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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 
37 namespace WebCore {
38 
39 class GraphicsContext;
40 class 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.
43 class Theme {
44 public:
Theme()45     Theme() { }
~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.
baselinePositionAdjustment(ControlPart)52     virtual int baselinePositionAdjustment(ControlPart) const { return 0; }
53 
54     // A method asking if the control changes its appearance when the window is inactive.
controlHasInactiveAppearance(ControlPart)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.
controlsCanHaveInactiveAppearance()59     virtual bool controlsCanHaveInactiveAppearance() const { return false; }
controlsCanHaveHoveredAppearance()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.
controlDrawsBorder(ControlPart)63     virtual bool controlDrawsBorder(ControlPart) const { return true; }
controlDrawsBackground(ControlPart)64     virtual bool controlDrawsBackground(ControlPart) const { return true; }
controlDrawsFocusOutline(ControlPart)65     virtual bool controlDrawsFocusOutline(ControlPart) const { return true; }
66 
67     // Methods for obtaining platform-specific colors.
selectionColor(ControlPart,ControlState,SelectionPart)68     virtual Color selectionColor(ControlPart, ControlState, SelectionPart) const { return Color(); }
textSearchHighlightColor()69     virtual Color textSearchHighlightColor() const { return Color(); }
70 
71     // CSS system colors and fonts
systemColor(ThemeColor)72     virtual Color systemColor(ThemeColor) const { return Color(); }
systemFont(ThemeFont,FontDescription &)73     virtual Font systemFont(ThemeFont, FontDescription&) const { return Font(); }
74 
75     // How fast the caret blinks in text fields.
caretBlinkInterval()76     virtual double caretBlinkInterval() const { return 0.5; }
77 
78     // Notification when the theme has changed
themeChanged()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.
controlFont(ControlPart,const Font & font,float)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.
controlSize(ControlPart,const Font &,const LengthSize & zoomedSize,float)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.
minimumControlSize(ControlPart,const Font &,float)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.
controlRequiresPreWhiteSpace(ControlPart)97     virtual bool controlRequiresPreWhiteSpace(ControlPart) const { return false; }
98 
99     // Method for painting a control. The rect is in zoomed coordinates.
paint(ControlPart,ControlStates,GraphicsContext *,const IntRect &,float,ScrollView *)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.
inflateControlPaintRect(ControlPart,ControlStates,IntRect &,float)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 html4.css.
110     static String defaultStyleSheet();
111 
112 private:
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.
118 Theme* platformTheme();
119 
120 } // namespace WebCore
121 
122 #endif // Theme_h
123