root/trunk/WebCore/html/CanvasRenderingContext2D.cpp

/*
 * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 * Copyright (C) 2007 Trolltech ASA
 * Copyright (C) 2007 Alp Toker <alp@atoker.com>
 *
 * 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 APPLE COMPUTER, INC. ``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 APPLE COMPUTER, INC. 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"
#include "CanvasRenderingContext2D.h"

#include "AffineTransform.h"
#include "CSSParser.h"
#include "CachedImage.h"
#include "CanvasGradient.h"
#include "CanvasPattern.h"
#include "CanvasPixelArray.h"
#include "CanvasStyle.h"
#include "Document.h"
#include "ExceptionCode.h"
#include "FloatConversion.h"
#include "Frame.h"
#include "GraphicsContext.h"
#include "HTMLCanvasElement.h"
#include "HTMLImageElement.h"
#include "HTMLNames.h"
#include "ImageBuffer.h"
#include "ImageData.h"
#include "KURL.h"
#include "NotImplemented.h"
#include "Page.h"
#include "RenderHTMLCanvas.h"
#include "SecurityOrigin.h"
#include "Settings.h"
#include <kjs/interpreter.h>
#include <stdio.h>
#include <wtf/MathExtras.h>

#if PLATFORM(QT)
#include <QPainter>
#include <QPixmap>
#include <QPainterPath>
#elif PLATFORM(CAIRO)
#include "CairoPath.h"
#include <cairo.h>
#endif

namespace WebCore {

using namespace HTMLNames;

CanvasRenderingContext2D::CanvasRenderingContext2D(HTMLCanvasElement* canvas)
    : m_canvas(canvas)
    , m_stateStack(1)
{
}

void CanvasRenderingContext2D::ref()
{
    m_canvas->ref();
}

void CanvasRenderingContext2D::deref()
{
    m_canvas->deref(); 
}

void CanvasRenderingContext2D::reset()
{
    m_stateStack.resize(1);
    m_stateStack.first() = State();
}

CanvasRenderingContext2D::State::State()
    : m_strokeStyle(CanvasStyle::create("black"))
    , m_fillStyle(CanvasStyle::create("black"))
    , m_lineWidth(1)
    , m_lineCap(ButtCap)
    , m_lineJoin(MiterJoin)
    , m_miterLimit(10)
    , m_shadowBlur(0)
    , m_shadowColor("black")
    , m_globalAlpha(1)
    , m_globalComposite(CompositeSourceOver)
    , m_appliedStrokePattern(false)
    , m_appliedFillPattern(false)
{
}

void CanvasRenderingContext2D::save()
{
    ASSERT(m_stateStack.size() >= 1);
    m_stateStack.append(state());
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
    c->save();
}

void CanvasRenderingContext2D::restore()
{
    ASSERT(m_stateStack.size() >= 1);
    if (m_stateStack.size() <= 1)
        return;
    m_path.transform(state().m_transform);
    m_stateStack.removeLast();
    m_path.transform(state().m_transform.inverse());
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
    c->restore();
}

CanvasStyle* CanvasRenderingContext2D::strokeStyle() const
{
    return state().m_strokeStyle.get();
}

void CanvasRenderingContext2D::setStrokeStyle(PassRefPtr<CanvasStyle> style)
{
    if (!style)
        return;

    if (m_canvas->originClean()) {
        if (CanvasPattern* pattern = style->pattern()) {
            if (!pattern->originClean())
                m_canvas->setOriginTainted();
        }
    }

    state().m_strokeStyle = style;
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
    state().m_strokeStyle->applyStrokeColor(c);
    state().m_appliedStrokePattern = false;
}

CanvasStyle* CanvasRenderingContext2D::fillStyle() const
{
    return state().m_fillStyle.get();
}

void CanvasRenderingContext2D::setFillStyle(PassRefPtr<CanvasStyle> style)
{
    if (!style)
        return;
 
    if (m_canvas->originClean()) {
        if (CanvasPattern* pattern = style->pattern()) {
            if (!pattern->originClean())
                m_canvas->setOriginTainted();
        }
    }

    state().m_fillStyle = style;
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
#if PLATFORM(CAIRO)
    // FIXME: hack to reduce code duplication in CanvasStyle.cpp
    state().m_fillStyle->applyStrokeColor(c);
#else
    state().m_fillStyle->applyFillColor(c);
#endif
    state().m_appliedFillPattern = false;
}

float CanvasRenderingContext2D::lineWidth() const
{
    return state().m_lineWidth;
}

void CanvasRenderingContext2D::setLineWidth(float width)
{
    if (!(width > 0))
        return;
    state().m_lineWidth = width;
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
    c->setStrokeThickness(width);
}

