graphicscontextcairo.cpp

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    const Vector<IntRect>& rects = focusRingRects();
    unsigned rectCount = rects.size();

    cairo_t* cr = m_data->cr;
    cairo_save(cr);
    cairo_push_group(cr);
    cairo_new_path(cr);

#if PLATFORM(GTK)
    GdkRegion* reg = gdk_region_new();
    for (unsigned i = 0; i < rectCount; i++) {
        GdkRectangle rect = rects[i];
        gdk_region_union_with_rect(reg, &rect);
    }
    gdk_cairo_region(cr, reg);
    gdk_region_destroy(reg);

    setColor(cr, color);
    cairo_set_line_width(cr, 2.0f);
    setPlatformStrokeStyle(DottedStroke);
#else
    int radius = (focusRingWidth() - 1) / 2;
    for (unsigned i = 0; i < rectCount; i++)
        addPath(Path::createRoundedRectangle(rects[i], FloatSize(radius, radius)));

    // Force the alpha to 50%.  This matches what the Mac does with outline rings.
    Color ringColor(color.red(), color.green(), color.blue(), 127);
    setColor(cr, ringColor);
    cairo_set_line_width(cr, focusRingWidth());
    setPlatformStrokeStyle(SolidStroke);
#endif

    cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
    cairo_stroke_preserve(cr);

    cairo_set_operator(cr, CAIRO_OPERATOR_CLEAR);
    cairo_set_fill_rule(cr, CAIRO_FILL_RULE_WINDING);
    cairo_fill(cr);

    cairo_pop_group_to_source(cr);
    cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
    cairo_paint(cr);
    cairo_restore(cr);
}

void GraphicsContext::drawLineForText(const IntPoint& origin, int width, bool printing)
{
    if (paintingDisabled())
        return;

    // This is a workaround for http://bugs.webkit.org/show_bug.cgi?id=15659
    StrokeStyle savedStrokeStyle = strokeStyle();
    setStrokeStyle(SolidStroke);

    IntPoint endPoint = origin + IntSize(width, 0);
    drawLine(origin, endPoint);

    setStrokeStyle(savedStrokeStyle);
}

void GraphicsContext::drawLineForMisspellingOrBadGrammar(const IntPoint& origin, int width, bool grammar)
{
    if (paintingDisabled())
        return;

    cairo_t* cr = m_data->cr;
    cairo_save(cr);

    // Convention is green for grammar, red for spelling
    // These need to become configurable
    if (grammar)
        cairo_set_source_rgb(cr, 0, 1, 0);
    else
        cairo_set_source_rgb(cr, 1, 0, 0);

#if PLATFORM(GTK)
    // We ignore most of the provided constants in favour of the platform style
    pango_cairo_show_error_underline(cr, origin.x(), origin.y(), width, cMisspellingLineThickness);
#else
    notImplemented();
#endif

    cairo_restore(cr);
}

FloatRect GraphicsContext::roundToDevicePixels(const FloatRect& frect)
{
    FloatRect result;
    double x = frect.x();
    double y = frect.y();
    cairo_t* cr = m_data->cr;
    cairo_user_to_device(cr, &x, &y);
    x = round(x);
    y = round(y);
    cairo_device_to_user(cr, &x, &y);
    result.setX(static_cast<float>(x));
    result.setY(static_cast<float>(y));
    x = frect.width();
    y = frect.height();
    cairo_user_to_device_distance(cr, &x, &y);
    x = round(x);
    y = round(y);
    cairo_device_to_user_distance(cr, &x, &y);
    result.setWidth(static_cast<float>(x));
    result.setHeight(static_cast<float>(y));
    return result;
}

void GraphicsContext::translate(float x, float y)
{
    if (paintingDisabled())
        return;

    cairo_t* cr = m_data->cr;
    cairo_translate(cr, x, y);
    m_data->translate(x, y);
}

