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Diffstat (limited to 'content/handlers/html/layout_internal.h')
| -rw-r--r-- | content/handlers/html/layout_internal.h | 738 |
1 files changed, 738 insertions, 0 deletions
diff --git a/content/handlers/html/layout_internal.h b/content/handlers/html/layout_internal.h new file mode 100644 index 000000000..d094462ec --- /dev/null +++ b/content/handlers/html/layout_internal.h @@ -0,0 +1,738 @@ +/* + * Copyright 2003 James Bursa <bursa@users.sourceforge.net> + * + * This file is part of NetSurf, http://www.netsurf-browser.org/ + * + * NetSurf is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * NetSurf is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +/** + * \file + * HTML layout private interface. + */ + +#ifndef NETSURF_HTML_LAYOUT_INTERNAL_H +#define NETSURF_HTML_LAYOUT_INTERNAL_H + +#define AUTO INT_MIN + +/* Fixed point percentage (a) of an integer (b), to an integer */ +#define FPCT_OF_INT_TOINT(a, b) (FIXTOINT(FDIV((a * b), F_100))) + +/** + * Layout a block formatting context. + * + * \param block BLOCK, INLINE_BLOCK, or TABLE_CELL to layout + * \param viewport_height Height of viewport in pixels or -ve if unknown + * \param content Memory pool for any new boxes + * \return true on success, false on memory exhaustion + * + * This function carries out layout of a block and its children, as described + * in CSS 2.1 9.4.1. + */ +bool layout_block_context( + struct box *block, + int viewport_height, + html_content *content); + +/** + * Layout a table. + * + * \param table table to layout + * \param available_width width of containing block + * \param content memory pool for any new boxes + * \return true on success, false on memory exhaustion + */ +bool layout_table( + struct box *table, + int available_width, + html_content *content); + +/** + * Layout a flex container. + * + * \param[in] flex table to layout + * \param[in] available_width width of containing block + * \param[in] content memory pool for any new boxes + * \return true on success, false on memory exhaustion + */ +bool layout_flex( + struct box *flex, + int available_width, + html_content *content); + +typedef uint8_t (*css_len_func)( + const css_computed_style *style, + css_fixed *length, css_unit *unit); +typedef uint8_t (*css_border_style_func)( + const css_computed_style *style); +typedef uint8_t (*css_border_color_func)( + const css_computed_style *style, + css_color *color); + +/** Array of per-side access functions for computed style margins. */ +extern const css_len_func margin_funcs[4]; + +/** Array of per-side access functions for computed style paddings. */ +extern const css_len_func padding_funcs[4]; + +/** Array of per-side access functions for computed style border_widths. */ +extern const css_len_func border_width_funcs[4]; + +/** Array of per-side access functions for computed style border styles. */ +extern const css_border_style_func border_style_funcs[4]; + +/** Array of per-side access functions for computed style border colors. */ +extern const css_border_color_func border_color_funcs[4]; + +/** Layout helper: Check whether box is a float. */ +static inline bool lh__box_is_float_box(const struct box *b) +{ + return b->type == BOX_FLOAT_LEFT || + b->type == BOX_FLOAT_RIGHT; +} + +/** Layout helper: Check whether box takes part in inline flow. */ +static inline bool lh__box_is_inline_flow(const struct box *b) +{ + return b->type == BOX_INLINE || + b->type == BOX_INLINE_FLEX || + b->type == BOX_INLINE_BLOCK || + b->type == BOX_TEXT || + b->type == BOX_INLINE_END; +} + +/** Layout helper: Check whether box takes part in inline flow. */ +static inline bool