lqr_carver_new_ext(3) [debian man page]

LQR_CARVER_NEW(3)					     LqR library API reference						 LQR_CARVER_NEW(3)

NAME

       lqr_carver_new, lqr_carver_new_ext - the LqrCarver object constructors

SYNOPSIS

       #include <lqr.h>

       LqrCarver* lqr_carver_new(guchar* buffer, gint width, gint height, gint channels);

       LqrCarver* lqr_carver_new_ext(void* buffer, gint width, gint height, gint channels, LqrColDepth colour_depth);

DESCRIPTION

       The functions lqr_carver_new and lqr_carver_new_ext create a new LqrCarver object from an image of size width * height with channels colour
       channels.

       The image must be stored in buffer as a plain array of unsigned chars (for lqr_carver_new) or the appropriate type cast to void (for
       lqr_carver_new_ext), ordered by row, then by column, then by colour channel.

       In the extended constructor lqr_carver_new_ext, the additional parameter colour_depth is required to specify the colour depth of the buffer
       (see LqrColDepth(3) for more information).

       After calling the function, the buffer will be owned by the LqrCarver object and must not be accessed any more, unless you subsequently
       call the lqr_carver_set_preserve_input_image(3) function.

       The image type is et automatically from the value of channels according to this table:

       Table 3.1. Image types assigned by default
       +---------+------------------+
       |channels | type 	    |
       +---------+------------------+
       |1	 | LQR_GREY_IMAGE   |
       +---------+------------------+
       |2	 | LQR_GREYA_IMAGE  |
       +---------+------------------+
       |3	 | LQR_RGB_IMAGE    |
       +---------+------------------+
       |4	 | LQR_RGBA_IMAGE   |
       +---------+------------------+
       |5	 | LQR_CMYKA_IMAGE  |
       +---------+------------------+
       |>5	 | LQR_CUSTOM_IMAGE |
       +---------+------------------+

RETURN VALUE

       The return value is the address of the newly created LqrCarver object, or NULL in case of failure (insufficient memory).

SEE ALSO

       LqrColDepth(3), LqrImageType(3), lqr_carver_destroy(3), lqr_carver_init(3), lqr_carver_set_preserve_input_image(3)

COPYRIGHT

       Copyright (C) 2007-2009 Carlo Baldassi

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

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)