IntPoint GraphicsContext::origin()
{
    cairo_matrix_t matrix;
    cairo_t* cr = m_data->cr;
    cairo_get_matrix(cr, &matrix);
    return IntPoint(static_cast<int>(matrix.x0), static_cast<int>(matrix.y0));
}

void GraphicsContext::setPlatformFillColor(const Color& col)
{
    // Cairo contexts can't hold separate fill and stroke colors
    // so we set them just before we actually fill or stroke
}

void GraphicsContext::setPlatformStrokeColor(const Color& col)
{
    // Cairo contexts can't hold separate fill and stroke colors
    // so we set them just before we actually fill or stroke
}

void GraphicsContext::setPlatformStrokeThickness(float strokeThickness)
{
    if (paintingDisabled())
        return;

    cairo_set_line_width(m_data->cr, strokeThickness);
}

void GraphicsContext::setPlatformStrokeStyle(const StrokeStyle& strokeStyle)
{
    static double dashPattern[] = {5.0, 5.0};
    static double dotPattern[] = {1.0, 1.0};

    if (paintingDisabled())
        return;

    switch (strokeStyle) {
    case NoStroke:
        // FIXME: is it the right way to emulate NoStroke?
        cairo_set_line_width(m_data->cr, 0);
        break;
    case SolidStroke:
        cairo_set_dash(m_data->cr, 0, 0, 0);
        break;
    case DottedStroke:
        cairo_set_dash(m_data->cr, dotPattern, 2, 0);
        break;
    case DashedStroke:
        cairo_set_dash(m_data->cr, dashPattern, 2, 0);
        break;
    }
}

void GraphicsContext::setURLForRect(const KURL& link, const IntRect& destRect)
{
    notImplemented();
}

void GraphicsContext::concatCTM(const TransformationMatrix& transform)
{
    if (paintingDisabled())
        return;

    cairo_t* cr = m_data->cr;
    const cairo_matrix_t matrix = cairo_matrix_t(transform);
    cairo_transform(cr, &matrix);
    m_data->concatCTM(transform);
}

void GraphicsContext::addInnerRoundedRectClip(const IntRect& rect, int thickness)
{
    if (paintingDisabled())
        return;

    clip(rect);

    Path p;
    FloatRect r(rect);
    // Add outer ellipse
    p.addEllipse(r);
    // Add inner ellipse
    r.inflate(-thickness);
    p.addEllipse(r);
    addPath(p);

    cairo_t* cr = m_data->cr;
    cairo_fill_rule_t savedFillRule = cairo_get_fill_rule(cr);
    cairo_set_fill_rule(cr, CAIRO_FILL_RULE_EVEN_ODD);
    cairo_clip(cr);
    cairo_set_fill_rule(cr, savedFillRule);
}

void GraphicsContext::clipToImageBuffer(const FloatRect& rect, const ImageBuffer* imageBuffer)
{
    if (paintingDisabled())
        return;

    notImplemented();
}

void GraphicsContext::setPlatformShadow(IntSize const&, int, Color const&)
{
    notImplemented();
}

void GraphicsContext::clearPlatformShadow()
{
    notImplemented();
}

void GraphicsContext::beginTransparencyLayer(float opacity)
{
    if (paintingDisabled())
        return;

    cairo_t* cr = m_data->cr;
    cairo_push_group(cr);
    m_data->layers.append(opacity);
    m_data->beginTransparencyLayer();
}

void GraphicsContext::endTransparencyLayer()
{
    if (paintingDisabled())
        return;

    cairo_t* cr = m_data->cr;

    cairo_pop_group_to_source(cr);
    cairo_paint_with_alpha(cr, m_data->layers.last());
    m_data->layers.removeLast();
    m_data->endTransparencyLayer();
}

void GraphicsContext::clearRect(const FloatRect& rect)
{
    if (paintingDisabled())
        return;

    cairo_t* cr = m_data->cr;

    cairo_save(cr);
    cairo_rectangle(cr, rect.x(), rect.y(), rect.width(), rect.height());
    cairo_set_operator(cr, CAIRO_OPERATOR_CLEAR);
    cairo_fill(cr);
    cairo_restore(cr);
}

void GraphicsContext::strokeRect(const FloatRect& rect, float width)
{
    if (paintingDisabled())
        return;

    cairo_t* cr = m_data->cr;
    cairo_save(cr);
    cairo_rectangle(cr, rect.x(), rect.y(), rect.width(), rect.height());
    cairo_set_line_width(cr, width);
    strokePath();
    cairo_restore(cr);
}

