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◆ main openmsx / src / imgui / freetype_utils.hh
2.3 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
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#ifndef FREETYPE_UTILS_HH
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#define FREETYPE_UTILS_HH
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#include "FileOperations.hh"
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#include "MSXException.hh"
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#include <cstdint>
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#include <span>
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#include <string>
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#include <ft2build.h>
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#include FT_FREETYPE_H
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namespace openmsx {
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/* Example usage:
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 *   FreeTypeLibrary library;
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 *   std::vector<std::string> result;
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 *   auto fontData = File(fontFilename).mmap<uint8_t>();
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 *   for (auto i : xrange(getNumFaces(library, fontData))) {
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 *       result.push_back(getFontDisplayName(library, fontData, i, fontFilename));
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 *   }
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 *   return result;
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 */
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struct FreeTypeLibrary
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{
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	FreeTypeLibrary(const FreeTypeLibrary&) = delete;
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	FreeTypeLibrary(FreeTypeLibrary&&) = delete;
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	FreeTypeLibrary& operator=(const FreeTypeLibrary&) = delete;
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	FreeTypeLibrary& operator=(FreeTypeLibrary&&) = delete;
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	FreeTypeLibrary()
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	{
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		if (FT_Init_FreeType(&library)) {
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			throw MSXException("Could not initialize FreeType library");
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		}
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	}
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	~FreeTypeLibrary()
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	{
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		FT_Done_FreeType(library);
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	}
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	FT_Library library;
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};
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struct FreeTypeFace
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{
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	FreeTypeFace(const FreeTypeFace&) = delete;
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	FreeTypeFace(FreeTypeFace&&) = delete;
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	FreeTypeFace& operator=(const FreeTypeFace&) = delete;
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	FreeTypeFace& operator=(FreeTypeFace&&) = delete;
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	FreeTypeFace(FreeTypeLibrary& library, std::span<const uint8_t> fontData, long faceIndex)
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	{
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		if (FT_New_Memory_Face(library.library, fontData.data(), fontData.size(), faceIndex, &face)) {
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			throw MSXException("Could not parse font");
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		}
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	}
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	~FreeTypeFace()
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	{
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		FT_Done_Face(face);
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	}
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	FT_Face face;
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};
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[[nodiscard]] inline long getNumFaces(FreeTypeLibrary& library, std::span<const uint8_t> fontData)
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{
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	FreeTypeFace face(library, fontData, -1);
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	return face.face->num_faces;
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}
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[[nodiscard]] inline std::string getFontDisplayName(
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	FreeTypeLibrary& library, const std::span<const uint8_t>& fontData, long faceIndex,
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	std::string_view fontFile)
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{
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	FreeTypeFace face(library, fontData, faceIndex);
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	auto toSV = [](const char* s) { return std::string_view(s ? s : ""); };
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	auto family = toSV(face.face->family_name);
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	auto style = toSV(face.face->style_name);
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	auto name = !family.empty()
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	          ? std::string(family)
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	          : std::string(FileOperations::stem(fontFile));
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	if (!style.empty() && (!family.empty() || style != family)) {
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		strAppend(name, " - ", style);
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	}
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	return name;
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}
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} // namespace openmsx
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#endif // FREETYPE_UTILS_HH