mrmBot-Matrix/natives/flip.cc

61 lines
No EOL
2 KiB
C++

#include <napi.h>
#include <vips/vips8>
using namespace std;
using namespace vips;
Napi::Value Flip(const Napi::CallbackInfo &info) {
Napi::Env env = info.Env();
Napi::Object result = Napi::Object::New(env);
try {
Napi::Object obj = info[0].As<Napi::Object>();
Napi::Buffer<char> data = obj.Get("data").As<Napi::Buffer<char>>();
bool flop =
obj.Has("flop") ? obj.Get("flop").As<Napi::Boolean>().Value() : false;
string type = obj.Get("type").As<Napi::String>().Utf8Value();
VOption *options = VImage::option()->set("access", "sequential");
VImage in =
VImage::new_from_buffer(data.Data(), data.Length(), "",
type == "gif" ? options->set("n", -1) : options)
.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;
size_t length;
out.write_to_buffer(("." + type).c_str(), &buf, &length);
result.Set("data", Napi::Buffer<char>::Copy(env, (char *)buf, length));
result.Set("type", type);
} catch (std::exception const &err) {
Napi::Error::New(env, err.what()).ThrowAsJavaScriptException();
} catch (...) {
Napi::Error::New(env, "Unknown error").ThrowAsJavaScriptException();
}
vips_error_clear();
vips_thread_shutdown();
return result;
}