third_party/WebKit/Source/core/layout/LayoutScrollbarTheme.cpp

/*
 * Copyright (C) 2008 Apple Inc. All Rights Reserved.
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 * modification, are permitted provided that the following conditions
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 *
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
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#include "core/layout/LayoutScrollbarTheme.h"

#include "core/layout/LayoutScrollbar.h"
#include "core/paint/ScrollbarPainter.h"
#include "platform/graphics/GraphicsContext.h"
#include "platform/graphics/paint/DrawingRecorder.h"
#include "platform/scroll/ScrollbarThemeClient.h"
#include "wtf/StdLibExtras.h"

namespace blink {

LayoutScrollbarTheme* LayoutScrollbarTheme::layoutScrollbarTheme()
{
    DEFINE_STATIC_LOCAL(LayoutScrollbarTheme, theme, ());
    return &theme;
}

void LayoutScrollbarTheme::buttonSizesAlongTrackAxis(const ScrollbarThemeClient& scrollbar, int& beforeSize, int& afterSize)
{
    IntRect firstButton = backButtonRect(scrollbar, BackButtonStartPart);
    IntRect secondButton = forwardButtonRect(scrollbar, ForwardButtonStartPart);
    IntRect thirdButton = backButtonRect(scrollbar, BackButtonEndPart);
    IntRect fourthButton = forwardButtonRect(scrollbar, ForwardButtonEndPart);
    if (scrollbar.orientation() == HorizontalScrollbar) {
        beforeSize = firstButton.width() + secondButton.width();
        afterSize = thirdButton.width() + fourthButton.width();
    } else {
        beforeSize = firstButton.height() + secondButton.height();
        afterSize = thirdButton.height() + fourthButton.height();
    }
}

bool LayoutScrollbarTheme::hasButtons(const ScrollbarThemeClient& scrollbar)
{
    int startSize;
    int endSize;
    buttonSizesAlongTrackAxis(scrollbar, startSize, endSize);
    return (startSize + endSize) <= (scrollbar.orientation() == HorizontalScrollbar ? scrollbar.width() : scrollbar.height());
}

bool LayoutScrollbarTheme::hasThumb(const ScrollbarThemeClient& scrollbar)
{
    return trackLength(scrollbar) - thumbLength(scrollbar) >= 0;
}

int LayoutScrollbarTheme::minimumThumbLength(const ScrollbarThemeClient& scrollbar)
{
    return toLayoutScrollbar(scrollbar).minimumThumbLength();
}

IntRect LayoutScrollbarTheme::backButtonRect(const ScrollbarThemeClient& scrollbar, ScrollbarPart partType, bool)
{
    return toLayoutScrollbar(scrollbar).buttonRect(partType);
}

IntRect LayoutScrollbarTheme::forwardButtonRect(const ScrollbarThemeClient& scrollbar, ScrollbarPart partType, bool)
{
    return toLayoutScrollbar(scrollbar).buttonRect(partType);
}

IntRect LayoutScrollbarTheme::trackRect(const ScrollbarThemeClient& scrollbar, bool)
{
    if (!hasButtons(scrollbar))
        return scrollbar.frameRect();

    int startLength;
    int endLength;
    buttonSizesAlongTrackAxis(scrollbar, startLength, endLength);

    return toLayoutScrollbar(scrollbar).trackRect(startLength, endLength);
}

IntRect LayoutScrollbarTheme::constrainTrackRectToTrackPieces(const ScrollbarThemeClient& scrollbar, const IntRect& rect)
{
    IntRect backRect = toLayoutScrollbar(scrollbar).trackPieceRectWithMargins(BackTrackPart, rect);
    IntRect forwardRect = toLayoutScrollbar(scrollbar).trackPieceRectWithMargins(ForwardTrackPart, rect);
    IntRect result = rect;
    if (scrollbar.orientation() == HorizontalScrollbar) {
        result.setX(backRect.x());
        result.setWidth(forwardRect.maxX() - backRect.x());
    } else {
        result.setY(backRect.y());
        result.setHeight(forwardRect.maxY() - backRect.y());
    }
    return result;
}

void LayoutScrollbarTheme::paintScrollCorner(GraphicsContext& context, const DisplayItemClient& displayItemClient, const IntRect& cornerRect)
{
    if (DrawingRecorder::useCachedDrawingIfPossible(context, displayItemClient, DisplayItem::ScrollbarCorner))
        return;

    DrawingRecorder recorder(context, displayItemClient, DisplayItem::ScrollbarCorner, cornerRect);
    // FIXME: Implement.
    context.fillRect(cornerRect, Color::white);
}

void LayoutScrollbarTheme::paintScrollbarBackground(GraphicsContext& context, const ScrollbarThemeClient& scrollbar)
{
    ScrollbarPainter(toLayoutScrollbar(scrollbar)).paintPart(context, ScrollbarBGPart, scrollbar.frameRect());
}

void LayoutScrollbarTheme::paintTrackBackground(GraphicsContext& context, const ScrollbarThemeClient& scrollbar, const IntRect& rect)
{
    ScrollbarPainter(toLayoutScrollbar(scrollbar)).paintPart(context, TrackBGPart, rect);
}

void LayoutScrollbarTheme::paintTrackPiece(GraphicsContext& context, const ScrollbarThemeClient& scrollbar, const IntRect& rect, ScrollbarPart part)
{
    ScrollbarPainter(toLayoutScrollbar(scrollbar)).paintPart(context, part, rect);
}

void LayoutScrollbarTheme::paintButton(GraphicsContext& context, const ScrollbarThemeClient& scrollbar, const IntRect& rect, ScrollbarPart part)
{
    ScrollbarPainter(toLayoutScrollbar(scrollbar)).paintPart(context, part, rect);
}

void LayoutScrollbarTheme::paintThumb(GraphicsContext& context, const ScrollbarThemeClient& scrollbar, const IntRect& rect)
{
    ScrollbarPainter(toLayoutScrollbar(scrollbar)).paintPart(context, ThumbPart, rect);
}

void LayoutScrollbarTheme::paintTickmarks(GraphicsContext& context, const ScrollbarThemeClient& scrollbar, const IntRect& rect)
{
    ScrollbarTheme::theme().paintTickmarks(context, scrollbar, rect);
}

}