Merge pull request #129 from jhludwig/warptransform

Warp Perspective Transform

examples/warp_image.js

@@ -0,0 +1,23 @@
+var cv = require('../lib/opencv');
+
+cv.readImage("./mona.png", function(err, im) {
+
+  var srcArray = [
+    0,0,
+    im.width(),0,
+    im.width(),im.height(),
+    0,im.height()];
+  var dstArray = [
+    0,0,
+    im.width()*.9,im.height()*.1,
+    im.width(),im.height(),
+    im.width()*.2,im.height()*.8];
+
+  var xfrmMat = im.getPerspectiveTransform(srcArray,dstArray);
+  img_warp = im.copy();
+  img_warp.warpPerspective(xfrmMat,im.width,im.height,[255,255,255]);
+
+  img_warp.save("/tmp/mona_warp.png");
+
+});
+

src/Matrix.cc

@@ -100,6 +100,9 @@ Matrix::Init(Handle<Object> target) {
 	NODE_SET_PROTOTYPE_METHOD(constructor, "pushBack", PushBack);
 
 	NODE_SET_PROTOTYPE_METHOD(constructor, "putText", PutText);
+    
+    NODE_SET_PROTOTYPE_METHOD(constructor, "getPerspectiveTransform", GetPerspectiveTransform); 
+    NODE_SET_PROTOTYPE_METHOD(constructor, "warpPerspective", WarpPerspective);
 
 	NODE_SET_METHOD(constructor, "Eye", Eye);
 
@@ -1756,3 +1759,54 @@ Matrix::PutText(const v8::Arguments& args) {
 
   return scope.Close(Undefined());
 }
+
+Handle<Value>
+Matrix::GetPerspectiveTransform(const v8::Arguments& args) {
+    HandleScope scope;
+
+    // extract quad args
+    Local<Object> srcArray = args[0]->ToObject();
+    Local<Object> tgtArray = args[1]->ToObject();
+
+    std::vector<cv::Point2f> src_corners(4);
+    std::vector<cv::Point2f> tgt_corners(4);
+    for (unsigned int i = 0; i < 4; i++) {
+        src_corners[i] = cvPoint(srcArray->Get(i*2)->IntegerValue(),srcArray->Get(i*2+1)->IntegerValue());
+        tgt_corners[i] = cvPoint(tgtArray->Get(i*2)->IntegerValue(),tgtArray->Get(i*2+1)->IntegerValue());
+    }
+
+    Local<Object> xfrm = Matrix::constructor->GetFunction()->NewInstance();
+    Matrix *xfrmmat = ObjectWrap::Unwrap<Matrix>(xfrm);
+    xfrmmat->mat = cv::getPerspectiveTransform(src_corners, tgt_corners);
+
+    return scope.Close(xfrm);
+}
+
+Handle<Value>
+Matrix::WarpPerspective(const v8::Arguments& args) {
+    SETUP_FUNCTION(Matrix)
+
+    Matrix *xfrm = ObjectWrap::Unwrap<Matrix>(args[0]->ToObject());
+
+    int width = args[1]->IntegerValue();
+    int height = args[2]->IntegerValue();
+
+    int flags = cv::INTER_LINEAR;
+    int borderMode = cv::BORDER_REPLICATE;
+
+    cv::Scalar borderColor(0, 0, 255);
+
+    if(args[3]->IsArray()) {
+        Local<Object> objColor = args[3]->ToObject();
+        borderColor = setColor(objColor);
+    }
+
+    cv::Mat res = cv::Mat(width, height, CV_32FC3);
+
+    cv::warpPerspective(self->mat, res, xfrm->mat, cv::Size(width, height), flags, borderMode, borderColor);
+
+    ~self->mat;
+    self->mat = res;
+
+    return scope.Close(v8::Null());
+}

src/Matrix.h

@@ -94,6 +94,8 @@ class Matrix: public node::ObjectWrap {
     JSFUNC(PushBack)
 
     JSFUNC(PutText)
+    JSFUNC(GetPerspectiveTransform) 
+    JSFUNC(WarpPerspective)
 /*
 	static Handle<Value> Val(const Arguments& args);
 	static Handle<Value> RowRange(const Arguments& args);
@@ -121,7 +123,8 @@ class Matrix: public node::ObjectWrap {
     static Handle<Value> Depth(const Arguments& args);
     static Handle<Value> Channels(const Arguments& args);
     static Handle<Value> StepOne(const Arguments& args);
-
+    static Handle<Value> GetPerspectiveTransform(const Arguments& args);
+    static Handle<Value> WarpPerspective(const Arguments& args);
 
 */