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#include "config.h"
#include "ScrollbarThemeChromiumLinux.h"

#include "PlatformContextSkia.h"
#include "PlatformMouseEvent.h"
#include "PlatformThemeChromiumGtk.h"
#include "Scrollbar.h"
#include "TransformationMatrix.h"

namespace WebCore {

static const int scrollbarThicknessValue = 15;
static const int buttonLength = 14;

ScrollbarTheme* ScrollbarTheme::nativeTheme()
{
    static ScrollbarThemeChromiumLinux theme;
    return &theme;
}

int ScrollbarThemeChromiumLinux::scrollbarThickness(ScrollbarControlSize controlSize)
{
    return scrollbarThicknessValue;
}

static void drawVertLine(SkCanvas* canvas, int x, int y1, int y2, const SkPaint& paint)
{
    SkIRect skrect;
    skrect.set(x, y1, x + 1, y2 + 1);
    canvas->drawIRect(skrect, paint);
}

static void drawHorizLine(SkCanvas* canvas, int x1, int x2, int y, const SkPaint& paint)
{
    SkIRect skrect;
    skrect.set(x1, y, x2 + 1, y + 1);
    canvas->drawIRect(skrect, paint);
}

static void drawBox(SkCanvas* canvas, const IntRect& rect, const SkPaint& paint)
{
    const int right = rect.x() + rect.width() - 1;
    const int bottom = rect.y() + rect.height() - 1;
    drawHorizLine(canvas, rect.x(), right, rect.y(), paint);
    drawVertLine(canvas, right, rect.y(), bottom, paint);
    drawHorizLine(canvas, rect.x(), right, bottom, paint);
    drawVertLine(canvas, rect.x(), rect.y(), bottom, paint);
}

void ScrollbarThemeChromiumLinux::paintTrackPiece(GraphicsContext* gc, Scrollbar* scrollbar, const IntRect& rect, ScrollbarPart partType)
{
    SkCanvas* const canvas = gc->platformContext()->canvas();
    SkPaint paint;
    SkIRect skrect;

    skrect.set(rect.x(), rect.y(), rect.x() + rect.width(), rect.y() + rect.height());
    SkScalar trackHSV[3];
    SkColorToHSV(PlatformThemeChromiumGtk::trackColor(), trackHSV);
    paint.setColor(PlatformThemeChromiumGtk::saturateAndBrighten(trackHSV, 0, 0));
    canvas->drawIRect(skrect, paint);

    SkScalar thumbHSV[3];
    SkColorToHSV(PlatformThemeChromiumGtk::thumbInactiveColor(),
                 thumbHSV);

    paint.setColor(PlatformThemeChromiumGtk::outlineColor(trackHSV, thumbHSV));
    drawBox(canvas, rect, paint);
}

void ScrollbarThemeChromiumLinux::paintButton(GraphicsContext* gc, Scrollbar* scrollbar, const IntRect& rect, ScrollbarPart part)
{
    PlatformThemeChromiumGtk::ArrowDirection direction;
    if (scrollbar->orientation() == HorizontalScrollbar) {
        if (part == BackButtonStartPart)
            direction = PlatformThemeChromiumGtk::West;
        else
            direction = PlatformThemeChromiumGtk::East;
    } else {
        if (part == BackButtonStartPart)
            direction = PlatformThemeChromiumGtk::North;
        else
            direction = PlatformThemeChromiumGtk::South;
    }

    ControlStates states = 0;
    // Determine if the button can be pressed.
    if (((direction == PlatformThemeChromiumGtk::West || direction == PlatformThemeChromiumGtk::North) && scrollbar->currentPos())
        || (direction == PlatformThemeChromiumGtk::East || direction == PlatformThemeChromiumGtk::South) && scrollbar->currentPos() != scrollbar->maximum())
        states |= EnabledState;

    if (states & EnabledState) {
        if (part == scrollbar->pressedPart())
            states |= PressedState;
        else if (part == scrollbar->hoveredPart())
            states |= HoverState;
    }

    PlatformThemeChromiumGtk::paintArrowButton(gc, rect, direction, states);
}

void ScrollbarThemeChromiumLinux::paintThumb(GraphicsContext* gc, Scrollbar* scrollbar, const IntRect& rect)
{
    const bool hovered = scrollbar->hoveredPart() == ThumbPart;
    const int midx = rect.x() + rect.width() / 2;
    const int midy = rect.y() + rect.height() / 2;
    const bool vertical = scrollbar->orientation() == VerticalScrollbar;
    SkCanvas* const canvas = gc->platformContext()->canvas();

    SkScalar thumb[3];
    SkColorToHSV(hovered
                 ? PlatformThemeChromiumGtk::thumbActiveColor()
                 : PlatformThemeChromiumGtk::thumbInactiveColor(),
                 thumb);

    SkPaint paint;
    paint.setColor(PlatformThemeChromiumGtk::saturateAndBrighten(thumb, 0, 0.02));

    SkIRect skrect;
    if (vertical)
        skrect.set(rect.x(), rect.y(), midx + 1, rect.y() + rect.height());
    else
        skrect.set(rect.x(), rect.y(), rect.x() + rect.width(), midy + 1);

    canvas->drawIRect(skrect, paint);

    paint.setColor(PlatformThemeChromiumGtk::saturateAndBrighten(thumb, 0, -0.02));

    if (vertical)
        skrect.set(midx + 1, rect.y(), rect.x() + rect.width(), rect.y() + rect.height());
    else
        skrect.set(rect.x(), midy + 1, rect.x() + rect.width(), rect.y() + rect.height());

    canvas->drawIRect(skrect, paint);

    SkScalar track[3];
    SkColorToHSV(PlatformThemeChromiumGtk::trackColor(), track);
    paint.setColor(PlatformThemeChromiumGtk::outlineColor(track, thumb));
    drawBox(canvas, rect, paint);

    if (rect.height() > 10 && rect.width() > 10) {
        const int grippyHalfWidth = 2;
        const int interGrippyOffset = 3;
        if (vertical) {
            drawHorizLine(canvas, midx - grippyHalfWidth, midx + grippyHalfWidth, midy - interGrippyOffset, paint);
            drawHorizLine(canvas, midx - grippyHalfWidth, midx + grippyHalfWidth, midy,                     paint);
            drawHorizLine(canvas, midx - grippyHalfWidth, midx + grippyHalfWidth, midy + interGrippyOffset, paint);
        } else {
            drawVertLine(canvas, midx - interGrippyOffset, midy - grippyHalfWidth, midy + grippyHalfWidth, paint);
            drawVertLine(canvas, midx,                     midy - grippyHalfWidth, midy + grippyHalfWidth, paint);
            drawVertLine(canvas, midx + interGrippyOffset, midy - grippyHalfWidth, midy + grippyHalfWidth, paint);
        }
    }
}

bool ScrollbarThemeChromiumLinux::shouldCenterOnThumb(Scrollbar*, const PlatformMouseEvent& evt)
{
    return (evt.shiftKey() && evt.button() == LeftButton) || (evt.button() == MiddleButton);
}

IntSize ScrollbarThemeChromiumLinux::buttonSize(Scrollbar* scrollbar)
{
    if (scrollbar->orientation() == VerticalScrollbar)
        return IntSize(scrollbarThicknessValue, buttonLength);

    // HorizontalScrollbar
    return IntSize(buttonLength, scrollbarThicknessValue);
}

int ScrollbarThemeChromiumLinux::minimumThumbLength(Scrollbar* scrollbar)
{
    // This matches Firefox on Linux.
    return 2 * scrollbarThickness(scrollbar->controlSize());
}

} // namespace WebCore