add comments for gfx classes and editors

src/app/gfx/bitmap.h

@@ -37,24 +37,50 @@ enum BitmapFormat {
 
 
 /**
- * @brief Represents a bitmap image.
+ * @brief Represents a bitmap image optimized for SNES ROM hacking.
  *
  * The `Bitmap` class provides functionality to create, manipulate, and display
- * bitmap images. It supports various operations such as creating a bitmap
- * object, creating and updating textures, applying palettes, and accessing
- * pixel data.
+ * bitmap images specifically designed for Link to the Past ROM editing. It supports:
+ * 
+ * Key Features:
+ * - SNES-specific pixel formats (4BPP, 8BPP, indexed)
+ * - Palette management with transparent color support
+ * - Tile extraction (8x8, 16x16) for ROM tile editing
+ * - Memory-efficient surface/texture management via Arena
+ * - Real-time editing with immediate visual feedback
+ * 
+ * Performance Optimizations:
+ * - Lazy texture creation (textures only created when needed)
+ * - Modified flag tracking to avoid unnecessary updates
+ * - Arena-based resource pooling to reduce allocation overhead
+ * - Direct pixel data manipulation for fast editing operations
+ * 
+ * ROM Hacking Specific:
+ * - SNES color format conversion (15-bit RGB to 8-bit indexed)
+ * - Tile-based editing for 8x8 and 16x16 SNES tiles
+ * - Palette index management for ROM palette editing
+ * - Support for multiple graphics sheets (223 total in YAZE)
  */
 class Bitmap {
  public:
   Bitmap() = default;
 
   /**
-   * @brief Create a bitmap with the given dimensions and data
+   * @brief Create a bitmap with the given dimensions and raw pixel data
+   * @param width Width in pixels (typically 128, 256, or 512 for SNES tilesheets)
+   * @param height Height in pixels (typically 32, 64, or 128 for SNES tilesheets)
+   * @param depth Color depth in bits per pixel (4, 8, or 16 for SNES)
+   * @param data Raw pixel data (indexed color values for SNES graphics)
    */
   Bitmap(int width, int height, int depth, const std::vector<uint8_t> &data);
 
   /**
-   * @brief Create a bitmap with the given dimensions, data, and palette
+   * @brief Create a bitmap with the given dimensions, data, and SNES palette
+   * @param width Width in pixels
+   * @param height Height in pixels  
+   * @param depth Color depth in bits per pixel
+   * @param data Raw pixel data (indexed color values)
+   * @param palette SNES palette for color mapping (15-bit RGB format)
    */
   Bitmap(int width, int height, int depth, const std::vector<uint8_t> &data,
          const SnesPalette &palette);
@@ -148,23 +174,41 @@ class Bitmap {
   void WriteColor(int position, const ImVec4 &color);
 
   /**
-   * @brief Set a pixel at the given x,y coordinates
+   * @brief Set a pixel at the given x,y coordinates with SNES color
+   * @param x X coordinate (0 to width-1)
+   * @param y Y coordinate (0 to height-1) 
+   * @param color SNES color (15-bit RGB format)
+   * @note Automatically finds closest palette index and marks bitmap as modified
    */
   void SetPixel(int x, int y, const SnesColor& color);
 
   /**
-   * @brief Resize the bitmap to new dimensions
+   * @brief Resize the bitmap to new dimensions (preserves existing data)
+   * @param new_width New width in pixels
+   * @param new_height New height in pixels
+   * @note Expands with black pixels, crops excess data
    */
   void Resize(int new_width, int new_height);
 
   /**
-   * @brief Extract an 8x8 tile from the bitmap
+   * @brief Extract an 8x8 tile from the bitmap (SNES standard tile size)
+   * @param tile_index Index of the tile in the tilesheet
+   * @param x X offset within the tile (0-7)
+   * @param y Y offset within the tile (0-7)
+   * @param tile_data Output buffer for tile pixel data (64 bytes for 8x8)
+   * @param tile_data_offset Current offset in tile_data buffer
+   * @note Used for ROM tile editing and tile extraction
    */
   void Get8x8Tile(int tile_index, int x, int y, std::vector<uint8_t> &tile_data,
                   int &tile_data_offset);
 
   /**
-   * @brief Extract a 16x16 tile from the bitmap
+   * @brief Extract a 16x16 tile from the bitmap (SNES metatile size)
+   * @param tile_x X coordinate of tile in tilesheet
+   * @param tile_y Y coordinate of tile in tilesheet
+   * @param tile_data Output buffer for tile pixel data (256 bytes for 16x16)
+   * @param tile_data_offset Current offset in tile_data buffer
+   * @note Used for ROM metatile editing and large tile extraction
    */
   void Get16x16Tile(int tile_x, int tile_y, std::vector<uint8_t> &tile_data,
                     int &tile_data_offset);