// Compute one line of output
inline void
doLine(Pixel *l0, Pixel *l1, Pixel *l2, Pixel *out, unsigned width, unsigned xderiv) {
if(xderiv)
doLineX(l0, l1, l2, out, width);
else
doLineY(l0, l1, l2, out, width);
}
static unsigned
update(int H, int W, Pixel *src, Pixel *dst, float *dst_32f,
unsigned lines, unsigned xderiv) {
if( !img ) {
img = malloc(H * W * sizeof(Pixel));
}
unsigned i, j;
for( i = 0; i < lines; i++ ) {
int at = (lineAt + i) * W;
int src_at = i * W;
for( j = 0; j < W; j++ )
img[at+j] = src[src_at+j];
}
unsigned produced = 0;
for( i = 0; i < lines; i++ ) {
int at = lineAt + i;
// at = 0 begin (zero lines)
if( at == 1 ) {
// first line
memset(dst, 0, sizeof(Pixel) * W);
memset(dst_32f, 0, sizeof(float) * W);
dst += W;
dst_32f += W;
produced++;
}
else if( at > 1 ) {
Pixel *img_cur = img + at * W;
if( xderiv ) {
doLineX( img_cur - W, img_cur, img_cur + W, dst, W );
doLineX_32f( img_cur - W, img_cur, img_cur + W, dst_32f, W );
}
else {
doLineY( img_cur - W, img_cur, img_cur + W, dst, W );
doLineY_32f( img_cur - W, img_cur, img_cur + W, dst_32f, W );
}
dst += W;
dst_32f += W;
produced++;
}
if( at == H - 1 ) {
// end (two lines)
memset(dst, 0, sizeof(Pixel) * W);
memset(dst_32f, 0, sizeof(float) * W);
dst += W;
dst_32f += W;
produced++;
}
}
return produced;
}