From d2448d151edad03fb2ca2274cb02426f5fb69582 Mon Sep 17 00:00:00 2001
From: Benji Dial <benji@benjidial.net>
Date: Sun, 19 May 2024 11:39:07 -0400
Subject: add font loading and rendering to daguerre

---
 libraries/daguerre/include/daguerre.hpp | 68 ++++++++++++++++++++++++++++++---
 libraries/daguerre/source/daguerre.cpp  | 45 ++++++++++++++++++++++
 2 files changed, 108 insertions(+), 5 deletions(-)

(limited to 'libraries')

diff --git a/libraries/daguerre/include/daguerre.hpp b/libraries/daguerre/include/daguerre.hpp
index 62d10f0..c236cb9 100644
--- a/libraries/daguerre/include/daguerre.hpp
+++ b/libraries/daguerre/include/daguerre.hpp
@@ -14,6 +14,16 @@ namespace daguerre {
     uint8_t b;
   };
 
+  static inline void default_overlay(hilbert_color &dest, const rgb24 &src) {
+    dest = __euler_encode_color(src.r, src.g, src.b);
+  }
+
+  static inline void default_overlay(rgb24 &dest, const bool &src) {
+    dest.r = src ? 255 : 0;
+    dest.g = src ? 255 : 0;
+    dest.b = src ? 255 : 0;
+  }
+
   template <class color_t>
   class image {
 
@@ -100,7 +110,7 @@ namespace daguerre {
   //from [from_x, from_x + width) x [from_y, from_y + height).
   template <
     class to_color_t, class from_color_t,
-    void overlay(to_color_t &dest, const from_color_t &src)>
+    void overlay(to_color_t &dest, const from_color_t &src) = default_overlay>
   void overlay_region(
     image<to_color_t> &to, unsigned to_x, unsigned to_y,
     const image<from_color_t> &from, unsigned from_x, unsigned from_y,
@@ -116,12 +126,60 @@ namespace daguerre {
 
   }
 
-  static inline void encode(hilbert_color &dest, const rgb24 &src) {
-    dest = __euler_encode_color(src.r, src.g, src.b);
-  }
-
   image<hilbert_color> get_hilbert_framebuffer();
 
   bool try_load_ppm(std::FILE *input, image<rgb24> &into);
 
+  static inline bool try_load_ppm(const char *path, image<rgb24> &into) {
+    std::FILE *f = std::fopen(path, "r");
+    if (!f)
+      return false;
+    bool success = try_load_ppm(f, into);
+    std::fclose(f);
+    return success;
+  }
+
+  //TODO: unicode
+  template <class color_t>
+  class fixed_bitmap_font {
+
+  public:
+    unsigned width;
+    unsigned height;
+    image<color_t> glyphs[128];
+
+    template <class target_color_t,
+      void overlay(target_color_t &dest, const color_t &src) = default_overlay>
+    void overlay_text(
+      image<target_color_t> &target, unsigned x,
+      unsigned y, const char *text) const {
+
+      while (1) {
+        uint8_t ch = (uint8_t)*text;
+        if (ch == 0)
+          return;
+        if (ch < 128) {
+          overlay_region<target_color_t, color_t, overlay>(
+            target, x, y, glyphs[ch], 0, 0, width, height);
+          x += width;
+        }
+        ++text;
+      }
+
+    }
+
+  };
+
+  bool try_load_psf(std::FILE *input, fixed_bitmap_font<bool> &into);
+
+  static inline bool try_load_psf(
+    const char *path, fixed_bitmap_font<bool> &into) {
+    std::FILE *f = std::fopen(path, "r");
+    if (!f)
+      return false;
+    bool success = try_load_psf(f, into);
+    std::fclose(f);
+    return success;
+  }
+
 }
diff --git a/libraries/daguerre/source/daguerre.cpp b/libraries/daguerre/source/daguerre.cpp
index 7c13a88..2f7fe4d 100644
--- a/libraries/daguerre/source/daguerre.cpp
+++ b/libraries/daguerre/source/daguerre.cpp
@@ -26,6 +26,7 @@ namespace daguerre {
     return n;
   }
 
+  //only supports p6 format
   bool try_load_ppm(std::FILE *input, image<rgb24> &into) {
 
     char header[3];
@@ -62,4 +63,48 @@ namespace daguerre {
 
   }
 
+  //assumes the font is in psf2 format, and has a unicode table
+  bool try_load_psf(std::FILE *input, fixed_bitmap_font<bool> &into) {
+
+    uint32_t header[8];
+    if (std::fread(header, 4, 8, input) != 8)
+      return false;
+
+    const uint32_t glyphs_start = header[2];
+    const uint32_t glyph_count = header[4];
+    const uint32_t glyph_length = header[5];
+    into.height = header[6];
+    into.width = header[7];
+
+    const uint32_t unicode_start = glyphs_start + glyph_count * glyph_length;
+    std::fseek(input, unicode_start, SEEK_SET);
+
+    uint32_t indices[128];
+
+    for (uint32_t index = 0; index < glyph_count; ++index) {
+      uint8_t ch;
+      std::fread(&ch, 1, 1, input);
+      if (ch < 128)
+        indices[ch] = index;
+      do
+        std::fread(&ch, 1, 1, input);
+      while (ch != 0xff);
+    }
+
+    for (uint8_t ch = 0; ch < 128; ++ch) {
+      std::fseek(input, glyphs_start + glyph_length * indices[ch], SEEK_SET);
+      into.glyphs[ch] = image<bool>(into.width, into.height);
+      for (unsigned h = 0; h < into.height; ++h)
+        for (unsigned wb = 0; wb < into.width; wb += 8) {
+          uint8_t byte;
+          std::fread(&byte, 1, 1, input);
+          for (unsigned x = 0; x < 8 && wb + x < into.width; ++x)
+            into.glyphs[ch].set(wb + x, h, (byte >> (7 - x)) & 1);
+        }
+    }
+
+    return true;
+
+  }
+
 }
-- 
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