mrmBot-Matrix/natives/reddit.cc

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#include <napi.h>
#include <vips/vips8>
using namespace std;
using namespace vips;
Napi::Value Reddit(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>>();
string text = obj.Get("caption").As<Napi::String>().Utf8Value();
string type = obj.Get("type").As<Napi::String>().Utf8Value();
string basePath = obj.Get("basePath").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);
string assetPath = basePath + "assets/images/reddit.png";
VImage tmpl = VImage::new_from_file(assetPath.c_str());
int width = in.width();
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int pageHeight = vips_image_get_page_height(in.get_image());
int n_pages = vips_image_get_n_pages(in.get_image());
string captionText = "<span foreground=\"white\">" + text + "</span>";
VImage textImage =
VImage::text(captionText.c_str(), VImage::option()
->set("rgba", true)
->set("font", "Roboto 62")
->set("align", VIPS_ALIGN_LOW));
VImage composited =
tmpl.composite2(textImage, VIPS_BLEND_MODE_OVER,
VImage::option()->set("x", 375)->set(
"y", (tmpl.height() - textImage.height()) - 64));
VImage watermark =
composited.resize((double)width / (double)composited.width());
vector<VImage> img;
for (int i = 0; i < n_pages; i++) {
VImage img_frame =
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type == "gif" ? in.crop(0, i * pageHeight, width, pageHeight) : in;
VImage frame = img_frame.join(watermark, VIPS_DIRECTION_VERTICAL,
VImage::option()->set("expand", true));
img.push_back(frame);
}
VImage final = VImage::arrayjoin(img, VImage::option()->set("across", 1));
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final.set(VIPS_META_PAGE_HEIGHT, pageHeight + watermark.height());
void *buf;
size_t length;
final.write_to_buffer(
("." + type).c_str(), &buf, &length,
type == "gif" ? VImage::option()->set("dither", 0) : 0);
vips_thread_shutdown();
Napi::Object result = Napi::Object::New(env);
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");
}
}