String CanvasRenderingContext2D::lineCap() const
{
    return lineCapName(state().m_lineCap);
}

void CanvasRenderingContext2D::setLineCap(const String& s)
{
    LineCap cap;
    if (!parseLineCap(s, cap))
        return;
    state().m_lineCap = cap;
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
    c->setLineCap(cap);
}

String CanvasRenderingContext2D::lineJoin() const
{
    return lineJoinName(state().m_lineJoin);
}

void CanvasRenderingContext2D::setLineJoin(const String& s)
{
    LineJoin join;
    if (!parseLineJoin(s, join))
        return;
    state().m_lineJoin = join;
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
    c->setLineJoin(join);
}

float CanvasRenderingContext2D::miterLimit() const
{
    return state().m_miterLimit;
}

void CanvasRenderingContext2D::setMiterLimit(float limit)
{
    if (!(limit > 0))
        return;
    state().m_miterLimit = limit;
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
    c->setMiterLimit(limit);
}

float CanvasRenderingContext2D::shadowOffsetX() const
{
    return state().m_shadowOffset.width();
}

void CanvasRenderingContext2D::setShadowOffsetX(float x)
{
    state().m_shadowOffset.setWidth(x);
    applyShadow();
}

float CanvasRenderingContext2D::shadowOffsetY() const
{
    return state().m_shadowOffset.height();
}

void CanvasRenderingContext2D::setShadowOffsetY(float y)
{
    state().m_shadowOffset.setHeight(y);
    applyShadow();
}

float CanvasRenderingContext2D::shadowBlur() const
{
    return state().m_shadowBlur;
}

void CanvasRenderingContext2D::setShadowBlur(float blur)
{
    state().m_shadowBlur = blur;
    applyShadow();
}

String CanvasRenderingContext2D::shadowColor() const
{
    // FIXME: What should this return if you called setShadow with a non-string color?
    return state().m_shadowColor;
}

void CanvasRenderingContext2D::setShadowColor(const String& color)
{
    state().m_shadowColor = color;
    applyShadow();
}

float CanvasRenderingContext2D::globalAlpha() const
{
    return state().m_globalAlpha;
}

void CanvasRenderingContext2D::setGlobalAlpha(float alpha)
{
    if (!(alpha >= 0 && alpha <= 1))
        return;
    state().m_globalAlpha = alpha;
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
    c->setAlpha(alpha);
}

String CanvasRenderingContext2D::globalCompositeOperation() const
{
    return compositeOperatorName(state().m_globalComposite);
}

void CanvasRenderingContext2D::setGlobalCompositeOperation(const String& operation)
{
    CompositeOperator op;
    if (!parseCompositeOperator(operation, op))
        return;
    state().m_globalComposite = op;
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
    c->setCompositeOperation(op);
}

void CanvasRenderingContext2D::scale(float sx, float sy)
{
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
    c->scale(FloatSize(sx, sy));
    state().m_transform.scale(sx, sy);
    m_path.transform(AffineTransform().scale(1.0/sx, 1.0/sy));
}

void CanvasRenderingContext2D::rotate(float angleInRadians)
{
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
    c->rotate(angleInRadians);
    state().m_transform.rotate(angleInRadians / piDouble * 180.0);
    m_path.transform(AffineTransform().rotate(-angleInRadians / piDouble * 180.0));
}

void CanvasRenderingContext2D::translate(float tx, float ty)
{
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
    c->translate(tx, ty);
    state().m_transform.translate(tx, ty);
    m_path.transform(AffineTransform().translate(-tx, -ty));
}

void CanvasRenderingContext2D::transform(float m11, float m12, float m21, float m22, float dx, float dy)
{
    GraphicsContext* c = drawingContext();
    if (!c)
        return;
    
    // HTML5 3.14.11.1 -- ignore any calls that pass non-finite numbers
    if (!isfinite(m11) | !isfinite(m21) | !isfinite(dx) | 
        !isfinite(m12) | !isfinite(m22) | !isfinite(dy))
        return;
    AffineTransform transform(m11, m12, m21, m22, dx, dy);
    c->concatCTM(transform);
    state().m_transform.multiply(transform);
    m_path.transform(transform.inverse());
}

void CanvasRenderingContext2D::setStrokeColor(const String& color)
{
    setStrokeStyle(CanvasStyle::create(color));
}

void CanvasRenderingContext2D::setStrokeColor(float grayLevel)
{
    setStrokeStyle(CanvasStyle::create(grayLevel, 1));
}

void CanvasRenderingContext2D::setStrokeColor(const String& color, float alpha)
{
    setStrokeStyle(CanvasStyle::create(color, alpha));
}

void CanvasRenderingContext2D::setStrokeColor(float grayLevel, float alpha)
{
    setStrokeStyle(CanvasStyle::create(grayLevel, alpha));
}

void CanvasRenderingContext2D::setStrokeColor(float r, float g, float b, float a)
{
    setStrokeStyle(CanvasStyle::create(r, g, b, a));
}

