mrmBot-Matrix/natives/flip.cc

#include "common.h"

#include <map>

#include <vips/vips8>

using namespace std;
using namespace vips;

char* Flip(string type, char* BufferData, size_t BufferLength, map<string, string> Arguments, size_t* DataSize) {

    bool flop = MAP_GET(Arguments, "flop") == "true";

	  VOption *options = VImage::option()->set("access", "sequential");

    VImage in =
        VImage::new_from_buffer(BufferData, BufferLength, "",
                                type == "gif" ? VImage::option()->set("n", -1)->set("access", "sequential") : 0)
            .colourspace(VIPS_INTERPRETATION_sRGB);
    if (!in.has_alpha()) in = in.bandjoin(255);

    VImage out;
    if (flop) {
      out = in.flip(VIPS_DIRECTION_HORIZONTAL);
    } else if (type == "gif") {
      // libvips gif handling is both a blessing and a curse
      vector<VImage> img;
      int pageHeight = vips_image_get_page_height(in.get_image());
      int nPages = vips_image_get_n_pages(in.get_image());
      for (int i = 0; i < nPages; i++) {
        VImage img_frame = in.crop(0, i * pageHeight, in.width(), pageHeight);
        VImage flipped = img_frame.flip(VIPS_DIRECTION_VERTICAL);
        img.push_back(flipped);
      }
      out = VImage::arrayjoin(img, VImage::option()->set("across", 1));
      out.set(VIPS_META_PAGE_HEIGHT, pageHeight);
    } else {
      out = in.flip(VIPS_DIRECTION_VERTICAL);
    }

    void* buf;
    out.write_to_buffer(
        ("." + type).c_str(), &buf, DataSize,
        type == "gif" ? VImage::option()->set("dither", 0)->set("reoptimise", 1)
                      : 0);

	vips_error_clear();
	vips_thread_shutdown();
	return (char*) buf;
}