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/* Font.h
Copyright (c) 2014-2020 by Michael Zahniser
Endless Sky 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.
Endless Sky 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
this program. If not, see <https://www.gnu.org/licenses/>.
*/
#pragma once
#include "../shader/Shader.h"
#include "../opengl.h"
#include <filesystem>
#include <functional>
#include <string>
class Color;
class DisplayText;
class ImageBuffer;
class Point;
// Class for drawing text in OpenGL. Each font is based on a single image with
// glyphs for each character in ASCII order (not counting control characters).
// The kerning between characters is automatically adjusted to look good. At the
// moment only plain ASCII characters are supported, not Unicode.
class Font {
public:
Font() noexcept = default;
explicit Font(const std::filesystem::path &imagePath);
void Load(const std::filesystem::path &imagePath);
// Draw a text string, subject to the given layout and truncation strategy.
void Draw(const DisplayText &text, const Point &point, const Color &color) const;
void DrawAliased(const DisplayText &text, double x, double y, const Color &color) const;
// Draw the given text string, e.g. post-formatting (or without regard to formatting).
void Draw(const std::string &str, const Point &point, const Color &color) const;
void DrawAliased(const std::string &str, double x, double y, const Color &color) const;
// Determine the string's width, without considering formatting.
int Width(const std::string &str, char after = ' ') const;
// Get the width of the text while accounting for the desired layout and truncation strategy.
int FormattedWidth(const DisplayText &text, char after = ' ') const;
int Height() const noexcept;
int Space() const noexcept;
static void ShowUnderlines(bool show) noexcept;
private:
static int Glyph(char c, bool isAfterSpace) noexcept;
void LoadTexture(ImageBuffer &image);
void CalculateAdvances(ImageBuffer &image);
void SetUpShader(float glyphW, float glyphH);
int WidthRawString(const char *str, char after = ' ') const noexcept;
std::string TruncateText(const DisplayText &text, int &width) const;
std::string TruncateBack(const std::string &str, int &width) const;
std::string TruncateFront(const std::string &str, int &width) const;
std::string TruncateMiddle(const std::string &str, int &width) const;
std::string TruncateEndsOrMiddle(const std::string &str, int &width,
std::function<std::string(const std::string &, int)> getResultString) const;
private:
const Shader *shader;
GLuint texture = 0;
int height = 0;
int space = 0;
mutable int screenWidth = 0;
mutable int screenHeight = 0;
mutable GLfloat scale[2]{0.f, 0.f};
GLfloat glyphWidth = 0.f;
GLfloat glyphHeight = 0.f;
static const int GLYPHS = 98;
int advance[GLYPHS * GLYPHS] = {};
int widthEllipses = 0;
};
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