No codec that outputs IMG_FMT_PKLE_XBGR8888? That makes the results I get very strange. The imgfmt() function was correct, but I switched back to integer display (rather than wasting space pasting that whole enum->const char * switch statement 
).
My load function is:
bool App::load_photo(const QString &name, img_t &img)
{
int rc;
TRACE();
memset(&img, 0, sizeof img);
set_img_format(img);
printf("request format 0x%08x\n", img.format);
rc = img_load_file(_ilib, name.toUtf8().data(), NULL, &img);
printf("loaded format 0x%08x\n", img.format);
if (rc != IMG_ERR_OK) {
qDebug() << __FUNCTION__ << rc << name;
return false;
}
return true;
}
set_img_format() is:
static void set_img_format(img_t &img)
{
img.format = IMG_FMT_RGBA8888;
img.flags |= IMG_FORMAT;
}
The output is:
load_photo request format 0x01001520 loaded format 0x01001120
0x400 is the alpha flag, of course, and it looks like it's being dropped. It looks like this is the cause of the issues with img_resize_fs and img_rotate_ortho.
Noting that img.format is now 0x01001120: For the rotations, when I request IMG_FMT_RGBA8888 as the destination format, it works just fine. If I just memset the structure and do not request a specific format, that's when I get IMG_ERR_NOSUPPORT:
void App::rotate_photo(const QString &name, img_t &img)
{
img_fixed_t angle = get_image_orientation(name.toUtf8().data());
img_t di;
int rc;
if (!angle)
return;
TRACE();
angle = IMG_ANGLE_90CW; /* override for sake of clarity in example */
memset(&di, 0, sizeof di);
printf("image format 0x%08x\n", img.format);
/* set_img_format(di); */
printf("request format 0x%08x\n", di.format);
rc = img_rotate_ortho(&img, &di, angle);
printf("rotated format 0x%08x\n", di.format);
if (rc != IMG_ERR_OK) {
qDebug() << __FUNCTION__ << rc;
return;
}
free(img.access.direct.data);
img = di;
}
(get_image_orientation() does only return one of the pre-defined angles, but since the image I'm rotating just needs 90CW, I explicitly set that for the sake of this test.)
output:
load_photo request format 0x01001520 loaded format 0x01001120 rotate_photo image format 0x01001120 request format 0x00000000 rotated format 0x01001120 rotate_photo 5
If I uncomment the set_img_format() line, the output is:
load_photo request format 0x01001520 loaded format 0x01001120 rotate_photo image format 0x01001120 request format 0x01001520 rotated format 0x01001520
Similarly, if I add img_resize_fs() back into the mix (similar structure to the rotation) and don't give it a destination image format, I get the following:
load_photo request format 0x01001520 loaded format 0x01001120 resize_photo image format 0x01001120 request format 0x00000000 resized format 0x01001120 resize_photo 5
So it looks like these functions don't like IMG_FMT_PKLE_XBGR8888, but if a different destination format is requested, the conversion will be done first and then rotating or resizing works.
The chunk of code calling these basically looks like:
...
if (!load_photo(name, img)) {
/* handle the error */
goto could_not_load_photo;
}
// resize_photo(img);
rotate_photo(name, img);
...
