C# 为图像添加图层
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C# add a layer to an image
提问by
I would like to add a layer to an image with the logo of the company.
我想为带有公司徽标的图像添加一个图层。
The logo should be placed on the center of the image (little opacity).
徽标应放置在图像的中心（不透明）。
How can I do that?
我怎样才能做到这一点？
回答by REA_ANDREW
Here is one I made earlier which creates a new badge for some images:
这是我之前制作的一个，它为一些图像创建了一个新的徽章：
EDIT, I designed the function which I supply a maxWidth and a maxHeight, it resizes without distortion.
编辑，我设计了提供 maxWidth 和 maxHeight 的函数，它可以在不失真的情况下调整大小。
Requirements:
要求：
using System.IO;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
The Code
编码
using (Image i = Image.FromFile(HttpContext.Current.Server.MapPath(fileName)))
{
float imageWidth = i.PhysicalDimension.Width;
float imageHeight = i.PhysicalDimension.Height;
float percentage = maxWidth / imageWidth;
float newWidth = imageWidth * percentage;
float newHeight = imageHeight * percentage;
if (newHeight > maxHeight)
{
percentage = maxHeight / newHeight;
newWidth = newWidth * percentage;
newHeight = newHeight * percentage;
}
using (Bitmap b = new Bitmap((int)newWidth, (int)newHeight))
{
using (Graphics g = Graphics.FromImage(b))
{
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
g.SmoothingMode = SmoothingMode.AntiAlias;
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
g.CompositingQuality = CompositingQuality.HighQuality;
g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
g.DrawImage(i, new Rectangle(0, 0, b.Width, b.Height));
if (effect == "new")
{
using (Image j = Image.FromFile(HttpContext.Current.Server.MapPath("/ImageEffects/") + "new.png", true))
{
g.DrawImage(j, new Rectangle(0, 0, 60, 60));
}
}
Image newImage = Image.FromHbitmap(b.GetHbitmap());
return newImage;
}
}
}
}
