mrmBot-Matrix/natives/swirl.cc

95 lines
3.4 KiB
C++
Raw Normal View History

#include <napi.h>
#include <vips/vips8>
using namespace std;
using namespace vips;
Napi::Value Swirl(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>>();
string type = obj.Get("type").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);
int pageHeight = vips_image_get_page_height(in.get_image());
int nPages = vips_image_get_n_pages(in.get_image());
int width = in.width();
double newWidth = width * 3;
double newHeight = pageHeight * 3;
vector<double> divSize = {newWidth / 2, newHeight / 2};
VImage index = VImage::xyz(newWidth, newHeight);
VImage center = index - divSize;
VImage polar = center
.copy(VImage::option()
->set("format", VIPS_FORMAT_COMPLEX)
->set("bands", 1))
.polar()
.copy(VImage::option()
->set("format", VIPS_FORMAT_FLOAT)
->set("bands", 2));
int size = min(width, pageHeight) / 2;
VImage test = (1 - polar.extract_band(0) / size);
VImage degrees = test.cast(VIPS_FORMAT_FLOAT).pow(2);
VImage angle = polar.extract_band(1) + degrees * 180;
VImage distortion = polar.extract_band(0)
.bandjoin(angle)
.copy(VImage::option()
->set("format", VIPS_FORMAT_COMPLEX)
->set("bands", 1))
.rect()
.copy(VImage::option()
->set("format", VIPS_FORMAT_FLOAT)
->set("bands", 2)) +
divSize;
vector<VImage> img;
for (int i = 0; i < nPages; i++) {
VImage img_frame =
type == "gif" ? in.crop(0, i * pageHeight, width, pageHeight) : in;
VImage distort =
img_frame
.gravity(VIPS_COMPASS_DIRECTION_CENTRE, newWidth, newHeight,
VImage::option()->set("extend", VIPS_EXTEND_COPY))
.mapim(distortion, VImage::option()->set(
"interpolate",
VInterpolate::new_from_name("bicubic")));
VImage frame = distort.crop(width, pageHeight, width, pageHeight);
img.push_back(frame);
}
VImage final = VImage::arrayjoin(img, VImage::option()->set("across", 1));
final.set(VIPS_META_PAGE_HEIGHT, pageHeight);
void *buf;
size_t length;
final.write_to_buffer(".gif", &buf, &length);
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;
}