mrmBot-Matrix/natives/flip.cc

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#include <napi.h>
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#include <vips/vips8>
using namespace std;
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using namespace vips;
Napi::Value Flip(const Napi::CallbackInfo &info) {
Napi::Env env = info.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();
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VOption *options = VImage::option()->set("access", "sequential");
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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);
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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 page_height = vips_image_get_page_height(in.get_image());
int n_pages = vips_image_get_n_pages(in.get_image());
for (int i = 0; i < n_pages; i++) {
VImage img_frame = in.crop(0, i * page_height, in.width(), page_height);
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, page_height);
} else {
out = in.flip(VIPS_DIRECTION_VERTICAL);
}
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void *buf;
size_t length;
out.write_to_buffer(("." + type).c_str(), &buf, &length);
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vips_thread_shutdown();
Napi::Object result = Napi::Object::New(env);
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result.Set("data", Napi::Buffer<char>::Copy(env, (char *)buf, length));
result.Set("type", type);
return result;
} catch (std::exception const &err) {
throw Napi::Error::New(env, err.what());
} catch (...) {
throw Napi::Error::New(env, "Unknown error");
}
}