lqr_carver_bias_add(3) [debian man page]

LQR_CARVER_BIAS_ADD(3)					     LqR library API reference					    LQR_CARVER_BIAS_ADD(3)

NAME

       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
       LqrCarver bias

SYNOPSIS

       #include <lqr.h>

       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, gint y_off);

       LqrRetVal lqr_carver_bias_add(LqrCarver* carver, gdouble* buffer, gint bias_factor);

       LqrRetVal lqr_carver_bias_add_rgb_area(LqrCarver* carver, gdouble* buffer, 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);

FOREWORD

       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
       absolute value).

       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.

RETURN VALUES

       The return values follow the Liquid Rescale library signalling system.

SEE ALSO

       LqrRetVal(3), lqr_carver_init(3), lqr_carver_rigmask_add(3)

COPYRIGHT

       Copyright (C) 2007-2009 Carlo Baldassi

LqR library 0.4.1 API (3:1:3)					    10 Maj 2009 					    LQR_CARVER_BIAS_ADD(3)

LQR_CARVER_RIGMASK_ADD(3)				     LqR library API reference					 LQR_CARVER_RIGMASK_ADD(3)

NAME

       lqr_carver_rigmask_add_xy, lqr_carver_rigmask_add_area, lqr_carver_rigmask_add, lqr_carver_rigmask_add_rgb_area, lqr_carver_rigmask_add_rgb
       - update an LqrCarver rigidity mask

SYNOPSIS

       #include <lqr.h>

       LqrRetVal lqr_carver_rigmask_add_xy(LqrCarver* carver, gdouble rigidity, gint x, gint y);

       LqrRetVal lqr_carver_rigmask_add_area(LqrCarver* carver, gdouble* buffer, gint width, gint height, gint x_off, gint y_off);

       LqrRetVal lqr_carver_rigmask_add(LqrCarver* carver, gdouble* buffer);

       LqrRetVal lqr_carver_rigmask_add_area(LqrCarver* carver, gdouble* buffer, gint channels, gint width, gint height, gint x_off, gint y_off);

       LqrRetVal lqr_carver_rigmask_add_rgb(LqrCarver* carver, gdouble* buffer, gint channels);

FOREWORD

       All the functions described in this page are used to add a rigidity mask to LqrCarver objects. Whenever one of these functions is called, a
       rigidity mask is activated for the whole image; the mask contains coefficients which modulate the value of the rigidity (which is set with
       lqr_carver_init(3)) in different areas of the image.

       It is very important to note that using no rigidity masks at all is equivalent to use a rigidity mask over the whole image with all the
       values set to 1.0, but, when first adding a rigidity mask to a LqrCarver object, all the pixels outside the affected area will have their
       rigidity set to zero; therefore, the functions lqr_carver_rigmask_add_xy, lqr_carver_rigmask_add_area and lqr_carver_rigmask_add_rgb_area
       actually affect the whole image, despite their name.

       All the functions must be called after lqr_carver_init and before lqr_carver_resize. If called multiple times over the same area, new
       values will replace the old ones.

SETTING THE RIGIDITY MASK PIXEL BY PIXEL

       The function lqr_carver_rigmask_add_xy sets the rigidity mask value of the x, y pixel of the image loaded into the LqrCarver object pointed
       to by carver

SETTING THE RIGIDITY MASK FROM A BUFFER

       The function lqr_carver_rigmask_add_area adds a rigidity mask to an area of the image loaded in 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 are specified through x_off and y_off. The rigidity mask area can exceed the boundary of the
       image, and the offsets can be negative.

       The values in the given buffer are scaled by the overall rigidity value set when calling the function lqr_carver_init.

       The function lqr_carver_rigmask_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.

SETTING THE RIGIDITY MASK FROM AN IMAGE

       The functions lqr_carver_rigmask_add_rgb_area and lqr_carver_rigmask_add_rgb are very similar to lqr_carver_rigmask_add_area and
       lqr_carver_rigmask_add, but 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 rigidity value 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_rigmask_add_area.

RETURN VALUE

       The return values follow the Liquid Rescale library signalling system.

SEE ALSO

       LqrRetVal(3), lqr_carver_init(3), lqr_carver_bias_add(3)

COPYRIGHT

       Copyright (C) 2007-2009 Carlo Baldassi

LqR library 0.4.1 API (3:1:3)					    10 Maj 2009 					 LQR_CARVER_RIGMASK_ADD(3)