ref: 17b0b503a940ef0cfb70ed1506a3132c0b6146d6
dir: /src/Font.cpp/
#include "Font.h"
#include <stdbool.h>
#include <stddef.h>
#include <stdlib.h>
#ifdef JAPANESE
#include <iconv.h>
#endif
#include <ft2build.h>
#include FT_FREETYPE_H
#include FT_LCD_FILTER_H
#include FT_BITMAP_H
#include "SDL.h"
// Uncomment for that authentic pre-Windows Vista feel
//#define DISABLE_FONT_ANTIALIASING
#undef MIN
#undef MAX
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#define MAX(a,b) ((a) > (b) ? (a) : (b))
typedef struct FontObject
{
FT_Library library;
FT_Face face;
#ifndef DISABLE_FONT_ANTIALIASING
bool lcd_mode;
#endif
#ifdef JAPANESE
iconv_t conv;
#endif
} FontObject;
static unsigned long UTF8ToCode(const unsigned char *string, unsigned int *bytes_read)
{
unsigned int length;
unsigned long charcode;
unsigned int zero_bit = 0;
for (unsigned char lead_byte = string[0]; zero_bit < 5 && (lead_byte & 0x80); ++zero_bit, lead_byte <<= 1);
switch (zero_bit)
{
case 0:
// Single-byte character
length = 1;
charcode = string[0];
break;
case 2:
case 3:
case 4:
length = zero_bit;
charcode = string[0] & (1 << (8 - zero_bit)) - 1;
for (unsigned int i = 1; i < zero_bit; ++i)
{
if ((string[i] & 0xC0) == 0x80)
{
charcode <<= 6;
charcode |= string[i] & ~0xC0;
}
else
{
// Error: Invalid continuation byte
length = 1;
charcode = 0xFFFD;
break;
}
}
break;
default:
// Error: Invalid lead byte
length = 1;
charcode = 0xFFFD;
break;
}
if (bytes_read)
*bytes_read = length;
return charcode;
}
FontObject* LoadFont(unsigned int cell_width, unsigned int cell_height, char *font_filename)
{
FontObject *font_object = (FontObject*)malloc(sizeof(FontObject));
FT_Init_FreeType(&font_object->library);
#ifndef DISABLE_FONT_ANTIALIASING
font_object->lcd_mode = FT_Library_SetLcdFilter(font_object->library, FT_LCD_FILTER_DEFAULT) != FT_Err_Unimplemented_Feature;
#endif
FT_New_Face(font_object->library, font_filename, 0, &font_object->face);
unsigned int best_cell_width = 0;
unsigned int best_cell_height = 0;
unsigned int best_pixel_width = 0;
unsigned int best_pixel_height = 0;
for (unsigned int i = 0;; ++i)
{
FT_Set_Pixel_Sizes(font_object->face, i, i);
const unsigned int current_cell_width = font_object->face->size->metrics.max_advance / 64;
const unsigned int current_cell_height = font_object->face->size->metrics.height / 64;
if (current_cell_width > cell_width && current_cell_height > cell_height)
{
break;
}
else
{
if (current_cell_width <= cell_width)
{
best_pixel_width = i;
best_cell_width = current_cell_width;
}
if (current_cell_height <= cell_height)
{
best_pixel_height = i;
best_cell_height = current_cell_height;
}
}
}
#ifdef JAPANESE
best_pixel_width = 0; // Cheap hack to make the font square
#endif
FT_Set_Pixel_Sizes(font_object->face, best_pixel_width, best_pixel_height);
#ifdef JAPANESE
font_object->conv = iconv_open("UTF-8", "SHIFT-JIS");
#endif
return font_object;
}
void DrawText(FontObject *font_object, SDL_Renderer *renderer, SDL_Texture *texture, int x, int y, unsigned long colour, const char *string, size_t string_length)
{
const unsigned char colours[3] = {(unsigned char)(colour >> 16), (unsigned char)(colour >> 8), (unsigned char)colour};
SDL_Texture *old_render_target = SDL_GetRenderTarget(renderer);
SDL_SetRenderTarget(renderer, texture);
int surface_width, surface_height;
SDL_GetRendererOutputSize(renderer, &surface_width, &surface_height);
SDL_Surface *surface = SDL_CreateRGBSurfaceWithFormat(0, surface_width, surface_height, 0, SDL_PIXELFORMAT_RGBA32);
SDL_RenderReadPixels(renderer, NULL, SDL_PIXELFORMAT_RGBA32, surface->pixels, surface->pitch);
unsigned char (*surface_buffer)[surface->pitch / 4][4] = (unsigned char (*)[surface->pitch / 4][4])surface->pixels;
FT_Face face = font_object->face;
unsigned int pen_x = 0;
const unsigned char *string_pointer = (unsigned char*)string;
const unsigned char *string_end = (unsigned char*)string + string_length;
