Interpolate plane initial implementation.

include/libyuv/planar_functions.h

Index: include/libyuv/planar_functions.h
diff --git a/include/libyuv/planar_functions.h b/include/libyuv/planar_functions.h
index 8d0b457137458445b6f818068d5d4bb89b7d7b14..5881d8249b9e5029b7175918c2f8ae559a82d4cf 100644
--- a/include/libyuv/planar_functions.h
+++ b/include/libyuv/planar_functions.h
@@ -401,6 +401,25 @@ int ARGBInterpolate(const uint8* src_argb0, int src_stride_argb0,
                     const uint8* src_argb1, int src_stride_argb1,
                     uint8* dst_argb, int dst_stride_argb,
                     int width, int height, int interpolation);
+// Interpolate 2 planes by specified amount (0 to 255).

[Diony Rosa, 2015/11/25 19:38:39]

I'd mention that this interpolation has the same meaning as in ArgbInterpolate
(0 means 100% src0, 255 means 99% src1, etc).

For readers that are looking at just InterpolatePlane without noticing
ArgbInterpolate above.

[fbarchard, 2015/11/25 19:56:57]

Done.

+LIBYUV_API
+int InterpolatePlane(const uint8* src0, int src_stride0,
+                     const uint8* src1, int src_stride1,
+                     uint8* dst, int dst_stride,
+                     int width, int height, int interpolation);
+
+// Interpolate 2 YUV images by specified amount (0 to 255).
+LIBYUV_API
+int I420Interpolate(const uint8* src0_y, int src0_stride_y,
+                    const uint8* src0_u, int src0_stride_u,
+                    const uint8* src0_v, int src0_stride_v,
+                    const uint8* src1_y, int src1_stride_y,
+                    const uint8* src1_u, int src1_stride_u,
+                    const uint8* src1_v, int src1_stride_v,
+                    uint8* dst_y, int dst_stride_y,
+                    uint8* dst_u, int dst_stride_u,
+                    uint8* dst_v, int dst_stride_v,
+                    int width, int height, int interpolation);
 
 #if defined(__pnacl__) || defined(__CLR_VER) || \
     (defined(__i386__) && !defined(__SSE2__))