Source/core/html/canvas/CanvasStyle.cpp

/*
 * Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
 * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies)
 * Copyright (C) 2007 Alp Toker <alp@atoker.com>
 * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
 *
 * 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 "core/html/canvas/CanvasStyle.h"

#include "CSSPropertyNames.h"
#include "core/css/CSSParser.h"
#include "core/css/StylePropertySet.h"
#include "core/html/HTMLCanvasElement.h"
#include "core/html/canvas/CanvasGradient.h"
#include "core/html/canvas/CanvasPattern.h"
#include "core/platform/graphics/GraphicsContext.h"
#include "wtf/Assertions.h"
#include "wtf/PassRefPtr.h"

namespace WebCore {

enum ColorParseResult { ParsedRGBA, ParsedCurrentColor, ParsedSystemColor, ParseFailed };

static ColorParseResult parseColor(RGBA32& parsedColor, const String& colorString, Document* document = 0)
{
    if (equalIgnoringCase(colorString, "currentcolor"))
        return ParsedCurrentColor;
    if (CSSParser::parseColor(parsedColor, colorString))
        return ParsedRGBA;
    if (CSSParser::parseSystemColor(parsedColor, colorString, document))
        return ParsedSystemColor;
    return ParseFailed;
}

RGBA32 currentColor(HTMLCanvasElement* canvas)
{
    if (!canvas || !canvas->inDocument() || !canvas->inlineStyle())
        return Color::black;
    RGBA32 rgba = Color::black;
    CSSParser::parseColor(rgba, canvas->inlineStyle()->getPropertyValue(CSSPropertyColor));
    return rgba;
}

bool parseColorOrCurrentColor(RGBA32& parsedColor, const String& colorString, HTMLCanvasElement* canvas)
{
    ColorParseResult parseResult = parseColor(parsedColor, colorString, canvas ? canvas->document() : 0);
    switch (parseResult) {
    case ParsedRGBA:
    case ParsedSystemColor:
        return true;
    case ParsedCurrentColor:
        parsedColor = currentColor(canvas);
        return true;
    case ParseFailed:
        return false;
    default:
        ASSERT_NOT_REACHED();
        return false;
    }
}

CanvasStyle::CanvasStyle(Type type, float overrideAlpha)
    : m_type(type)
    , m_overrideAlpha(overrideAlpha)
{
}

CanvasStyle::CanvasStyle(RGBA32 rgba)
    : m_type(RGBA)
    , m_rgba(rgba)
{
}

CanvasStyle::CanvasStyle(float grayLevel, float alpha)
    : m_type(RGBA)
    , m_rgba(makeRGBA32FromFloats(grayLevel, grayLevel, grayLevel, alpha))
{
}

CanvasStyle::CanvasStyle(float r, float g, float b, float a)
    : m_type(RGBA)
    , m_rgba(makeRGBA32FromFloats(r, g, b, a))
{
}

CanvasStyle::CanvasStyle(float c, float m, float y, float k, float a)
    : m_type(CMYKA)
    , m_rgba(makeRGBAFromCMYKA(c, m, y, k, a))
    , m_cmyka(c, m, y, k, a)
{
}

CanvasStyle::CanvasStyle(PassRefPtr<CanvasGradient> gradient)
    : m_type(Gradient)
    , m_gradient(gradient)
{
}

CanvasStyle::CanvasStyle(PassRefPtr<CanvasPattern> pattern)
    : m_type(ImagePattern)
    , m_pattern(pattern)
{
}

PassRefPtr<CanvasStyle> CanvasStyle::createFromString(const String& color, Document* document)
{
    RGBA32 rgba;
    ColorParseResult parseResult = parseColor(rgba, color, document);
    switch (parseResult) {
    case ParsedRGBA:
    case ParsedSystemColor:
        return adoptRef(new CanvasStyle(rgba));
    case ParsedCurrentColor:
        return adoptRef(new CanvasStyle(CurrentColor));
    case ParseFailed:
        return 0;
    default:
        ASSERT_NOT_REACHED();
        return 0;
    }
}

