wxWidgets with MVC Error code SIGSEGV when calling controller function - c++

Question

I use wxWidgets with MVC pattern and im having trouble when i call the controller functions in the View
compareRGB(...),compareALPHA(...) and compareHSV(...)
for compare two images with a tolerance.Basically when the functions are called the program crash with code error
Process finished with exit code 139 (interrupted by signal 11: SIGSEGV)
I've tried every solution but the error is still here.
In this moment the function only print a word on terminal.
This is the code that cause error(the other functions work perfectly):
void View::compareImages(wxCommandEvent &event){
int imagesActive = imagesActivatedCount();
wxString mode = getMode();
double tolerance = colorToleranceSlider->GetValue();
if(imagesActive < 2){
wxMessageBox(_("SELEZIONARE DUE IMMAGINI DA COMPARARE"),_("ERRORE"),wxOK | wxICON_EXCLAMATION);
}
else if(mode.IsSameAs(_("RGB"))){
wxString pathImage1 = *activeImages;
wxString pathImage2 = *(activeImages + 1);
controller.compareRGB(pathImage1,pathImage2,tolerance);
}
else if(mode.IsSameAs(_("HSV"))){
wxString pathImage1 = *activeImages;
wxString pathImage2 = *(activeImages + 1);
controller.compareHSV(pathImage1,pathImage2,tolerance);
}
else if(mode.IsSameAs(_("ALPHA"))){
wxString pathImage1 = *activeImages;
wxString pathImage2 = *(activeImages + 1);
controller.compareAlpha(pathImage1,pathImage2,tolerance);
}
else{
wxMessageBox(_("SCEGLIERE METODO DI COMPARAZIONE"),_("ERRORE"),wxOK | wxICON_EXCLAMATION);
}
}
The complete source:
#include "View.h"
enum{
PANEL_ID,
BUTTON_ADD,
BUTTON_REMOVE,
BUTTON_ACTIVATE,
BUTTON_COMPARE,
SLIDER_COLOR,
MODE_SELECTOR,
LIST_ID,
ABOUT,
STATIC_ID,
VALUE_SLIDER
};
/*Event table of the view*/
wxBEGIN_EVENT_TABLE(View,wxFrame)
EVT_BUTTON(BUTTON_ADD,View::loadImages)
EVT_BUTTON(BUTTON_REMOVE,View::removeImages)
EVT_BUTTON(BUTTON_ACTIVATE,View::activateSelectedImages)
EVT_BUTTON(BUTTON_COMPARE,View::compareImages)
EVT_BUTTON(BUTTON_ACTIVATE,View::activateSelectedImages)
EVT_MENU(ABOUT,View::onAbout)
EVT_MENU(wxID_EXIT,View::onExit)
EVT_SLIDER(SLIDER_COLOR,View::onSliderUpdate)
wxEND_EVENT_TABLE()
View::View(const std::string title, const wxPoint &pos, const wxSize &size, AbstractModel& model, AbstractController& c):model(model),controller(c) ,wxFrame(NULL,wxID_ANY,title,pos,size) {
model.registerObserver(this); //registration view for successive notification
//View implementation
}
void View::update(int eventCode) {
}
/*Delete the selected images
* the while cicle it afflict only the image selected*/
void View::removeImages(wxCommandEvent& event){
long item;
while((item = list->GetNextItem(-1,wxLIST_NEXT_ALL,wxLIST_STATE_SELECTED)) != -1){
list->DeleteItem(item);
}
}
/*load images on storage
* It load the paths in the list view but in the model there is a map that associate
* the wxImage object with his relative path*/
void View::loadImages(wxCommandEvent& event){
wxFileDialog* fileDialog=new wxFileDialog(this, _("Scegli una o più foto"),wxEmptyString,wxEmptyString,wxFileSelectorDefaultWildcardStr,wxFD_MULTIPLE);
if(fileDialog->ShowModal() == wxID_CANCEL){
return;
}
wxArrayString paths;
fileDialog->GetPaths(paths);
try {
for (auto iterator = paths.begin(); iterator < paths.end(); ++iterator) {
list->InsertItem(0,*iterator);
}
}
catch (std::exception& error) {
std::cout << "Caught exception: " << error.what() << std::endl;
}
}
int View::imagesActivatedCount() {