void CanvasRenderingContext2D::setStrokeColor(float c, float m, float y, float k, float a)
{
    setStrokeStyle(CanvasStyle::create(c, m, y, k, a));
}

void CanvasRenderingContext2D::setFillColor(const String& color)
{
    setFillStyle(CanvasStyle::create(color));
}

void CanvasRenderingContext2D::setFillColor(float grayLevel)
{
    setFillStyle(CanvasStyle::create(grayLevel, 1));
}

void CanvasRenderingContext2D::setFillColor(const String& color, float alpha)
{
    setFillStyle(CanvasStyle::create(color, 1));
}

void CanvasRenderingContext2D::setFillColor(float grayLevel, float alpha)
{
    setFillStyle(CanvasStyle::create(grayLevel, alpha));
}

void CanvasRenderingContext2D::setFillColor(float r, float g, float b, float a)
{
    setFillStyle(CanvasStyle::create(r, g, b, a));
}

void CanvasRenderingContext2D::setFillColor(float c, float m, float y, float k, float a)
{
    setFillStyle(CanvasStyle::create(c, m, y, k, a));
}

void CanvasRenderingContext2D::beginPath()
{
    m_path.clear();
}

void CanvasRenderingContext2D::closePath()
{
    m_path.closeSubpath();
}

void CanvasRenderingContext2D::moveTo(float x, float y)
{
    if (!isfinite(x) | !isfinite(y))
        return;
    m_path.moveTo(FloatPoint(x, y));
}

void CanvasRenderingContext2D::lineTo(float x, float y)
{
    if (!isfinite(x) | !isfinite(y))
        return;
    m_path.addLineTo(FloatPoint(x, y));
}

void CanvasRenderingContext2D::quadraticCurveTo(float cpx, float cpy, float x, float y)
{
    if (!isfinite(cpx) | !isfinite(cpy) | !isfinite(x) | !isfinite(y))
        return;
    m_path.addQuadCurveTo(FloatPoint(cpx, cpy), FloatPoint(x, y));
}

void CanvasRenderingContext2D::bezierCurveTo(float cp1x, float cp1y, float cp2x, float cp2y, float x, float y)
{
    if (!isfinite(cp1x) | !isfinite(cp1y) | !isfinite(cp2x) | !isfinite(cp2y) | !isfinite(x) | !isfinite(y))
        return;
    m_path.addBezierCurveTo(FloatPoint(cp1x, cp1y), FloatPoint(cp2x, cp2y), FloatPoint(x, y));
}

void CanvasRenderingContext2D::arcTo(float x0, float y0, float x1, float y1, float r, ExceptionCode& ec)
{
    ec = 0;
    if (!isfinite(x0) | !isfinite(y0) | !isfinite(x1) | !isfinite(y1) | !isfinite(r))
        return;
    
    if (r < 0) {
        ec = INDEX_SIZE_ERR;
        return;
    }
    
    m_path.addArcTo(FloatPoint(x0, y0), FloatPoint(x1, y1), r);
}

void CanvasRenderingContext2D::arc(float x, float y, float r, float sa, float ea, bool anticlockwise, ExceptionCode& ec)
{
    ec = 0;
    if (!isfinite(x) | !isfinite(y) | !isfinite(r) | !isfinite(sa) | !isfinite(ea))
        return;
    
    if (r < 0) {
        ec = INDEX_SIZE_ERR;
        return;
    }
    
    m_path.addArc(FloatPoint(x, y), r, sa, ea, anticlockwise);
}
    
static bool validateRectForCanvas(float& x, float& y, float& width, float& height)
{
    if (!isfinite(x) | !isfinite(y) | !isfinite(width) | !isfinite(height))
        return false;
    
    if (width < 0) {
        width = -width;
        x -= width;
    }
    
    if (height < 0) {
        height = -height;
        y -= height;
    }
    
    return true;
}

void CanvasRenderingContext2D::rect(float x, float y, float width, float height)
{
    if (!validateRectForCanvas(x, y, width, height))
        return;
        
    m_path.addRect(FloatRect(x, y, width, height));
}

#if ENABLE(DASHBOARD_SUPPORT)
void CanvasRenderingContext2D::clearPathForDashboardBackwardCompatibilityMode()
{
    if (Settings* settings = m_canvas->document()->settings())
        if (settings->usesDashboardBackwardCompatibilityMode())
            m_path.clear();
}
#endif

void CanvasRenderingContext2D::fill()
{
    GraphicsContext* c = drawingContext();
    if (!c)
        return;

    c->beginPath();
    c->addPath(m_path);
    if (!m_path.isEmpty())
        willDraw(m_path.boundingRect());

#if PLATFORM(CG)
    if (state().m_fillStyle->canvasGradient()) {
        // Shading works on the entire clip region, so convert the current path to a clip.
        c->save();
        CGContextClip(c->platformContext());
        CGContextDrawShading