зеркало из https://github.com/mozilla/gecko-dev.git
98 строки
3.6 KiB
C++
98 строки
3.6 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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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 "nsCSSProps.h"
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class nsAtom;
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class nsIDocument;
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class nsCSSValue;
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class nsStaticAtom;
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struct nsMediaFeature;
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typedef void (*nsMediaFeatureValueGetter)(nsIDocument* aDocument,
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const nsMediaFeature* aFeature,
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nsCSSValue& aResult);
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struct nsMediaFeature
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{
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nsStaticAtom** 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 eCSSUnit_Pixel
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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),
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// eCSSUnit_Pixel (for dppx), 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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enum RequirementFlags : uint8_t {
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// Bitfield of requirements that must be satisfied in order for this
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// media feature to be active.
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eNoRequirements = 0,
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eHasWebkitPrefix = 1 << 0, // Feature name must start w/ "-webkit-", even
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// before any "min-"/"max-" qualifier.
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// Feature is only supported if the pref
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// "layout.css.prefixes.device-pixel-ratio-webkit" is enabled.
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// (Should only be used for -webkit-device-pixel-ratio.)
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eWebkitDevicePixelRatioPrefEnabled = 1 << 1,
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// Feature is only usable from UA sheets and chrome:// urls.
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eUserAgentAndChromeOnly = 1 << 2,
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};
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uint8_t mReqFlags;
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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 int32_t*: keyword table in
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// the same format as the keyword tables in nsCSSProps.
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const nsCSSProps::KTableEntry* mKeywordTable;
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// If mGetter == GetSystemMetric (which implies mValueType ==
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// eBoolInteger): nsAtom * const *, for the system metric.
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nsAtom * 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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{
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public:
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static void InitSystemMetrics();
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static void FreeSystemMetrics();
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static void Shutdown();
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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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