static bool isDeletableElement(const Node* node)
{
    if (!node || !node->isHTMLElement() || !node->inDocument() || !node->isContentEditable())
        return false;

    const int minimumWidth = 25;
    const int minimumHeight = 25;
    const unsigned minimumVisibleBorders = 3;

    RenderObject* renderer = node->renderer();
    if (!renderer || renderer->width() < minimumWidth || renderer->height() < minimumHeight)
        return false;

    if (renderer->isTable())
        return true;

    if (node->hasTagName(ulTag) || node->hasTagName(olTag))
        return true;

    if (renderer->isPositioned())
        return true;

    // allow block elements (excluding table cells) that have some non-transparent borders
    if (renderer->isRenderBlock() && !renderer->isTableCell()) {
        RenderStyle* style = renderer->style();
        if (style && style->hasBorder()) {
            unsigned visibleBorders = style->borderTop().isVisible() + style->borderBottom().isVisible() + style->borderLeft().isVisible() + style->borderRight().isVisible();
            if (visibleBorders >= minimumVisibleBorders)
                return true;
        }
    }

    return false;
}
bool RenderTheme::paintMeter(RenderObject* renderObject, const RenderObject::PaintInfo& paintInfo, const IntRect& rect)
{
    // Some platforms do not have a native gauge widget, so we draw here a default implementation.
    RenderMeter* renderMeter = toRenderMeter(renderObject);
    RenderStyle* style = renderObject->style();
    int left = style->borderLeft().width() + style->paddingLeft().value();
    int top = style->borderTop().width() + style->paddingTop().value();
    int right = style->borderRight().width() + style->paddingRight().value();
    int bottom = style->borderBottom().width() + style->paddingBottom().value();
    FloatRect innerRect(rect.x() + left, rect.y() + top, rect.width() - left - right, rect.height() - top - bottom);

    HTMLMeterElement* element = static_cast<HTMLMeterElement*>(renderMeter->node());
    double min = element->min();
    double max = element->max();
    double value = element->value();

    if (min >= max) {
        paintInfo.context->fillRect(innerRect, Color::black, style->colorSpace());
        return false;
    }

    // Paint the background first
    paintInfo.context->fillRect(innerRect, Color::lightGray, style->colorSpace());

    FloatRect valueRect;

    if (rect.width() < rect.height()) {
        // Vertical gauge
        double scale = innerRect.height() / (max - min);
        valueRect.setLocation(FloatPoint(innerRect.x(), innerRect.y() + narrowPrecisionToFloat((max - value) * scale)));
        valueRect.setSize(FloatSize(innerRect.width(), narrowPrecisionToFloat((value - min) * scale)));
    } else if (renderMeter->style()->direction() == RTL) {
        // right to left horizontal gauge
        double scale = innerRect.width() / (max - min);
        valueRect.setLocation(FloatPoint(innerRect.x() + narrowPrecisionToFloat((max - value) * scale), innerRect.y()));
        valueRect.setSize(FloatSize(narrowPrecisionToFloat((value - min) * scale), innerRect.height()));
    } else {
        // left to right horizontal gauge
        double scale = innerRect.width() / (max - min);
        valueRect.setLocation(innerRect.location());
        valueRect.setSize(FloatSize(narrowPrecisionToFloat((value - min)) * scale, innerRect.height()));
    }
    if (!valueRect.isEmpty())
        paintInfo.context->fillRect(valueRect, Color::black, style->colorSpace());

    return false;
}
static bool isDeletableElement(const Node* node)
{
    if (!node || !node->isHTMLElement() || !node->inDocument() || !node->isContentEditable())
        return false;

    // In general we want to only draw the UI arround object of a certain area, but we still keep the min width/height to
    // make sure we don't end up with very thin or very short elements getting the UI.
    const int minimumArea = 2500;
    const int minimumWidth = 48;
    const int minimumHeight = 16;
    const unsigned minimumVisibleBorders = 1;

    RenderObject* renderer = node->renderer();
    if (!renderer || !renderer->isBox())
        return false;

    // Disallow the body element since it isn't practical to delete, and the deletion UI would be clipped.
    if (node->hasTagName(bodyTag))
        return false;

    // Disallow elements with any overflow clip, since the deletion UI would be clipped as well. <rdar://problem/6840161>
    if (renderer->hasOverflowClip())
        return false;

    // Disallow Mail blockquotes since the deletion UI would get in the way of editing for these.
    if (isMailBlockquote(node))
        return false;

    RenderBox* box = toRenderBox(renderer);
    IntRect borderBoundingBox = box->borderBoundingBox();
    if (borderBoundingBox.width() < minimumWidth || borderBoundingBox.height() < minimumHeight)
        return false;

    if ((borderBoundingBox.width() * borderBoundingBox.height()) < minimumArea)
        return false;

    if (renderer->isTable())
        return true;

    if (node->hasTagName(ulTag) || node->hasTagName(olTag) || node->hasTagName(iframeTag))
        return true;

    if (renderer->isPositioned())
        return true;

    if (renderer->isRenderBlock() && !renderer->isTableCell()) {
        RenderStyle* style = renderer->style();
        if (!style)
            return false;

        // Allow blocks that have background images
        if (style->hasBackgroundImage() && style->backgroundImage()->canRender(1.0f))
            return true;

        // Allow blocks with a minimum number of non-transparent borders
        unsigned visibleBorders = style->borderTop().isVisible() + style->borderBottom().isVisible() + style->borderLeft().isVisible() + style->borderRight().isVisible();
        if (visibleBorders >= minimumVisibleBorders)
            return true;

        // Allow blocks that have a different background from it's parent
        Node* parentNode = node->parentNode();
        if (!parentNode)
            return false;

        RenderObject* parentRenderer = parentNode->renderer();
        if (!parentRenderer)
            return false;

        RenderStyle* parentStyle = parentRenderer->style();
        if (!parentStyle)
            return false;

        if (style->hasBackground() && (!parentStyle->hasBackground() || style->backgroundColor() != parentStyle->backgroundColor()))
            return true;
    }

    return false;
}