我有一个项目，可以将图像格式文件转换为图标文件。但是，在转换图像后，图像的颜色发生了变化。
以下是我的代码
Bitmap theBitmap = new Bitmap(theImage, new Size(width, height));
IntPtr Hicon = theBitmap.GetHicon();// Get an Hicon for myBitmap.
Icon newIcon = Icon.FromHandle(Hicon);// Create a new icon from the handle.
FileStream fs = new FileStream(@"c:\Icon\" + filename + ".ico", FileMode.OpenOrCreate);//Write Icon to File Stream
有人知道如何解决这个问题吗？
Bitmap.GetHicon()非常适合创建在任何可以运行.NET代码的Windows版本上都能良好工作的图标，包括旧版的Windows 98和Windows 2000。这些操作系统不支持花哨的图标。
因此，您得到的图标仅使用预先设定的基本颜色调色板中的16种颜色，结果可能会相当令人失望。
Bitmap或Icon类没有选项可以获得更好的结果。通常情况下，您需要使用图标编辑器来创建良好的图标，其中应该包括不同尺寸和颜色深度的多个图像，以便它们能够与任何视频适配器设置和任何操作系统版本兼容。特别是从1600万色缩减到256或16种颜色，这是一个需要多种方法才能实现的非平凡操作，而且没有一种方法是完美的。一个好的图标编辑器具备您需要的工具，让这些操作足够好用。
更新：这已经成为一个非常过时的问题，XP是昨天的产物了。如今，您可以使用这个代码生成外观非常好看的图标。
public void ConvertToIco(Image img, string file, int size)
{
Icon icon;
using (var msImg = new MemoryStream())
using (var msIco = new MemoryStream())
{
img.Save(msImg, ImageFormat.Png);
using (var bw = new BinaryWriter(msIco))
{
bw.Write((short)0); //0-1 reserved
bw.Write((short)1); //2-3 image type, 1 = icon, 2 = cursor
bw.Write((short)1); //4-5 number of images
bw.Write((byte)size); //6 image width
bw.Write((byte)size); //7 image height
bw.Write((byte)0); //8 number of colors
bw.Write((byte)0); //9 reserved
bw.Write((short)0); //10-11 color planes
bw.Write((short)32); //12-13 bits per pixel
bw.Write((int)msImg.Length); //14-17 size of image data
bw.Write(22); //18-21 offset of image data
bw.Write(msImg.ToArray()); // write image data
bw.Flush();
bw.Seek(0, SeekOrigin.Begin);
icon = new Icon(msIco);
}
}
using (var fs = new FileStream(file, FileMode.Create, FileAccess.Write))
{
icon.Save(fs);
}
}
File.WriteAllBytes(file, bytes)，其中bytes是一个字节数组即可。 - Timstring icoFile = "C:\path\to\file.ico";
FreeImageBitmap fiBitmap = new FreeImageBitmap(theBitmap);
fiBitmap.Rescale(48, 48, FREE_IMAGE_FILTER.FILTER_BICUBIC);
fiBitmap.Save(icoFile);
fiBitmap.Rescale(32, 32, FREE_IMAGE_FILTER.FILTER_BICUBIC);
fiBitmap.SaveAdd(icoFile);
fiBitmap.Rescale(16, 16, FREE_IMAGE_FILTER.FILTER_BICUBIC);
fiBitmap.SaveAdd(icoFile);
我已经创建了一个简单的函数，它接受要转换的图像字符串和保存路径。.ico格式可以在Chrome和其他浏览器上使用。
public void ConvertToIco(string pathImageToConvert, string pathToSave)
{
Bitmap bmp = new Bitmap(pathImageToConvert);
bmp.Save(pathToSave, System.Drawing.Imaging.ImageFormat.Icon);
}
这里是路径的示例
pathImageToConvert = "yourpath/" + image.extension
pathToSave = "yourpath/" + image.ico
Bitmap theBitmap = new Bitmap(theImage, new Size(width, height));
theBitmap.Save(@"C:\Icon\" + filename + ".ico", System.Drawing.Imaging.ImageFormat.Icon);
如果您需要动态生成图标（我的应用程序具有不断变化的数量），如果必须使用编辑器，那么您将会很失望。
Ruiwei Bu（darkfall）在github上展示了如何实现。由于我们当然不支持XP和更低版本，这对我们来说已经足够。
使用我放置代码的类的示例：
Dim ico As New Icons With {.state = Iconstates.OK, .UpgradeNum = "123"}
Dim tempfile = "C:\file5.ico"
ico.GetIcon(tempfile)
Dim newicon As New Icon(tempfile)
使用Darkfall代码的类：
Imports System.Drawing.Imaging
Imports System.IO
Public Class Icons
Property UpgradeNum As String
Property state As Iconstates
Function GetIcon(Optional OptionalSave As String = "") As Icon
Dim bmp As New Bitmap(16, 16)
Using g = Graphics.FromImage(bmp)
g.Clear(Color.Transparent)
g.SmoothingMode = Drawing2D.SmoothingMode.AntiAlias
Select Case state
Case Iconstates.OK
g.FillEllipse(Brushes.Green, 1, 1, 14, 14)
