/*

 * 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 "RenderMathMLRoot.h"

#include "GraphicsContext.h"

#include "MathMLNames.h"

namespace WebCore {

using namespace MathMLNames;

// Left margin of the radical (px)

const int gRadicalLeftMargin = 3;

// 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 = 0.8;

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

const float gRadicalTopLeftPointYPos = 0.625; 

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

const float gRadicalLeftEndYShift = 0.05;

// Root padding around the base (%)

const float gRootPadding = 0.2;

// 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;

RenderMathMLRoot::RenderMathMLRoot(Node *expression) 

: RenderMathMLBlock(expression) 

{

}

void RenderMathMLRoot::addChild(RenderObject* child, RenderObject* )

{

    if (isEmpty()) {

        // Add a block for the index

        RenderBlock* block = new (renderArena()) RenderBlock(node());

        RefPtr<RenderStyle> indexStyle = makeBlockStyle();

        indexStyle->setDisplay(INLINE_BLOCK);

        block->setStyle(indexStyle.release());

        RenderBlock::addChild(block);

        // FIXME: the wrapping does not seem to be needed anymore.

        // this is the base, so wrap it so we can pad it

        block = new (renderArena()) RenderBlock(node());

        RefPtr<RenderStyle> baseStyle = makeBlockStyle();

        baseStyle->setDisplay(INLINE_BLOCK);

        baseStyle->setPaddingLeft(Length(5 * gRadicalWidth , Percent));

        block->setStyle(baseStyle.release());

        RenderBlock::addChild(block);

        block->addChild(child);

    } else {

        // always add to the index

        firstChild()->addChild(child);

    }

}

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

{

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

    if (info.context->paintingDisabled())

        return;

    tx += x();

    ty += y();

    RenderBoxModelObject* indexBox = toRenderBoxModelObject(lastChild());

    int maxHeight = indexBox->offsetHeight();

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

    if (!maxHeight)

        maxHeight = style()->fontSize();

    int width = indexBox->offsetWidth();

    int indexWidth = 0;

    RenderObject* current = firstChild();

    while (current != lastChild()) {

        if (current->isBoxModelObject()) {

            RenderBoxModelObject* box = toRenderBoxModelObject(current);

            indexWidth += box->offsetWidth();

        }

        current = current->nextSibling();

    }

    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;

    int rootPad = static_cast<int>(gRootPadding * style()->fontSize());

    int start = tx + indexWidth + gRadicalLeftMargin + style()->paddingLeft().value() - rootPad;

    ty += style()->paddingTop().value() - rootPad;

    FloatPoint topStart(start - topStartShift, ty);

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

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

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

    info.context->save();

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

    info.context->setStrokeStyle(SolidStroke);

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

    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 RenderMathMLRoot::layout()

{

    RenderBlock::layout();

    int maxHeight = toRenderBoxModelObject(lastChild())->offsetHeight();

    RenderObject* current = lastChild()->firstChild();

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

    if (!maxHeight)

        maxHeight = style()->fontSize();

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

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

    int topStartShift = 0;

    if (maxHeight > thresholdHeight && thresholdHeight) {

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

        if (shift > 1.)

            shift = 1.;

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

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

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

    }

    // Positioning of the index

    RenderBoxModelObject* indexBox = toRenderBoxModelObject(firstChild()->firstChild());

    int indexShift = indexBox->offsetWidth() + topStartShift;

    int radicalHeight = static_cast<int>((1 - gRadicalTopLeftPointYPos) * maxHeight);

    int rootMarginTop = radicalHeight + style()->paddingBottom().value() + indexBox->offsetHeight() - (maxHeight + static_cast<int>(gRootPadding * style()->fontSize()));

    style()->setPaddingLeft(Length(indexShift, Fixed));

    if (rootMarginTop > 0)

        style()->setPaddingTop(Length(rootMarginTop + static_cast<int>(gRootPadding * style()->fontSize()), Fixed));

    setNeedsLayoutAndPrefWidthsRecalc();

    markContainingBlocksForLayout();

    RenderBlock::layout();

    indexBox->style()->setBottom(Length(radicalHeight + style()->paddingBottom().value(), Fixed));

    // Now that we've potentially changed its position, we need layout the index again.

    indexBox->setNeedsLayoutAndPrefWidthsRecalc();

    indexBox->layout();

}

}

#endif // ENABLE(MATHML)