mrmBot-Matrix/natives/speed.cc

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#include <napi.h>
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#include <vips/vips8>
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using namespace std;
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using namespace vips;
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void *memset16(void *m, uint16_t val, size_t count) {
uint16_t *buf = (uint16_t *)m;
while (count--) *buf++ = val;
return m;
}
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void vipsRemove(Napi::Env *env, Napi::Object *result, Napi::Buffer<char> data,
int speed) {
VOption *options = VImage::option()->set("access", "sequential");
VImage in = VImage::new_from_buffer(data.Data(), data.Length(), "",
options->set("n", -1))
.colourspace(VIPS_INTERPRETATION_sRGB);
if (!in.has_alpha()) in = in.bandjoin(255);
int width = in.width();
int page_height = vips_image_get_page_height(in.get_image());
int n_pages = vips_image_get_n_pages(in.get_image());
vector<VImage> img;
for (int i = 0; i < n_pages; i += speed) {
VImage img_frame = in.crop(0, i * page_height, width, page_height);
img.push_back(img_frame);
}
VImage out = VImage::arrayjoin(img, VImage::option()->set("across", 1));
out.set(VIPS_META_PAGE_HEIGHT, page_height);
void *buf;
size_t length;
out.write_to_buffer(".gif", &buf, &length);
vips_thread_shutdown();
result->Set("data", Napi::Buffer<char>::Copy(*env, (char *)buf, length));
}
Napi::Value Speed(const Napi::CallbackInfo &info) {
Napi::Env env = info.Env();
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try {
Napi::Object obj = info[0].As<Napi::Object>();
Napi::Buffer<char> data = obj.Get("data").As<Napi::Buffer<char>>();
bool slow =
obj.Has("slow") ? obj.Get("slow").As<Napi::Boolean>().Value() : false;
string type = obj.Get("type").As<Napi::String>().Utf8Value();
int speed =
obj.Has("speed") ? obj.Get("speed").As<Napi::Number>().Int32Value() : 2;
Napi::Object result = Napi::Object::New(env);
char *fileData = data.Data();
char *match = (char *)"\x00\x21\xF9\x04";
vector<uint16_t> old_delays;
bool removeFrames = false;
char *lastPos;
int amount = 0;
lastPos = (char *)memchr(fileData, '\x00', data.Length());
while (lastPos != NULL) {
if (memcmp(lastPos, match, 4) != 0) {
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lastPos = (char *)memchr(lastPos + 1, '\x00',
(data.Length() - (lastPos - fileData)) - 1);
continue;
}
++amount;
uint16_t old_delay;
memcpy(&old_delay, lastPos + 5, 2);
old_delays.push_back(old_delay);
lastPos = (char *)memchr(lastPos + 1, '\x00',
(data.Length() - (lastPos - fileData)) - 1);
}
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int currentFrame = 0;
lastPos = (char *)memchr(fileData, '\x00', data.Length());
while (lastPos != NULL) {
if (memcmp(lastPos, match, 4) != 0) {
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lastPos = (char *)memchr(lastPos + 1, '\x00',
(data.Length() - (lastPos - fileData)) - 1);
continue;
}
uint16_t new_delay = slow ? old_delays[currentFrame] * speed
: old_delays[currentFrame] / speed;
if (!slow && new_delay <= 1) {
removeFrames = true;
break;
}
memset16(lastPos + 5, new_delay, 1);
lastPos = (char *)memchr(lastPos + 1, '\x00',
(data.Length() - (lastPos - fileData)) - 1);
++currentFrame;
}
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result.Set("data", Napi::Buffer<char>::Copy(env, fileData, data.Length()));
if (removeFrames) vipsRemove(&env, &result, data, speed);
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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}