keep aspect ratio while resizing the window

openglcanvas.cpp

@@ -157,11 +157,11 @@ void OpenGLCanvas::initializeGL(){
     struct stat testbuf;
     if(stat(input_image,&testbuf)){
         fprintf(stderr,"the default image file does not exist!\n");
-        free(input_image);
         load_image(QFileDialog::getOpenFileName(this,tr("Choose Panorama File")).toStdString().c_str());
     }else{
         load_image(input_image);
     }
+    free(input_image);
 
     // mesh resolution
     int m,n;
@@ -196,9 +196,7 @@ void OpenGLCanvas::initializeGL(){
     numberOfIndices = meshNumIndices;
     triangleIndices = indices;
 
-    free(input_image);
     setShaders();
-
 }
 
 void OpenGLCanvas::define_texture_coordinates(float *texCoord, int m, int n, float min_phi, float max_phi, float min_lambda, float max_lambda){
@@ -458,8 +456,10 @@ void OpenGLCanvas::readTextureBytes(const char * const progname,
 }
 
 void OpenGLCanvas::resizeGL(int w, int h){
-    glViewport(0,0,w,h);
-
+    if(w>h)
+        glViewport(0,(h-w)/2,w,w);
+    else
+        glViewport((w-h)/2,0,h,h);
 }
 
 char * OpenGLCanvas::textFileRead(char *fn) {

openglcanvas.h

@@ -86,9 +86,8 @@ private:
     unsigned int * triangleIndices;
     float * verticesPositions;
     float * textureCoordinates;
-    float windowWidth;
-    float windowHeight;
-
+    //float windowWidth;
+    //float windowHeight;
 };
 
 #endif // OPENGLCANVAS_H