img_expand_getfunc()

Get a function to convert a palette format to a direct format

Synopsis:

#include <img.h>

img_expand_f *img_expand_getfunc( img_format_t src,
                                  img_format_t lut )

Arguments:

src

The palette-based img_format_t image format to convert from

lut

The img_format_t direct image format to convert to

Library:

img

Description:

This function returns a pointer to a data conversion function (or NULL if the requested conversion is not supported) which you can call to “expand” (that is, convert) a run of pixels from a palette-based format src to a “direct” format in a lookup table lut. A conversion function takes the form:

void img_expand_f( const uint8 *src,
                   uint8 *dst,
                   unsigned n,
                   const uint8 *lut);

Here's a sample procedure for converting from PAL8 to ARGB1555:

1. Convert your lookup table to the destination format:

   img_convert_data(IMG_FMT_PKHE_ARGB8888, palette, IMG_FMT_PKLE_ARGB1555, palette, npalette);

2. Get the handle to the expand function that will expand the data:

   img_expand_getfunc(IMG_FMT_PAL8, IMG_FMT_PKLE_ARGB1555);

3. Call the expand function for each run of indexed data you want to expand:

   expand_f(sptr, dptr, npixels, palette);

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You can use img_dtransform_create() instead to abstract the details of expansion and conversion.

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Returns:

IMG_ERR_OK

Success.

IMG_ERR_NOSUPPORT

One of the formats specified is invalid.

Classification:

Image library

See also:

img_convert_data(), img_dtransform_create(), IMG_FMT_BPL(), img_lib_attach()