Add premultiply option to fromBytes

mapnik · Jan 5, 2017 · f8d02d0 · f8d02d0
1 parent d2a7271
commit f8d02d0
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Showing 2 changed files with 61 additions and 16 deletions.
diff --git a/src/mapnik_image.cpp b/src/mapnik_image.cpp
@@ -2385,12 +2385,13 @@ v8::Local<v8::Value> Image::_openSync(Nan::NAN_METHOD_ARGS_TYPE info)
 typedef struct {
     uv_work_t request;
     image_ptr im;
-    const char *data;
-    size_t dataLength;
-    bool error;
     std::string error_name;
     Nan::Persistent<v8::Object> buffer;
     Nan::Persistent<v8::Function> cb;
+    bool premultiply;
+    const char *data;
+    size_t dataLength;
+    bool error;
 } image_mem_ptr_baton_t;
 
 typedef struct {
@@ -3302,6 +3303,8 @@ v8::Local<v8::Value> Image::_fromBufferSync(Nan::NAN_METHOD_ARGS_TYPE info)
  *
  * @name fromBytesSync
  * @param {Buffer} buffer - image buffer
+ * @param {Object} [options]
+ * @param {Boolean} [options.premultiply] - Default false, if true, then the image will be premultiplied before being returned
  * @returns {mapnik.Image} image object
  * @instance
  * @memberof Image
@@ -3399,13 +3402,36 @@ NAN_METHOD(Image::fromBytes)
         return;
     }
 
+    bool premultiply = false;
+    if (info.Length() >= 2)
+    {
+        if (info[1]->IsObject())
+        {
+            v8::Local<v8::Object> options = v8::Local<v8::Object>::Cast(info[1]);
+            if (options->Has(Nan::New("premultiply").ToLocalChecked()))
+            {
+                v8::Local<v8::Value> pre_val = options->Get(Nan::New("premultiply").ToLocalChecked());
+                if (!pre_val.IsEmpty() && pre_val->IsBoolean())
+                {
+                    premultiply = pre_val->BooleanValue();
+                }
+                else
+                {
+                    Nan::ThrowTypeError("premultiply option must be a boolean");
+                    return;
+                }
+            }
+        }
+    }
+
     image_mem_ptr_baton_t *closure = new image_mem_ptr_baton_t();
     closure->request.data = closure;
     closure->error = false;
     closure->cb.Reset(callback.As<v8::Function>());
     closure->buffer.Reset(obj.As<v8::Object>());
     closure->data = node::Buffer::Data(obj);
     closure->dataLength = node::Buffer::Length(obj);
+    closure->premultiply = premultiply;
     uv_queue_work(uv_default_loop(), &closure->request, EIO_FromBytes, (uv_after_work_cb)EIO_AfterFromBytes);
     return;
 }
@@ -3420,6 +3446,9 @@ void Image::EIO_FromBytes(uv_work_t* req)
         if (reader.get())
         {
             closure->im = std::make_shared<mapnik::image_any>(reader->read(0,0,reader->width(),reader->height()));
+            if (closure->premultiply) {
+                mapnik::premultiply_alpha(*closure->im);
+            }
         }
         else
         {

diff --git a/test/image.test.js b/test/image.test.js
@@ -92,22 +92,24 @@ describe('mapnik.Image ', function() {
     });
 
     it('should throw with invalid binary read from buffer', function(done) {
-        assert.throws(function() { new mapnik.Image.fromBytesSync(); });
-        assert.throws(function() { new mapnik.Image.fromBytes(); });
-        assert.throws(function() { new mapnik.Image.fromBytes(null); });
-        assert.throws(function() { new mapnik.Image.fromBytes(null, function(err, result) {}); });
-        assert.throws(function() { new mapnik.Image.fromBytes({}); });
-        assert.throws(function() { new mapnik.Image.fromBytes({}, function(err, result) {}); });
-        assert.throws(function() { new mapnik.Image.fromBytesSync({}); });
-        assert.throws(function() { new mapnik.Image.fromBytes(new Buffer(0)); });
-        assert.throws(function() { new mapnik.Image.fromBytes(new Buffer(0), null); });
-        assert.throws(function() { new mapnik.Image.fromBytesSync(new Buffer(1024)); });
+        assert.throws(function() { mapnik.Image.fromBytesSync(); });
+        assert.throws(function() { mapnik.Image.fromBytes(); });
+        assert.throws(function() { mapnik.Image.fromBytes(null); });
+        assert.throws(function() { mapnik.Image.fromBytes(null, function(err, result) {}); });
+        assert.throws(function() { mapnik.Image.fromBytes({}); });
+        assert.throws(function() { mapnik.Image.fromBytes({}, function(err, result) {}); });
+        assert.throws(function() { mapnik.Image.fromBytesSync({}); });
+        assert.throws(function() { mapnik.Image.fromBytes(new Buffer(0)); });
+        assert.throws(function() { mapnik.Image.fromBytes(new Buffer(0),{premultiply:1},function(){}); });
+        assert.throws(function() { mapnik.Image.fromBytes(new Buffer(0), null); });
+        assert.throws(function() { mapnik.Image.fromBytesSync(new Buffer(1024)); });
         var buffer = new Buffer('\x89\x50\x4E\x47\x0D\x0A\x1A\x0A' + new Array(48).join('\0'), 'binary');
-        assert.throws(function() { new mapnik.Image.fromBytesSync(buffer); });
+        assert.throws(function() { mapnik.Image.fromBytesSync(buffer); });
         buffer = new Buffer('\x89\x50\x4E\x47\x0D\x0A\x1A\x0A', 'binary');
-        assert.throws(function() { new mapnik.Image.fromBytesSync(buffer); });
-        var stuff = new mapnik.Image.fromBytes(buffer, function(err, result) {
+        assert.throws(function() { mapnik.Image.fromBytesSync(buffer); });
+        var stuff = mapnik.Image.fromBytes(buffer, function(err, result) {
             assert.throws(function() { if (err) throw err; });
+
             done();
         });
     });
@@ -1576,6 +1578,20 @@ describe('mapnik.Image ', function() {
         assert.throws(function() { var im = new mapnik.Image.fromBufferSync(2, 2, b, {'painted':null}); });
     });
 
+    it('fromBytes can premultiply in async/threadpool', function(done) {
+        var data = require('fs').readFileSync(__dirname + '/support/a.png');
+        var image = mapnik.Image.fromBytesSync(data);
+        mapnik.Image.fromBytes(data, {premultiply:false}, function(err, im) {
+            if (err) throw err;
+            assert.ok(!im.premultiplied());
+            mapnik.Image.fromBytes(data, {premultiply:true}, function(err, im) {
+                if (err) throw err;
+                assert.ok(im.premultiplied());
+                done();
+            });
+        });
+    });
+
     it('resizes consistently', function(done) {
         var data = require('fs').readFileSync(__dirname + '/support/a.png');
         var image = mapnik.Image.fromBytesSync(data);