palladium/source/lithium/font.cpp

/*
MIT License
Copyright (c) 2024 - 2025 René Amthor (tobid7)

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
 */

#ifdef PD_LITHIUM_BUILD_SHARED
#define STB_TRUETYPE_IMPLEMENTATION
#endif
#include <pd/external/stb_truetype.h>

#include <pd/lithium/font.hpp>
#include <pd/lithium/renderer.hpp>

namespace PD {
namespace LI {
PD_LITHIUM_API void Font::LoadTTF(const std::string &path, int height) {
  TT::Scope st("LI_LoadTTF_" + path);
  PixelHeight = height;  // Set internel pixel height
  // Use NextPow2 to be able to use sizes between for example 16 and 32
  // before it only was possible to use 8, 16, 32, 64 as size
  int texszs = BitUtil::GetPow2(height * 16);
  // Load stbtt
  stbtt_fontinfo inf;
  std::ifstream loader(path, std::ios::binary);
  if (!loader.is_open()) return;
  loader.seekg(0, std::ios::end);
  size_t len = loader.tellg();
  loader.seekg(0, std::ios::beg);
  unsigned char *buffer = new unsigned char[len];
  loader.read(reinterpret_cast<char *>(buffer), len);
  loader.close();
  stbtt_InitFont(&inf, buffer, 0);
  // clang-format off
  // Disable clang here cause dont want a garbage looking line
  std::vector<PD::u8> font_tex(texszs * texszs * 4);  // Create font Texture
  // clang-format on
  float scale = stbtt_ScaleForPixelHeight(&inf, PixelHeight);

  int ascent, descent, lineGap;
  stbtt_GetFontVMetrics(&inf, &ascent, &descent, &lineGap);
  int baseline = static_cast<int>(ascent * scale);

  std::map<u32, int> buf_cache;  // Cache to not render same codepoint tex twice

  /// Load Codepoints
  auto tex = Texture::New();
  fvec2 off;
  for (u32 ii = 0x0000; ii < 0xFFFF; ii++) {
    int i = stbtt_FindGlyphIndex(&inf, ii);
    if (i == 0) {
      continue;
    }
    if (stbtt_IsGlyphEmpty(&inf, i)) {
      continue;
    }

    Codepoint c;
    int w = 0, h = 0, xo = 0, yo = 0;
    unsigned char *bitmap =
        stbtt_GetCodepointBitmap(&inf, scale, scale, i, &w, &h, &xo, &yo);
    int x0, y0, x1, y1;
    stbtt_GetCodepointBitmapBox(&inf, i, scale, scale, &x0, &y0, &x1, &y1);

    // Check if Codepoint exists as hash and if it is use its already written
    // data
    u32 hashed_map = IO::HashMemory(std::vector<u8>(bitmap, bitmap + (w * h)));
    if (buf_cache.find(hashed_map) != buf_cache.end()) {
      c = GetCodepoint(buf_cache[hashed_map]);
      c.pCodepoint = i;
      CodeMap[i] = c;
      free(bitmap);
      continue;
    } else {
      buf_cache[hashed_map] = i;
    }

    if (off.x + w > texszs) {
      off.y += PixelHeight;
      off.x = 0;
    }

    // Set UV Data
    fvec4 uvs;
    uvs.x = static_cast<float>(off.x) / texszs;
    uvs.y = static_cast<float>(off.y) / texszs;
    uvs.z = static_cast<float>((off.x + w) / texszs);
    uvs.w = static_cast<float>((off.y + h) / texszs);
    if (pBackend->Flags & LIBackendFlags_FlipUV_Y) {
      uvs.y = 1.f - uvs.y;
      uvs.w = 1.f - uvs.w;
    }
    c.SimpleUV = uvs;
    c.Tex = tex;
    c.Size = fvec2(w, h);
    c.Offset = baseline + yo;

    // Render glyph
    for (int y = 0; y < h; ++y) {
      for (int x = 0; x < w; ++x) {
        int map_pos = (((off.y + y) * texszs + (off.x + x))) * 4;
        font_tex[map_pos + 0] = 255;
        font_tex[map_pos + 1] = 255;
        font_tex[map_pos + 2] = 255;
        font_tex[map_pos + 3] = bitmap[x + y * w];
      }
    }

    free(bitmap);
    CodeMap[i] = c;

    // Small Patch to avoid some possible artifacts
    off.x += w + 1;
    if (off.x + w > texszs) {
      off.y += PixelHeight;
      if (off.y + PixelHeight > texszs) {
        break;
      }
      off.x = 0;
    }
  }
  // Load the Texture and append to list
  {
    auto t = pBackend->LoadTexture(font_tex, texszs, texszs, Texture::RGBA32,
                                   Texture::LINEAR);
    tex->CopyOther(t);
  }
  Textures.push_back(tex);
}

