gecko-dev/layout/xul/SimpleXULLeafFrame.h
Emilio Cobos Álvarez 38b10eafda Bug 1824236 - Stop using XUL layout for scrollbars. r=jwatt
This rewrites scrollbar layout to work with regular reflow rather than
box layout.

Overall it's about the same amount of code (mostly because
nsScrollbarFrame::Reflow is sorta hand-rolled), but it cleans up a bit
and it is progress towards removing XUL layout altogether, without
getting into much deeper refactoring.

This also blocks some other performance improvements and refactorings I
want to make in this code.

We make some assumptions to simplify the code that to some extent were
made already before, both explicitly and by virtue of using XUL layout.

In particular, we assume that scrollbar / slider / thumb has no border or
padding and that the writing-mode is horizontal ltr.

Differential Revision: https://phabricator.services.mozilla.com/D173489
2023-03-27 20:54:53 +00:00

47 lines
1.7 KiB
C++

/* -*- 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 http://mozilla.org/MPL/2.0/. */
// A simple frame class for XUL frames that are leafs on the tree but need
// background / border painting, and for some reason or another need special
// code (like event handling code) which we haven't ported to the DOM.
//
// This should generally not be used for new frame classes.
#ifndef mozilla_SimpleXULLeafFrame_h
#define mozilla_SimpleXULLeafFrame_h
#include "nsLeafFrame.h"
namespace mozilla {
// Shared class for thumb and scrollbar buttons.
class SimpleXULLeafFrame : public nsLeafFrame {
public:
NS_DECL_FRAMEARENA_HELPERS(SimpleXULLeafFrame)
// TODO: Look at appearance instead maybe?
nscoord GetIntrinsicISize() override { return 0; }
nscoord GetIntrinsicBSize() override { return 0; }
void Reflow(nsPresContext* aPresContext, ReflowOutput& aDesiredSize,
const ReflowInput& aReflowInput,
nsReflowStatus& aStatus) override;
explicit SimpleXULLeafFrame(ComputedStyle* aStyle,
nsPresContext* aPresContext, ClassID aClassID)
: nsLeafFrame(aStyle, aPresContext, aClassID) {}
explicit SimpleXULLeafFrame(ComputedStyle* aStyle,
nsPresContext* aPresContext)
: SimpleXULLeafFrame(aStyle, aPresContext, kClassID) {}
friend nsIFrame* NS_NewSimpleXULLeafFrame(mozilla::PresShell* aPresShell,
ComputedStyle* aStyle);
};
} // namespace mozilla
#endif