137 lines
3.4 KiB
C++
137 lines
3.4 KiB
C++
#include "StarFont.hpp"
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#include "StarFile.hpp"
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#include "StarFormat.hpp"
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#include <ft2build.h>
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#include FT_FREETYPE_H
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namespace Star {
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constexpr int FontLoadFlags = FT_LOAD_FORCE_AUTOHINT;
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struct FTContext {
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FT_Library library;
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FTContext() {
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library = nullptr;
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if (FT_Init_FreeType(&library))
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throw FontException("Could not initialize freetype library.");
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}
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~FTContext() {
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if (library) {
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FT_Done_FreeType(library);
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library = nullptr;
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}
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}
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};
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FTContext ftContext;
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struct FontImpl {
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FT_Face face;
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};
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FontPtr Font::loadTrueTypeFont(String const& fileName, unsigned pixelSize) {
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return loadTrueTypeFont(make_shared<ByteArray>(File::readFile(fileName)), pixelSize);
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}
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FontPtr Font::loadTrueTypeFont(ByteArrayConstPtr const& bytes, unsigned pixelSize) {
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FontPtr font = make_shared<Font>();
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font->m_fontBuffer = bytes;
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shared_ptr<FontImpl> fontImpl = make_shared<FontImpl>();
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if (FT_New_Memory_Face(
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ftContext.library, (FT_Byte const*)font->m_fontBuffer->ptr(), font->m_fontBuffer->size(), 0, &fontImpl->face))
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throw FontException("Could not load font from buffer");
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font->m_fontImpl = fontImpl;
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font->setPixelSize(pixelSize);
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return font;
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}
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Font::Font() : m_pixelSize(0), m_alphaThreshold(0) {}
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FontPtr Font::clone() const {
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return Font::loadTrueTypeFont(m_fontBuffer, m_pixelSize);
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}
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void Font::setPixelSize(unsigned pixelSize) {
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if (pixelSize == 0) {
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pixelSize = 1;
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}
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if (m_pixelSize == pixelSize)
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return;
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if (FT_Set_Pixel_Sizes(m_fontImpl->face, pixelSize, 0))
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throw FontException(strf("Cannot set font pixel size to: {}", pixelSize));
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m_pixelSize = pixelSize;
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}
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void Font::setAlphaThreshold(uint8_t alphaThreshold) {
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m_alphaThreshold = alphaThreshold;
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}
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unsigned Font::height() const {
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return m_pixelSize;
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}
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unsigned Font::width(String::Char c) {
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if (auto width = m_widthCache.maybe({c, m_pixelSize})) {
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return *width;
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} else {
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FT_Load_Char(m_fontImpl->face, c, FontLoadFlags);
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unsigned newWidth = (m_fontImpl->face->glyph->linearHoriAdvance + 32768) / 65536;
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m_widthCache.insert({c, m_pixelSize}, newWidth);
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return newWidth;
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}
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}
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std::pair<Image, Vec2I> Font::render(String::Char c) {
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if (!m_fontImpl)
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throw FontException("Font::render called on uninitialized font.");
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FT_Face face = m_fontImpl->face;
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FT_UInt glyph_index = FT_Get_Char_Index(face, c);
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if (FT_Load_Glyph(face, glyph_index, FontLoadFlags) != 0)
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return {};
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/* convert to an anti-aliased bitmap */
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if (FT_Render_Glyph(face->glyph, FT_RENDER_MODE_NORMAL) != 0)
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return {};
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FT_GlyphSlot slot = face->glyph;
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unsigned width = slot->bitmap.width;
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unsigned height = slot->bitmap.rows;
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Image image(width + 2, height + 2, PixelFormat::RGBA32);
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Vec4B white(255, 255, 255, 0);
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image.fill(white);
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for (unsigned y = 0; y != height; ++y) {
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uint8_t* p = slot->bitmap.buffer + y * slot->bitmap.pitch;
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for (unsigned x = 0; x != width; ++x) {
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if (x < width && y < height) {
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uint8_t value = *(p + x);
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if (m_alphaThreshold) {
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if (value >= m_alphaThreshold) {
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white[3] = 255;
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image.set(x + 1, height - y, white);
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}
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} else if (value) {
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white[3] = value;
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image.set(x + 1, height - y, white);
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}
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}
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}
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}
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return { std::move(image), {slot->bitmap_left - 1, (slot->bitmap_top - height) + (m_pixelSize / 4) - 1} };
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}
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}
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