ladybird/Userland/Libraries/LibGfx/TextLayout.h
Andreas Kling b2d3ceaec5 LibGfx: Make text painting better at aligning vector fonts vertically
This is achieved by simplifying the logic in TextLayout. We get rid
of all the various ways that the layout bounding rect can get cropped.
Then we make sure to use the right pixel metrics.

Finally we use the font's own line gap metrics instead of hard-coding 4.

The end result is that text painted with vector fonts now gets pretty
reasonable vertical alignment in most cases.
2023-01-06 12:02:21 +01:00

68 lines
1.9 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021, sin-ack <sin-ack@protonmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/DeprecatedString.h>
#include <AK/Forward.h>
#include <AK/Utf32View.h>
#include <AK/Utf8View.h>
#include <AK/Vector.h>
#include <LibGfx/Font/Font.h>
#include <LibGfx/Forward.h>
#include <LibGfx/Rect.h>
#include <LibGfx/TextElision.h>
#include <LibGfx/TextWrapping.h>
namespace Gfx {
// FIXME: This currently isn't an ideal way of doing things; ideally, TextLayout
// would be doing the rendering by painting individual glyphs. However, this
// would regress our Unicode bidirectional text support. Therefore, fixing this
// requires:
// - Moving the bidirectional algorithm either here, or some place TextLayout
// can access;
// - Making TextLayout render the given text into something like a Vector<Line>
// where:
// using Line = Vector<DirectionalRun>;
// struct DirectionalRun {
// Utf32View glyphs;
// Vector<int> advance;
// TextDirection direction;
// };
// - Either;
// a) Making TextLayout output these Lines directly using a given Painter, or
// b) Taking the Lines from TextLayout and painting each glyph.
class TextLayout {
public:
TextLayout(Gfx::Font const& font, Utf8View const& text, FloatRect const& rect)
: m_font(font)
, m_font_metrics(font.pixel_metrics())
, m_text(text)
, m_rect(rect)
{
}
Vector<DeprecatedString, 32> lines(TextElision elision, TextWrapping wrapping) const
{
return wrap_lines(elision, wrapping);
}
FloatRect bounding_rect(TextWrapping) const;
private:
Vector<DeprecatedString, 32> wrap_lines(TextElision, TextWrapping) const;
DeprecatedString elide_text_from_right(Utf8View) const;
Font const& m_font;
FontPixelMetrics m_font_metrics;
Utf8View m_text;
FloatRect m_rect;
};
}