Basic glyph compression

lib/EpdFont/EpdFontData.h

@@ -5,6 +5,7 @@
 #include <cstdint>
 
 /// Font data stored PER GLYPH
+#pragma pack(push, 1)
 typedef struct {
   uint8_t width;        ///< Bitmap dimensions in pixels
   uint8_t height;       ///< Bitmap dimensions in pixels
@@ -13,7 +14,9 @@ typedef struct {
   int16_t top;          ///< Y dist from cursor pos to UL corner
   uint16_t dataLength;  ///< Size of the font data.
   uint32_t dataOffset;  ///< Pointer into EpdFont->bitmap
+  bool compressed;
 } EpdGlyph;
+#pragma pack(pop)
 
 /// Glyph interval structure
 typedef struct {

lib/EpdFont/scripts/fontconvert.py

@@ -17,7 +17,7 @@ parser.add_argument("--2bit", dest="is2Bit", action="store_true", help="generate
 parser.add_argument("--additional-intervals", dest="additional_intervals", action="append", help="Additional code point intervals to export as min,max. This argument can be repeated.")
 args = parser.parse_args()
 
-GlyphProps = namedtuple("GlyphProps", ["width", "height", "advance_x", "left", "top", "data_length", "data_offset", "code_point"])
+GlyphProps = namedtuple("GlyphProps", ["width", "height", "advance_x", "left", "top", "data_length", "data_offset", "compressed", "code_point"])
 
 font_stack = [freetype.Face(f) for f in args.fontstack]
 is2Bit = args.is2Bit
@@ -124,7 +124,6 @@ def load_glyph(code_point):
             face.load_glyph(glyph_index, freetype.FT_LOAD_RENDER)
             return face
         face_index += 1
-    print(f"code point {code_point} ({hex(code_point)}) not found in font stack!", file=sys.stderr)
     return None
 
 unmerged_intervals = sorted(intervals + add_ints)
@@ -242,6 +241,12 @@ for i_start, i_end in intervals:
 
         # Build output data
         packed = bytes(pixels)
+        compressed = zlib.compress(packed)
+        is_compressed = len(compressed) < len(packed) * 0.9
+        # Use compressed data only if it's at least 10% smaller
+        if is_compressed:
+            packed = compressed
+
         glyph = GlyphProps(
             width = bitmap.width,
             height = bitmap.rows,
@@ -250,6 +255,7 @@ for i_start, i_end in intervals:
             top = face.glyph.bitmap_top,
             data_length = len(packed),
             data_offset = total_size,
+            compressed = 'true' if is_compressed else 'false',
             code_point = code_point,
         )
         total_size += len(packed)

lib/GfxRenderer/GfxRenderer.cpp

@@ -1,6 +1,33 @@
 #include "GfxRenderer.h"
 
 #include <Utf8.h>
+#include <miniz.h>
+
+namespace {
+bool inflateOneShot(const uint8_t* inputBuf, const size_t deflatedSize, uint8_t* outputBuf, const size_t inflatedSize) {
+  // Setup inflator
+  const auto inflator = static_cast<tinfl_decompressor*>(malloc(sizeof(tinfl_decompressor)));
+  if (!inflator) {
+    Serial.printf("[%lu] [ZIP] Failed to allocate memory for inflator\n", millis());
+    return false;
+  }
+  memset(inflator, 0, sizeof(tinfl_decompressor));
+  tinfl_init(inflator);
+
+  size_t inBytes = deflatedSize;
+  size_t outBytes = inflatedSize;
+  const tinfl_status status = tinfl_decompress(inflator, inputBuf, &inBytes, nullptr, outputBuf, &outBytes,
+                                               TINFL_FLAG_PARSE_ZLIB_HEADER | TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF);
+  free(inflator);
+
+  if (status != TINFL_STATUS_DONE) {
+    Serial.printf("[%lu] [ZIP] tinfl_decompress() failed with status %d\n", millis(), status);
+    return false;
+  }
+
+  return true;
+}
+}  // namespace
 
 void GfxRenderer::insertFont(const int fontId, EpdFontFamily font) { fontMap.insert({fontId, font}); }
 
@@ -616,15 +643,42 @@ void GfxRenderer::renderChar(const EpdFontFamily& fontFamily, const uint32_t cp,
   }
 
   const int is2Bit = fontFamily.getData(style)->is2Bit;
-  const uint32_t offset = glyph->dataOffset;
+  // const uint32_t offset = glyph->dataOffset;
+  // const uint32_t dataLength = glyph->dataLength;
   const uint8_t width = glyph->width;
   const uint8_t height = glyph->height;
   const int left = glyph->left;
+  const size_t outputDataSize = is2Bit ? ((width * height + 3) / 4) : ((width * height + 7) / 8);
 
-  const uint8_t* bitmap = nullptr;
-  bitmap = &fontFamily.getData(style)->bitmap[offset];
+  if (outputDataSize != glyph->dataLength && !glyph->compressed) {
+    Serial.printf("[%lu] [GFX] Glyph bitmap size mismatch for codepoint %d (expected %zu, got %d)\n", millis(), cp,
+                  outputDataSize, glyph->dataLength);
+  }
+
+  uint8_t* bitmapData = nullptr;
+  const uint8_t* bitmap;
+
+  if (glyph->compressed) {
+    bitmapData = static_cast<uint8_t*>(malloc(outputDataSize));
+    if (!bitmapData) {
+      Serial.printf("[%lu] [GFX] Failed to allocate memory for glyph bitmap for codepoint %d\n", millis(), cp);
+      return;
+    }
+
+    const auto success = inflateOneShot(&fontFamily.getData(style)->bitmap[glyph->dataOffset], glyph->dataLength,
+                                        bitmapData, outputDataSize);
+    if (!success) {
+      Serial.printf("[%lu] [GFX] Failed to inflate glyph bitmap for codepoint %d\n", millis(), cp);
+      free(bitmapData);
+      *x += glyph->advanceX;
+      return;
+    }
+
+    bitmap = bitmapData;
+  } else {
+    bitmap = &fontFamily.getData(style)->bitmap[glyph->dataOffset];
+  }
 
-  if (bitmap != nullptr) {
   for (int glyphY = 0; glyphY < height; glyphY++) {
     const int screenY = *y - glyph->top + glyphY;
     for (int glyphX = 0; glyphX < width; glyphX++) {
@@ -660,6 +714,9 @@ void GfxRenderer::renderChar(const EpdFontFamily& fontFamily, const uint32_t cp,
       }
     }
   }
+
+  if (bitmapData) {
+    free(bitmapData);
   }
 
   *x += glyph->advanceX;

lib/ZipFile/ZipFile.cpp

@@ -4,6 +4,7 @@
 #include <SDCardManager.h>
 #include <miniz.h>
 
+namespace {
 bool inflateOneShot(const uint8_t* inputBuf, const size_t deflatedSize, uint8_t* outputBuf, const size_t inflatedSize) {
   // Setup inflator
   const auto inflator = static_cast<tinfl_decompressor*>(malloc(sizeof(tinfl_decompressor)));
@@ -27,6 +28,7 @@ bool inflateOneShot(const uint8_t* inputBuf, const size_t deflatedSize, uint8_t*
 
   return true;
 }
+}  // namespace
 
 bool ZipFile::loadAllFileStatSlims() {
   const bool wasOpen = isOpen();