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#include "StarFont.hpp"
#include "StarFile.hpp"
#include "StarFormat.hpp"
#include <ft2build.h>
#include FT_FREETYPE_H
namespace Star {
constexpr int FontLoadFlags = FT_LOAD_FORCE_AUTOHINT;
struct FTContext {
FT_Library library;
FTContext() {
library = nullptr;
if (FT_Init_FreeType(&library))
throw FontException("Could not initialize freetype library.");
}
~FTContext() {
if (library) {
FT_Done_FreeType(library);
library = nullptr;
}
}
};
FTContext ftContext;
struct FontImpl {
FT_Face face;
};
FontPtr Font::loadTrueTypeFont(String const& fileName, unsigned pixelSize) {
return loadTrueTypeFont(make_shared<ByteArray>(File::readFile(fileName)), pixelSize);
}
FontPtr Font::loadTrueTypeFont(ByteArrayConstPtr const& bytes, unsigned pixelSize) {
FontPtr font = make_shared<Font>();
font->m_fontBuffer = bytes;
shared_ptr<FontImpl> fontImpl = make_shared<FontImpl>();
if (FT_New_Memory_Face(
ftContext.library, (FT_Byte const*)font->m_fontBuffer->ptr(), font->m_fontBuffer->size(), 0, &fontImpl->face))
throw FontException("Could not load font from buffer");
font->m_fontImpl = fontImpl;
font->setPixelSize(pixelSize);
return font;
}
Font::Font() : m_pixelSize(0) {}
FontPtr Font::clone() const {
return Font::loadTrueTypeFont(m_fontBuffer, m_pixelSize);
}
void Font::setPixelSize(unsigned pixelSize) {
if (pixelSize == 0) {
pixelSize = 1;
}
if (m_pixelSize == pixelSize)
return;
if (FT_Set_Pixel_Sizes(m_fontImpl->face, pixelSize, 0))
throw FontException(strf("Cannot set font pixel size to: {}", pixelSize));
m_pixelSize = pixelSize;
}
unsigned Font::height() const {
return m_pixelSize;
}
unsigned Font::width(String::Char c) {
if (auto width = m_widthCache.maybe({c, m_pixelSize})) {
return *width;
} else {
FT_Load_Char(m_fontImpl->face, c, FontLoadFlags);
unsigned newWidth = (m_fontImpl->face->glyph->advance.x + 32) / 64;
m_widthCache.insert({c, m_pixelSize}, newWidth);
return newWidth;
}
}
std::pair<Image, int> Font::render(String::Char c) {
if (!m_fontImpl)
throw FontException("Font::render called on uninitialized font.");
FT_Face face = m_fontImpl->face;
FT_UInt glyph_index = FT_Get_Char_Index(face, c);
if (FT_Load_Glyph(face, glyph_index, FontLoadFlags) != 0)
return {};
/* convert to an anti-aliased bitmap */
if (FT_Render_Glyph(face->glyph, FT_RENDER_MODE_NORMAL) != 0)
return {};
FT_GlyphSlot slot = face->glyph;
unsigned int width = slot->bitmap.width;
unsigned int height = slot->bitmap.rows;
Image image(width, height, PixelFormat::RGBA32);
for (int y = 0; y < height; ++y) {
unsigned char* p = slot->bitmap.buffer + y * slot->bitmap.pitch;
for (int x = 0; x < width; ++x) {
if (x >= 0 && y >= 0 && x < width && y < height) {
unsigned char val = *(p + x);
image.set(x, height - y - 1, Vec4B(255, 255, 255, val));
} else {
image.set(x, height - y - 1, Vec4B(255, 255, 255, 0));
}
}
}
return { move(image), (slot->bitmap_top - (int)height) + m_pixelSize / 4 };
}
}
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