// GetGoogleSpec returns a google-specific tile spec, which includes how the tile is positioned relative to
// scaled volume boundaries. Not that the size parameter is the desired size and not what is required to fit
// within a scaled volume.
func (d *Data) GetGoogleSpec(scaling Scaling, plane dvid.DataShape, offset dvid.Point3d, size dvid.Point2d) (*GoogleTileSpec, error) {
tile := new(GoogleTileSpec)
tile.offset = offset
// Convert combination of plane and size into 3d size.
sizeWant, err := dvid.GetPoint3dFrom2d(plane, size, 1)
if err != nil {
return nil, err
}
tile.sizeWant = sizeWant
// Determine which geometry is appropriate given the scaling and the shape/orientation
tileSpec, err := GetTileSpec(scaling, plane)
if err != nil {
return nil, err
}
geomIndex, found := d.TileMap[*tileSpec]
if !found {
return nil, fmt.Errorf("Could not find scaled volume in %q for %s with scaling %d", d.DataName(), plane, scaling)
}
geom := d.Scales[geomIndex]
tile.gi = geomIndex
tile.channelCount = geom.ChannelCount
tile.channelType = geom.ChannelType
// Get the # bytes for each pixel
switch geom.ChannelType {
case "uint8":
tile.bytesPerVoxel = 1
case "float":
tile.bytesPerVoxel = 4
case "uint64":
tile.bytesPerVoxel = 8
default:
return nil, fmt.Errorf("Unknown volume channel type in %s: %s", d.DataName(), geom.ChannelType)
}
// Check if the tile is completely outside the volume.
volumeSize := geom.VolumeSize
if offset[0] >= volumeSize[0] || offset[1] >= volumeSize[1] || offset[2] >= volumeSize[2] {
tile.outside = true
return tile, nil
}
// Check if the tile is on the edge and adjust size.
var adjSize dvid.Point3d = sizeWant
maxpt, err := offset.Expand2d(plane, size)
for i := 0; i < 3; i++ {
if maxpt[i] > volumeSize[i] {
tile.edge = true
adjSize[i] = volumeSize[i] - offset[i]
}
}
tile.size = adjSize
return tile, nil
}
