1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-20 05:15:06 +00:00
serenity/Userland/Libraries/LibGfx/Font/ScaledFont.cpp
Andreas Kling 44025e837f LibGfx: Use float when calculating text width in ScaledFont
This fixes an issue where we'd truncate the fractional part of each
glyph width, often making the returned width slightly too short.
2022-07-09 22:16:18 +02:00

107 lines
3.3 KiB
C++

/*
* Copyright (c) 2022, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Utf32View.h>
#include <AK/Utf8View.h>
#include <LibGfx/Font/ScaledFont.h>
namespace Gfx {
int ScaledFont::width(StringView view) const { return unicode_view_width(Utf8View(view)); }
int ScaledFont::width(Utf8View const& view) const { return unicode_view_width(view); }
int ScaledFont::width(Utf32View const& view) const { return unicode_view_width(view); }
template<typename T>
ALWAYS_INLINE int ScaledFont::unicode_view_width(T const& view) const
{
if (view.is_empty())
return 0;
float width = 0;
float longest_width = 0;
u32 last_code_point = 0;
for (auto code_point : view) {
if (code_point == '\n' || code_point == '\r') {
longest_width = max(width, longest_width);
width = 0;
last_code_point = code_point;
continue;
}
u32 glyph_id = glyph_id_for_code_point(code_point);
auto kerning = glyphs_horizontal_kerning(last_code_point, code_point);
width += kerning + glyph_metrics(glyph_id).advance_width;
last_code_point = code_point;
}
longest_width = max(width, longest_width);
return longest_width;
}
RefPtr<Gfx::Bitmap> ScaledFont::rasterize_glyph(u32 glyph_id) const
{
auto glyph_iterator = m_cached_glyph_bitmaps.find(glyph_id);
if (glyph_iterator != m_cached_glyph_bitmaps.end())
return glyph_iterator->value;
auto glyph_bitmap = m_font->rasterize_glyph(glyph_id, m_x_scale, m_y_scale);
m_cached_glyph_bitmaps.set(glyph_id, glyph_bitmap);
return glyph_bitmap;
}
Gfx::Glyph ScaledFont::glyph(u32 code_point) const
{
auto id = glyph_id_for_code_point(code_point);
auto bitmap = rasterize_glyph(id);
auto metrics = glyph_metrics(id);
return Gfx::Glyph(bitmap, metrics.left_side_bearing, metrics.advance_width, metrics.ascender);
}
u8 ScaledFont::glyph_width(u32 code_point) const
{
auto id = glyph_id_for_code_point(code_point);
auto metrics = glyph_metrics(id);
return metrics.advance_width;
}
int ScaledFont::glyph_or_emoji_width(u32 code_point) const
{
auto id = glyph_id_for_code_point(code_point);
auto metrics = glyph_metrics(id);
return metrics.advance_width;
}
float ScaledFont::glyphs_horizontal_kerning(u32 left_code_point, u32 right_code_point) const
{
if (left_code_point == 0 || right_code_point == 0)
return 0.f;
auto left_glyph_id = glyph_id_for_code_point(left_code_point);
auto right_glyph_id = glyph_id_for_code_point(right_code_point);
if (left_glyph_id == 0 || right_glyph_id == 0)
return 0.f;
return m_font->glyphs_horizontal_kerning(left_glyph_id, right_glyph_id, m_x_scale);
}
u8 ScaledFont::glyph_fixed_width() const
{
return glyph_metrics(glyph_id_for_code_point(' ')).advance_width;
}
Gfx::FontPixelMetrics ScaledFont::pixel_metrics() const
{
auto metrics = m_font->metrics(m_x_scale, m_y_scale);
return Gfx::FontPixelMetrics {
.size = (float)pixel_size(),
.x_height = (float)x_height(),
.advance_of_ascii_zero = (float)glyph_width('0'),
.glyph_spacing = (float)glyph_spacing(),
.ascent = metrics.ascender,
.descent = -metrics.descender,
.line_gap = metrics.line_gap,
};
}
}