composition.cpp

奇趣公司比较新的qt/emd版本

    rect.translate(-size.width()/2, -size.height()/2);
    return rect;
}

void CompositionRenderer::updateCirclePos()
{
    if (m_current_object != NoObject)
        return;
    QDateTime dt = QDateTime::currentDateTime();
    qreal t = (dt.toTime_t() * 1000 + dt.time().msec()) / 1000.0;

    qreal x = width() / 2.0 + (cos(t) + sin(-t*2)) * width() / 2.0;
    qreal y = height() / 2.0 + (sin(t) + cos(t * 3)) * height() / 2.0;

    m_circle_pos = QLineF(m_circle_pos, QPointF(x, y)).pointAt(0.01);
}

void CompositionRenderer::drawBase(QPainter &p)
{
    p.setPen(Qt::NoPen);

    QLinearGradient rect_gradient(0, 0, 0, height());
    rect_gradient.setColorAt(0, Qt::red);
    rect_gradient.setColorAt(.17, Qt::yellow);
    rect_gradient.setColorAt(.33, Qt::green);
    rect_gradient.setColorAt(.50, Qt::cyan);
    rect_gradient.setColorAt(.66, Qt::blue);
    rect_gradient.setColorAt(.81, Qt::magenta);
    rect_gradient.setColorAt(1, Qt::red);
    p.setBrush(rect_gradient);
    p.drawRect(width() / 2, 0, width() / 2, height());

    QLinearGradient alpha_gradient(0, 0, width(), 0);
    alpha_gradient.setColorAt(0, Qt::white);
    alpha_gradient.setColorAt(0.2, Qt::white);
    alpha_gradient.setColorAt(0.5, Qt::transparent);
    alpha_gradient.setColorAt(0.8, Qt::white);
    alpha_gradient.setColorAt(1, Qt::white);

    p.setCompositionMode(QPainter::CompositionMode_DestinationIn);
    p.setBrush(alpha_gradient);
    p.drawRect(0, 0, width(), height());

    p.setCompositionMode(QPainter::CompositionMode_DestinationOver);

    p.setPen(Qt::NoPen);
    p.setRenderHint(QPainter::SmoothPixmapTransform);
    p.drawImage(rect(), m_image);
}

void CompositionRenderer::drawSource(QPainter &p)
{
    p.setPen(Qt::NoPen);
    p.setRenderHint(QPainter::Antialiasing);
    p.setCompositionMode(m_composition_mode);

    QRectF circle_rect = rectangle_around(m_circle_pos);
    QColor color = QColor::fromHsvF(m_circle_hue / 360.0, 1, 1, m_circle_alpha / 255.0);
    QLinearGradient circle_gradient(circle_rect.topLeft(), circle_rect.bottomRight());
    circle_gradient.setColorAt(0, color.light());
    circle_gradient.setColorAt(0.5, color);
    circle_gradient.setColorAt(1, color.dark());
    p.setBrush(circle_gradient);

    p.drawEllipse(circle_rect);
}

void CompositionRenderer::paint(QPainter *painter)
{
    if (m_animation_enabled)
        updateCirclePos();

#ifdef QT_OPENGL_SUPPORT
    if (usesOpenGL()) {

        int new_pbuf_size = m_pbuffer_size;
        if (size().width() > m_pbuffer_size ||
            size().height() > m_pbuffer_size)
            new_pbuf_size *= 2;

        if (size().width() < m_pbuffer_size/2 &&
            size().height() < m_pbuffer_size/2)
            new_pbuf_size /= 2;

        if (!m_pbuffer || new_pbuf_size != m_pbuffer_size) {
            if (m_pbuffer) {
                m_pbuffer->deleteTexture(m_base_tex);
                m_pbuffer->deleteTexture(m_compositing_tex);
                delete m_pbuffer;
            }

