mirror of
https://github.com/RGBCube/serenity
synced 2025-05-16 15:34:58 +00:00
ada48a1daf
This adds the option to pass a subpixel offset when fetching a glyph from a font, this offset is currently snapped to thirds of a pixel (i.e. 0, 0.33, 0.66). This is then used when rasterizing the glyph, which is then cached like usual. Note that when using subpixel offsets you're trading a bit of space for accuracy. With the current third of a pixel offsets you can end up with up to 9 bitmaps per glyph.
119 lines
3.7 KiB
C++
119 lines
3.7 KiB
C++
/*
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* Copyright (c) 2022, the SerenityOS developers.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Utf32View.h>
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#include <AK/Utf8View.h>
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#include <LibGfx/Font/ScaledFont.h>
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namespace Gfx {
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float ScaledFont::width(StringView view) const { return unicode_view_width(Utf8View(view)); }
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float ScaledFont::width(Utf8View const& view) const { return unicode_view_width(view); }
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float ScaledFont::width(Utf32View const& view) const { return unicode_view_width(view); }
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template<typename T>
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ALWAYS_INLINE float ScaledFont::unicode_view_width(T const& view) const
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{
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if (view.is_empty())
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return 0;
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float width = 0;
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float longest_width = 0;
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u32 last_code_point = 0;
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for (auto code_point : view) {
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if (code_point == '\n' || code_point == '\r') {
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longest_width = max(width, longest_width);
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width = 0;
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last_code_point = code_point;
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continue;
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}
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u32 glyph_id = glyph_id_for_code_point(code_point);
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auto kerning = glyphs_horizontal_kerning(last_code_point, code_point);
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width += kerning + glyph_metrics(glyph_id).advance_width;
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last_code_point = code_point;
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}
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longest_width = max(width, longest_width);
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return longest_width;
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}
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RefPtr<Gfx::Bitmap> ScaledFont::rasterize_glyph(u32 glyph_id, GlyphSubpixelOffset subpixel_offset) const
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{
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GlyphIndexWithSubpixelOffset index { glyph_id, subpixel_offset };
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auto glyph_iterator = m_cached_glyph_bitmaps.find(index);
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if (glyph_iterator != m_cached_glyph_bitmaps.end())
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return glyph_iterator->value;
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auto glyph_bitmap = m_font->rasterize_glyph(glyph_id, m_x_scale, m_y_scale, subpixel_offset);
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m_cached_glyph_bitmaps.set(index, glyph_bitmap);
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return glyph_bitmap;
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}
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Gfx::Glyph ScaledFont::glyph(u32 code_point) const
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{
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return glyph(code_point, GlyphSubpixelOffset { 0, 0 });
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}
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Gfx::Glyph ScaledFont::glyph(u32 code_point, GlyphSubpixelOffset subpixel_offset) const
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{
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auto id = glyph_id_for_code_point(code_point);
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auto bitmap = rasterize_glyph(id, subpixel_offset);
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auto metrics = glyph_metrics(id);
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return Gfx::Glyph(bitmap, metrics.left_side_bearing, metrics.advance_width, metrics.ascender);
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}
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float ScaledFont::glyph_left_bearing(u32 code_point) const
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{
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auto id = glyph_id_for_code_point(code_point);
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return glyph_metrics(id).left_side_bearing;
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}
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float ScaledFont::glyph_width(u32 code_point) const
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{
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auto id = glyph_id_for_code_point(code_point);
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auto metrics = glyph_metrics(id);
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return metrics.advance_width;
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}
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float ScaledFont::glyph_or_emoji_width(u32 code_point) const
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{
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auto id = glyph_id_for_code_point(code_point);
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auto metrics = glyph_metrics(id);
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return metrics.advance_width;
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}
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float ScaledFont::glyphs_horizontal_kerning(u32 left_code_point, u32 right_code_point) const
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{
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if (left_code_point == 0 || right_code_point == 0)
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return 0.f;
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auto left_glyph_id = glyph_id_for_code_point(left_code_point);
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auto right_glyph_id = glyph_id_for_code_point(right_code_point);
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if (left_glyph_id == 0 || right_glyph_id == 0)
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return 0.f;
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return m_font->glyphs_horizontal_kerning(left_glyph_id, right_glyph_id, m_x_scale);
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}
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u8 ScaledFont::glyph_fixed_width() const
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{
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return glyph_metrics(glyph_id_for_code_point(' ')).advance_width;
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}
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Gfx::FontPixelMetrics ScaledFont::pixel_metrics() const
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{
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auto metrics = m_font->metrics(m_x_scale, m_y_scale);
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return Gfx::FontPixelMetrics {
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.size = (float)pixel_size(),
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.x_height = (float)x_height(),
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.advance_of_ascii_zero = (float)glyph_width('0'),
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.glyph_spacing = (float)glyph_spacing(),
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.ascent = metrics.ascender,
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.descent = -metrics.descender,
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.line_gap = metrics.line_gap,
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};
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}
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}
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