mrmBot-Matrix/natives/watermark.cc

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#include <napi.h>
#include <vips/vips8>
using namespace std;
using namespace vips;
Napi::Value Watermark(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 water = obj.Get("water").As<Napi::String>().Utf8Value();
int gravity = obj.Get("gravity").As<Napi::Number>().Int64Value();
bool resize = obj.Has("resize")
? obj.Get("resize").As<Napi::Boolean>().Value()
: false;
float yscale = obj.Has("yscale")
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? obj.Get("yscale").As<Napi::Number>().FloatValue()
: false;
bool append = obj.Has("append")
? obj.Get("append").As<Napi::Boolean>().Value()
: false;
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bool alpha =
obj.Has("alpha") ? obj.Get("alpha").As<Napi::Boolean>().Value() : false;
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bool flip =
obj.Has("flip") ? obj.Get("flip").As<Napi::Boolean>().Value() : false;
bool mc = obj.Has("mc") ? obj.Get("mc").As<Napi::Boolean>().Value() : false;
string basePath = obj.Get("basePath").As<Napi::String>().Utf8Value();
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);
string merged = basePath + water;
VImage watermark = VImage::new_from_file(merged.c_str());
int width = in.width();
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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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if (flip) {
watermark = watermark.flip(VIPS_DIRECTION_HORIZONTAL);
}
if (resize && append) {
watermark = watermark.resize((double)width / (double)watermark.width());
} else if (resize && yscale) {
watermark = watermark.resize(
(double)width / (double)watermark.width(),
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VImage::option()->set("vscale", (double)(pageHeight * yscale) /
(double)watermark.height()));
} else if (resize) {
watermark =
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watermark.resize((double)pageHeight / (double)watermark.height());
}
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int x = 0, y = 0;
switch (gravity) {
case 1:
break;
case 2:
x = (width / 2) - (watermark.width() / 2);
break;
case 3:
x = width - watermark.width();
break;
case 5:
x = (width / 2) - (watermark.width() / 2);
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y = (pageHeight / 2) - (watermark.height() / 2);
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break;
case 6:
x = width - watermark.width();
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y = (pageHeight / 2) - (watermark.height() / 2);
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break;
case 8:
x = (width / 2) - (watermark.width() / 2);
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y = pageHeight - watermark.height();
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break;
case 9:
x = width - watermark.width();
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y = pageHeight - watermark.height();
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break;
}
vector<VImage> img;
int addedHeight = 0;
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VImage contentAlpha;
VImage frameAlpha;
VImage bg;
VImage frame;
for (int i = 0; i < nPages; i++) {
VImage img_frame =
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type == "gif" ? in.crop(0, i * pageHeight, width, pageHeight) : in;
if (append) {
VImage appended = img_frame.join(watermark, VIPS_DIRECTION_VERTICAL,
VImage::option()->set("expand", true));
addedHeight = watermark.height();
img.push_back(appended);
} else if (mc) {
VImage padded =
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img_frame.embed(0, 0, width, pageHeight + 15,
VImage::option()->set("background", 0xffffff));
VImage composited =
padded.composite2(watermark, VIPS_BLEND_MODE_OVER,
VImage::option()
->set("x", width - 190)
->set("y", padded.height() - 22));
addedHeight = 15;
img.push_back(composited);
} else {
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VImage composited;
if (alpha) {
if (i == 0) {
contentAlpha = watermark.extract_band(0).embed(
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x, y, width, pageHeight,
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VImage::option()->set("extend", "white"));
frameAlpha = watermark.extract_band(1).embed(
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x, y, width, pageHeight,
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VImage::option()->set("extend", "black"));
bg =
frameAlpha.new_from_image({0, 0, 0}).copy(VImage::option()->set(
"interpretation", VIPS_INTERPRETATION_sRGB));
frame = bg.bandjoin(frameAlpha);
if (type == "jpg" || type == "jpeg") {
type = "png";
}
}
VImage content =
img_frame.extract_band(0, VImage::option()->set("n", 3))
.bandjoin(contentAlpha & img_frame.extract_band(3));
composited =
content.composite2(frame, VIPS_BLEND_MODE_OVER,
VImage::option()->set("x", x)->set("y", y));
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} else {
composited =
img_frame.composite2(watermark, VIPS_BLEND_MODE_OVER,
VImage::option()->set("x", x)->set("y", y));
}
img.push_back(composited);
}
}
VImage final = VImage::arrayjoin(img, VImage::option()->set("across", 1));
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final.set(VIPS_META_PAGE_HEIGHT, pageHeight + addedHeight);
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");
}
}