From a2493bcc0ab6d9925ce7a104c29d98c5cbb8195c Mon Sep 17 00:00:00 2001
From: Essem <smswessem@gmail.com>
Date: Sun, 11 Sep 2022 02:09:44 -0500
Subject: [PATCH] Port swirl to vips (based on jcupitt's implementation)

---
 natives/swirl.cc | 113 ++++++++++++++++++++++++++++++-----------------
 1 file changed, 73 insertions(+), 40 deletions(-)

diff --git a/natives/swirl.cc b/natives/swirl.cc
index e1fc555..6471555 100644
--- a/natives/swirl.cc
+++ b/natives/swirl.cc
@@ -1,62 +1,95 @@
-#include <Magick++.h>
 #include <napi.h>
 
-#include <iostream>
-#include <list>
+#include <vips/vips8>
 
 using namespace std;
-using namespace Magick;
+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();
-    int delay =
-        obj.Has("delay") ? obj.Get("delay").As<Napi::Number>().Int32Value() : 0;
 
-    Blob blob;
+    VOption *options = VImage::option()->set("access", "sequential");
 
-    list<Image> frames;
-    list<Image> coalesced;
-    list<Image> mid;
-    try {
-      readImages(&frames, Blob(data.Data(), data.Length()));
-    } catch (Magick::WarningCoder &warning) {
-      cerr << "Coder Warning: " << warning.what() << endl;
-    } catch (Magick::Warning &warning) {
-      cerr << "Warning: " << warning.what() << endl;
+    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);
     }
-    coalesceImages(&coalesced, frames.begin(), frames.end());
+    VImage final = VImage::arrayjoin(img, VImage::option()->set("across", 1));
+    final.set(VIPS_META_PAGE_HEIGHT, pageHeight);
 
-    for (Image &image : coalesced) {
-      image.swirl(180);
-      image.magick(type);
-      mid.push_back(image);
-    }
+    void *buf;
+    size_t length;
+    final.write_to_buffer(".gif", &buf, &length);
 
-    optimizeTransparency(mid.begin(), mid.end());
-
-    if (type == "gif") {
-      for (Image &image : mid) {
-        image.quantizeDither(false);
-        image.quantize();
-        if (delay != 0) image.animationDelay(delay);
-      }
-    }
-
-    writeImages(mid.begin(), mid.end(), &blob);
-
-    Napi::Object result = Napi::Object::New(env);
-    result.Set("data", Napi::Buffer<char>::Copy(env, (char *)blob.data(),
-                                                blob.length()));
+    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());
+    Napi::Error::New(env, err.what()).ThrowAsJavaScriptException();
   } catch (...) {
-    throw Napi::Error::New(env, "Unknown error");
+    Napi::Error::New(env, "Unknown error").ThrowAsJavaScriptException();
   }
+
+  vips_error_clear();
+  vips_thread_shutdown();
+  return result;
 }
\ No newline at end of file