Is there a limit on the size of an image that can be encoded using image file codecs available from .NET?
I'm trying to encode images> 4 GB in size, but it just doesn't work (or doesn't work properly, that is, it writes an unreadable file) using .bmp, .jpg, .png or .tif encoders.
When I reduce the image size to <2GB it works with .jpg, but not with .bmp, .tif or .png.
My next attempt is to try libtiff because I know that tiff files are for large images.
What is a good file format for large images? or am I just pushing file format restrictions?
(All this runs on a 64-bit operating system (WinXP 64) with 8 GB of RAM and compiled using the x64 architecture.)
Random r = new Random((int)DateTime.Now.Ticks); int width = 64000; int height = 64000; int stride = (width % 4) > 0 ? width + (width % 4) : width; UIntPtr dataSize = new UIntPtr((ulong)stride * (ulong)height); IntPtr p = Program.VirtualAlloc(IntPtr.Zero, dataSize, Program.AllocationType.COMMIT | Program.AllocationType.RESERVE, Program.MemoryProtection.READWRITE); Bitmap bmp = new Bitmap(width, height, stride, PixelFormat.Format8bppIndexed, p); BitmapData bd = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadWrite, bmp.PixelFormat); ColorPalette cp = bmp.Palette; for (int i = 0; i < cp.Entries.Length; i++) { cp.Entries[i] = Color.FromArgb(i, i, i); } bmp.Palette = cp; unsafe { for (int y = 0; y < bd.Height; y++) { byte* row = (byte*)bd.Scan0.ToPointer() + (y * bd.Stride); for (int x = 0; x < bd.Width; x++) { *(row + x) = (byte)r.Next(256); } } } bmp.UnlockBits(bd); bmp.Save(@"c:\test.jpg", ImageFormat.Jpeg); bmp.Dispose(); Program.VirtualFree(p, UIntPtr.Zero, 0x8000);
I also tried using the GC pinned memory area, but this is limited to <2 GB.
Random r = new Random((int)DateTime.Now.Ticks); int bytesPerPixel = 4; int width = 4000; int height = 4000; int padding = 4 - ((width * bytesPerPixel) % 4); padding = (padding == 4 ? 0 : padding); int stride = (width * bytesPerPixel) + padding; UInt32[] pixels = new UInt32[width * height]; GCHandle gchPixels = GCHandle.Alloc(pixels, GCHandleType.Pinned); using (Bitmap bmp = new Bitmap(width, height, stride, PixelFormat.Format32bppPArgb, gchPixels.AddrOfPinnedObject())) { for (int y = 0; y < height; y++) { int row = (y * width); for (int x = 0; x < width; x++) { pixels[row + x] = (uint)r.Next(); } } bmp.Save(@"c:\test.jpg", ImageFormat.Jpeg); } gchPixels.Free();