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74 lines
2.8 KiB
C++
74 lines
2.8 KiB
C++
/* vim: set shiftwidth=4 tabstop=8 autoindent cindent expandtab: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* the features that media queries can test */
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#ifndef nsMediaFeatures_h_
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#define nsMediaFeatures_h_
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#include "nscore.h"
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class nsIAtom;
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class nsPresContext;
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class nsCSSValue;
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struct nsMediaFeature;
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typedef nsresult
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(* nsMediaFeatureValueGetter)(nsPresContext* aPresContext,
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const nsMediaFeature* aFeature,
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nsCSSValue& aResult);
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struct nsMediaFeature {
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nsIAtom **mName; // extra indirection to point to nsGkAtoms members
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enum RangeType { eMinMaxAllowed, eMinMaxNotAllowed };
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RangeType mRangeType;
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enum ValueType {
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// All value types allow eCSSUnit_Null to indicate that no value
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// was given (in addition to the types listed below).
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eLength, // values are such that nsCSSValue::IsLengthUnit() is true
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eInteger, // values are eCSSUnit_Integer
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eFloat, // values are eCSSUnit_Number
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eBoolInteger,// values are eCSSUnit_Integer (0, -0, or 1 only)
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eIntRatio, // values are eCSSUnit_Array of two eCSSUnit_Integer
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eResolution, // values are in eCSSUnit_Inch (for dpi) or
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// eCSSUnit_Centimeter (for dpcm)
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eEnumerated, // values are eCSSUnit_Enumerated (uses keyword table)
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eIdent // values are eCSSUnit_Ident
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// Note that a number of pieces of code (both for parsing and
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// for matching of valueless expressions) assume that all numeric
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// value types cannot be negative. The parsing code also does
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// not allow zeros in eIntRatio types.
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};
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ValueType mValueType;
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union {
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// In static arrays, it's the first member that's initialized. We
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// need that to be void* so we can initialize both other types.
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// This member should never be accessed by name.
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const void* mInitializer_;
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// If mValueType == eEnumerated: const PRInt32*: keyword table in
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// the same format as the keyword tables in nsCSSProps.
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const PRInt32* mKeywordTable;
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// If mGetter == GetSystemMetric (which implies mValueType ==
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// eBoolInteger): nsIAtom * const *, for the system metric.
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nsIAtom * const * mMetric;
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} mData;
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// A function that returns the current value for this feature for a
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// given presentation. If it returns eCSSUnit_Null, the feature is
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// not present.
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nsMediaFeatureValueGetter mGetter;
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};
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class nsMediaFeatures {
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public:
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// Terminated with an entry whose mName is null.
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static const nsMediaFeature features[];
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};
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#endif /* !defined(nsMediaFeatures_h_) */
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