.\"     Title: \fBlqr_carver_get_energy\fR
.\"    Author: Carlo Baldassi
.\" Generator: DocBook XSL Stylesheets v1.73.2 <http://docbook.sf.net/>
.\"      Date: 10 Maj 2009
.\"    Manual: LqR library API reference
.\"    Source: LqR library 0.4.1 API (3:1:3)
.\"
.TH "\FBLQR_CARVER_GET_ENERGY\FR" "3" "10 Maj 2009" "LqR library 0.4.1 API (3:1:3)" "LqR library API reference"
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.SH "NAME"
lqr_carver_get_energy, lqr_carver_get_true_energy, lqr_carver_get_energy_image \- get the energy map for a LqrCarver object
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <lqr\&.h>
.fi
.ft
.HP 32
.BI "LqrRetVal lqr_carver_get_energy(LqrCarver*\ " "carver" ", gfloat\ *\ " "buffer" ", gint\ " "orientation" ");"
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <lqr\&.h>
.fi
.ft
.HP 37
.BI "LqrRetVal lqr_carver_get_true_energy(LqrCarver*\ " "carver" ", gfloat\ *\ " "buffer" ", gint\ " "orientation" ");"
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <lqr\&.h>
.fi
.ft
.HP 32
.BI "LqrRetVal lqr_carver_get_energy(LqrCarver*\ " "carver" ", void\ *\ " "buffer" ", gint\ " "orientation" ", LqrColDepth\ " "col_depth" ", LqrImageType\ " "image_type" ");"
.SH "DESCRIPTION"
.PP
The function
\fBlqr_carver_get_energy\fR
writes the energy map of the
LqrCarver
object pointed to by
\fIcarver\fR
to the given
\fIbuffer\fR, in a format suitable for plotting: all values are in the range between
0
and
1, and the true values are mapped nonlinearly and stretched on this whole range, so that the differences between the middle values are enhanced with respect to very high or very low values\&.
.PP
The
\fIorientation\fR
parameter must be either
0
to get the energy map used for horizontal scalings, or
1
to get the map for vertical scalings\&.
.PP
The buffer must be allocated by the user before calling this function, and its size must be at least
\fIwidth\fR * \fIheight\fR, where
\fIwidth\fR
and
\fIheight\fR
are the current width and height of the
\fIcarver\fR\&. The energy values are ordered by row first, then by column\&.
.PP
The outcome will include the effect of the bias added to the
\fIcarver\fR, if any\&.
.PP
This function can be called over non\-initialised
LqrCarver
objects, e\&.g\&. to provide previews on the effect of different energy functions, but it can also be invoked at any later time\&. Note, however, that in this latter case the
\fIcarver\fR
could be flattened if necessary, therefore the function invocation is potentially destructive of the internal visibiliy map\&.
.PP
The function
\fBlqr_carvet_get_true_energy\fR
is identical to the previous one, but the resulting buffer will contain the true energy, not scaled nor shifted\&.
.PP
The function
\fBlqr_carver_get_energy_image\fR
is very similar to the function
\fBlqr_carveR_get_energy\fR, but it can be used to fill directly an image buffer of the format specified through the additional parameters
\fIcol_depth\fR
and
\fIimage_type\fR
(see
\fBLqrColDepth\fR(3)
and
\fBLqrImageType\fR(3))\&. The
\fIbuffer\fR
must be passed as
\fBvoid*\fR, but it must point to a memory area with sufficient allocated space for the chosen image type and colour depth\&. The image type cannot be
LQR_CUSTOM_IMAGE\&.
.PP
For any choice of the parameters describing the image, the resulting
\fIbuffer\fR
will hold a greyscale image, ranging from black (lowest energy) to white (highest energy)\&. The opacity (alpha) will be set to
1, if present\&. All the information will be stored in the black channel in
LQR_CMYK_IMAGE
and
LQR_CMYKA_IMAGE
image types\&.
.SH "RETURN VALUES"
.PP
The return values follow the Liquid Rescale library signalling system\&. The function
\fBlqr_carver_get_energy_image\fR
will return an error if
\fIimage_type\fR
is
LQR_CUSTOM_IMAGE\&.
.SH "SEE ALSO"
.PP

\fBlqr_carver_set_energy_function_builtin\fR(3), \fBlqr_carver_set_energy_function\fR(3), \fBlqr_carver_bias_add\fR(3)
.SH "COPYRIGHT"
Copyright \(co 2007-2009 Carlo Baldassi
.br