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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* the features that media queries can test */
#ifndef nsMediaFeatures_h_
#define nsMediaFeatures_h_
#include "nsCSSProps.h"
class nsIAtom;
class nsPresContext;
class nsCSSValue;
struct nsMediaFeature;
typedef nsresult
(* nsMediaFeatureValueGetter)(nsPresContext* aPresContext,
const nsMediaFeature* aFeature,
nsCSSValue& aResult);
struct nsMediaFeature
{
nsIAtom **mName; // extra indirection to point to nsGkAtoms members
enum RangeType { eMinMaxAllowed, eMinMaxNotAllowed };
RangeType mRangeType;
enum ValueType {
// All value types allow eCSSUnit_Null to indicate that no value
// was given (in addition to the types listed below).
eLength, // values are such that nsCSSValue::IsLengthUnit() is true
eInteger, // values are eCSSUnit_Integer
eFloat, // values are eCSSUnit_Number
eBoolInteger,// values are eCSSUnit_Integer (0, -0, or 1 only)
eIntRatio, // values are eCSSUnit_Array of two eCSSUnit_Integer
eResolution, // values are in eCSSUnit_Inch (for dpi),
// eCSSUnit_Pixel (for dppx), or
// eCSSUnit_Centimeter (for dpcm)
eEnumerated, // values are eCSSUnit_Enumerated (uses keyword table)
eIdent // values are eCSSUnit_Ident
// Note that a number of pieces of code (both for parsing and
// for matching of valueless expressions) assume that all numeric
// value types cannot be negative. The parsing code also does
// not allow zeros in eIntRatio types.
};
ValueType mValueType;
enum RequirementFlags : uint8_t {
// Bitfield of requirements that must be satisfied in order for this
// media feature to be active.
eNoRequirements = 0,
eHasWebkitPrefix = 1 << 0, // Feature name must start w/ "-webkit-", even
// before any "min-"/"max-" qualifier.
// Feature is only supported if the pref
// "layout.css.prefixes.device-pixel-ratio-webkit" is enabled.
// (Should only be used for -webkit-device-pixel-ratio.)
eWebkitDevicePixelRatioPrefEnabled = 1 << 1
};
uint8_t mReqFlags;
union {
// In static arrays, it's the first member that's initialized. We
// need that to be void* so we can initialize both other types.
// This member should never be accessed by name.
const void* mInitializer_;
// If mValueType == eEnumerated: const int32_t*: keyword table in
// the same format as the keyword tables in nsCSSProps.
const nsCSSProps::KTableEntry* mKeywordTable;
// If mGetter == GetSystemMetric (which implies mValueType ==
// eBoolInteger): nsIAtom * const *, for the system metric.
nsIAtom * const * mMetric;
} mData;
// A function that returns the current value for this feature for a
// given presentation. If it returns eCSSUnit_Null, the feature is
// not present.
nsMediaFeatureValueGetter mGetter;
};
class nsMediaFeatures
{
public:
// Terminated with an entry whose mName is null.
static const nsMediaFeature features[];
};
#endif /* !defined(nsMediaFeatures_h_) */
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