Method display

dgl/src/OpenGL.cpp:160–217

// --------------------------------------------------------------------------------------------------------------------

void SubWidget::PrivateData::display(const uint width, const uint height, const double autoScaleFactor)
{
    if (skipDrawing)
        return;

    bool needsDisableScissor = false;

    if (needsViewportScaling)
    {
        // limit viewport to widget bounds
        const int x = absolutePos.getX();
        const int w = static_cast<int>(self->getWidth());
        const int h = static_cast<int>(self->getHeight());

        if (d_isNotZero(viewportScaleFactor) && d_isNotEqual(viewportScaleFactor, 1.0))
        {
            glViewport(x,
                       -d_roundToIntPositive(height * viewportScaleFactor - height + absolutePos.getY()),
                       d_roundToIntPositive(width * viewportScaleFactor),
                       d_roundToIntPositive(height * viewportScaleFactor));
        }
        else
        {
            const int y = static_cast<int>(height - self->getHeight()) - absolutePos.getY();
            glViewport(x, y, w, h);
        }
    }
    else if (needsFullViewportForDrawing || (absolutePos.isZero() && self->getSize() == Size<uint>(width, height)))
    {
        // full viewport size
        glViewport(0, 0, static_cast<int>(width), static_cast<int>(height));
    }
    else
    {
        // set viewport pos
        glViewport(d_roundToIntPositive(absolutePos.getX() * autoScaleFactor),
                   -d_roundToIntPositive(absolutePos.getY() * autoScaleFactor),
                   static_cast<int>(width),
                   static_cast<int>(height));

        // then cut the outer bounds
        glScissor(d_roundToIntPositive(absolutePos.getX() * autoScaleFactor),
                  d_roundToIntPositive(height - (static_cast<int>(self->getHeight()) + absolutePos.getY()) * autoScaleFactor),
                  d_roundToIntPositive(self->getWidth() * autoScaleFactor),
                  d_roundToIntPositive(self->getHeight() * autoScaleFactor));

        glEnable(GL_SCISSOR_TEST);
        needsDisableScissor = true;
    }

    // display widget
    self->onDisplay();

    if (needsDisableScissor)
        glDisable(GL_SCISSOR_TEST);

    selfw->pData->displaySubWidgets(width, height, autoScaleFactor);
}