allow to set callback as gif writer

src/animated_gif.cpp

@@ -5,6 +5,8 @@
 #include "animated_gif.h"
 #include "buffer_compat.h"
 
+#include <iostream>
+
 using namespace v8;
 using namespace node;
 
@@ -20,6 +22,7 @@ AnimatedGif::Initialize(Handle<Object> target)
     NODE_SET_PROTOTYPE_METHOD(t, "getGif", GetGif);
     NODE_SET_PROTOTYPE_METHOD(t, "end", End);
     NODE_SET_PROTOTYPE_METHOD(t, "setOutputFile", SetOutputFile);
+    NODE_SET_PROTOTYPE_METHOD(t, "setOutputCallback", SetOutputCallback);
     target->Set(String::NewSymbol("AnimatedGif"), t->GetFunction());
 }
 
@@ -242,3 +245,36 @@ AnimatedGif::SetOutputFile(const Arguments &args)
     return Undefined();
 }
 
+int
+stream_writer(GifFileType *gif_file, const GifByteType *data, int size)
+{
+    AnimatedGif *gif = (AnimatedGif *)gif_file->UserData;
+    Buffer *retbuf = Buffer::New(size);
+    memcpy(BufferData(retbuf), data, size);
+    Handle<Value> argv[1] = {
+      retbuf->handle_
+    };
+    //Local<Value> callback_v = gif->Wrap()->Get(String::New("ondata"));
+    //assert(callback_v->IsFunction());
+    //Local<Function> callback = Local<Function>::Cast(callback_v);
+    gif->ondata->Call(Context::GetCurrent()->Global(), 1, argv);
+    return size;
+}
+
+Handle<Value>
+AnimatedGif::SetOutputCallback(const Arguments &args)
+{
+    HandleScope scope;
+
+    if (args.Length() != 1)
+        return VException("One argument required - path to output file.");
+
+    if (!args[0]->IsFunction())
+        return VException("First argument must be string.");
+
+    Local<Function> callback = Local<Function>::Cast(args[0]);
+    AnimatedGif *gif = ObjectWrap::Unwrap<AnimatedGif>(args.This());
+    gif->ondata = Persistent<Function>::New(callback);
+    gif->gif_encoder.set_output_func(stream_writer, (void*)gif);
+    return Undefined();
+}

src/animated_gif.h

@@ -16,6 +16,9 @@ class AnimatedGif : public node::ObjectWrap {
     Color transparency_color;
 
 public:
+
+    v8::Persistent<v8::Function> ondata;
+
     static void Initialize(v8::Handle<v8::Object> target);
 
     AnimatedGif(int wwidth, int hheight, buffer_type bbuf_type);
@@ -28,6 +31,7 @@ class AnimatedGif : public node::ObjectWrap {
     static v8::Handle<v8::Value> End(const v8::Arguments &args);
     static v8::Handle<v8::Value> GetGif(const v8::Arguments &args);
     static v8::Handle<v8::Value> SetOutputFile(const v8::Arguments &args);
+    static v8::Handle<v8::Value> SetOutputCallback(const v8::Arguments &args);
 };
 
 #endif

src/gif_encoder.cpp

@@ -235,7 +235,7 @@ GifEncoder::get_gif_len() const
 // Animated Gif Encoder
 AnimatedGifEncoder::AnimatedGifEncoder(int wwidth, int hheight, buffer_type bbuf_type) :
     width(wwidth), height(hheight), buf_type(bbuf_type),
-    gif_buf(NULL), output_color_map(NULL), gif_file(NULL), color_map_size(256),
+    gif_buf(NULL), output_color_map(NULL), gif_file(NULL), color_map_size(256), write_func(0), write_user_data(0),
     headers_set(false) {}
 
 AnimatedGifEncoder::~AnimatedGifEncoder() { end_encoding(); }
@@ -258,17 +258,19 @@ void
 AnimatedGifEncoder::new_frame(unsigned char *data, int delay)
 {
     if (!gif_file) {
-        if (file_name.empty()) { // memory writer
+       if (write_func != NULL) {
+            int nError;
+            gif_file = EGifOpen(write_user_data, write_func, &nError);
+            if (!gif_file) throw "EGifOpen in AnimatedGifEncoder::new_frame failed";
+        } else if (file_name.empty()) { // memory writer
             int nError;
             gif_file = EGifOpen(&gif, gif_writer, &nError);
             if (!gif_file) throw "EGifOpen in AnimatedGifEncoder::new_frame failed";
-        }
-        else {
+        } else {
             int nError;
             gif_file = EGifOpenFileName(file_name.c_str(), FALSE, &nError);
             if (!gif_file) throw "EGifOpenFileName in AnimatedGifEncoder::new_frame failed";
         }
-
         output_color_map = GifMakeMapObject(color_map_size, ext_web_safe_palette);
         if (!output_color_map) throw "MakeMapObject in AnimatedGifEncoder::new_frame failed";
 
@@ -323,7 +325,7 @@ AnimatedGifEncoder::new_frame(unsigned char *data, int delay)
     if (EGifPutImageDesc(gif_file, 0, 0, width, height, FALSE, NULL) == GIF_ERROR) {
         throw "EGifPutImageDesc in AnimatedGifEncoder::new_frame failed";
     }
-  
+
     GifByteType *gif_bufp = gif_buf;
     for (int i = 0; i < height; i++) {
         if (EGifPutLine(gif_file, gif_bufp, width) == GIF_ERROR) {
@@ -372,3 +374,9 @@ AnimatedGifEncoder::set_output_file(const char *ffile_name)
     file_name = ffile_name;
 }
 
+void
+AnimatedGifEncoder::set_output_func(OutputFunc func, void *user_data)
+{
+   write_func = func;
+   write_user_data = user_data;
+}

src/gif_encoder.h

@@ -48,6 +48,8 @@ class AnimatedGifEncoder {
     Color transparency_color;
 
     std::string file_name;
+    OutputFunc write_func;
+    void *write_user_data;
 
     void end_encoding();
 public:
@@ -61,6 +63,7 @@ class AnimatedGifEncoder {
     void set_transparency_color(const Color &c);
 
     void set_output_file(const char *ffile_name);
+    void set_output_func(OutputFunc func, void* user_data);
 
     const unsigned char *get_gif() const;
     const int get_gif_len() const;