int count = 0;
long item = -1;
while((item = list->GetNextItem(item,wxLIST_NEXT_ALL,wxLIST_STATE_DONTCARE)) != -1){
if (list->GetItemText(item,1).IsSameAs(_("*")))
{
count++;
}
}
return count;
}
/*Deselect the activated images
* this function is called on activatedSelectImages function for deselect before activate the new images
* For practical reasons the function scan every row in the list and if in the column next to him is present the "*"
* symbol it deselect him and clear the activated images array
*/
void View::deselectImages() {
long item = -1;
while((item = list->GetNextItem(item,wxLIST_NEXT_ALL,wxLIST_STATE_DONTCARE)) != -1){
if(list->GetItemText(item,1).IsSameAs(_("*"))){
list->SetItem(item,1,_(""));
}
}
}
void View::activateSelectedImages(wxCommandEvent& event) {
int imageActive = imagesActivatedCount();
int itemCount=0;
long item = -1;
wxString arr[2];
if(imageActive >= 2 || list->GetSelectedItemCount() >= 2)
{
deselectImages();
imageActive = 0;
}
while((item = list->GetNextItem(item,wxLIST_NEXT_ALL,wxLIST_STATE_SELECTED)) != -1){
if(itemCount < 2){
list->SetItem(item,1,_("*"));
itemCount++;
imageActive++;
}
}
if (imageActive == 2)
{
itemCount = 0;
item = -1;
wxString text;
while((item = list->GetNextItem(item,wxLIST_NEXT_ALL,wxLIST_STATE_DONTCARE)) != -1){
text = list->GetItemText(item,1);
if (text.IsSameAs(_("*"))){
arr[itemCount]=list->GetItemText(item);
itemCount++;
}
}
activeImages = arr;
std::cout<< *activeImages << std::endl;
std::cout << *(activeImages + 1) << std::endl;
}
}
void View::compareImages(wxCommandEvent &event){
int imagesActive = imagesActivatedCount();
wxString mode = getMode();
double tolerance = colorToleranceSlider->GetValue();
if(imagesActive < 2){
wxMessageBox(_("SELEZIONARE DUE IMMAGINI DA COMPARARE"),_("ERRORE"),wxOK | wxICON_EXCLAMATION);
}
else if(mode.IsSameAs(_("RGB"))){
wxString pathImage1 = *activeImages;
wxString pathImage2 = *(activeImages + 1);
controller.compareRGB(pathImage1,pathImage2,tolerance);
}
else if(mode.IsSameAs(_("HSV"))){
wxString pathImage1 = *activeImages;
wxString pathImage2 = *(activeImages + 1);
controller.compareHSV(pathImage1,pathImage2,tolerance);
}
else if(mode.IsSameAs(_("ALPHA"))){
wxString pathImage1 = *activeImages;
wxString pathImage2 = *(activeImages + 1);
controller.compareAlpha(pathImage1,pathImage2,tolerance);
}
else{
wxMessageBox(_("SCEGLIERE METODO DI COMPARAZIONE"),_("ERRORE"),wxOK | wxICON_EXCLAMATION);
}
}
}
The controller source:
#include "Controller.h"
Controller::Controller(AbstractModel& model) : model(model){}
void Controller::removeImages(wxArrayString paths) {
for(int it = 0; it < paths.size();it++){
model.removeImage(paths[it]);
}
}
void Controller::loadImages(wxArrayString paths) {
for(int it = 0; it < paths.size(); it++){
model.loadImage(paths[it]);
}
}
void Controller::compareRGB(wxString path1, wxString path2, double tolerance) {
std::cout<<"A"<<std::endl;
}
void Controller::compareAlpha(wxString path1, wxString path2, double tolerance) {
std::cout<<"B"<<std::endl;
}
void Controller::compareHSV(wxString path1, wxString path2, double tolerance) {
std::cout<<"C"<<std::endl;
}

Answer 1

As you mention in the comment,
activeImages is a wxString*
So there you have it: activeImages = arr. The latter is a local variable which will be freed at the end of activateSelectedImages(). When using activeImages later in compareImages(), you are getting undefined behavior.