我有一个类似下面的函数。
// Convert To JPG
//
public string AlltoJPG(FileInfo foo)
{
// Get file extension
string fileExtension = foo.Extension;
// Get file name without extenstion
string fileName = foo.Name.Replace(foo.Extension, string.Empty) + ".jpg";
/*------------------------------------------------------------------------*/
/// <Check for PNG File Format>
if (fileExtension == ".png" || fileExtension == ".PNG")
{
System.Drawing.Image img = System.Drawing.Image.FromFile(foo.FullName);
// Assumes img is the PNG you are converting
using (Bitmap b = new Bitmap(img.Width, img.Height))
{
using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(b))
{
g.Clear(System.Drawing.Color.White);
g.DrawImageUnscaled(img, 0, 0);
}
// Save the image as a JPG
b.Save(fileName, System.Drawing.Imaging.ImageFormat.Jpeg);
}
}
/*------------------------------------------------------------------------*/
/// <Check for GIF File Format>
if (fileExtension == ".gif" || fileExtension == ".GIF")
{
System.Drawing.Image img = System.Drawing.Image.FromFile(foo.FullName);
// Construct a bitmap from the image resource.
Bitmap bmp1 = new Bitmap(img.Width, img.Height);
// Save the image as a JPG
bmp1.Save(fileName, System.Drawing.Imaging.ImageFormat.Jpeg);
}
/*------------------------------------------------------------------------*/
/// <Check for BMP File Format>
if (fileExtension == ".bmp" || fileExtension == ".BMP")
{
System.Drawing.Image img = System.Drawing.Image.FromFile(foo.FullName);
// Construct a bitmap from the image resource.
Bitmap bmp1 = new Bitmap(img.Width, img.Height);
// Save the image as a JPG
bmp1.Save(fileName, System.Drawing.Imaging.ImageFormat.Jpeg);
}
/*------------------------------------------------------------------------*/
/// <Check for TIFF File Format>
if (fileExtension == ".tiff" || fileExtension == ".TIFF")
{
System.Drawing.Image img = System.Drawing.Image.FromFile(foo.FullName);
// Construct a bitmap from the image resource.
Bitmap bmp1 = new Bitmap(img.Width, img.Height);
// Save the image as a JPG
bmp1.Save(fileName, System.Drawing.Imaging.ImageFormat.Jpeg);
}
/*------------------------------------------------------------------------*/
fileName = foo.DirectoryName + "\\" + fileName;
return fileName;
}
我想转换 bmp
,png
,gif
,tiff
文件格式 jpg
但 GDI+
作为给出。
System.OutOfMemoryException was unhandled Message=Bellek yetersiz. Source=System.Drawing StackTrace: konum.Drawing.Image.FromFile(String filename, Boolean useEmbeddedColorManagement)。System.Drawing.Image.FromFile(String filename, Boolean useEmbeddedColorManagement)魔图。System.Drawing.Image.FromFile(String filename)
那么如何才能避免这种情况的发生,并至少转换为 PNG
和 BMP
文件到 JPG
?
下面是一张错误的图片。
我发现问题了!是PNG的alpha通道造成的。我发现问题了!是PNG的alpha通道造成的。
感谢max,下面的链接解决了我的问题。
public static void SetAlpha(this Bitmap bmp, byte alpha)
{
if(bmp == null) throw new ArgumentNullException("bmp");
var data = bmp.LockBits(
new Rectangle(0, 0, bmp.Width, bmp.Height),
System.Drawing.Imaging.ImageLockMode.ReadWrite,
System.Drawing.Imaging.PixelFormat.Format32bppArgb);
var line = data.Scan0;
var eof = line + data.Height * data.Stride;
while(line != eof)
{
var pixelAlpha = line + 3;
var eol = pixelAlpha + data.Width * 4;
while(pixelAlpha != eol)
{
System.Runtime.InteropServices.Marshal.WriteByte(
pixelAlpha, alpha);
pixelAlpha += 4;
}
line += data.Stride;
}
bmp.UnlockBits(data);
}
用法。
var pngImage = new Bitmap("filename.png");
pngImage.SetAlpha(255);
设置alpha后,它开始正常工作。
缺少gif、png和tiff代码块。using
子句,并泄露了GDI的引用。