
Product Product,
Size Size,
HttpPostedFileBase PostedFile) {
using (Image Image = Image.FromStream(PostedFile.InputStream)) {
this.Resize(String.Format("{0}/{1}.temp", Path, Product.ProductId), Size, Image, HighQualityEncoder);
};
}
private void Purge(
Product Product) {
string Temp = String.Format("{0}/{1}.temp", Path, Product.ProductId);
if (File.Exists(Temp)) {
File.Delete(Temp);
};
foreach (Img Img in Product.Imgs) {
string Cropped = String.Format("{0}/{1}.cropped", Path, Img.ImageId);
if (File.Exists(Cropped)) {
File.Delete(Cropped);
};
};
}
public void Resize(
string FileName,
Size Size,
Image Image,
EncoderParameters EncoderParameters) {
if (Size.Height == 0) {
Size.Height = (int)(Image.Height / ((float)Image.Width / (float)Size.Width));
};
using (Bitmap Bitmap = new Bitmap(Size.Width, Size.Height)) {
using (Graphics Graphics = Graphics.FromImage(Bitmap)) {
Graphics.CompositingMode = CompositingMode.SourceCopy;
Graphics.CompositingQuality = CompositingQuality.HighQuality;
Graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
Graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
Graphics.SmoothingMode = SmoothingMode.HighQuality;
Graphics.DrawImage(Image, new Rectangle(0, 0, Size.Width, Size.Height));
};
Bitmap.Save(FileName, JpegCodecInfo, EncoderParameters);
};
}
}
}
此图像显示了红色箭头所指的“重影”轮廓。
最佳答案
关于底部的黑线是因为你没有处理纵横比。
double aspectRatio = imageWidth/imageHeight;
double boxRatio = maxWidth/maxHeight;
double scaleFactor = 0;
if (boxRatio > aspectRatio)
//Use height, since that is the most restrictive dimension of box.
scaleFactor = maxHeight / imageHeight;
else
scaleFactor = maxWidth / imageWidth;
double newWidth = imageWidth * scaleFactor;
double newHeight = imageHeight * scaleFactor;
来源:http://nathanaeljones.com/163/20-image-resizing-pitfalls/
关于c# - 调整大小后图像周围的 GhoSTLy 轮廓,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/4496496/