module Raster:sig
..end
WARNING. This interface is subject to change in the future.
Raster data organizes data samples of any dimension in discrete 1D, 2D (images) or 3D space.
A sample has a semantics that defines its dimension and the meaning of its components. For example a 4D sample could represent a linear sRGBA sample. Samples are stored in a linear buffer of scalars of a given type. A sample can use one scalar per component, can be packed in a single scalar or may have no direct obvious relationship to buffer scalars (compressed data). The sample format defines the semantics and scalar storage of a sample.
A raster data value is a collection of samples indexed by width, height and depth (i.e. x, y, z) stored in a buffer. It defines the sample data, the extents of the index and the sample format. The optional resolution in samples per meters of a raster data can specify its physical dimension.
Spatial convention. If the sample index has to be interpreted
spatially. It must be interpreted relative to the origin of a
right-handed coordinate system. This means that the first sample,
indexed by (0,0,0)
is the bottom-left backmost sample
(bottom-left sample for a 2D image).
Index sizes. Index sizes are specified using
size types which are made of floats as it is more
pratical in most scenarios. These floats should however be integral floats. The function Gg.Raster.v
, Gg.Raster.Sample.scalar_count
and Gg.Raster.sub
ensure this by applying Gg.Float.round
to these values.
This means that the raster size functions when called with
meters = false
will always return sizes that are integral floats that
you can convert to integers safely without having to think about
rounding issues. Note also that index sizes are always strictly
positive.
module Sample:sig
..end
typet =
Gg.raster
val v : ?res:Gg.v3 ->
?first:int ->
?w_stride:int ->
?h_stride:int ->
[ `D1 of float | `D2 of Gg.size2 | `D3 of Gg.size3 ] ->
Sample.format -> Gg.buffer -> t
v res first w_stride h_stride size sf buf
is raster data with
sample format sf
and buffer b
.
size
, specify the index extents. height and depth if unspecified
default to 1
. All extents must be strictly positive.first
, buffer scalar index where the data of the first sample
is stored.w_stride
, number of samples (not buffer scalars) to skip
to go from the first sample of a line to the first sample of the next
line. Defaults to the index width.h_stride
, number of lines to skip to go from the first line
of a plane to the first line of the next plane. Defaults to the
index height.res
, is an optional sample resolution specification in
samples per meters.
For certain sample formats first
, w_stride
and h_stride
can be
used to specify subspaces in the collection of samples, see Gg.Raster.sub
.
The function Gg.Raster.scalar_strides
can be used to easily compute the
linear buffer scalar index where a sample (x,y,z)
starts.
Raises Invalid_argument
if the elements of size
are not stricly
positive, if first
is negative, if w_stride
or h_stride
are
smaller than the index width or height or if the scalar type of
sf
doesn't match (Raster.buffer_scalar_type b)
.
val res : t -> Gg.v3 option
res r
is r
's resolution in sample per meters, if any.val get_res : t -> Gg.v3
val first : t -> int
first r
is the buffer scalar index where the first sample
is stored.val w_stride : t -> int
w_stride r
is the number of samples to skip to go
from the first sample of a line to the first sample of
the next line.val h_stride : t -> int
h_stride r
is the number of lines to skip to go
from the first line of a plane to the first
line of the next plane.val sample_format : t -> Sample.format
sample_format r
is r
's sample format.val buffer : t -> Gg.buffer
buffer r
is r
's format.
In these functions have an optional meter
argument that
defaults to false
. If false
the result is in integral number
of samples. If true
the result is in meters according
to the rasters' resolution. If the raster has no
resolution, Gg.Raster.res_default
is used in all dimensions.
val wi : t -> int
wi r
is r
's index width in number of samples.val hi : t -> int
hi r
is r
's index height in number of samples.val di : t -> int
d r
is r
's index height in number of samples.val w : ?meters:bool -> t -> float
w r
is r
's index width.val h : ?meters:bool -> t -> float
h r
is r
's index height.val d : ?meters:bool -> t -> float
d r
is r
's index depth.val size1 : ?meters:bool -> t -> Gg.size1
size1 r
is r
's index width.val size2 : ?meters:bool -> t -> Gg.size2
size2 r
is r
's index width and height.val size3 : ?meters:bool -> t -> Gg.size3
size3 r
is r
's index width, height and depth.val box1 : ?meters:bool -> ?mid:bool -> ?o:float -> t -> Gg.box1
box1 meters mid o r
is a box with origin o
and size (size1
meters r)
. If mid
is true
(defaults to false
), o
specifies the mid point of the box. o
defaults to 0.val box2 : ?meters:bool -> ?mid:bool -> ?o:Gg.p2 -> t -> Gg.box2
box2 meters mid o r
is a box with origin o
and size (size2
meters r)
. If mid
is true
(defaults to false
), o
specifies the mid point of the box. o
defaults to Gg.P2.o
.val box3 : ?meters:bool -> ?mid:bool -> ?o:Gg.p3 -> t -> Gg.box3
box3 meters mid o r
is a box with origin o
and size
(size3 meters r)
. If mid
is true
(defaults to false
),
o
specifies the mid point of the box. o
defaults to Gg.P3.o
.val dim : t -> int
dim r
is r
's index dimension from 1 to 3. Note that
this is not derived from the case size given to Gg.Raster.v
for creating r
.
It is derived from the size (w,h,d)
as follows: (w,1,1)
means 1,
(w,h,1)
with h > 1
means 2, (w,h,d)
with h,d > 1
means 3.val kind : t -> [ `D1 | `D2 | `D3 ]
val sub : [ `D1 of Gg.box1 | `D2 of Gg.box2 | `D3 of Gg.box3 ] ->
t -> t
sub region
is a raster corresponding to a subset of the
index of r
. Both r
and the resulting raster share
the same buffer. The integral origin of the box defines the
new sample origin of the raster data and its integral
size the new size of the index.
If the dimension of the box is smaller than the raster the
result is in the first line (y = 0
) and/or layer (z = 0
) of
the raster r
.
Raises Invalid_argument,
if the sample format of r
is packed,
if the origin is out of bounds or if new size is larger than
r
's size.
val scalar_strides : t -> int * int * int
scalar_strides r
is (x_stride, y_stride, z_stride)
where
x_stride
is the number of buffer scalars from sample to sample.y_stride
is the number of buffer scalars from line to line.z_stride
is the number of buffer scalars from plane to plane.(x,y,z)
starts is given by:
(Raster.first r) + z * z_stride + y * y_stride + x * x_stride
Invalid_argument
if the sample format of r
is
packed.val equal : t -> t -> bool
equal r r'
is r = r'
.val compare : t -> t -> int
compare r r'
is Pervasives.compare r r'
.val pp : Format.formatter -> t -> unit
pp ppf t
prints a textual represenation of t
on ppf
. Doesn't
print the buffer samples.val res_default : float
res_default
is 11811spm (300spi).val spm_of_spi : float -> float
spm_of_spi spi
is the samples per meter corresponding to
the samples per inch spi
.val spm_to_spi : float -> float
spm_to_spi spm
is the samples per inch corresponding to the
samples per meters spm
.