Marshal.Copy/UnlockBits hangs
本文关键字:hangs UnlockBits Copy Marshal | 更新日期: 2023-09-27 18:30:07
用户选择图像的一部分进行剪切和粘贴操作。我创建了一个新位图,将选定的部分粘贴到新图像中,擦除源数组并将其粘贴回旧图像中。工作,但至少有一半时间挂起"尝试读取或写入受保护的内存"。这通常表示其他内存已损坏。
有什么想法或帮助吗?
public BitmapSource CutToNew(double left, double top, double width, double height, double pageWidth, double pageHeight)
{
var destBmp = new Bitmap((int)pageWidth, (int)pageHeight);
var g = Graphics.FromImage(destBmp);
g.FillRectangle(new SolidBrush(Color.White), 0, 0,
(int)pageHeight, (int)pageWidth);
g.Dispose();
var croppedArea = new Rectangle((int)left, (int)top, (int)width, (int)height);
BitmapData croppedSource = _bitmapImage.LockBits(croppedArea,
ImageLockMode.ReadWrite, BitmapImage.PixelFormat);
var croppedDestArea = new Rectangle((int)left, (int)top, (int)width, (int)height);
BitmapData croppedDest = destBmp.LockBits(croppedDestArea,
ImageLockMode.WriteOnly, BitmapImage.PixelFormat);
// Create data array to hold bmpSource pixel data
int stride = croppedSource.Stride;
int numBytes = stride * (int)height;
var srcData = new byte[numBytes];
var destData = new byte[numBytes];
Marshal.Copy(croppedSource.Scan0, srcData, 0, numBytes);
//Tried creating a separate array in case that helped.
Array.Copy(srcData, destData, srcData.Length);
//Often hangs here with Attempted to read or write protected memory.
Marshal.Copy(destData, 0, croppedDest.Scan0, numBytes);
destBmp.UnlockBits(croppedDest);
var retVal = new DocAppImage {BitmapImage = destBmp};
destBmp.Dispose();
//Blank the source area
for (int y = 0; y < srcData.Length; y++)
srcData[y] = 0xFF;
Marshal.Copy(srcData, 0, croppedSource.Scan0, numBytes);
_bitmapImage.UnlockBits(croppedSource);
return retVal.bmpSource;
}
private Bitmap _bitmapImage;
public Bitmap BitmapImage
{
get
{
if (_bitmapImage != null)
return _bitmapImage;
if (FileImage != null)
{
var stream = new MemoryStream(FileImage); //Fileimage=TIFF read from file.
_bitmapImage = new Bitmap(stream);
return _bitmapImage;
}
return null;
}
set
{
if (value != null)
{
ImageCodecInfo codecInfo = GetImageCodecInfo("TIFF");
... implementation to set the bitmap image.
创建新对象时,您可能需要尝试指定PixelFormat
。
例如:
var destBmp = new Bitmap((int)pageWidth, (int)pageHeight, PixelFormat.Format24bppRgb);