End Select
g.DrawString(UpgradeNum, New Font("Small Fonts", 6), Brushes.Aquamarine, 0, 0)
End Using
bmp.Save(OptionalSave & ".png")
Dim outputStream As New MemoryStream()
Dim size As Integer = bmp.Size.Width
If Not ConvertToIcon(bmp, outputStream, size) Then
Return Nothing
End If
If OptionalSave > "" Then
Using file = New FileStream(OptionalSave, FileMode.Create, System.IO.FileAccess.Write)
outputStream.WriteTo(file)
file.Close()
End Using
End If
outputStream.Seek(0, SeekOrigin.Begin)
Return New Icon(outputStream)
End Function
''' <summary>
''' Converts a PNG image to an icon (ico)
''' </summary>
''' <param name="inputBitmap">The input stream</param>
''' <param name="output">The output stream</param>
''' <param name="size">Needs to be a factor of 2 (16x16 px by default)</param>
''' <param name="preserveAspectRatio">Preserve the aspect ratio</param>
''' <returns>Wether or not the icon was succesfully generated</returns>
Public Shared Function ConvertToIcon(inputBitmap As Bitmap, output As Stream, Optional size As Integer = 16, Optional preserveAspectRatio As Boolean = False) As Boolean
Dim width As Single = size, height As Single = size
Dim newBitmap = New Bitmap(inputBitmap, New Size(CInt(width), CInt(height)))
If newBitmap Is Nothing Then
Return False
End If
' save the resized png into a memory stream for future use
Using memoryStream As New MemoryStream()
newBitmap.Save(memoryStream, ImageFormat.Png)
Dim iconWriter = New BinaryWriter(output)
If output Is Nothing OrElse iconWriter Is Nothing Then
Return False
End If
' 0-1 reserved, 0
iconWriter.Write(CByte(0))
iconWriter.Write(CByte(0))
' 2-3 image type, 1 = icon, 2 = cursor
iconWriter.Write(CShort(1))
' 4-5 number of images
iconWriter.Write(CShort(1))
' image entry 1
' 0 image width
iconWriter.Write(CByte(width))
' 1 image height
iconWriter.Write(CByte(height))
' 2 number of colors
iconWriter.Write(CByte(0))
' 3 reserved
iconWriter.Write(CByte(0))
' 4-5 color planes
iconWriter.Write(CShort(0))
' 6-7 bits per pixel
iconWriter.Write(CShort(32))
' 8-11 size of image data
iconWriter.Write(CInt(memoryStream.Length))
' 12-15 offset of image data
iconWriter.Write(CInt(6 + 16))
' write image data
' png data must contain the whole png data file
iconWriter.Write(memoryStream.ToArray())
iconWriter.Flush()
End Using
Return True
End Function
End Class
' https://gist.github.com/darkfall/1656050
'=======================================================
'Service provided by Telerik (www.telerik.com)
'Conversion powered by NRefactory.
'Twitter: @telerik
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'=======================================================
看起来 .Net Framework 没有任何图标编码器；因此，您无法保存任何真正的图标文件。保存的文件只是一个 PNG 文件。
如果您的项目中直接包含BMP图像，那么使用BMP很容易。下面的代码可以正常工作。
<code>
try
{
Bitmap b = new Bitmap(".\\ConnApp.bmp");
IntPtr pIcon = b.GetHicon();
Icon i = Icon.FromHandle(pIcon);
this.Icon = i;
logInfo("Icon loaded ?" + i);
// save ico file. This you can directly assign Icon to your Form (Properties -> Icon -> choose)
// the exe Icon you can assign from Application -> Properties -> Icon and Manifest -> select icon.
FileStream SourceStream = File.Create("\\pos2.ico");
i.Save(SourceStream);
SourceStream.Close();
i.Dispose();
} catch (Exception ex1) {
logInfo("Error on iconload " + ex1);
}
</code>
GetHicon()不是无损转换。 - DonBoitnott