/*

 * Copyright (C) 2009 Alex Milowski (alex@milowski.com). All rights reserved.

 * Copyright (C) 2010 François Sausset (sausset@gmail.com). All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include "config.h"

#if ENABLE(MATHML)

#include "RenderMathMLSquareRoot.h"

#include "GraphicsContext.h"

#include "MathMLNames.h"

#include "Path.h"

namespace WebCore {

using namespace MathMLNames;

// Bottom padding of the radical (px)

const int gRadicalBasePad = 3;

// Threshold above which the radical shape is modified to look nice with big bases (%)

const float gThresholdBaseHeight = 1.5;

// Radical width (%)

const float gRadicalWidth = 0.75;

// Horizontal position of the bottom point of the radical (%)

const float gRadicalBottomPointXPos= 0.5;

// Horizontal position of the top left point of the radical (%)

const float gRadicalTopLeftPointXPos = 0.2;

// Vertical position of the top left point of the radical (%)

const float gRadicalTopLeftPointYPos = 0.5; 

// Vertical shift of the left end point of the radical (%)

const float gRadicalLeftEndYShift = 0.05;

// Additional bottom root padding (%)

const float gRootBottomPadding = 0.2;

// Radical line thickness (%)

const float gRadicalLineThickness = 0.02;

// Radical thick line thickness (%)

const float gRadicalThickLineThickness = 0.1;

RenderMathMLSquareRoot::RenderMathMLSquareRoot(Node *expression) 

    : RenderMathMLBlock(expression) 

{

}

void RenderMathMLSquareRoot::paint(PaintInfo& info, int tx, int ty)

{

    RenderMathMLBlock::paint(info, tx, ty);

    if (info.context->paintingDisabled())

        return;

    tx += x();

    ty += y();

    int maxHeight = 0;

    int width = 0;

    RenderObject* current = firstChild();

    while (current) {

        if (current->isBoxModelObject()) {

            RenderBoxModelObject* box = toRenderBoxModelObject(current);

            // Check to see if this box has a larger height

            if (box->offsetHeight() > maxHeight)

                maxHeight = box->offsetHeight();

            width += box->offsetWidth();

        }

        current = current->nextSibling();

    }

    // default to the font size in pixels if we're empty

    if (!maxHeight)

        maxHeight = style()->fontSize();

    int frontWidth = static_cast<int>(style()->fontSize() * gRadicalWidth);

    int topStartShift = 0;

    // Base height above which the shape of the root changes

    int thresholdHeight = static_cast<int>(gThresholdBaseHeight * style()->fontSize());

    if (maxHeight > thresholdHeight && thresholdHeight) {

        float shift = (maxHeight - thresholdHeight) / static_cast<float>(thresholdHeight);

        if (shift > 1.)

            shift = 1.;

        topStartShift = static_cast<int>(gRadicalBottomPointXPos * frontWidth * shift);

    }

    width += topStartShift;

    FloatPoint topStart(tx + frontWidth - topStartShift, ty);

    FloatPoint bottomLeft(tx + frontWidth * gRadicalBottomPointXPos , ty + maxHeight + gRadicalBasePad);

    FloatPoint topLeft(tx + frontWidth * gRadicalTopLeftPointXPos , ty + gRadicalTopLeftPointYPos * maxHeight);

    FloatPoint leftEnd(tx , topLeft.y() + gRadicalLeftEndYShift * style()->fontSize());

    info.context->save();

    info.context->setStrokeThickness(gRadicalLineThickness * style()->fontSize());

    info.context->setStrokeStyle(SolidStroke);

    info.context->setStrokeColor(style()->visitedDependentColor(CSSPropertyColor), DeviceColorSpace);

    info.context->setLineJoin(MiterJoin);

    info.context->setMiterLimit(style()->fontSize());

    Path root;

    root.moveTo(FloatPoint(topStart.x() + width , ty));

    // draw top

    root.addLineTo(topStart);

    // draw from top left corner to bottom point of radical

    root.addLineTo(bottomLeft);

    // draw from bottom point to top of left part of radical base "pocket"

    root.addLineTo(topLeft);

    // draw to end

    root.addLineTo(leftEnd);

    info.context->beginPath();

    info.context->addPath(root);

    info.context->strokePath();

    info.context->save();

    // Build a mask to draw the thick part of the root.

    Path mask;

    mask.moveTo(topStart);

    mask.addLineTo(bottomLeft);

    mask.addLineTo(topLeft);

    mask.addLineTo(FloatPoint(2 * topLeft.x() - leftEnd.x(), 2 * topLeft.y() - leftEnd.y()));

    info.context->beginPath();

    info.context->addPath(mask);

    info.context->clip(mask);

    // Draw the thick part of the root.

    info.context->setStrokeThickness(gRadicalThickLineThickness * style()->fontSize());

    info.context->setLineCap(SquareCap);

    Path line;

    line = line.createLine(bottomLeft, topLeft);

    info.context->beginPath();

    info.context->addPath(line);

    info.context->strokePath();

    info.context->restore();

    info.context->restore();

}

void RenderMathMLSquareRoot::layout()

{

    int maxHeight = 0;

    RenderObject* current = firstChild();

    while (current) {

        if (current->isBoxModelObject()) {

            RenderBoxModelObject* box = toRenderBoxModelObject(current);

            if (box->offsetHeight() > maxHeight)

                maxHeight = box->offsetHeight();

            box->style()->setVerticalAlign(BASELINE);

        }

        current = current->nextSibling();

    }

    if (!maxHeight)

        maxHeight = style()->fontSize();

    if (maxHeight > static_cast<int>(gThresholdBaseHeight * style()->fontSize()))

        style()->setPaddingBottom(Length(static_cast<int>(gRootBottomPadding * style()->fontSize()), Fixed));

    RenderBlock::layout();

}

}

#endif // ENABLE(MATHML)