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ministromayor

SDL: rescale jpeg surface.

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I'm trying to rescale a surface obtained via IMG_LoadJPG_RW with zoomSurface with and whithout smooting and mi app crash with segmentation fault. I'm sure my stack is fine, at least with my code.

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The code involved with the problem:

Sorry: Class & object & method names in spanish. ;-)

imgmgr.h :

SDL_Surface *imagen;
SDL_RWops *rwop;

imgmgr.cpp :

AdministradorImagenes::
AdministradorImagenes()
{
imagen = NULL;
rwop = NULL;
}

SDL_Surface *AdministradorImagenes::
cargaImagen(char *ruta)
{
rwop = SDL_RWFromFile(ruta, "rb");
imagen = IMG_LoadJPG_RW(rwop);
return imagen;
}

SDL_Surface *AdministradorImagenes::
cargaQImagen(char *ruta)
{
SDL_Surface *orig = cargaImagen(ruta);
double w = orig->w/4;
double h = orig->h/4;
SDL_Surface *resc = zoomSurface(orig, w, h, SMOOTHING_OFF);
return resc;
}

principal.cpp :

AdministradorImagenes img_adm;
foto = img_adm.cargaQImagen(argv[1]);

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Several of those functions can return NULL, such as SDL_RWFromFile or IMG_LoadJPG_RW. You should be checking for that first.

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I have already checked with debuger (gdb) I know exactly where the error ocurrs:

SDL_Surface *resc = zoomSurface(orig, w, h, SMOOTHING_OFF);

I left SDL_image and i'm using jpeglib instead. Now I have a SDL_Surface with my thumbnail but whith some problems, doesn't matters I'll deal with this errors by myself.

SDL_image creates an SDL_Surface with the jpeg image in a 1:1 scale. then I preferr to scale at loading time directly with jpeglib.

however, If somebody knows how to rescale an existing SDL_Surface with pixels within...

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