#include "ImageWidget.h"

ImageWidget::ImageWidget(QWidget* parent, int width, int height) :
    QGLWidget(parent), _imageRef(NULL) {

    setFormat(QGLFormat(QGL::SampleBuffers));
    setAutoFillBackground(true);

    setMinimumSize(width, height);
    setMaximumSize(width, height);
}

void ImageWidget::refreshImage(IplImage* image) {

    _imageRef = image;
    update();
}

void ImageWidget::setupViewPort(int width, int height) {

    glViewport(0, 0, static_cast<GLsizei> (width), static_cast<GLsizei> (height));
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    gluOrtho2D(0.0, static_cast<GLdouble> (width), 0.0, static_cast<GLdouble> (height));
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

void ImageWidget::resizeGL(int width, int height) {

    setupViewPort(width, height);
}

void ImageWidget::paintEvent(QPaintEvent *paintEvent) {

    //--- Make this widget the current context for OpenGL drawing
    makeCurrent();

    //Save current state, QPainter modifies MODELVIEW matrix.
    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();

    setupViewPort(width(), height());

    glClear(GL_COLOR_BUFFER_BIT| GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();

    drawBackgroundImage();

    //Restore state after drawing pure openGL
    glMatrixMode(GL_MODELVIEW);
    glPopMatrix();

    QPainter painter(this);
    painter.end();

    //--- Set OpenGL drawing context to no area
    doneCurrent();
}

void ImageWidget::drawBackgroundImage() {

    if (_imageRef != NULL) {

        //Flip image around y axis to be displayed correctly; IplImage's coordinate system is the upside-down of openGL's.
        glPixelZoom(1.0f, -1.0f);
        glRasterPos2i(0, height());
        glDrawPixels(_imageRef->width, _imageRef->height, GL_BGR_EXT, GL_UNSIGNED_BYTE, _imageRef->imageData);
    } else {
        logWARNING("Null background image.");
    }
}

#include "ImageWidget.moc"