PNG - How to always output about vips

[franklinwise]

Mainly I want to preserve transparency on all images. I've been digging through the code... looks like it's not implemented.

[shifr]

Hi, franklinwise
Resize func saves all images as JPEG with libvips core function "vips_jpegsave_buffer". You can see this at line 296 in vips.go

I've solved this problem by adding into vips.h

int
vips_pngsave_custom(VipsImage *in, void **buf, size_t *len, int strip, int quality, int interlace)
{
    return vips_pngsave_buffer(in, buf, len, "interlace", interlace, NULL);
}

And into vips.go

    if typ == PNG {
        C.vips_pngsave_custom(colourspaced, &ptr, &length, 1, C.int(o.Quality), 0)
    } else {
        C.vips_jpegsave_custom(colourspaced, &ptr, &length, 1, C.int(o.Quality), 0)
    }

[franklinwise]

great thank you @shifr