reflow_types.h

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#pragma once
 
#include <stddef.h>
#include <stdint.h>
 
#include "ra8_err.h"
#include "ra8_glyph_atlas.h" /* ra8_glyph_atlas_t for the Layer-3 glyph cache (#164) */
#include "reflow_css.h"      /* ra8_css_sheet_t for the content-CSS cascade (#111)   */
#include "reflow_image.h"    /* ra8_img_arena_t for the decode scratch               */
 
/* ===========================================================================
 * Compile-time limits
 * ===========================================================================
 */

typedef enum : uint32_t {
  k_reflow_max_tokens         = 4096U,  
  k_reflow_text_pool_bytes    = 65536U, 
  k_reflow_max_glyphs         = 32768U, 
  k_reflow_max_pages          = 256U,   
  k_reflow_max_lines_per_page = 96U,    
  k_reflow_max_images         = 64U,    
  k_reflow_max_links          = 255U,   
  k_reflow_max_link_rects     = 512U,   
  k_reflow_max_anchors        = 256U,   
  k_reflow_max_faces          = 8U,     
} reflow_limits_t;

typedef enum : uint16_t {
  k_reflow_margin_px        = 16U,  
  k_reflow_line_spacing_num = 12U,  
  k_reflow_line_spacing_den = 10U,  
  k_reflow_paragraph_gap_px = 8U,   
  k_reflow_indent_px        = 24U,  
  k_reflow_default_font_px  = 18U,  
  k_reflow_min_font_px      = 8U,   
  k_reflow_max_font_px      = 96U,  
  k_reflow_min_font_bytes   = 16U,  
  k_reflow_h1_scale_pct     = 200U, 
  k_reflow_h2_scale_pct     = 175U, 
  k_reflow_h3_scale_pct     = 150U, 
  k_reflow_h4_scale_pct     = 125U, 
  k_reflow_h5_scale_pct     = 110U, 
  k_reflow_h6_scale_pct     = 100U, 
  k_reflow_pct_full         = 100U, 
} reflow_layout_t;

typedef enum : uint8_t {
  k_reflow_tag_unknown    = 0U,  
  k_reflow_tag_p          = 1U,  
  k_reflow_tag_h1         = 2U,  
  k_reflow_tag_h2         = 3U,  
  k_reflow_tag_h3         = 4U,  
  k_reflow_tag_h4         = 5U,  
  k_reflow_tag_h5         = 6U,  
  k_reflow_tag_h6         = 7U,  
  k_reflow_tag_em         = 8U,  
  k_reflow_tag_strong     = 9U,  
  k_reflow_tag_b          = 10U, 
  k_reflow_tag_i          = 11U, 
  k_reflow_tag_br         = 12U, 
  k_reflow_tag_hr         = 13U, 
  k_reflow_tag_ul         = 14U, 
  k_reflow_tag_ol         = 15U, 
  k_reflow_tag_li         = 16U, 
  k_reflow_tag_blockquote = 17U, 
  k_reflow_tag_a          = 18U, 
  k_reflow_tag_img        = 19U, 
  k_reflow_tag_table      = 20U, 
  k_reflow_tag_tr         = 21U, 
  k_reflow_tag_td         = 22U, 
  k_reflow_tag_th         = 23U, 
  k_reflow_tag_link       = 24U, 
} reflow_html_tag_t;

typedef enum : uint8_t {
  k_reflow_style_normal    = 0U,       
  k_reflow_style_bold      = 1U << 0U, 
  k_reflow_style_italic    = 1U << 1U, 
  k_reflow_style_underline = 1U << 2U, 
} reflow_font_style_t;

typedef enum : uint8_t {
  k_reflow_face_shift = 4U,    
  k_reflow_face_mask  = 0x0FU, 
} reflow_face_pack_t;

typedef enum : uint8_t {
  k_reflow_align_left    = 0U, 
  k_reflow_align_right   = 1U, 
  k_reflow_align_center  = 2U, 
  k_reflow_align_justify = 3U, 
} reflow_align_t;

typedef enum : uint8_t {
  k_reflow_tok_block_start = 0U, 
  k_reflow_tok_block_end   = 1U, 
  k_reflow_tok_text        = 2U, 
  k_reflow_tok_break       = 3U, 
  k_reflow_tok_rule        = 4U, 
  k_reflow_tok_image       = 5U, 
} reflow_token_kind_t;
 