void GraphicsContext::setLineCap(LineCap lineCap)
{
    if (paintingDisabled())
        return;

    cairo_line_cap_t cairoCap = CAIRO_LINE_CAP_BUTT;
    switch (lineCap) {
        case ButtCap:
            // no-op
            break;
        case RoundCap:
            cairoCap = CAIRO_LINE_CAP_ROUND;
            break;
        case SquareCap:
            cairoCap = CAIRO_LINE_CAP_SQUARE;
            break;
    }
    cairo_set_line_cap(m_data->cr, cairoCap);
}

void GraphicsContext::setLineDash(const DashArray& dashes, float dashOffset)
{
    cairo_set_dash(m_data->cr, dashes.data(), dashes.size(), dashOffset);
}

void GraphicsContext::setLineJoin(LineJoin lineJoin)
{
    if (paintingDisabled())
        return;

    cairo_line_join_t cairoJoin = CAIRO_LINE_JOIN_MITER;
    switch (lineJoin) {
        case MiterJoin:
            // no-op
            break;
        case RoundJoin:
            cairoJoin = CAIRO_LINE_JOIN_ROUND;
            break;
        case BevelJoin:
            cairoJoin = CAIRO_LINE_JOIN_BEVEL;
            break;
    }
    cairo_set_line_join(m_data->cr, cairoJoin);
}

void GraphicsContext::setMiterLimit(float miter)
{
    if (paintingDisabled())
        return;

    cairo_set_miter_limit(m_data->cr, miter);
}

void GraphicsContext::setAlpha(float alpha)
{
    m_common->state.globalAlpha = alpha;
}

float GraphicsContext::getAlpha()
{
    return m_common->state.globalAlpha;
}

static inline cairo_operator_t toCairoOperator(CompositeOperator op)
{
    switch (op) {
        case CompositeClear:
            return CAIRO_OPERATOR_CLEAR;
        case CompositeCopy:
            return CAIRO_OPERATOR_SOURCE;
        case CompositeSourceOver:
            return CAIRO_OPERATOR_OVER;
        case CompositeSourceIn:
            return CAIRO_OPERATOR_IN;
        case CompositeSourceOut:
            return CAIRO_OPERATOR_OUT;
        case CompositeSourceAtop:
            return CAIRO_OPERATOR_ATOP;
        case CompositeDestinationOver:
            return CAIRO_OPERATOR_DEST_OVER;
        case CompositeDestinationIn:
            return CAIRO_OPERATOR_DEST_IN;
        case CompositeDestinationOut:
            return CAIRO_OPERATOR_DEST_OUT;
        case CompositeDestinationAtop:
            return CAIRO_OPERATOR_DEST_ATOP;
        case CompositeXOR:
            return CAIRO_OPERATOR_XOR;
        case CompositePlusDarker:
            return CAIRO_OPERATOR_SATURATE;
        case CompositeHighlight:
            // There is no Cairo equivalent for CompositeHighlight.
            return CAIRO_OPERATOR_OVER;
        case CompositePlusLighter:
            return CAIRO_OPERATOR_ADD;
        default:
            return CAIRO_OPERATOR_SOURCE;
    }
}

void GraphicsContext::setCompositeOperation(CompositeOperator op)
{
    if (paintingDisabled())
        return;

    cairo_set_operator(m_data->cr, toCairoOperator(op));
}

void GraphicsContext::beginPath()
{
    if (paintingDisabled())
        return;

    cairo_t* cr = m_data->cr;
    cairo_new_path(cr);
}

void GraphicsContext::addPath(const Path& path)
{
    if (paintingDisabled())
        return;

    cairo_t* cr = m_data->cr;
    cairo_path_t* p = cairo_copy_path(path.platformPath()->m_cr);
    cairo_append_path(cr, p);
    cairo_path_destroy(p);
}

void GraphicsContext::clip(const Path& path)
{
    if (paintingDisabled())
        return;

    cairo_t* cr = m_data->cr;
    cairo_path_t* p = cairo_copy_path(path.platformPath()->m_cr);
    cairo_append_path(cr, p);
    cairo_path_destroy(p);
    cairo_fill_rule_t savedFillRule = cairo_get_fill_rule(cr);
    cairo_set_fill_rule(cr, CAIRO_FILL_RULE_WINDING);
    cairo_clip(cr);
    cairo_set_fill_rule(cr, savedFillRule);
    m_data->clip(path);
}

void GraphicsContext::clipOut(const Path& path)
{
    if (paintingDisabled())
        return;

