1/*
2 * Copyright (C) 2008 Apple Inc. All Rights Reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef Theme_h
27#define Theme_h
28
29#include "Color.h"
30#include "Font.h"
31#include "IntRect.h"
32#include "LengthBox.h"
33#include "LengthSize.h"
34#include "PlatformString.h"
35#include "ThemeTypes.h"
36
37namespace WebCore {
38
39class GraphicsContext;
40class ScrollView;
41
42// Unlike other platform classes, Theme does extensively use virtual functions.  This design allows a platform to switch between multiple themes at runtime.
43class Theme {
44public:
45    Theme() { }
46    virtual ~Theme() { }
47
48    // A method to obtain the baseline position adjustment for a "leaf" control.  This will only be used if a baseline
49    // position cannot be determined by examining child content. Checkboxes and radio buttons are examples of
50    // controls that need to do this.  The adjustment is an offset that adds to the baseline, e.g., marginTop() + height() + |offset|.
51    // The offset is not zoomed.
52    virtual int baselinePositionAdjustment(ControlPart) const { return 0; }
53
54    // A method asking if the control changes its appearance when the window is inactive.
55    virtual bool controlHasInactiveAppearance(ControlPart) const { return false; }
56
57    // General methods for whether or not any of the controls in the theme change appearance when the window is inactive or
58    // when hovered over.
59    virtual bool controlsCanHaveInactiveAppearance() const { return false; }
60    virtual bool controlsCanHaveHoveredAppearance() const { return false; }
61
62    // Used by RenderTheme::isControlStyled to figure out if the native look and feel should be turned off.
63    virtual bool controlDrawsBorder(ControlPart) const { return true; }
64    virtual bool controlDrawsBackground(ControlPart) const { return true; }
65    virtual bool controlDrawsFocusOutline(ControlPart) const { return true; }
66
67    // Methods for obtaining platform-specific colors.
68    virtual Color selectionColor(ControlPart, ControlState, SelectionPart) const { return Color(); }
69    virtual Color textSearchHighlightColor() const { return Color(); }
70
71    // CSS system colors and fonts
72    virtual Color systemColor(ThemeColor) const { return Color(); }
73    virtual Font systemFont(ThemeFont, FontDescription&) const { return Font(); }
74
75    // How fast the caret blinks in text fields.
76    virtual double caretBlinkInterval() const { return 0.5; }
77
78    // Notification when the theme has changed
79    virtual void themeChanged() { }
80
81    // Methods used to adjust the RenderStyles of controls.
82
83    // The font description result should have a zoomed font size.
84    virtual FontDescription controlFont(ControlPart, const Font& font, float /*zoomFactor*/) const { return font.fontDescription(); }
85
86    // The size here is in zoomed coordinates already.  If a new size is returned, it also needs to be in zoomed coordinates.
87    virtual LengthSize controlSize(ControlPart, const Font&, const LengthSize& zoomedSize, float /*zoomFactor*/) const { return zoomedSize; }
88
89    // Returns the minimum size for a control in zoomed coordinates.
90    virtual LengthSize minimumControlSize(ControlPart, const Font&, float /*zoomFactor*/) const { return LengthSize(Length(0, Fixed), Length(0, Fixed)); }
91
92    // Allows the theme to modify the existing padding/border.
93    virtual LengthBox controlPadding(ControlPart, const Font&, const LengthBox& zoomedBox, float zoomFactor) const;
94    virtual LengthBox controlBorder(ControlPart, const Font&, const LengthBox& zoomedBox, float zoomFactor) const;
95
96    // Whether or not whitespace: pre should be forced on always.
97    virtual bool controlRequiresPreWhiteSpace(ControlPart) const { return false; }
98
99    // Method for painting a control. The rect is in zoomed coordinates.
100    virtual void paint(ControlPart, ControlStates, GraphicsContext*, const IntRect& /*zoomedRect*/, float /*zoomFactor*/, ScrollView*) const { }
101
102    // Some controls may spill out of their containers (e.g., the check on an OS X checkbox).  When these controls repaint,
103    // the theme needs to communicate this inflated rect to the engine so that it can invalidate the whole control.
104    // The rect passed in is in zoomed coordinates, so the inflation should take that into account and make sure the inflation
105    // amount is also scaled by the zoomFactor.
106    virtual void inflateControlPaintRect(ControlPart, ControlStates, IntRect& /*zoomedRect*/, float /*zoomFactor*/) const { }
107
108    // This method is called once, from RenderTheme::adjustDefaultStyleSheet(), to let each platform adjust
109    // the default CSS rules in html.css.
110    static String defaultStyleSheet();
111
112private:
113    mutable Color m_activeSelectionColor;
114    mutable Color m_inactiveSelectionColor;
115};
116
117// Function to obtain the theme.  This is implemented in the platform-specific subclasses.
118Theme* platformTheme();
119
120} // namespace WebCore
121
122#endif // Theme_h
123