/* ===========================================================================
 * Forward declarations (opaque payloads)
 * ===========================================================================
 */

typedef enum : uint32_t {
  k_reflow_color_inherit = 0xFFFFFFFFU, 
} reflow_color_t;

typedef struct {
  uint8_t  kind;        
  uint8_t  tag;         
  uint8_t  style;       
  uint8_t  reserved;    
  uint32_t text_off;    
  uint32_t text_len;    
  uint32_t color;       
  uint16_t css_font_px; 
  uint16_t reserved16;  
} reflow_token_t;

typedef struct {
  int32_t  x;        
  int32_t  y;        
  int32_t  cp;       
  uint32_t color;    
  uint16_t font_px;  
  uint8_t  style;    
  uint8_t  reserved; 
} reflow_glyph_t;

typedef struct {
  uint32_t glyph_first; 
  uint32_t glyph_count; 
} reflow_page_t;

typedef struct {
  int32_t  x;          
  int32_t  y;          
  int32_t  w;          
  int32_t  h;          
  uint32_t src_off;    
  uint32_t src_len;    
  uint32_t page_index; 
  uint32_t reserved;   
} reflow_image_box_t;

typedef ra8_err_t (*reflow_image_loader_fn)(void*           ctx,
                                            const char*     href,
                                            uint32_t        href_len,
                                            const uint8_t** out_bytes,
                                            size_t*         out_len);

typedef ra8_err_t (*reflow_css_loader_fn)(void*           ctx,
                                          const char*     href,
                                          uint32_t        href_len,
                                          const uint8_t** out_bytes,
                                          size_t*         out_len);

typedef struct {
  uint32_t href_off; 
  uint32_t href_len; 
} reflow_link_target_t;

typedef struct {
  int32_t  x;          
  int32_t  y;          
  int32_t  w;          
  int32_t  h;          
  uint32_t target;     
  uint32_t page_index; 
} reflow_link_rect_t;

typedef struct {
  uint32_t id_off;     
  uint32_t id_len;     
  uint32_t page_index; 
  int32_t  y;          
} reflow_anchor_t;

typedef enum : uint8_t {
  k_reflow_href_empty            = 0U, 
  k_reflow_href_fragment         = 1U, 
  k_reflow_href_chapter          = 2U, 
  k_reflow_href_chapter_fragment = 3U, 
  k_reflow_href_external         = 4U, 
} reflow_href_kind_t;
 
/* ===========================================================================
 * Engine handle
 * ===========================================================================
 */

typedef enum : uint8_t {
  k_reflow_face_pad8 = 7, 
} reflow_face_pad_t;

typedef struct {
  const uint8_t* blob;                     
  size_t         len;                      
  uint8_t        css_face_idx;             
  uint8_t        pad8[k_reflow_face_pad8]; 
} reflow_face_t;

typedef struct {
  /* --- viewport + style ------------------------------------------------ */
  uint16_t viewport_w; 
  uint16_t viewport_h; 
  uint16_t font_px;    
  uint16_t reserved16; 
  uint32_t body_color; 
  uint32_t link_color; 
 
  /* --- font (caller-owned TTF blob) ------------------------------------ */
  const uint8_t* font_data;                 
  size_t         font_len;                  
  reflow_face_t  faces[k_reflow_max_faces]; 
  uint8_t        face_count;                
 
  /* --- cached chapter input ------------------------------------------- */
  const uint8_t* xhtml_buf; 
  size_t         xhtml_len; 
 
  /* --- token stream --------------------------------------------------- */
  reflow_token_t tokens[k_reflow_max_tokens];         
  uint32_t       token_count;                         
  uint8_t        text_pool[k_reflow_text_pool_bytes]; 
  uint32_t       text_pool_used;                      
 
  /* --- laid-out glyphs ------------------------------------------------ */
  reflow_glyph_t glyphs[k_reflow_max_glyphs]; 
  uint32_t       glyph_count;                 
  reflow_page_t  pages[k_reflow_max_pages];   
  uint32_t       page_count;                  
 
  /* --- image rendering (#106) ---------------------------------------- */
  reflow_image_loader_fn img_loader;     
  void*                  img_loader_ctx; 
  ra8_img_arena_t*       img_arena;      
  reflow_css_loader_fn   css_loader;     
  void*                  css_loader_ctx; 
  reflow_image_box_t image_boxes[k_reflow_max_images];
  uint32_t image_box_count;
 
  /* --- hyperlinks + anchors (#110) ----------------------------------- */
  reflow_link_target_t link_targets[k_reflow_max_links];    
  uint32_t             link_target_count;                   
  reflow_link_rect_t   link_rects[k_reflow_max_link_rects]; 
  uint32_t             link_rect_count;                     
  reflow_anchor_t      anchors[k_reflow_max_anchors];       
  uint32_t             anchor_count;                        
 
  /* --- content CSS cascade (#111) ------------------------------------ */
  ra8_css_sheet_t css; 
 
  /* --- glyph atlas (Layer-3 cache, #164) ----------------------------- */
  ra8_glyph_atlas_t* glyph_atlas; 
 
  /* --- lifecycle ------------------------------------------------------ */
  uint8_t in_use;       
  uint8_t reserved8[3]; 
} reflow_t;