public static string GetEncoderVersion()
{
uint v = (uint)NativeMethods.WebPGetEncoderVersion();
var revision = v % 256;
var minor = (v >> 8) % 256;
var major = (v >> 16) % 256;
return(major + "." + minor + "." + revision);
}
/// <summary>
/// Encodes the given RGB(A) bitmap to an unmanged memory buffer (returned via result/length). Specify quality = -1 for lossless, otherwise specify a value between 0 and 100.
/// </summary>
/// <param name="b"></param>
/// <param name="quality"></param>
/// <param name="result"></param>
/// <param name="length"></param>
public void Encode(Bitmap b, float quality, out IntPtr result, out long length)
{
if (quality < -1)
{
quality = -1;
}
if (quality > 100)
{
quality = 100;
}
int w = b.Width;
int h = b.Height;
var bd = b.LockBits(new Rectangle(0, 0, w, h), System.Drawing.Imaging.ImageLockMode.ReadOnly, b.PixelFormat);
try {
result = IntPtr.Zero;
if (b.PixelFormat == System.Drawing.Imaging.PixelFormat.Format32bppArgb)
{
if (quality == -1)
{
length = (long)NativeMethods.WebPEncodeLosslessBGRA(bd.Scan0, w, h, bd.Stride, ref result);
}
else
{
length = (long)NativeMethods.WebPEncodeBGRA(bd.Scan0, w, h, bd.Stride, quality, ref result);
}
}
else if (b.PixelFormat == System.Drawing.Imaging.PixelFormat.Format24bppRgb)
{
if (quality == -1)
{
length = (long)NativeMethods.WebPEncodeLosslessBGR(bd.Scan0, w, h, bd.Stride, ref result);
}
else
{
length = (long)NativeMethods.WebPEncodeBGR(bd.Scan0, w, h, bd.Stride, quality, ref result);
}
}
else
{
using (Bitmap b2 = b.Clone(new Rectangle(0, 0, b.Width, b.Height), System.Drawing.Imaging.PixelFormat.Format32bppArgb))
{
Encode(b2, quality, out result, out length);
}
}
if (length == 0)
{
throw new Exception("WebP encode failed!");
}
} finally {
b.UnlockBits(bd);
}
}
/// <summary>
/// Encodes the given RGB(A) bitmap to the given stream. Specify quality = -1 for lossless, otherwise specify a value between 0 and 100.
/// </summary>
/// <param name="from"></param>
/// <param name="to"></param>
/// <param name="quality"></param>
public void Encode(Bitmap from, Stream to, float quality)
{
IntPtr result;
long length;
Encode(from, quality, out result, out length);
try {
byte[] buffer = new byte[4096];
for (int i = 0; i < length; i += buffer.Length)
{
int used = (int)Math.Min((int)buffer.Length, length - i);
Marshal.Copy((IntPtr)((long)result + i), buffer, 0, used);
to.Write(buffer, 0, used);
}
} finally {
NativeMethods.WebPSafeFree(result);
}
}
