mrmBot-Matrix/natives/caption.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 Caption(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 caption = obj.Get("caption").As<Napi::String>().Utf8Value();
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string font = obj.Get("font").As<Napi::String>().Utf8Value();
string type = obj.Get("type").As<Napi::String>().Utf8Value();
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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);
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int width = in.width();
int size = width / 10;
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int pageHeight = vips_image_get_page_height(in.get_image());
int nPages = vips_image_get_n_pages(in.get_image());
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int textWidth = width - ((width / 25) * 2);
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string font_string = (font == "roboto" ? "Roboto Condensed" : font) + " " +
(font != "impact" ? "bold" : "normal") + " " +
to_string(size);
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string captionText = "<span background=\"white\">" + caption + "</span>";
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VImage text =
VImage::text(captionText.c_str(), VImage::option()
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->set("rgba", true)
->set("align", VIPS_ALIGN_CENTRE)
->set("font", font_string.c_str())
->set("width", textWidth));
VImage captionImage =
((text == (vector<double>){0, 0, 0, 0}).bandand())
.ifthenelse(255, text)
.gravity(VIPS_COMPASS_DIRECTION_CENTRE, width, text.height() + size,
VImage::option()->set("extend", "white"));
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vector<VImage> img;
for (int i = 0; i < nPages; i++) {
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VImage img_frame =
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type == "gif" ? in.crop(0, i * pageHeight, width, pageHeight) : in;
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VImage frame = captionImage.join(
img_frame, VIPS_DIRECTION_VERTICAL,
VImage::option()->set("background", 0xffffff)->set("expand", true));
img.push_back(frame);
}
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VImage final = VImage::arrayjoin(img, VImage::option()->set("across", 1));
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final.set(VIPS_META_PAGE_HEIGHT, pageHeight + captionImage.height());
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void *buf;
size_t length;
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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>::New(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");
}
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}