[SOLVED]Best method to display dynamic images

  • Trying to create a image that is changed once a button is pressed. Currently able to display an image fine using setpixmap.

    However what I am wondering is, is this the preferred method for displaying images ?

    Essentially what I am trying to achieve is be able to change an image displayed based on conditions, so I have created a test program below. However I am not sure how to proceed to make the image change. I thought maybe loading two pixmaps into the heap and then setting a QLabel (don't care if it is a QLabel just want to display an image inside a widget) using setpixmap, however to me this seems like an inefficient method (there is never a time when both are being displayed only one at a time). Am I going in the right direction or should I be looking at other methods ?

    @#include "widget.h"

    #include <QVBoxLayout>
    #include <QLabel>
    #include <QPushButton>

    Widget::Widget(QWidget *parent)
    : QWidget(parent)
    QPixmap image1("C:\Users\Documents\QPixmap\radaroff.png");
    QPixmap image2("C:\Users\Documents\QPixmap\radaron.png");
    QVBoxLayout * layout = new QVBoxLayout(this);
    QLabel * Label = new QLabel(this);
    QPushButton * Button = new QPushButton(this);



    @#ifndef WIDGET_H
    #define WIDGET_H

    #include <QWidget>

    #include "gui_image.h"

    class Widget : public QWidget

    Widget(QWidget *parent = 0);

    gui_image * Main_Image;


    #endif // WIDGET_H

    @#include "widget.h"
    #include <QApplication>

    int main(int argc, char *argv[])
    QApplication a(argc, argv);
    Widget w;

    return a.exec(&#41;;


    Also there will only be a maximum of 3 images so if there is a better method please let me know.

  • Lifetime Qt Champion


    That looks correct for you purpose.

    On a side note, you should use the unix notation for paths. Less likely to write wrong things

  • Yea good point SGaist didn't think of that btw when I was coding this by mistake wrote this.

    QPixmap fImage = filename_off

    where as filename_off is a QString to the file being used by the pixmap, which actually worked to my surprise. So checked the documentation for an overloaded operator that took a QString and couldn't find one. So even though it wasn't in the documentation i'm presuming:

    QPixmap fImage = filename_off

    is the same as

    QPixmap fImage = QPixmap(filename_off)

    ?? Am I right in my thinking?

  • Lifetime Qt Champion

    AFAIK, the third constructor is used here to construct the pixmap since the two last parameters have default values.

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