#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1,4,0)
    cairo_t* cr = m_data->cr;
    double x1, y1, x2, y2;
    cairo_clip_extents(cr, &x1, &y1, &x2, &y2);
    cairo_rectangle(cr, x1, y1, x2 - x1, y2 - y1);
    addPath(path);

    cairo_fill_rule_t savedFillRule = cairo_get_fill_rule(cr);
    cairo_set_fill_rule(cr, CAIRO_FILL_RULE_EVEN_ODD);
    cairo_clip(cr);
    cairo_set_fill_rule(cr, savedFillRule);
#else
    notImplemented();
#endif
}

void GraphicsContext::rotate(float radians)
{
    if (paintingDisabled())
        return;

    cairo_rotate(m_data->cr, radians);
    m_data->rotate(radians);
}

void GraphicsContext::scale(const FloatSize& size)
{
    if (paintingDisabled())
        return;

    cairo_scale(m_data->cr, size.width(), size.height());
    m_data->scale(size);
}

void GraphicsContext::clipOut(const IntRect& r)
{
    if (paintingDisabled())
        return;

#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1,4,0)
    cairo_t* cr = m_data->cr;
    double x1, y1, x2, y2;
    cairo_clip_extents(cr, &x1, &y1, &x2, &y2);
    cairo_rectangle(cr, x1, x2, x2 - x1, y2 - y1);
    cairo_rectangle(cr, r.x(), r.y(), r.width(), r.height());
    cairo_fill_rule_t savedFillRule = cairo_get_fill_rule(cr);
    cairo_set_fill_rule(cr, CAIRO_FILL_RULE_EVEN_ODD);
    cairo_clip(cr);
    cairo_set_fill_rule(cr, savedFillRule);
#else
    notImplemented();
#endif
}

void GraphicsContext::clipOutEllipseInRect(const IntRect& r)
{
    if (paintingDisabled())
        return;

    Path p;
    p.addEllipse(r);
    clipOut(p);
}

void GraphicsContext::fillRoundedRect(const IntRect& r, const IntSize& topLeft, const IntSize& topRight, const IntSize& bottomLeft, const IntSize& bottomRight, const Color& color)
{
    if (paintingDisabled())
        return;

    cairo_t* cr = m_data->cr;
    cairo_save(cr);
    beginPath();
    addPath(Path::createRoundedRectangle(r, topLeft, topRight, bottomLeft, bottomRight));
    setColor(cr, color);
    cairo_fill(cr);
    cairo_restore(cr);
}

#if PLATFORM(GTK)
void GraphicsContext::setGdkExposeEvent(GdkEventExpose* expose)
{
    m_data->expose = expose;
}

GdkEventExpose* GraphicsContext::gdkExposeEvent() const
{
    return m_data->expose;
}

GdkDrawable* GraphicsContext::gdkDrawable() const
{
    if (!m_data->expose)
        return 0;

    return GDK_DRAWABLE(m_data->expose->window);
}
#endif

void GraphicsContext::setPlatformShouldAntialias(bool enable)
{
    if (paintingDisabled())
        return;

    // When true, use the default Cairo backend antialias mode (usually this
    // enables standard 'grayscale' antialiasing); false to explicitly disable
    // antialiasing. This is the same strategy as used in drawConvexPolygon().
    cairo_set_antialias(m_data->cr, enable ? CAIRO_ANTIALIAS_DEFAULT : CAIRO_ANTIALIAS_NONE);
}

void GraphicsContext::setImageInterpolationQuality(InterpolationQuality)
{
}

InterpolationQuality GraphicsContext::imageInterpolationQuality() const
{
    return InterpolationDefault;
}

} // namespace WebCore

#endif // PLATFORM(CAIRO)