while (string_pointer != string_end)
{
#ifdef JAPANESE
size_t out_size = 4;
unsigned char out_buffer[4]; // Max UTF-8 length is four bytes
unsigned char *out_pointer = out_buffer;
size_t in_size = ((*string_pointer >= 0x81 && *string_pointer <= 0x9F) || (*string_pointer >= 0xE0 && *string_pointer <= 0xEF)) ? 2 : 1;
unsigned char in_buffer[2];
unsigned char *in_pointer = in_buffer;
for (size_t i = 0; i < in_size; ++i)
in_buffer[i] = string_pointer[i];
string_pointer += in_size;
iconv(font_object->conv, (char**)&in_pointer, &in_size, (char**)&out_pointer, &out_size);
const unsigned long val = UTF8ToCode(out_buffer, NULL);
#else
unsigned int bytes_read;
const unsigned long val = UTF8ToCode(string_pointer, &bytes_read);
string_pointer += bytes_read;
#endif
unsigned int glyph_index = FT_Get_Char_Index(face, val);
#ifndef DISABLE_FONT_ANTIALIASING
FT_Load_Glyph(face, glyph_index, FT_LOAD_RENDER | (font_object->lcd_mode ? FT_LOAD_TARGET_LCD : 0));
#else
FT_Load_Glyph(face, glyph_index, FT_LOAD_RENDER | FT_LOAD_MONOCHROME);
#endif
FT_Bitmap converted;
FT_Bitmap_New(&converted);
FT_Bitmap_Convert(font_object->library, &face->glyph->bitmap, &converted, 1);
const int letter_x = x + pen_x + face->glyph->bitmap_left;
const int letter_y = y + ((FT_MulFix(face->ascender, face->size->metrics.y_scale) + (64 - 1)) / 64) - (face->glyph->metrics.horiBearingY / 64);
for (int iy = MAX(-letter_y, 0); letter_y + iy < MIN(letter_y + converted.rows, surface_height); ++iy)
{
if (face->glyph->bitmap.pixel_mode == FT_PIXEL_MODE_LCD)
{
for (int ix = MAX(-letter_x, 0); letter_x + ix < MIN(letter_x + (int)converted.width / 3, surface_width); ++ix)
{
const unsigned char (*font_buffer)[converted.pitch / 3][3] = (unsigned char (*)[converted.pitch / 3][3])converted.buffer;
const unsigned char *font_pixel = font_buffer[iy][ix];
unsigned char *surface_pixel = surface_buffer[letter_y + iy][letter_x + ix];
if (font_pixel[0] || font_pixel[1] || font_pixel[2])
{
for (unsigned int j = 0; j < 3; ++j)
{
const double alpha = pow((font_pixel[j] / 255.0), 1.0 / 1.8); // Gamma correction
surface_pixel[j] = (colours[j] * alpha) + (surface_pixel[j] * (1.0 - alpha)); // Alpha blending
}
surface_pixel[3] = 0xFF;
}
}
}
else if (face->glyph->bitmap.pixel_mode == FT_PIXEL_MODE_GRAY)
{
for (int ix = MAX(-letter_x, 0); letter_x + ix < MIN(letter_x + (int)converted.width, surface_width); ++ix)
{
unsigned char (*font_buffer)[converted.pitch] = (unsigned char (*)[converted.pitch])converted.buffer;
const double alpha = pow((double)font_buffer[iy][ix] / (converted.num_grays - 1), 1.0 / 1.8); // Gamma-corrected
unsigned char *surface_pixel = surface_buffer[letter_y + iy][letter_x + ix];
if (alpha)
{
for (unsigned int j = 0; j < 3; ++j)
surface_pixel[j] = (colours[j] * alpha) + (surface_pixel[j] * (1.0 - alpha)); // Alpha blending
surface_pixel[3] = 0xFF;
}
}
}
else if (face->glyph->bitmap.pixel_mode == FT_PIXEL_MODE_MONO)
{
for (int ix = MAX(-letter_x, 0); letter_x + ix < MIN(letter_x + (int)converted.width, surface_width); ++ix)
{
unsigned char (*font_buffer)[converted.pitch] = (unsigned char (*)[converted.pitch])converted.buffer;
unsigned char *surface_pixel = surface_buffer[letter_y + iy][letter_x + ix];
if (font_buffer[iy][ix])
{
for (unsigned int j = 0; j < 3; ++j)
surface_pixel[j] = colours[j];
surface_pixel[3] = 0xFF;
}
}
}
}
FT_Bitmap_Done(font_object->library, &converted);
pen_x += face->glyph->advance.x / 64;
}
SDL_Texture *screen_texture = SDL_CreateTextureFromSurface(renderer, surface);
SDL_FreeSurface(surface);
SDL_RenderCopy(renderer, screen_texture, NULL, NULL);
SDL_DestroyTexture(screen_texture);
SDL_SetRenderTarget(renderer, old_render_target);
}
void UnloadFont(FontObject *font_object)
{
#ifdef JAPANESE
iconv_close(font_object->conv);
#endif
FT_Done_Face(font_object->face);
FT_Done_FreeType(font_object->library);
}