Image processing error

Hi everyone. I have a problem, I'm creating a simple Image Processing app, at part of brightness adjustment i can't run this function, when it's called then app will be crashed. I have two forms, one of form is mainwindow, one else is sub form to adjust brightness.

Code:

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//mainwindow.cpp
 
void MainWindow::brightnessProcessing(int value)
{
    QImage image = imageLabel->pixmap()->toImage();
    int w = image.width();
    int h = image.height();
    QColor c;
    int r, g, b;
    for(int i=0; i<h; i++)
        for(int j=0; j<w; j++) {
            c = image.pixel(i, j);
            r = c.red()+value;
            g = c.green()+value;
            b = c.blue()+value;
            image.setPixel(i, j, qRgb(r, g, b));
        }
    imageLabel->setPixmap(QPixmap::fromImage(image));
}

---

Code:

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//mainwindow.h
 
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
#include <QtWidgets>
 
namespace Ui {
class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
    void brightnessProcessing(int value);
 
private slots:
    ..........
 
private:
    Ui::MainWindow *ui;
    QImage *image;
    QLabel *imageLabel;
    QScrollArea *scrollArea;
    QScrollBar *scrollBar;
    double scaleFactor;
 
    void scaleImage(double factor);
    void adjustScrollBar(QScrollBar *scrollBar, double factor);
};
 
#endif // MAINWINDOW_H

---

Code:

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//brightnesscontrast.cpp
 
void BrightnessContrast::on_horizontalSliderBrightness_valueChanged(int value)
{
    ui->lineEditBrightness->setText(QString::number(value));
    respond.brightnessProcessing(value);
}

---

Code:

---

//brightnesscontrast.h
 
#ifndef BRIGHTNESSCONTRAST_H
#define BRIGHTNESSCONTRAST_H
 
#include <QDialog>
#include <QtWidgets>
#include "mainwindow.h"
 
namespace Ui {
class BrightnessContrast;
}
 
class BrightnessContrast : public QDialog
{
    Q_OBJECT
 
public:
    explicit BrightnessContrast(QWidget *parent = 0);
    ~BrightnessContrast();
 
private slots:
    void on_horizontalSliderBrightness_valueChanged(int value);
 
    void on_horizontalSliderContrast_valueChanged(int value);
 
private:
    Ui::BrightnessContrast *ui;
    MainWindow respond;
};
 
#endif // BRIGHTNESSCONTRAST_H

---

anyhelp!

Run your program in your debugger and determine where your program crashes. Then work the conditions that cause it to crash there.

Having an instance of the MainWindow in your dialog as a member variable is unusual.
What happens when the existing red, green, or blue value is 255?

I have run my program in debugger, have identified where my program crashes but i don't understand error parameters means what. So can't fix to error
it here

http://i.upanh.com/riildt

i also have edited member variables

Code:

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r = qBound<int>(0, c.red() + value, 255);
g = qBound<int>(0, c.green() + value, 255);
b = qBound<int>(0, c.blue() + value, 255);

---

Quote:

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Originally Posted by bachkimfly

I have run my program in debugger, have identified where my program crashes but i don't understand error parameters means what. So can't fix to error
it here

---

And since you don't tell us the error we can't help you either.

Is imageLabel a valid pointer?

Cheers,
_

Quote:

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Originally Posted by anda_skoa

And since you don't tell us the error we can't help you either.

Is imageLabel a valid pointer?

Cheers,
_

---

Actually, I can't determine correct error, if that be can then I used quick search in net. I have run debugger and output above, hope it is useful.
Yes, imageLabel is a valid pointer!

Post the backtrace.

backtrace for 4 breakpoints here:

Code:

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#2  0x0000000000406a40 in MainWindow::brightnessProcessing (this=0x7fffffffc838, value=1) at ../../qt workspace/Auroras/mainwindow.cpp:161
        image = <incomplete type>
        w = 32767
        c = {cspec = 4294952960, ct = {argb = {alpha = 32767, red = 0, green = 49696, blue = 196, pad = 0}, ahsv = {alpha = 32767, hue = 0, saturation = 49696, value = 196, pad = 0}, acmyk = {alpha = 32767, cyan = 0, magenta = 49696, yellow = 196, black = 0}, ahsl = {alpha = 32767, hue = 0, saturation = 49696, lightness = 196, pad = 0}, array = {32767, 0, 49696, 196, 0}}}
        g = 4232186
        h = -20672
        r = 32767
        b = 0
#3  0x000000000040973c in BrightnessContrast::on_horizontalSliderBrightness_valueChanged (this=0x7fffffffc800, value=1) at ../../qt workspace/Auroras/brightnesscontrast.cpp:19
No locals.
#4  0x000000000040a5c5 in BrightnessContrast::qt_static_metacall (_o=0x7fffffffc800, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0x7fffffffb1c0) at moc_brightnesscontrast.cpp:73
        _t = 0x7fffffffc800
#5  0x000000000040a6da in BrightnessContrast::qt_metacall (this=0x7fffffffc800, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0x7fffffffb1c0) at moc_brightnesscontrast.cpp:106
No locals.

---

Seems like BrightnessContrast instance is an invalid pointer.

I import mainwindow into BrightnessContrast and declare:

Code:

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MainWindow respond;
respond.brightnessProcessing(value);

---

This right?

I posted backtrace wrong, I editted in #7

Could you explain why you did the thing Chris pointed out a couple of posts ago -- made MainWindow a member variable of a QDialog subclass?

Can you give me a few link? I not yet reat it.
------------------------------------

I'm trying "made MainWindow a member variable of a QDialog subclass"

Quote:

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Originally Posted by bachkimfly

I'm trying "made MainWindow a member variable of a QDialog subclass"

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Yes, we can see that. But why are you trying to do this?

If don't made MainWindow a member variable of a QDialog, how to can executable event in QDialog. So what is your idea?

Quote:

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Originally Posted by bachkimfly

If don't made MainWindow a member variable of a QDialog, how to can executable event in QDialog.

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I don't understand what you mean.

I want to catch event slider value changed, but brightness processing function which at MainWindow, if don't made MainWindow as a member variable of a BrightnessContrast dialog, i dont know to executable event slider value changed. your idea!

P/s: now, it's 5:22 AM, a tonight don't sleep, i want to go to sleep

Quote:

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Originally Posted by bachkimfly

I want to catch event slider value changed, but brightness processing function which at MainWindow, if don't made MainWindow as a member variable of a BrightnessContrast dialog, i dont know to executable event slider value changed. your idea!

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Don't you already have an instance of the main window which launched the dialog? Do you understand the difference between a class and an instance of a class?

Alright! I need have to initialize object of MainWindow class, right?. I asked in #9.
So what is I can understand for "made MainWindow a member variable of a QDialog subclass". Patently, I misconstrued.

Quote:

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Originally Posted by bachkimfly

Alright! I need have to initialize object of MainWindow class, right?

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No, I'm assuming you already have such an object somewhere.

Let's make a deal - if you keep ignoring my questions, I will start ignoring yours.

Quote:

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Originally Posted by wysota

No, I'm assuming you already have such an object somewhere.

Let's make a deal - if you keep ignoring my questions, I will start ignoring yours.

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I don't ignore, I answered by the question "I need have to initialize object of MainWindow class, right?". That means I don't have an instance of the main window which launched the dialog and I understand the difference between a class and an instance of a class. I think so.

But I feel we are going around.