ncplane_as_rgba returns NULL after a blitting image with transparent background on a plane

[Albrict]

Please include the following data:

• export | egrep 'LANG|LC_CTYPE|TERM'

   declare -x COLORTERM="truecolor"
   declare -x GDM_LANG="en_US.UTF-8"
   declare -x LANG="en_US.UTF-8"
   declare -x TERM="alacritty" 
  

• notcurses version (available from notcurses-demo i)
  notcurses-demo version 3.0.9

• terminal name + version
  Alacritty, version: 0.11.0-4

Issue

If you blit PNG image with transparent background on a plane, render it and then try get RGBA data from it using ncplane_as_rgba - you will get NULL. But if you load an image with some background - function will work properly. Same behavior if the plane is not filled, but have some graphics on it.

Code

#include <notcurses/notcurses.h>
int main(int argc, char **argv) 
{   
    struct notcurses *nc = notcurses_init(NULL, stdout);
    struct ncplane *std_plane = notcurses_stdplane(nc);
    struct ncvisual_options opts; 

    memset(&opts, 0, sizeof(struct ncvisual_options));
    opts.n = std_plane;
    opts.x = 0;
    opts.y = 0;
    opts.begy = 0;
    opts.begx = 0;
    opts.lenx = ncplane_dim_x(std_plane);
    opts.leny = ncplane_dim_y(std_plane); 
    opts.blitter = NCBLIT_1x1;
    opts.pxoffx = 0;
    opts.pxoffy = 0;

    struct ncvisual *visual = ncvisual_from_file("test.png");
    ncvisual_resize(visual, opts.leny, opts.lenx);
    std_plane = ncvisual_blit(nc, visual, &opts);
    notcurses_render(nc);
    
    uint32_t *data = ncplane_as_rgba(std_plane, NCBLIT_1x1, 0, 0, ncplane_dim_y(std_plane), ncplane_dim_x(std_plane), NULL, NULL);
    if (data == NULL) {
        notcurses_stop(nc);
        fprintf(stderr, "Can't get rgba array\n");
        exit(EXIT_FAILURE);
    }
    notcurses_stop(nc);
    return EXIT_SUCCESS;
}

[dankamongmen]

thanks for the quality report! i'll look into this asap.