/* * This file is part of NetSurf, http://netsurf.sourceforge.net/ * Licensed under the GNU General Public License, * http://www.opensource.org/licenses/gpl-license * Copyright 2005 James Bursa * Copyright 2003 Phil Mellor */ /** \file * Box tree construction and manipulation (interface). * * This stage of rendering converts a tree of xmlNodes (produced by libxml2) * to a tree of struct box. The box tree represents the structure of the * document as given by the CSS display and float properties. * * For example, consider the following HTML: * \code *

Example Heading

Example paragraph with emphasised text etc.

\endcode * * This would produce approximately the following box tree with default CSS * rules: * \code * BOX_BLOCK (corresponds to h1) * BOX_INLINE_CONTAINER * BOX_INLINE "Example Heading" * BOX_BLOCK (p) * BOX_INLINE_CONTAINER * BOX_INLINE "Example paragraph " * BOX_INLINE "with emphasised text" (em) * BOX_INLINE "etc." \endcode * * Note that the em has been collapsed into the INLINE_CONTAINER. * * If these CSS rules were applied: * \code * h1 { display: table-cell } * p { display: table-cell } * em { float: left; width: 5em } \endcode * * then the box tree would instead look like this: * \code * BOX_TABLE * BOX_TABLE_ROW_GROUP * BOX_TABLE_ROW * BOX_TABLE_CELL (h1) * BOX_INLINE_CONTAINER * BOX_INLINE "Example Heading" * BOX_TABLE_CELL (p) * BOX_INLINE_CONTAINER * BOX_INLINE "Example paragraph " * BOX_FLOAT_LEFT (em) * BOX_BLOCK * BOX_INLINE_CONTAINER * BOX_INLINE "with emphasised text" * BOX_INLINE "etc." \endcode * * Here implied boxes have been added and a float is present. * * A box tree is "normalized" if the following is satisfied: * \code * parent permitted child nodes * BLOCK, INLINE_BLOCK BLOCK, INLINE_CONTAINER, TABLE * INLINE_CONTAINER INLINE, INLINE_BLOCK, FLOAT_LEFT, FLOAT_RIGHT, BR, TEXT, * INLINE_END * INLINE none * TABLE at least 1 TABLE_ROW_GROUP * TABLE_ROW_GROUP at least 1 TABLE_ROW * TABLE_ROW at least 1 TABLE_CELL * TABLE_CELL BLOCK, INLINE_CONTAINER, TABLE (same as BLOCK) * FLOAT_(LEFT|RIGHT) exactly 1 BLOCK or TABLE \endcode */ #ifndef _NETSURF_RENDER_BOX_H_ #define _NETSURF_RENDER_BOX_H_ #include #include #include "libxml/HTMLparser.h" struct box; struct column; struct css_style; struct object_params; struct object_param; /** Type of a struct box. */ typedef enum { BOX_BLOCK, BOX_INLINE_CONTAINER, BOX_INLINE, BOX_TABLE, BOX_TABLE_ROW, BOX_TABLE_CELL, BOX_TABLE_ROW_GROUP, BOX_FLOAT_LEFT, BOX_FLOAT_RIGHT, BOX_INLINE_BLOCK, BOX_BR, BOX_TEXT, BOX_INLINE_END } box_type; struct rect { int x0, y0; int x1, y1; }; /** Node in box tree. All dimensions are in pixels. */ struct box { /** Type of box. */ box_type type; /** Style for this box. 0 for INLINE_CONTAINER and FLOAT_*. */ struct css_style * style; /** Coordinate of left padding edge relative to parent box, or relative * to ancestor that contains this box in float_children for FLOAT_. */ int x; /** Coordinate of top padding edge, relative as for x. */ int y; int width; /**< Width of content box (excluding padding etc.). */ int height; /**< Height of content box (excluding padding etc.). */ /* These four variables determine the maximum extent of a box's * descendants. They are relative to the x,y coordinates of the box. * * Their use depends on the overflow CSS property: * * Overflow: Usage: * visible The content of the box is displayed within these * dimensions. * hidden These are ignored. Content is plotted within the box * dimensions. * scroll These are used to determine the extent of the * scrollable area. * auto As "scroll". */ int descendant_x0; /**< left edge of descendants */ int descendant_y0; /**< top edge of descendants */ int descendant_x1; /**< right edge of descendants */ int descendant_y1; /**< bottom edge of descendants */ int margin[4]; /**< Margin: TOP, RIGHT, BOTTOM, LEFT. */ int padding[4]; /**< Padding: TOP, RIGHT, BOTTOM, LEFT. */ int border[4]; /**< Border width: TOP, RIGHT, BOTTOM, LEFT. */ int scroll_x; /**< Horizontal scroll of descendants. */ int scroll_y; /**< Vertical scroll of descendants. */ /** Width of box taking all line breaks (including margins etc). Must * be non-negative. */ int min_width; /** Width that would be taken with no line breaks. Must be * non-negative. */ int max_width; /**< Byte offset within a textual representation of this content. */ size_t byte_offset; char *text; /**< Text, or 0 if none. Unterminated. */ size_t length; /**< Length of text. */ /** Text is followed by a space. */ unsigned int space : 1; /** This box is a continuation of the previous box (eg from line * breaking). */ unsigned int clone : 1; char *href; /**< Link, or 0. */ const char *target; /**< Link target, or 0. */ char *title; /**< Title, or 0. */ unsigned int columns; /**< Number of columns for TABLE / TABLE_CELL. */ unsigned int rows; /**< Number of rows for TABLE only. */ unsigned int start_column; /**< Start column for TABLE_CELL only. */ struct box *next; /**< Next sibling box, or 0. */ struct box *prev; /**< Previous sibling box, or 0. */ struct box *children; /**< First child box, or 0. */ struct box *last; /**< Last child box, or 0. */ struct box *parent; /**< Parent box, or 0. */ struct box *fallback; /**< Fallback children for object, or 0. */ /** INLINE_END box corresponding to this INLINE box, or INLINE box * corresponding to this INLINE_END box. */ struct box *inline_end; /** First float child box, or 0. Float boxes are in the tree twice, in * this list for the block box which defines the area for floats, and * also in the standard tree given by children, next, prev, etc. */ struct box *float_children; /** Next sibling float box. */ struct box *next_float; struct column *col; /**< Array of table column data for TABLE only. */ /** Form control data, or 0 if not a form control. */ struct form_control* gadget; char *usemap; /** (Image)map to use with this object, or 0 if none */ char *id; /**< value of id attribute (or name for anchors) */ /** Background image for this box, or 0 if none */ struct content *background; /** Object in this box (usually an image), or 0 if none. */ struct content* object; /** Parameters for the object, or 0. */ struct object_params *object_params; }; /** Table column data. */ struct column { /** Type of column. */ enum { COLUMN_WIDTH_UNKNOWN, COLUMN_WIDTH_FIXED, COLUMN_WIDTH_AUTO, COLUMN_WIDTH_PERCENT, COLUMN_WIDTH_RELATIVE } type; /** Preferred width of column. Pixels for FIXED, percentage for PERCENT, * relative units for RELATIVE, unused for AUTO. */ int width; /** Minimum width of content. */ int min; /** Maximum width of content. */ int max; }; /** Parameters for