mrmBot-Matrix/natives/uncaption.cc

69 lines
2.2 KiB
C++

#include <napi.h>
#include <vips/vips8>
using namespace std;
using namespace vips;
Napi::Value Uncaption(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>>();
float tolerance = obj.Has("tolerance")
? obj.Get("tolerance").As<Napi::Number>().FloatValue()
: 0.5;
string type = obj.Get("type").As<Napi::String>().Utf8Value();
VOption *options = VImage::option();
VImage in =
VImage::new_from_buffer(data.Data(), data.Length(), "",
type == "gif" ? options->set("n", -1)->set("access", "sequential") : options)
.colourspace(VIPS_INTERPRETATION_sRGB);
if (!in.has_alpha()) in = in.bandjoin(255);
int width = in.width();
int pageHeight = vips_image_get_page_height(in.get_image());
int nPages = vips_image_get_n_pages(in.get_image());
VImage first =
in.crop(0, 0, 3, pageHeight).colourspace(VIPS_INTERPRETATION_B_W) >
(255 * tolerance);
int top, captionWidth, captionHeight;
first.find_trim(&top, &captionWidth, &captionHeight);
vector<VImage> img;
int newHeight = pageHeight - top;
if (top == pageHeight) {
newHeight = pageHeight;
top = 0;
}
for (int i = 0; i < nPages; i++) {
VImage img_frame =
in.crop(0, (i * pageHeight) + top, width, newHeight);
img.push_back(img_frame);
}
VImage final = VImage::arrayjoin(img, VImage::option()->set("across", 1));
final.set(VIPS_META_PAGE_HEIGHT, newHeight);
void *buf;
size_t length;
final.write_to_buffer(
("." + type).c_str(), &buf, &length,
type == "gif" ? VImage::option()->set("dither", 0)->set("reoptimise", 1) : 0);
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;
}