mrmBot-Matrix/natives/freeze.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 Freeze(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>>();
bool loop =
obj.Has("loop") ? obj.Get("loop").As<Napi::Boolean>().Value() : false;
string type = obj.Get("type").As<Napi::String>().Utf8Value();
int frame = obj.Has("frame")
? obj.Get("frame").As<Napi::Number>().Int32Value()
: -1;
Napi::Object result = Napi::Object::New(env);
char *fileData = data.Data();
char *match = (char *)"\x21\xFF\x0BNETSCAPE2.0\x03\x01";
char *descriptor = (char *)"\x2C\x00\x00\x00\x00";
char *lastPos;
bool none = true;
if (loop) {
char *newData = (char *)malloc(data.Length() + 19);
memcpy(newData, fileData, data.Length());
lastPos = (char *)memchr(newData, '\x2C', data.Length());
while (lastPos != NULL) {
if (memcmp(lastPos, descriptor, 5) != 0) {
lastPos = (char *)memchr(lastPos + 1, '\x2C',
(data.Length() - (lastPos - newData)) - 1);
continue;
}
memcpy(lastPos + 19, lastPos, (data.Length() - (lastPos - newData)));
memcpy(lastPos, match, 16);
memcpy(lastPos + 16, "\x00\x00\x00", 3);
result.Set("data",
Napi::Buffer<char>::Copy(env, newData, data.Length() + 19));
none = false;
break;
}
if (none)
result.Set("data",
Napi::Buffer<char>::Copy(env, newData, data.Length()));
} else if (frame >= 0 && !loop) {
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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);
int page_height = vips_image_get_page_height(in.get_image());
int n_pages = vips_image_get_n_pages(in.get_image());
int framePos = clamp(frame, 0, (int)n_pages);
VImage out = in.crop(0, 0, in.width(), page_height * (framePos + 1));
out.set(VIPS_META_PAGE_HEIGHT, page_height);
out.set("loop", loop ? 0 : 1);
void *buf;
size_t length;
out.write_to_buffer(("." + type).c_str(), &buf, &length);
vips_thread_shutdown();
result.Set("data", Napi::Buffer<char>::Copy(env, (char *)buf, length));
} else {
lastPos = (char *)memchr(fileData, '\x21', data.Length());
while (lastPos != NULL) {
if (memcmp(lastPos, match, 16) != 0) {
lastPos = (char *)memchr(lastPos + 1, '\x21',
(data.Length() - (lastPos - fileData)) - 1);
continue;
}
memcpy(lastPos, lastPos + 19,
(data.Length() - (lastPos - fileData)) - 19);
result.Set("data",
Napi::Buffer<char>::Copy(env, fileData, data.Length() - 19));
none = false;
break;
}
if (none)
result.Set("data",
Napi::Buffer<char>::Copy(env, fileData, data.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");
}
}