mrmBot-Matrix/natives/uncaption.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 Uncaption(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>>();
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float tolerance = obj.Has("tolerance")
? obj.Get("tolerance").As<Napi::Number>().FloatValue()
: 0.5;
string type = obj.Get("type").As<Napi::String>().Utf8Value();
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VOption *options = VImage::option();
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VImage in =
VImage::new_from_buffer(data.Data(), data.Length(), "",
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type == "gif" ? options->set("n", -1)->set("access", "sequential") : options)
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.colourspace(VIPS_INTERPRETATION_sRGB);
if (!in.has_alpha()) in = in.bandjoin(255);
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int width = in.width();
int page_height = vips_image_get_page_height(in.get_image());
int n_pages = vips_image_get_n_pages(in.get_image());
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VImage first =
in.crop(0, 0, 3, page_height).colourspace(VIPS_INTERPRETATION_B_W) >
(255 * tolerance);
int top, captionWidth, captionHeight;
first.find_trim(&top, &captionWidth, &captionHeight);
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vector<VImage> img;
for (int i = 0; i < n_pages; i++) {
VImage img_frame =
in.crop(0, (i * page_height) + top, width, page_height - top);
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img.push_back(img_frame);
}
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VImage final = VImage::arrayjoin(img, VImage::option()->set("across", 1));
final.set(VIPS_META_PAGE_HEIGHT, page_height - top);
void *buf;
size_t length;
final.write_to_buffer(
("." + type).c_str(), &buf, &length,
type == "gif" ? VImage::option()->set("dither", 0) : 0);
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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");
}
}