Qt cannot save pixmap

Question

Hello i have a strange problem to save pixmap.

My Widget Header

public:
  QPixmap *base;  //Base Poses
  QPixmap *Hair;  //Hair
  QPixmap *Composited;  //Final Composition

  bool compisition = false;

  void Composite();

My Widget Cpp

At paintEvent

 base = &pic;
    Hair = &hairs;

    if(compisition)
    {
        QPixmap pix(128,192);
        QPainter *p = new QPainter(&pix);

        p->drawPixmap(0,0,128,192,*base);
        p->drawPixmap(0,0,128,192,*Hair);

        Composited = &pix;
        compisition = false;
    }
void AnimPreview::Composite()
{
    compisition = true;
    this->update();


}

At main form source

void MainWindow::on_commandLinkButton_clicked()
{
    QString file = QFileDialog::getSaveFileName(this,
                                               tr("Save Sprite file"),
                                               "",tr("File PNG (*.png)"));

    const QPixmap *pix = ui->SpriteFront->pixmap();

    if(!file.isEmpty())
    {
        QFile files(file);
        files.open(QIODevice::WriteOnly);

        ui->SpriteFront->Composite();
        ui->SpriteFront->Composited->save(&files,"PNG");
    }
}

When i try to save a file, the process work but whit on error

An unhandled win32 exception

For more information complete code here

https://pastebin.com/GtaVCXGf

Answer 1

I have avoided reviewing where the error can be generated since there are many possible sources of the problem, among them the following:

• It is not necessary that you create QPixmap pointers since in the end you will have the job of eliminating it from memory.

• The same happens with QPainter since it only needs to be a local variable, in addition to that the painting is not done immediately, to be sure that it is painted you must call its end() method.

• paintEvent is a protected method, so by design we prefer it to remain so.

• It is not necessary to use a QFile to save an image, you can directly pass the filename to it.

Considering all the above, we obtain the following:

*.h

#ifndef ANIMPREVIEW_H
#define ANIMPREVIEW_H

#include <QLabel>
#include <QPixmap>

class AnimPreview : public QLabel
{
public:
    AnimPreview(QWidget *parent = 0);

    void Rotate(int value);
    void Composite();
    void Create(int _sex, int _hair);
    QPixmap Composited;

private:
    int sex = 0;
    int hair = 0;
    bool draw = true;

    int rotation = 0;
    const int offsetX = 16;
    const int offsetY = 32;

    QPixmap base;
    QPixmap Hair;
    bool compisition = false;

protected:
    void paintEvent(QPaintEvent *);
};

#endif // ANIMPREVIEW_H

*.cpp

#include "animpreview.h"

#include <QPainter>

AnimPreview::AnimPreview(QWidget *parent):QLabel(parent)
{
}

void AnimPreview::paintEvent(QPaintEvent *){

    QPainter p(this);
    QPixmap pic;
    QPixmap hairs;

    if(draw)
    {
        //Sesso
        switch(sex)
        {
        case 0:
            pic.load(":/Male/Base/Res/man_f.png");
            break;
        case 1:
            pic.load(":/Male/Base/Res/woman_f.png");

            break;
        }

        //capelli
        if(sex == 1)
        {
            switch(hair)
            {
            case 1:
                hairs.load(":/Female/Hair/Res/7_aqua.png");
                break;
            case 2:
                hairs.load(":/Female/Hair/Res/5_gold.png");
                break;
            }
        }

        if(sex == 0)
        {
            switch (hair)
            {
            case 0:
                break;
            case 1:
                hairs.load(":/Male/Hair/Res/1_aqua.png");
                break;
            case 2:
                hairs.load(":/Male/Hair/Res/14_black.png");
                break;
            }
        }

    }

    p.drawPixmap(width()/2 - offsetX,height()/2 - offsetY,pic,0,rotation,32,48);
    p.drawPixmap(width()/2 - offsetX,height()/2 - offsetY,hairs,0,rotation,32,48);
    p.drawRect(0,0, width()-1, height()-1);

    base = pic;
    Hair = hairs;

    if(compisition)
    {
        QPixmap pix(128,192);
        QPainter p(&pix);

        p.drawPixmap(0,0,128,192, base);
        p.drawPixmap(0,0,128,192, Hair);

        p.end();

        Composited = pix;
        compisition = false;
    }
}

void AnimPreview::Rotate(int value)
{
    rotation = value;
    update();
}

void AnimPreview::Create(int _sex, int _hair)
{
    sex = _sex;
    hair = _hair;
    draw = true;
}

void AnimPreview::Composite()
{
    compisition = true;
    update();
}

---

void MainWindow::on_commandLinkButton_clicked()
{
    QString file = QFileDialog::getSaveFileName(this,
                                                tr("Save Sprite file"),
                                                "",tr("File PNG (*.png)"));

    if(!file.isEmpty())
    {
        ui->SpriteFront->Composite();
        ui->SpriteFront->Composited.save(file,"PNG");
    }
}