private void GetWebpInfo(IntPtr ptrRawWebP, int webpDataSize, out int width, out int height, out bool has_alpha, out bool has_animation, out string format)
{
VP8StatusCode result;
WebPBitstreamFeatures features = new WebPBitstreamFeatures();
result = WebPWrapper.WebPGetFeatures(ptrRawWebP, webpDataSize, ref features);
if (result == 0)
{
width = features.Width;
height = features.Height;
has_alpha = (features.Has_alpha == 1);
has_animation = (features.Has_animation == 1);
switch (features.Format)
{
case 1:
format = "lossy";
break;
case 2:
format = "lossless";
break;
default:
format = "undefined";
break;
}
}
else
{
throw new Exception(result.ToString());
}
}
private void decodeWebP(MemoryStream stream)
{
Bitmap bmp = null;
Bitmap firstbmp = null;
bool firstbitmap = true;
BitmapData bmpData = null;
IntPtr dec = (IntPtr)0;
const int UintBytes = 4;
byte [] rawWebP = stream.ToArray();
UIntPtr dataSize = (UIntPtr)rawWebP.Length;
GCHandle pinnedWebP = GCHandle.Alloc(rawWebP, GCHandleType.Pinned);
IntPtr ptrData = pinnedWebP.AddrOfPinnedObject();
try
{
//Get info about webp image
GetWebpInfo(ptrData, rawWebP.Length, out int imgWidth, out int imgHeight, out bool hasAlpha, out bool hasAnimation, out string format);
if (hasAnimation)
{
//demux the image
WebPData webpdata = new WebPData()
{
bytes = ptrData, size = dataSize
};
WebPAnimDecoderOptions dec_options = new WebPAnimDecoderOptions();
//init decoder options with default values
WebPWrapper.WebPAnimDecoderOptionsInit(ref dec_options);
//set color mode to blue green red alpha to match up with how the bitmap is formatted
dec_options.color_mode = WEBP_CSP_MODE.MODE_BGRA;
//create the decoder
dec = WebPWrapper.WebPAnimDecoderNew(ref webpdata, ref dec_options);
IntPtr buf;
int timestamp;
uint outputSize;
WebPAnimInfo animinfo = new WebPAnimInfo();
//get animation info
WebPWrapper.WebPAnimDecoderGetInfo(dec, ref animinfo);
imgWidth = (int)animinfo.canvas_width;
imgHeight = (int)animinfo.canvas_height;
int prevtimestamp = 0;
bool first = true;
while (WebPWrapper.WebPAnimDecoderHasMoreFrames(dec) == 1)
{
//get next frame
WebPWrapper.WebPAnimDecoderGetNext(dec, out buf, out timestamp);
//copy frame into an Image (Bitmap)
bmp = new Bitmap(imgWidth, imgHeight, PixelFormat.Format32bppArgb);
bmpData = bmp.LockBits(new Rectangle(0, 0, imgWidth, imgHeight), ImageLockMode.WriteOnly, bmp.PixelFormat);
outputSize = (uint)(bmpData.Stride * imgHeight);
WebPWrapper.CopyMemory(bmpData.Scan0, buf, outputSize);
bmp.UnlockBits(bmpData);
//Add frame to the list
AddFrame(bmp, (timestamp - prevtimestamp) / 10);
prevtimestamp = timestamp;
bmpData = null;
if (first)
{
ActiveImage = bmp;
Height = imgHeight;
Width = imgWidth;
first = false;
}
}
WebPWrapper.WebPAnimDecoderReset(dec);
WebPWrapper.WebPAnimDecoderDelete(dec);
dec = (IntPtr)0;
IsAnimated = true;
}
else
{
//Create a Bitmap and Lock all pixels to be written
if (hasAlpha)
{
bmp = new Bitmap(imgWidth, imgHeight, PixelFormat.Format32bppArgb);
}
else
{
bmp = new Bitmap(imgWidth, imgHeight, PixelFormat.Format24bppRgb);
}
bmpData = bmp.LockBits(new Rectangle(0, 0, imgWidth, imgHeight), ImageLockMode.WriteOnly, bmp.PixelFormat);
//Uncompress the image
int outputSize = bmpData.Stride * imgHeight;
if (bmp.PixelFormat == PixelFormat.Format24bppRgb)
{
WebPWrapper.WebPDecodeBGRInto(ptrData, rawWebP.Length, bmpData.Scan0, outputSize, bmpData.Stride);
}
else
{
WebPWrapper.WebPDecodeBGRAInto(ptrData, rawWebP.Length, bmpData.Scan0, outputSize, bmpData.Stride);
}
ActiveImage = bmp;
Height = imgHeight;
Width = imgWidth;
}
}
catch (Exception e) {
GuiEngine.Current.log(e.ToString());
}
finally
{
//Unlock the pixels
if (bmpData != null)
{
bmp.UnlockBits(bmpData);
}
if (dec != (IntPtr)0)
{
WebPWrapper.WebPAnimDecoderDelete(dec);
}
//Free memory
if (pinnedWebP.IsAllocated)
{
pinnedWebP.Free();
}
}
}