            m_pbuffer = new QGLPixelBuffer(QSize(new_pbuf_size, new_pbuf_size), QGLFormat::defaultFormat(), glWidget());
            m_pbuffer->makeCurrent();
            m_base_tex = m_pbuffer->generateDynamicTexture();
            m_compositing_tex = m_pbuffer->generateDynamicTexture();
            m_pbuffer_size = new_pbuf_size;
        }

        if (size() != m_previous_size) {
            m_previous_size = size();
            QPainter p(m_pbuffer);
            p.setCompositionMode(QPainter::CompositionMode_Source);
            p.fillRect(QRect(0, 0, m_pbuffer->width(), m_pbuffer->height()), Qt::transparent);
            drawBase(p);
            m_pbuffer->updateDynamicTexture(m_base_tex);
        }

        qreal x_fraction = width()/float(m_pbuffer->width());
        qreal y_fraction = height()/float(m_pbuffer->height());

        {
            QPainter p(m_pbuffer);
            p.setCompositionMode(QPainter::CompositionMode_Source);
            p.fillRect(QRect(0, 0, m_pbuffer->width(), m_pbuffer->height()), Qt::transparent);

            p.save();
            glBindTexture(GL_TEXTURE_2D, m_base_tex);
            glEnable(GL_TEXTURE_2D);
            glColor4f(1.,1.,1.,1.);

            glBegin(GL_QUADS);
            {                
                glTexCoord2f(0, 1.0);
                glVertex2f(0, 0);
                
                glTexCoord2f(x_fraction, 1.0);
                glVertex2f(width(), 0);
                
                glTexCoord2f(x_fraction, 1.0-y_fraction);
                glVertex2f(width(), height());
                
                glTexCoord2f(0, 1.0-y_fraction);
                glVertex2f(0, height());
            }
            glEnd();
            
            glDisable(GL_TEXTURE_2D);
            p.restore();

            drawSource(p);
            m_pbuffer->updateDynamicTexture(m_compositing_tex);
        }

        glWidget()->makeCurrent();
        glBindTexture(GL_TEXTURE_2D, m_compositing_tex);
        glEnable(GL_TEXTURE_2D);
        glColor4f(1.,1.,1.,1.);
        glBegin(GL_QUADS);
        {
            glTexCoord2f(0, 1.0);
            glVertex2f(0, 0);
                
            glTexCoord2f(x_fraction, 1.0);
            glVertex2f(width(), 0);
                
            glTexCoord2f(x_fraction, 1.0-y_fraction);
            glVertex2f(width(), height());
                
            glTexCoord2f(0, 1.0-y_fraction);
            glVertex2f(0, height());
        }
        glEnd();
        glDisable(GL_TEXTURE_2D);
    } else
#endif
    {
        // using a QImage
        if (m_buffer.size() != size()) {
            m_buffer = QImage(size(), QImage::Format_ARGB32_Premultiplied);
            m_base_buffer = QImage(size(), QImage::Format_ARGB32_Premultiplied);

            m_base_buffer.fill(0);

            QPainter p(&m_base_buffer);

            drawBase(p);
        }

        memcpy(m_buffer.bits(), m_base_buffer.bits(), m_buffer.numBytes());

        {
            QPainter p(&m_buffer);
            drawSource(p);
        }

        painter->drawImage(0, 0, m_buffer);
    }
    
    if (m_animation_enabled)
        update();
}

void CompositionRenderer::mousePressEvent(QMouseEvent *e)
{
    setDescriptionEnabled(false);

    QRectF circle = rectangle_around(m_circle_pos);

    if (circle.contains(e->pos())) {
        m_current_object = Circle;
        m_offset = circle.center() - e->pos();
    } else {
        m_current_object = NoObject;
    }
}

void CompositionRenderer::mouseMoveEvent(QMouseEvent *e)
{
    if (m_current_object == Circle) setCirclePos(e->pos() + m_offset);
}

void CompositionRenderer::mouseReleaseEvent(QMouseEvent *)
{
    m_current_object = NoObject;
}