flutter_flutter/engine/public/platform/WebThemeEngine.h

/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * 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.
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * 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
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef WebThemeEngine_h
#define WebThemeEngine_h

#include "WebCanvas.h"
#include "WebColor.h"
#include "WebSize.h"

namespace blink {

struct WebRect;

// FIXME: crbug.com/327471. We need to merge the Apple and non-Apple implementations.

class WebThemeEngine {
public:
    // The current state of the associated Part.
    enum State {
        StateDisabled,
        StateHover, // non-Apple
        StateNormal, // non-Apple
        StatePressed,
        StateFocused, // non-Apple
        StateReadonly, // non-Apple
        StateInactive, // Apple-specific
        StateActive, // Apple-specific
    };

    // FIXME: The next section describes stuff only used on the Apple port.
    enum Size {
        SizeRegular,
        SizeSmall,
    };

    enum ScrollbarOrientation {
        ScrollbarOrientationHorizontal,
        ScrollbarOrientationVertical,
    };

    enum ScrollbarParent {
        ScrollbarParentScrollView,
        ScrollbarParentRenderLayer,
    };

    struct ScrollbarInfo {
        ScrollbarOrientation orientation;
        ScrollbarParent parent;
        int maxValue;
        int currentValue;
        int visibleSize;
        int totalSize;
    };

    virtual void paintScrollbarThumb(WebCanvas*, State, Size, const WebRect&, const ScrollbarInfo&) { }

    // FIXME: The remaining definitions are only used on the non-Apple ports.

    // The UI part which is being accessed.
    enum Part {
        // ScrollbarTheme parts
        PartScrollbarDownArrow,
        PartScrollbarLeftArrow,
        PartScrollbarRightArrow,
        PartScrollbarUpArrow,
        PartScrollbarHorizontalThumb,
        PartScrollbarVerticalThumb,
        PartScrollbarHorizontalTrack,
        PartScrollbarVerticalTrack,

        // RenderTheme parts
        PartCheckbox,
        PartRadio,
        PartButton,
        PartMenuList,
        PartSliderTrack,
        PartSliderThumb,
        PartInnerSpinButton,
        PartProgressBar
    };


    // Extra parameters for drawing the PartScrollbarHorizontalTrack and
    // PartScrollbarVerticalTrack.
    struct ScrollbarTrackExtraParams {
        bool isBack; // Whether this is the 'back' part or the 'forward' part.

        // The bounds of the entire track, as opposed to the part being painted.
        int trackX;
        int trackY;
        int trackWidth;
        int trackHeight;
    };

    // Extra parameters for PartCheckbox, PartPushButton and PartRadio.
    struct ButtonExtraParams {
        bool checked;
        bool indeterminate; // Whether the button state is indeterminate.
        bool isDefault; // Whether the button is default button.
        bool hasBorder;
        WebColor backgroundColor;
    };

    // Extra parameters for PartMenuList
    struct MenuListExtraParams {
        bool hasBorder;
        bool hasBorderRadius;
        int arrowX;
        int arrowY;
        int arrowHeight;
        WebColor backgroundColor;
        bool fillContentArea;
    };

    // Extra parameters for PartSliderTrack and PartSliderThumb
    struct SliderExtraParams {
        bool vertical;
        bool inDrag;
    };

    // Extra parameters for PartInnerSpinButton
    struct InnerSpinButtonExtraParams {
        bool spinUp;
        bool readOnly;
    };

    // Extra parameters for PartProgressBar
    struct ProgressBarExtraParams {
        bool determinate;
        int valueRectX;
        int valueRectY;
        int valueRectWidth;
        int valueRectHeight;
    };

    union ExtraParams {
        ScrollbarTrackExtraParams scrollbarTrack;
        ButtonExtraParams button;
        MenuListExtraParams menuList;
        SliderExtraParams slider;
        InnerSpinButtonExtraParams innerSpin;
        ProgressBarExtraParams progressBar;
    };

    // Gets the size of the given theme part. For variable sized items
    // like vertical scrollbar thumbs, the width will be the required width of
    // the track while the height will be the minimum height.
    virtual WebSize getSize(Part) { return WebSize(); }
    // Paint the given the given theme part.
    virtual void paint(WebCanvas*, Part, State, const WebRect&, const ExtraParams*) { }
};

} // namespace blink

#endif