Source code

Revision control

Other Tools

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 */
/* constants used throughout the Layout module */
#ifndef LayoutConstants_h___
#define LayoutConstants_h___
#include "mozilla/EnumSet.h"
#include "nsSize.h" // for NS_MAXSIZE
#include "Units.h"
* Constant used to indicate an unconstrained size.
* NOTE: The constants defined in this file are semantically used as symbolic
* values, so user should not depend on the underlying numeric values. If
* new specific use cases arise, define a new constant here.
// NS_AUTOOFFSET is assumed to have the same value as NS_UNCONSTRAINEDSIZE.
// +1 is to avoid clamped huge margin values being processed as auto margins
namespace mozilla {
* Bit-flags to pass to various functions that compute sizes like
* nsIFrame::ComputeSize().
enum class ComputeSizeFlag : uint8_t {
* Set if the frame is in a context where non-replaced blocks should
* shrink-wrap (e.g., it's floating, absolutely positioned, or
* inline-block).
* Set if we'd like to compute our 'auto' bsize, regardless of our actual
* corresponding computed value. (e.g. to get an intrinsic bsize for flex
* items when resolving automatic minimum size in the main axis during flexbox
* layout.)
* Indicates that we should clamp the margin-box min-size to the given CB
* size. This is used for implementing the grid area clamping here:
IClampMarginBoxMinSize, // clamp in our inline axis
BClampMarginBoxMinSize, // clamp in our block axis
* The frame is stretching (per CSS Box Alignment) and doesn't have an
* Automatic Minimum Size in the indicated axis.
* (may be used for both flex/grid items, but currently only used for Grid)
IApplyAutoMinSize, // only has an effect when eShrinkWrap is false
using ComputeSizeFlags = mozilla::EnumSet<ComputeSizeFlag>;
* The fallback size of width is 300px and the aspect-ratio is 2:1, based on
* CSS2 section 10.3.2 and CSS Sizing Level 3 section 5.1:
inline constexpr CSSIntCoord kFallbackIntrinsicWidthInPixels(300);
inline constexpr CSSIntCoord kFallbackIntrinsicHeightInPixels(150);
inline constexpr CSSIntSize kFallbackIntrinsicSizeInPixels(
kFallbackIntrinsicWidthInPixels, kFallbackIntrinsicHeightInPixels);
inline constexpr nscoord kFallbackIntrinsicWidth =
kFallbackIntrinsicWidthInPixels * AppUnitsPerCSSPixel();
inline constexpr nscoord kFallbackIntrinsicHeight =
kFallbackIntrinsicHeightInPixels * AppUnitsPerCSSPixel();
inline constexpr nsSize kFallbackIntrinsicSize(kFallbackIntrinsicWidth,
* This is used in some nsLayoutUtils functions.
* Declared here so that fewer files need to include nsLayoutUtils.h.
enum class IntrinsicISizeType { MinISize, PrefISize };
} // namespace mozilla
#endif // LayoutConstants_h___