我需要转换一些基于 System.Drawing 的代码才能使用此 .NET Core 兼容库:
https://github.com/SixLabors/ImageSharp
下面基于 System.Drawing 的代码调整图像大小并裁剪边缘,返回要保存的内存流。这可以通过 ImageSharp 库实现吗?
private static Stream Resize(Stream inStream, int newWidth, int newHeight)
{
var img = Image.Load(inStream);
if (newWidth != img.Width || newHeight != img.Height)
{
var ratioX = (double)newWidth / img.Width;
var ratioY = (double)newHeight / img.Height;
var ratio = Math.Max(ratioX, ratioY);
var width = (int)(img.Width * ratio);
var height = (int)(img.Height * ratio);
var newImage = new Bitmap(width, height);
Graphics.FromImage(newImage).DrawImage(img, 0, 0, width, height);
img = newImage;
if (img.Width != newWidth || img.Height != newHeight)
{
var startX = (Math.Max(img.Width, newWidth) - Math.Min(img.Width, newWidth)) / 2;
var startY = (Math.Max(img.Height, newHeight) - Math.Min(img.Height, newHeight)) / 2;
img = Crop(img, newWidth, newHeight, startX, startY);
}
}
var ms = new MemoryStream();
img.Save(ms, ImageFormat.Jpeg);
ms.Position = 0;
return ms;
}
private static Image Crop(Image image, int newWidth, int newHeight, int startX = 0, int startY = 0)
{
if (image.Height < newHeight)
newHeight = image.Height;
if (image.Width < newWidth)
newWidth = image.Width;
using (var bmp = new Bitmap(newWidth, newHeight, PixelFormat.Format24bppRgb))
{
bmp.SetResolution(72, 72);
using (var g = Graphics.FromImage(bmp))
{
g.SmoothingMode = SmoothingMode.AntiAlias;
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
g.DrawImage(image, new Rectangle(0, 0, newWidth, newHeight), startX, startY, newWidth, newHeight, GraphicsUnit.Pixel);
var ms = new MemoryStream();
bmp.Save(ms, ImageFormat.Jpeg);
image.Dispose();
var outimage = Image.FromStream(ms);
return outimage;
}
}
}
最佳答案
是的, super 简单。
using (var inStream = ...)
using (var outStream = new MemoryStream())
using (var image = Image.Load(inStream, out IImageFormat format))
{
image.Mutate(
i => i.Resize(width, height)
.Crop(new Rectangle(x, y, cropWidth, cropHeight)));
image.Save(outStream, format);
}
编辑
如果您想保持原始图像不变,可以使用Clone
方法。
using (var inStream = ...)
using (var outStream = new MemoryStream())
using (var image = Image.Load(inStream, out IImageFormat format))
{
var clone = image.Clone(
i => i.Resize(width, height)
.Crop(new Rectangle(x, y, cropWidth, cropHeight)));
clone.Save(outStream, format);
}
您甚至可以将其优化为对 Resize
的单个方法调用通过接受带有“ResizeMode.Crop”的 ResizeOptions
实例的重载。这将允许您调整大小到一个比例,然后剪掉该比例之外的任何多余内容。
关于c# - 如何使用 ImageSharp 调整中心大小并裁剪图像,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/55298428/