public override ImageData Read(Stream stream, ImageMetaData info)
{
using (var reader = new WebPDecoder (stream, (WebPMetaData)info))
{
reader.Decode();
return ImageData.Create (info, reader.Format, null, reader.Output);
}
}
int last_y; // coordinate of the line that was last output
#endregion Fields
#region Methods
public int EmitSampledRGB(WebPDecoder dec)
{
var input = dec.Cache;
var output = dec.Output;
int dst_stride = dec.Stride;
int dst = mb_y * dst_stride;
for (int j = 0; j < mb_h; ++j)
{
YuvToBgraRow (input, y, u, v, output, dst, mb_w);
y += y_stride;
if (0 != (j & 1))
{
u += uv_stride;
v += uv_stride;
}
dst += dst_stride;
}
return mb_h;
}
void EmitAlphaRGB(WebPDecoder dec, int expected_num_lines_out)
{
int base_rgba = mb_y * dec.Stride;
int dst = base_rgba + 3;
DispatchAlpha (alpha_plane, a, width, mb_w, mb_h, dec.Output, dst, dec.Stride);
}
public bool Put(WebPDecoder dec)
{
if (mb_w <= 0 || mb_h <= 0)
return false;
int num_lines_out = EmitSampledRGB (dec);
if (alpha_plane != null)
EmitAlphaRGB (dec, num_lines_out);
last_y += num_lines_out;
return true;
}
public void Init(WebPDecoder dec)
{
mb_y = 0;
y = dec.cache_y_;
u = dec.cache_u_;
v = dec.cache_v_;
y_stride = dec.cache_y_stride_;
uv_stride = dec.cache_uv_stride_;
alpha_plane = dec.AlphaPlane;
a = 0;
last_y = 0;
}
