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- /*
- * Copyright (C) 2021 Christopher J. Howard
- *
- * This file is part of Antkeeper source code.
- *
- * Antkeeper source code is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * Antkeeper source code is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
- */
-
- #include "type/freetype/typeface.hpp"
- #include <stdexcept>
- #include <string>
-
- namespace type {
- namespace freetype {
-
- typeface::typeface(FT_Library library, FT_Face face, unsigned char* buffer):
- library(library),
- face(face),
- buffer(buffer),
- height(-1.0f)
- {}
-
- typeface::~typeface()
- {
- FT_Done_Face(face);
- delete[] buffer;
- FT_Done_FreeType(library);
- }
-
- bool typeface::has_kerning() const
- {
- return FT_HAS_KERNING(face);
- }
-
- bool typeface::has_glyph(char32_t code) const
- {
- return FT_Get_Char_Index(face, static_cast<FT_ULong>(code)) != 0;
- }
-
- bool typeface::get_metrics(float height, font_metrics& metrics) const
- {
- // Set font size
- set_face_pixel_size(height);
-
- // Get font metrics
- metrics.ascent = face->size->metrics.ascender / 64.0f;
- metrics.descent = face->size->metrics.descender / 64.0f;
- metrics.linegap = face->size->metrics.height / 64.0f;
- metrics.linespace = metrics.ascent - metrics.descent + metrics.linegap;
- metrics.underline_position = FT_MulFix(face->underline_position, face->size->metrics.y_scale) / 64.0f;
- metrics.underline_thickness = FT_MulFix(face->underline_thickness, face->size->metrics.y_scale) / 64.0f;
- metrics.max_horizontal_advance = face->size->metrics.max_advance / 64.0f;
- metrics.max_vertical_advance = FT_MulFix(face->max_advance_height, face->size->metrics.y_scale) / 64.0f;
-
- return true;
- }
-
- bool typeface::get_metrics(float height, char32_t code, glyph_metrics& metrics) const
- {
- // Set font size
- set_face_pixel_size(height);
-
- // Get index of glyph
- FT_UInt glyph_index = FT_Get_Char_Index(face, static_cast<FT_ULong>(code));
-
- // Load glyph and render bitmap
- FT_Error error = FT_Load_Glyph(face, glyph_index, FT_LOAD_DEFAULT);
- if (error)
- {
- throw std::runtime_error("FreeType failed to load glyph (error code " + std::to_string(error) + ")");
- }
-
- // Get glyph metrics
- metrics.width = face->glyph->metrics.width / 64.0f;
- metrics.height = face->glyph->metrics.height / 64.0f;
- metrics.horizontal_bearing.x = face->glyph->metrics.horiBearingX / 64.0f;
- metrics.horizontal_bearing.y = face->glyph->metrics.horiBearingY / 64.0f;
- metrics.vertical_bearing.x = face->glyph->metrics.vertBearingX / 64.0f;
- metrics.vertical_bearing.y = face->glyph->metrics.vertBearingY / 64.0f;
- metrics.horizontal_advance = face->glyph->metrics.horiAdvance / 64.0f;
- metrics.vertical_advance = face->glyph->metrics.vertAdvance / 64.0f;
-
- return true;
- }
-
- bool typeface::get_bitmap(float height, char32_t code, image& bitmap) const
- {
- // Set font size
- set_face_pixel_size(height);
-
- // Get index of glyph
- FT_UInt glyph_index = FT_Get_Char_Index(face, static_cast<FT_ULong>(code));
-
- // Load glyph and render bitmap
- FT_Error error = FT_Load_Glyph(face, glyph_index, FT_LOAD_RENDER | FT_LOAD_TARGET_(FT_RENDER_MODE_NORMAL));
- if (error)
- {
- throw std::runtime_error("FreeType failed to load glyph (error code " + std::to_string(error) + ")");
- }
-
- // Format and resize bitmap
- bitmap.resize(0, 0);
- bitmap.format(sizeof(unsigned char), 1);
- bitmap.resize(face->glyph->bitmap.width, face->glyph->bitmap.rows);
-
- // Copy glyph bitmap data in bitmap
- std::memcpy(bitmap.get_pixels(), face->glyph->bitmap.buffer, bitmap.get_size());
-
- return true;
- }
-
- bool typeface::get_kerning(float height, char32_t first, char32_t second, float2& offset) const
- {
- // Check if typeface has kerning information
- if (!has_kerning())
- return false;
-
- // Set font size
- set_face_pixel_size(height);
-
- // Get indices of the two glyphs
- FT_UInt first_index = FT_Get_Char_Index(face, static_cast<FT_ULong>(first));
- FT_UInt second_index = FT_Get_Char_Index(face, static_cast<FT_ULong>(second));
-
- // Get kerning vector
- FT_Vector kerning;
- FT_Error error = FT_Get_Kerning(face, first_index, second_index, FT_KERNING_DEFAULT, &kerning);
- if (error)
- {
- throw std::runtime_error("FreeType failed to get kerning vector (error code " + std::to_string(error) + ")");
- }
-
- offset = float2{static_cast<float>(kerning.x), static_cast<float>(kerning.y)} / 64.0f;
-
- return true;
- }
-
- void typeface::set_face_pixel_size(float height) const
- {
- if (this->height == height)
- return;
-
- FT_Error error = FT_Set_Pixel_Sizes(face, 0, static_cast<FT_UInt>(height));
- if (error)
- {
- throw std::runtime_error("FreeType failed to set face size (error code " + std::to_string(error) + ")");
- }
-
- this->height = height;
- }
-
- } // namespace freetype
- } // namespace type
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