PD_LITHIUM_API Font::Codepoint &Font::GetCodepoint(u32 cp) {
  // Check if codepoijt exist or return a static invalid one
  auto res = CodeMap.find(cp);
  if (res == CodeMap.end()) {
    static Codepoint invalid;
    invalid.pInvalid = true;
    return invalid;
  }
  return res->second;
}

PD_LITHIUM_API fvec2 Font::GetTextBounds(const std::string &text, float scale) {
  // Use wstring for exemple for german äöü
  auto wtext = Strings::MakeWstring(text);
  // Create a temp position and offset as [0, 0]
  fvec2 res;
  float x = 0;
  // Curent Font Scale
  float cfs = (DefaultPixelHeight * scale) / (float)PixelHeight;
  float lh = (float)PixelHeight * cfs;
  size_t index = 0;
  for (auto &it : wtext) {
    if (it == '\0') {
      break;
    }
    index++;
    auto cp = GetCodepoint(it);
    if (cp.pInvalid && it != '\n' && it != '\t' && it != ' ') {
      continue;
    }
    switch (it) {
      case '\n':
        res.y += lh;
        res.x = std::max(res.x, x);
        x = 0.f;
        break;
      case '\t':
        x += 16 * cfs;
        break;
      case ' ':
        x += 2 * cfs;
      // Fall trough here to get the same result as in
      // TextCommand if/else Section
      default:
        x += cp.Size.x * cfs;
        if (index != wtext.size()) {
          x += 2 * cfs;
        }
        break;
    }
  }
  res.x = std::max(res.x, x);
  res.y += lh;
  return res;
}

PD_LITHIUM_API void Font::CmdTextEx(Vec<Command::Ref> &cmds, const fvec2 &pos,
                                    u32 color, float scale,
                                    const std::string &text, LITextFlags flags,
                                    const fvec2 &box) {
  fvec2 off;
  float cfs = (DefaultPixelHeight * scale) / (float)PixelHeight;
  float lh = (float)PixelHeight * cfs;
  fvec2 td;
  fvec2 rpos = pos;
  fvec2 rbox = box;
  if (flags & (LITextFlags_AlignMid | LITextFlags_AlignRight)) {
    td = GetTextBounds(text, scale);
  }
  if (flags & LITextFlags_AlignMid) {
    rpos = rbox * 0.5 - td * 0.5 + pos;
  }
  if (flags & LITextFlags_AlignRight) {
    rpos.x = rpos.x - td.x;
  }

  std::vector<std::string> lines;
  std::istringstream iss(text);
  std::string tmp;
  while (std::getline(iss, tmp)) {
    lines.push_back(tmp);
  }

  for (auto &it : lines) {
    /*if (flags & LITextFlags_Short) {
      fvec2 tmp_dim;
      it = ShortText(it, box.x() - pos.x(), tmp_dim);
    }*/
    auto wline = Strings::MakeWstring(it);
    auto cmd = Command::New();
    auto Tex = GetCodepoint(wline[0]).Tex;
    cmd->Tex = Tex;
    for (auto &jt : wline) {
      auto cp = GetCodepoint(jt);
      if ((cp.pInvalid && jt != '\n' && jt != '\t') && jt != '\r') {
        continue;
      }
      if (Tex != cp.Tex) {
        cmds.Add(cmd);
        cmd = Command::New();
        Tex = cp.Tex;
        cmd->Tex = Tex;
      }
      if (jt == '\t') {
        off.x += 16 * cfs;
      } else {
        if (jt != ' ') {
          if (flags & LITextFlags_Shaddow) {
            // Draw
            Rect rec = Renderer::PrimRect(
                rpos + vec2(off.x + 1, off.x + (cp.Offset * cfs)) + 1,
                cp.Size * cfs, 0.f);
            Renderer::CmdQuad(cmd, rec, cp.SimpleUV, 0xff111111);
          }
          // Draw
          Rect rec = Renderer::PrimRect(
              rpos + off + fvec2(0, (cp.Offset * cfs)), cp.Size * cfs, 0.f);
          Renderer::CmdQuad(cmd, rec, cp.SimpleUV, color);
        } else {
          off.x += 2 * cfs;
        }
        off.x += cp.Size.x * cfs + 2 * cfs;
      }
    }
    cmds.Add(cmd);
    off.y += lh;
    off.x = 0;
  }
}
}  // namespace LI
}  // namespace PD