third_party/WebKit/Source/platform/Theme.h

   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 "platform/LengthBox.h"
  30 #include "platform/LengthSize.h"
  31 #include "platform/PlatformExport.h"
  32 #include "platform/ThemeTypes.h"
  33 #include "platform/fonts/FontDescription.h"
  34 #include "platform/geometry/IntRect.h"
  35 #include "platform/graphics/Color.h"
  36 #include "wtf/Forward.h"
  37
  38 namespace blink {
  39
  40 class GraphicsContext;
  41 class ScrollableArea;
  42
  43 // Unlike other platform classes, Theme does extensively use virtual functions.  This design allows a platform to switch between multiple themes at runtime.
  44 class PLATFORM_EXPORT Theme {
  45 public:
  46     Theme() { }
  47     virtual ~Theme() { }
  48
  49     // A method to obtain the baseline position adjustment for a "leaf" control.  This will only be used if a baseline
  50     // position cannot be determined by examining child content. Checkboxes and radio buttons are examples of
  51     // controls that need to do this.  The adjustment is an offset that adds to the baseline, e.g., marginTop() + height() + |offset|.
  52     // The offset is not zoomed.
  53     virtual int baselinePositionAdjustment(ControlPart) const { return 0; }
  54
  55     // A method asking if the control changes its appearance when the window is inactive.
  56     virtual bool controlHasInactiveAppearance(ControlPart) const { return false; }
  57
  58     // General methods for whether or not any of the controls in the theme change appearance when the window is inactive or
  59     // when hovered over.
  60     virtual bool controlsCanHaveInactiveAppearance() const { return false; }
  61     virtual bool controlsCanHaveHoveredAppearance() const { return false; }
  62
  63     // Used by LayoutTheme::isControlStyled to figure out if the native look and feel should be turned off.
  64     virtual bool controlDrawsBorder(ControlPart) const { return true; }
  65     virtual bool controlDrawsBackground(ControlPart) const { return true; }
  66     virtual bool controlDrawsFocusOutline(ControlPart) const { return true; }
  67
  68     // Methods for obtaining platform-specific colors.
  69     virtual Color selectionColor(ControlPart, ControlState, SelectionPart) const { return Color(); }
  70     virtual Color textSearchHighlightColor() const { return Color(); }
  71
  72     // CSS system colors and fonts
  73     virtual Color systemColor(ThemeColor) const { return Color(); }
  74
  75     // How fast the caret blinks in text fields.
  76     virtual double caretBlinkInterval() const { return 0.5; }
  77
  78     // Methods used to adjust the ComputedStyles of controls.
  79
  80     // The font description result should have a zoomed font size.
  81     virtual FontDescription controlFont(ControlPart, const FontDescription& fontDescription, float /*zoomFactor*/) const { return fontDescription; }
  82
  83     // The size here is in zoomed coordinates already.  If a new size is returned, it also needs to be in zoomed coordinates.
  84     virtual LengthSize controlSize(ControlPart, const FontDescription&, const LengthSize& zoomedSize, float /*zoomFactor*/) const { return zoomedSize; }
  85
  86     // Returns the minimum size for a control in zoomed coordinates.
  87     virtual LengthSize minimumControlSize(ControlPart, const FontDescription&, float /*zoomFactor*/) const { return LengthSize(Length(0, Fixed), Length(0, Fixed)); }
  88
  89     // Allows the theme to modify the existing padding/border.
  90     virtual LengthBox controlPadding(ControlPart, const FontDescription&, const LengthBox& zoomedBox, float zoomFactor) const;
  91     virtual LengthBox controlBorder(ControlPart, const FontDescription&, const LengthBox& zoomedBox, float zoomFactor) const;
  92
  93     // Whether or not whitespace: pre should be forced on always.
  94     virtual bool controlRequiresPreWhiteSpace(ControlPart) const { return false; }
  95
  96     // Method for painting a control. The rect is in zoomed coordinates.
  97     virtual void paint(ControlPart, ControlStates, GraphicsContext*, const IntRect& /*zoomedRect*/, float /*zoomFactor*/, ScrollableArea*) const { }
  98
  99     // Add visual overflow (e.g., the check on an OS X checkbox). The rect passed in is in zoomed coordinates so
 100     // the inflation should take that into account and make sure the inflation amount is also scaled by the zoomFactor.
 101     virtual void addVisualOverflow(ControlPart, ControlStates, float zoomFactor, IntRect& borderBox) const { }
 102
 103 private:
 104     mutable Color m_activeSelectionColor;
 105     mutable Color m_inactiveSelectionColor;
 106 };
 107
 108 PLATFORM_EXPORT Theme* platformTheme();
 109
 110 } // namespace blink
 111
 112 #endif // Theme_h