Is there a limit on the size of image that can be encoded using the image file codecs available from .NET?
I'm trying to encode images > 4GB in size, but it simply does not work (or does not work properly i.e. writes out an unreadable file) with .bmp, .jpg, .png or the .tif encoders.
When I lower the image size to < 2GB it does work with the .jpg but not the .bmp, .tif or .png.
My next attempt would be to try libtiff because I know tiff files are meant for large images.
What is a good file format for large images? or am I just hitting the file format limitations?
(All of this is being done on a 64 bit operating system (WinXP 64) w/ 8 GB of RAM and compiled using 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 have also tried using a pinned GC memory region, but this is limited to < 2GB.
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();