sources/libs/nvll_osd/textbackend/backend.hpp

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/*
 * SPDX-FileCopyrightText: Copyright (c) 2023-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#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