backend.hpp

Go to the documentation of this file.

/*
 * SPDX-FileCopyrightText: Copyright (c) 2023-2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 * SPDX-License-Identifier: LicenseRef-NvidiaProprietary
 *
 * NVIDIA CORPORATION, its affiliates and licensors retain all intellectual
 * property and proprietary rights in and to this material, related
 * documentation and any modifications thereto. Any use, reproduction,
 * disclosure or distribution of this material and related documentation
 * without an express license agreement from NVIDIA CORPORATION or
 * its affiliates is strictly prohibited.
 */
 
#ifndef TEXT_BACKEND_HPP
#define TEXT_BACKEND_HPP
 
#include <vector>
#include <memory>
#include <tuple>
 
// #define ENABLE_TEXT_BACKEND_PANGO
// #define ENABLE_TEXT_BACKEND_STB
#define MAX_FONT_SIZE 200
 
enum class TextBackendType : int {
    None         = 0,
    PangoCairo   = 1,
    StbTrueType  = 2
};
 
class WordMeta{
public:
    virtual int width() const = 0;
    virtual int height() const = 0;
    virtual int x_offset_on_bitmap() const = 0;
    virtual int xadvance(int font_size, bool empty=false) const = 0;
};
 
class WordMetaMapper{
public:
    virtual WordMeta* query(unsigned long int word) = 0;
};
 
class TextBackend{
public:
    virtual std::vector<unsigned long int> split_utf8(const char* utf8_text) = 0;
    virtual std::tuple<int, int, int> measure_text(const std::vector<unsigned long int>& words, unsigned int font_size, const char* font) = 0;
    virtual void add_build_text(const std::vector<unsigned long int>& words, unsigned int font_size, const char* font) = 0;
    virtual void build_bitmap(void* stream = nullptr) = 0;
    virtual WordMetaMapper* query(const char* font, int font_size) = 0;
    virtual unsigned char* bitmap_device_pointer() const = 0;
    virtual int bitmap_width() const = 0;
    virtual int compute_y_offset(int max_glyph_height, int h, WordMeta* word, int font_size) const = 0;
    virtual int uniform_font_size(int size) const = 0;
};
 
const char* text_backend_type_name(TextBackendType backend);
std::shared_ptr<TextBackend> create_text_backend(TextBackendType backend);
std::string concat_font_name_size(const char* name, int size);
 
#endif // TEXT_BACKEND_HPP