fixe example 05-1

example_05-01.cpp

@@ -1,4 +1,4 @@
-// alphablend <imageA> <image B> <x> <y> <width> <height> <alpha> <beta>
+// alphablend <imageA> <image B> <x> <y> <<alpha> <beta>
 //
 #include <opencv2/opencv.hpp>
 #include <opencv2/core/core.hpp>
@@ -10,9 +10,12 @@ using namespace std;
 
 void help(const char **argv) {
   cout << "\n\n"
-   << "This program alpha blends on image onto another \n"
+   << "This program alpha blends the first image onto the other \n"
+   << "alpha is the blending of the first image and beta onto the second\n"
    << "Call:\n"
-   << argv[0] << " <imageA> <image B> <x> <y> <width> <height> <alpha> <beta>\n\n"
+   << argv[0] << " <path/blend_this_img> <path/onto_this_img> <where_to_blend_x> <where_to_blend_y> <alpha> <beta>\n\n"
+   << "Example:\n"
+   << " ./example_05-01 ../faceTemplate.jpg ../faces.png 230 155 0.8 0.2\n"
    << endl;
 }
 
@@ -21,8 +24,8 @@ void help(const char **argv) {
 int main( int argc, const char** argv )
 {
 	help(argv);
-	if(argc != 9) {
-		cout << "\nERROR: Wrong # of parameters (9), you had " << argc \n" << endl;
+	if(argc != 7) {
+		cout << "ERROR: Wrong # of parameters (7), you had " << argc  << "\n" << endl;
 		return -1;
 	}
 
@@ -33,24 +36,35 @@ int main( int argc, const char** argv )
   cv::Mat src1 = cv::imread(argv[1],1);
   cv::Mat src2 = cv::imread(argv[2],1);
 
-  if( argc==9 && !src1.empty() && !src2.empty() ) {
+	int from_w = src1.size().width;
+	int from_h = src1.size().height;
+	int to_w = src2.size().width;
+	int to_h = src2.size().height;
+
+
+  if( argc==7 && !src1.empty() && !src2.empty() ) {
 
     // Four more arguments tell where in src1 to paste the chunk taken from
     // src2. Note that the width and height also specify what portion of
     // src2 to actually use.
     //
     int x = atoi(argv[3]);
     int y = atoi(argv[4]);
-    int w = atoi(argv[5]);
-    int h = atoi(argv[6]);
+
+	// Make sure we don't exceed bounds:
+	if((x < 0) || (y < 0) || (x > to_w - 1) || (y > to_h - 1) || (x+from_w > to_w - 1) || (y+from_h > to_h)) {
+		cout << "\nError, at (x,y) (" << x << ", " << y <<"), your input image [w,h] [" << from_w << ", " 
+		<< from_h << "] doesn't fit within the blend to image [w,h] [" << to_w << ", " << to_h  <<"]\n" << endl;
+		return -1;
+	}
 
     // Two more arguments set the blending coefficients.
     //
-    double alpha = (double)atof(argv[7]);
-    double beta  = (double)atof(argv[8]);
+    double alpha = (double)atof(argv[5]);
+    double beta  = (double)atof(argv[6]);
 
-    cv::Mat roi1( src1, cv::Rect(x,y,w,h) );
-    cv::Mat roi2( src2, cv::Rect(0,0,w,h) );
+    cv::Mat roi1( src1, cv::Rect(0,0,from_w - 1,from_h - 1) ); //Just take the whole thing
+    cv::Mat roi2( src2, cv::Rect(x,y,from_w - 1, from_h - 1) );
 
     // Blend together the image src2 onto the image src1
     // at the specified location.