Display and divide the image

[kiransu123]

BIG Sorry, I didn't noticed that you use QT3, my code was for QT4.

However I analyze your code.

PaintWidget::PaintWidget(const QString &filename,QWidget *parent):QGLWidget(parent){
    data.load(filename);
    gldata=QGLWidget::convertToGLFormat(data);   //This is error you must have valid OpenGL context
    resize(data.size());
}

PaintWidget::PaintWidget(const QString &filename,QWidget *parent):QGLWidget(parent){
    data.load(filename);
    gldata=QGLWidget::convertToGLFormat(data);   //This is error you must have valid OpenGL context
    resize(data.size());
}

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For displaying half image you can use, QImage::copy()

void PaintWidget::paintGL(){
   QImage halfImage = data.copy(0, 0, data.width()/2, data.height()/2);
   gldata = QGLWidget::convertToGLFormat(halfImage);
   glDrawPixels(gldata.width(), gldata.height(), GL_RGBA, GL_UNSIGNED_TYPE, gldata.bits());
}

void PaintWidget::paintGL(){
   QImage halfImage = data.copy(0, 0, data.width()/2, data.height()/2);
   gldata = QGLWidget::convertToGLFormat(halfImage);
   glDrawPixels(gldata.width(), gldata.height(), GL_RGBA, GL_UNSIGNED_TYPE, gldata.bits());
}

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Thank you very much
can you tell me how to display small image or some copied image by copy() on full screen