9c073c74f4
This patch implements support for the width/height properties on MathML elements [1]. The general algorithm from the spec is as follows: (1) The outcome of the math layout is a "math content box". (2) The content box sets its size from computed width/height values. If auto, it's the one of the "math content box". This patch ignores percentage values for now [2] [3]. (3) math content box is shifted so that its inline-start and top edges aligns with the ones of the content box. There are exceptions elements like mfrac and munder/mover/munderover which instead horizontally center the math content box within the content box. For baseline adjustment, we follow what Chromium does, see [4]. (4) Padding+border are added around the content box. Note that we ignore the box-sizing property for now [5]. The patch essentially tweaks the various MathML layout algorithms to perform steps (3) and (4) before the calls to GetBorderPaddingForPlace and InflateReflowAndBoundingMetrics. [1] https://w3c.github.io/mathml-core/#layout-algorithms [2] https://github.com/w3c/mathml-core/issues/76 [3] https://github.com/w3c/mathml-core/issues/77 [4] https://github.com/w3c/mathml-core/issues/259 [5] https://github.com/w3c/mathml-core/issues/257 Below is more information about test coverage: - width-height-001: Verify that width, height, inline-size and block-size properties sets the size of the content box. This test used to verify they are ignored, this patch fixes the `<meta name="assert">` tag. It also adds a test for the case the specified size is smaller than the content (we force non empty descendants to make sure this content is large enough) and to verify the width is used for the preferred width. - width-height-002, width-height-003: These are reftests visually checking offsets of the math content box within a larger content box (specified by width/height) for the mtext, mrow, mpadded, mfrac, msqrt, mroot, in LTR/RTL modes. In particular they allow to verify some painted elements like fraction bar and radical symbols. - width-height-004: This test more directly checks that the math content box is horizontally centered within a larger content box for munder, mover, munderover and mfrac. This patch extends the test to cover the case when the math content box is wider (i.e. overflowing outside the content box) and removes unnecessary specified height. - width-height-005: New test for other layout algorithm that don't center the math content box, checking inline-start edges of children when a width is specified. We check both LTR/RTL modes and wider/narrower content boxes. - width-height-006: Same but checking the top edges for larger/smaller height and verifying that baseline is perserved. Differential Revision: https://phabricator.services.mozilla.com/D221436
91 lines
3.0 KiB
C++
91 lines
3.0 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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#ifndef nsMathMLmunderoverFrame_h___
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#define nsMathMLmunderoverFrame_h___
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#include "mozilla/Attributes.h"
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#include "nsIReflowCallback.h"
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#include "nsMathMLContainerFrame.h"
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namespace mozilla {
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class PresShell;
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} // namespace mozilla
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//
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// <munderover> -- attach an underscript-overscript pair to a base
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//
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class nsMathMLmunderoverFrame final : public nsMathMLContainerFrame,
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public nsIReflowCallback {
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public:
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NS_DECL_FRAMEARENA_HELPERS(nsMathMLmunderoverFrame)
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friend nsIFrame* NS_NewMathMLmunderoverFrame(mozilla::PresShell* aPresShell,
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ComputedStyle* aStyle);
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nsresult Place(DrawTarget* aDrawTarget, const PlaceFlags& aFlags,
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ReflowOutput& aDesiredSize) override;
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NS_IMETHOD InheritAutomaticData(nsIFrame* aParent) override;
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NS_IMETHOD TransmitAutomaticData() override;
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NS_IMETHOD UpdatePresentationData(uint32_t aFlagsValues,
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uint32_t aFlagsToUpdate) override;
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void Destroy(DestroyContext&) override;
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nsresult AttributeChanged(int32_t aNameSpaceID, nsAtom* aAttribute,
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int32_t aModType) override;
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uint8_t ScriptIncrement(nsIFrame* aFrame) override;
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// nsIReflowCallback.
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bool ReflowFinished() override;
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void ReflowCallbackCanceled() override;
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protected:
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explicit nsMathMLmunderoverFrame(ComputedStyle* aStyle,
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nsPresContext* aPresContext)
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: nsMathMLContainerFrame(aStyle, aPresContext, kClassID),
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mIncrementUnder(false),
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mIncrementOver(false) {}
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virtual ~nsMathMLmunderoverFrame();
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private:
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bool IsMathContentBoxHorizontallyCentered() const final;
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// Helper to set the "increment script level" flag on the element belonging
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// to a child frame given by aChildIndex.
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//
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// When this flag is set, the style system will increment the scriptlevel for
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// the child element. This is needed for situations where the style system
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// cannot itself determine the scriptlevel (mfrac, munder, mover, munderover).
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//
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// This should be called during reflow.
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//
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// We set the flag and if it changed, we request appropriate restyling and
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// also queue a post-reflow callback to ensure that restyle and reflow happens
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// immediately after the current reflow.
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void SetIncrementScriptLevel(uint32_t aChildIndex, bool aIncrement);
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void SetPendingPostReflowIncrementScriptLevel();
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bool mIncrementUnder;
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bool mIncrementOver;
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struct SetIncrementScriptLevelCommand {
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uint32_t mChildIndex;
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bool mDoIncrement;
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};
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nsTArray<SetIncrementScriptLevelCommand>
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mPostReflowIncrementScriptLevelCommands;
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};
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#endif /* nsMathMLmunderoverFrame_h___ */
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