lqr_carver_bias_add_xy, lqr_carver_bias_add_area, lqr_carver_bias_add,
lqr_carver_bias_add_rgb_area, lqr_carver_bias_add_rgb - update an
LqrRetVal lqr_carver_bias_add_xy(LqrCarver* carver, gdouble bias,
gint x, gint y);
LqrRetVal lqr_carver_bias_add_area(LqrCarver* carver, gdouble* buffer,
gint bias_factor, gint width,
gint height, gint x_off,
LqrRetVal lqr_carver_bias_add(LqrCarver* carver, gdouble* buffer,
LqrRetVal lqr_carver_bias_add_rgb_area(LqrCarver* carver,
gint bias_factor, gint channels,
gint width, gint height,
gint x_off, gint y_off);
LqrRetVal lqr_carver_bias_add_rgb(LqrCarver* carver, gdouble* buffer,
gint bias_factor, gint channels);
All the functions described in this page are used to add a bias to
LqrCarver objects. A positive biased pixel will be more likely to be
avoided by seams, and thus be preserved during rescaling, while a
negative bias has the opposite effect.
All of these functions must be called before lqr_carver_resize(3). If
called multiple times, the biases added at each call will sum up.
ADDING A BIAS PIXEL BY PIXEL
The function lqr_carver_bias_add_xy adds a bias to the x, y pixel of
the image loaded into the LqrCarver object pointed to by carver
A typical value for bias_factor would be 1000 (in absolute value).
ADDING A BIAS FROM A BUFFER
The function lqr_carver_bias_add_area adds a bias to an area of the
image loaded into the LqrCarver object pointed to by carver.
The parameter buffer must point to an array of doubles of size width *
height, ordered first by rows, then by columns.
The offset of the area relative to the image can be specified through
x_off and y_off. The bias area can exceed the boundary of the image,
and the offsets can be negative.
The parameter bias_factor is an overall bias scale. A typical value
when the buffer contents are of the order of 1 would be 1000 (in
The function lqr_carver_bias_add can be used when the area to add is of
the same size of the image loaded in the LqrCarver object and the
offsets are 0.
ADDING A BIAS FROM AN IMAGE
The functions lqr_carver_bias_add_rgb_area and lqr_carver_bias_add_rgb
are very similar to lqr_carver_bias_add_area and lqr_carver_bias_add,
except that they use 8-bit multi-channel images as inputs.
The number of channels in the image is passed via the parameter
channels. The last channel is assumed to be the alpha (opacity) channel
if channels is equal to 2 or greater than 3 (if this is not the case,
use the previous functions).
The bias is computed from the average of the colour channels,
multiplied by the value of the alpha channel if present. For example,
in RGBA images a white, nontransparent pixel is equivalent to a value
of 1.0 when using a buffer in lqr_carver_bias_add_area.
The return values follow the Liquid Rescale library signalling system.
LqrRetVal(3), lqr_carver_init(3), lqr_carver_rigmask_add(3)
Copyright © 2007-2009 Carlo Baldassi