PassRefPtr<CanvasStyle> CanvasStyle::createFromStringWithOverrideAlpha(const String& color, float alpha)
{
    RGBA32 rgba;
    ColorParseResult parseResult = parseColor(rgba, color);
    switch (parseResult) {
    case ParsedRGBA:
        return adoptRef(new CanvasStyle(colorWithOverrideAlpha(rgba, alpha)));
    case ParsedCurrentColor:
        return adoptRef(new CanvasStyle(CurrentColorWithOverrideAlpha, alpha));
    case ParseFailed:
        return 0;
    default:
        ASSERT_NOT_REACHED();
        return 0;
    }
}

PassRefPtr<CanvasStyle> CanvasStyle::createFromGradient(PassRefPtr<CanvasGradient> gradient)
{
    if (!gradient)
        return 0;
    return adoptRef(new CanvasStyle(gradient));
}
PassRefPtr<CanvasStyle> CanvasStyle::createFromPattern(PassRefPtr<CanvasPattern> pattern)
{
    if (!pattern)
        return 0;
    return adoptRef(new CanvasStyle(pattern));
}

bool CanvasStyle::isEquivalentColor(const CanvasStyle& other) const
{
    if (m_type != other.m_type)
        return false;

    switch (m_type) {
    case RGBA:
        return m_rgba == other.m_rgba;
    case CMYKA:
        return m_cmyka.c == other.m_cmyka.c
            && m_cmyka.m == other.m_cmyka.m
            && m_cmyka.y == other.m_cmyka.y
            && m_cmyka.k == other.m_cmyka.k
            && m_cmyka.a == other.m_cmyka.a;
    case Gradient:
    case ImagePattern:
    case CurrentColor:
    case CurrentColorWithOverrideAlpha:
        return false;
    }

    ASSERT_NOT_REACHED();
    return false;
}

bool CanvasStyle::isEquivalentRGBA(float r, float g, float b, float a) const
{
    if (m_type != RGBA)
        return false;

    return m_rgba == makeRGBA32FromFloats(r, g, b, a);
}

bool CanvasStyle::isEquivalentCMYKA(float c, float m, float y, float k, float a) const
{
    if (m_type != CMYKA)
        return false;

    return c == m_cmyka.c
        && m == m_cmyka.m
        && y == m_cmyka.y
        && k == m_cmyka.k
        && a == m_cmyka.a;
}

void CanvasStyle::applyStrokeColor(GraphicsContext* context)
{
    if (!context)
        return;
    switch (m_type) {
    case RGBA:
        context->setStrokeColor(m_rgba);
        break;
    case CMYKA: {
        // FIXME: Do this through platform-independent GraphicsContext API.
        // We'll need a fancier Color abstraction to support CMYKA correctly
        context->setStrokeColor(m_rgba);
        break;
    }
    case Gradient:
        context->setStrokeGradient(canvasGradient()->gradient());
        break;
    case ImagePattern:
        context->setStrokePattern(canvasPattern()->pattern());
        break;
    case CurrentColor:
    case CurrentColorWithOverrideAlpha:
        ASSERT_NOT_REACHED();
        break;
    }
}

void CanvasStyle::applyFillColor(GraphicsContext* context)
{
    if (!context)
        return;
    switch (m_type) {
    case RGBA:
        context->setFillColor(m_rgba);
        break;
    case CMYKA: {
        // FIXME: Do this through platform-independent GraphicsContext API.
        // We'll need a fancier Color abstraction to support CMYKA correctly
        context->setFillColor(m_rgba);
        break;
    }
    case Gradient:
        context->setFillGradient(canvasGradient()->gradient());
        break;
    case ImagePattern:
        context->setFillPattern(canvasPattern()->pattern());
        break;
    case CurrentColor:
    case CurrentColorWithOverrideAlpha:
        ASSERT_NOT_REACHED();
        break;
    }
}

}