lh__box_is_flex_container(const struct box *b) +{ + return b->type == BOX_FLEX || + b->type == BOX_INLINE_FLEX; +} + +/** Layout helper: Check whether box takes part in inline flow. */ +static inline bool lh__box_is_flex_item(const struct box *b) +{ + return (b->parent != NULL) && lh__box_is_flex_container(b->parent); +} + +/** Layout helper: Check whether box is inline level. (Includes BR.) */ +static inline bool lh__box_is_inline_level(const struct box *b) +{ + return lh__box_is_inline_flow(b) || + b->type == BOX_BR; +} + +/** Layout helper: Check whether box is inline level. (Includes BR, floats.) */ +static inline bool lh__box_is_inline_content(const struct box *b) +{ + return lh__box_is_float_box(b) || + lh__box_is_inline_level(b); +} + +/** Layout helper: Check whether box is an object. */ +static inline bool lh__box_is_object(const struct box *b) +{ + return b->object || + (b->flags & (IFRAME | REPLACE_DIM)); +} + +/** Layout helper: Check whether box is replaced. */ +static inline bool lh__box_is_replace(const struct box *b) +{ + return b->gadget || + lh__box_is_object(b); +} + +/** Layout helper: Check for CSS border on given side. */ +static inline bool lh__have_border( + enum box_side side, + const css_computed_style *style) +{ + return border_style_funcs[side](style) != CSS_BORDER_STYLE_NONE; +} + +static inline bool lh__box_is_absolute(const struct box *b) +{ + return css_computed_position(b->style) == CSS_POSITION_ABSOLUTE || + css_computed_position(b->style) == CSS_POSITION_FIXED; +} + +static inline bool lh__flex_main_is_horizontal(const struct box *flex) +{ + const css_computed_style *style = flex->style; + + assert(style != NULL); + + switch (css_computed_flex_direction(style)) { + default: /* Fallthrough. */ + case CSS_FLEX_DIRECTION_ROW: /* Fallthrough. */ + case CSS_FLEX_DIRECTION_ROW_REVERSE: + return true; + case CSS_FLEX_DIRECTION_COLUMN: /* Fallthrough. */ + case CSS_FLEX_DIRECTION_COLUMN_REVERSE: + return false; + } +} + +static inline bool lh__flex_direction_reversed(const struct box *flex) +{ + switch (css_computed_flex_direction(flex->style)) { + default: /* Fallthrough. */ + case CSS_FLEX_DIRECTION_ROW_REVERSE: /* Fallthrough. */ + case CSS_FLEX_DIRECTION_COLUMN_REVERSE: + return true; + case CSS_FLEX_DIRECTION_ROW: /* Fallthrough. */ + case CSS_FLEX_DIRECTION_COLUMN: + return false; + } +} + +static inline int lh__non_auto_margin(const struct box *b, enum box_side side) +{ + return (b->margin[side] == AUTO) ? 0 : b->margin[side]; +} + +static inline int lh__delta_outer_height(const struct box *b) +{ + return b->padding[TOP] + + b->padding[BOTTOM] + + b->border[TOP].width + + b->border[BOTTOM].width + + lh__non_auto_margin(b, TOP) + + lh__non_auto_margin(b, BOTTOM); +} + +static inline int lh__delta_outer_width(const struct box *b) +{ + return b->padding[LEFT] + + b->padding[RIGHT] + + b->border[LEFT].width + + b->border[RIGHT].width + + lh__non_auto_margin(b, LEFT) + + lh__non_auto_margin(b, RIGHT); +} + +static inline int lh__delta_outer_main( + const struct box *flex, + const struct box *b) +{ + if (lh__flex_main_is_horizontal(flex)) { + return lh__delta_outer_width(b); + } else { + return lh__delta_outer_height(b); + } +} + +static inline int lh__delta_outer_cross( + const struct box *flex, + const struct box *b) +{ + if (lh__flex_main_is_horizontal(flex) == false) { + return lh__delta_outer_width(b); + } else { + return lh__delta_outer_height(b); + } +} + +static inline int *lh__box_size_main_ptr( + bool horizontal, + struct box *b) +{ + return horizontal ? &b->width : &b->height; +} + +static inline int *lh__box_size_cross_ptr( + bool horizontal, + struct box *b) +{ + return horizontal ? &b->height : &b->width; +} + +static inline int lh__box_size_main( + bool horizontal, + const struct box *b) +{ + return horizontal ? b->width : b->height; +} + +static inline int lh__box_size_cross( + bool horizontal, + const struct box *b) +{ + return horizontal ? b->height : b->width; +} + +static inline bool lh__box_size_cross_is_auto( + bool horizontal, + struct box *b) +{ + css_fixed length; + css_unit unit; + + if (horizontal) { + return css_computed_height(b->style, + &length, &unit) == CSS_HEIGHT_AUTO; + } else { + return css_computed_width(b->style, + &length, &unit) == CSS_WIDTH_AUTO; + } +} + +static inline enum css_align_self_e lh__box_align_self( + const struct box *flex, + const struct box *item) +{ + enum css_align_self_e align_self = css_computed_align_self(item->style); + + if (align_self == CSS_ALIGN_SELF_AUTO) { + align_self = css_computed_align_items(flex->style); + } + + return align_self; +} + +/** + * Determine width of margin, borders, and padding on one side of a box. + * + * \param unit_len_ctx CSS length conversion context for document + * \param style style to measure + * \param side side of box to measure + * \param margin whether margin width is required + * \param border whether border width is required + * \param padding whether padding width is required + * \param fixed increased by sum of fixed margin, border, and padding + * \param frac increased by sum of fractional margin and padding + */ +static inline void calculate_mbp_width( + const css_unit_ctx *unit_len_ctx, + const css_computed_style *style, + unsigned int side, + bool margin, + bool border, + bool padding, + int *fixed, + float *frac) +{ + css_fixed value = 0; + css_unit unit = CSS_UNIT_PX; + + assert(style); + + /* margin */ + if (margin) { + enum css_margin_e type; + + type = margin_funcs[side](style, &value, &unit); + if (type == CSS_MARGIN_SET) { + if (unit == CSS_UNIT_PCT) { + *frac += FIXTOFLT(FDIV(value, F_100)); + } else { + *fixed += FIXTOINT(css_unit_len2device_px( + style, unit_len_ctx, + value, unit)); + } + } + } + + /* border */ + if (border) { + if (lh__have_border(side, style)) { + border_width_funcs[side](style, &value, &unit); + + *fixed += FIXTOINT(css_unit_len2device_px( + style, unit_len_ctx, + value, unit)); + } + } + + /* padding */ + if (padding) { + padding_funcs[side](style, &value, &unit); + if (unit == CSS_UNIT_PCT) { + *frac += FIXTOFLT(FDIV(value, F_100)); + } else { + *fixed += FIXTOINT(css_unit_len2device_px( + style, unit_len_ctx, + value, unit)); + } + } +} + +/** + * Adjust a specified width or height for the box-sizing property. + * + * This turns the specified dimension into a content-box dimension. + * + * \param unit_len_ctx Length conversion context + * \param box gadget to adjust dimensions of + * \param available_width width of containing block + * \param setwidth set true if the dimension to be tweaked is a width, + * else set false for a height + * \param dimension current value for given width/height dimension. + * updated to new value after consideration of + * gadget properties. + */ +static inline void layout_handle_box_sizing( + const css_unit_ctx *unit_len_ctx, + const struct box *box, + int available_width, + bool setwidth, + int *dimension) +{ + enum css_box_sizing_e bs; + + assert(box && box->style); + + bs = css_computed_box_sizing(box->style); + + if (bs == CSS_BOX_SIZING_BORDER_BOX) { + int orig = *dimension; + int fixed = 0; + float frac = 0; + + calculate_mbp_width(unit_len_ctx, box->style, + setwidth ? LEFT : TOP, + false, true, true, &fixed, &frac); + calculate_mbp_width(unit_len_ctx, box->style, + setwidth ? RIGHT : BOTTOM, + false, true, true, &fixed, &frac); + orig -= frac * available_width + fixed; + *dimension = orig > 0 ? orig : 0; + } +} + +/** + * Calculate width, height, and thickness of margins, paddings, and borders. + * + * \param unit_len_ctx Length conversion context + * \param available_width width of containing block + * \param viewport_height height of viewport in pixels or -ve if unknown + * \param box current box + * \param style style giving width, height, margins, paddings, + * and borders + * \param width updated to width, may be NULL + * \param height updated to height, may be NULL + * \param max_width updated to max-width, may be NULL + * \param min_width updated to min-width, may be NULL + * \param max_height updated to max-height, may be NULL + * \param min_height updated to min-height, may be NULL + * \param margin filled with margins, may be NULL + * \param padding filled with paddings, may be NULL + * \param border filled with border widths, may be NULL + */ +static inline void layout_find_dimensions( + const css_unit_ctx *unit_len_ctx, + int available_width, + int viewport_height, + const struct box *box, + const css_computed_style *style, + int *width, + int *height, + int *max_width, + int *min_width, + int *max_height, + int *min_height, + int margin[4], + int padding[4], + struct box_border border[4]) +{ + struct box *containing_block = NULL; + unsigned int i; + + if (width) { + enum css_width_e wtype; + css_fixed value = 0; + css_unit unit = CSS_UNIT_PX; + + wtype = css_computed_width(style, &value, &unit); + + if (wtype == CSS_WIDTH_SET) { + if (unit == CSS_UNIT_PCT) { + *width = FPCT_OF_INT_TOINT( + value, available_width); + } else { + *width = FIXTOINT(css_unit_len2device_px( + style, unit_len_ctx, + value, unit)); + } + } else { + *width = AUTO; + } + + if (*width != AUTO) { + layout_handle_box_sizing(unit_len_ctx, box, + available_width, true, width); + } + } + + if (height) { + enum css_height_e htype; + css_fixed value = 0; + css_unit unit = CSS_UNIT_PX; + + htype = css_computed_height(style, &value, &unit); + + if (htype == CSS_HEIGHT_SET) { + if (unit == CSS_UNIT_PCT) { + enum css_height_e cbhtype; + + if (css_computed_position(box->style) == + CSS_POSITION_ABSOLUTE && + box->parent) { + /* Box is absolutely positioned */ + assert(box->float_container); + containing_block = box->float_container; + } else if (box->float_container && + css_computed_position(box->style) != + CSS_POSITION_ABSOLUTE && + (css_computed_float(box->style) == + CSS_FLOAT_LEFT || + css_computed_float(box->style) == + CSS_FLOAT_RIGHT)) { + /* Box is a float */ + assert(box->parent && + box->parent->parent && + box->parent->parent->parent); + + containing_block = + box->parent->parent->parent; + } else if (box->parent && box->parent->type != + BOX_INLINE_CONTAINER) { + /* Box is a block level element */ + containing_block = box->parent; + } else if (box->parent && box->parent->type == + BOX_INLINE_CONTAINER) { + /* Box is an inline block */ + assert(box->parent->parent); + containing_block = box->parent->parent; + } + + if (containing_block) { + css_fixed f = 0; + css_unit u = CSS_UNIT_PX; + + cbhtype = css_computed_height( + containing_block->style, + &f, &u); + } + + if (containing_block && + containing_block->height != AUTO && + (css_computed_position(box->style) == + CSS_POSITION_ABSOLUTE || + cbhtype == CSS_HEIGHT_SET)) { + /* Box is absolutely positioned or its + * containing block has a valid + * specified height. + * (CSS 2.1 Section 10.5) */ + *height = FPCT_OF_INT_TOINT(value, + containing_block->height); + } else if ((!box->parent || + !box->parent->parent) && + viewport_height >= 0) { + /* If root element or it's child + * (HTML or BODY) */ + *height = FPCT_OF_INT_TOINT(value, + viewport_height); + } else { + /* precentage height not permissible + * treat height as auto */ + *height = AUTO; + } + } else { + *height = FIXTOINT(css_unit_len2device_px( + style, unit_len_ctx, + value, unit)); + } + } else { + *height = AUTO; + } + + if (*height != AUTO) { + layout_handle_box_sizing(unit_len_ctx, box, + available_width, false, height); + } + } + + if (max_width) { + enum css_max_width_e type; + css_fixed value = 0; + css_unit unit = CSS_UNIT_PX; + + type = css_computed_max_width(style, &value, &unit); + + if (type == CSS_MAX_WIDTH_SET) { + if (unit == CSS_UNIT_PCT) { + *max_width = FPCT_OF_INT_TOINT(value, + available_width); + } else { + *max_width = FIXTOINT(css_unit_len2device_px( + style, unit_len_ctx, + value, unit)); + } + } else { + /* Inadmissible */ + *max_width = -1; + } + + if (*max_width != -1) { + layout_handle_box_sizing(unit_len_ctx, box, + available_width, true, max_width); + } + } + + if (min_width) { + enum css_min_width_e type; + css_fixed value = 0; + css_unit unit = CSS_UNIT_PX; + + type = ns_computed_min_width(style, &value, &unit); + + if (type == CSS_MIN_WIDTH_SET) { + if (unit == CSS_UNIT_PCT) { + *min_width = FPCT_OF_INT_TOINT(value, + available_width); + } else { + *min_width = FIXTOINT(css_unit_len2device_px( + style, unit_len_ctx, + value, unit)); + } + } else { + /* Inadmissible */ + *min_width = 0; + } + + if (*min_width != 0) { + layout_handle_box_sizing(unit_len_ctx, box, + available_width, true, min_width); + } + } + + if (max_height) { + enum css_max_height_e type; + css_fixed value = 0; + css_unit unit = CSS_UNIT_PX; + + type = css_computed_max_height(style, &value, &unit); + + if (type == CSS_MAX_HEIGHT_SET) { + if (unit == CSS_UNIT_PCT) { + /* TODO: handle percentage */ + *max_height = -1; + } else { + *max_height = FIXTOINT(css_unit_len2device_px( + style, unit_len_ctx, + value, unit)); + } + } else { + /* Inadmissible */ + *max_height = -1; + } + } + + if (min_height) { + enum css_min_height_e type; + css_fixed value = 0; + css_unit unit = CSS_UNIT_PX; + + type = ns_computed_min_height(style, &value, &unit); + + if (type == CSS_MIN_HEIGHT_SET) { + if (unit == CSS_UNIT_PCT) { + /* TODO: handle percentage */ + *min_height = 0; + } else { + *min_height = FIXTOINT(css_unit_len2device_px( + style, unit_len_ctx, + value, unit)); + } + } else { + /* Inadmissible */ + *min_height = 0; + } + } + + for (i = 0; i != 4; i++) { + if (margin) { + enum css_margin_e type = CSS_MARGIN_AUTO; + css_fixed value = 0; + css_unit unit = CSS_UNIT_PX; + + type = margin_funcs[i](style, &value, &unit); + + if (type == CSS_MARGIN_SET) { + if (unit == CSS_UNIT_PCT) { + margin[i] = FPCT_OF_INT_TOINT(value, + available_width); + } else { + margin[i] = FIXTOINT(css_unit_len2device_px( + style, unit_len_ctx, + value, unit)); + } + } else { + margin[i] = AUTO; + } + } + + if (padding) { + css_fixed value = 0; + css_unit unit = CSS_UNIT_PX; + + padding_funcs[i](style, &value, &unit); + + if (unit == CSS_UNIT_PCT) { + padding[i] = FPCT_OF_INT_TOINT(value, + available_width); + } else { + padding[i] = FIXTOINT(css_unit_len2device_px( + style, unit_len_ctx, + value, unit)); + } + } + + /* Table cell borders are populated in table.c */ + if (border && box->type != BOX_TABLE_CELL) { + enum css_border_style_e bstyle = CSS_BORDER_STYLE_NONE; + css_color color = 0; + css_fixed value = 0; + css_unit unit = CSS_UNIT_PX; + + border_width_funcs[i](style, &value, &unit); + bstyle = border_style_funcs[i](style); + border_color_funcs[i](style, &color); + + border[i].style = bstyle; + border[i].c = color; + + if (bstyle == CSS_BORDER_STYLE_HIDDEN || + bstyle == CSS_BORDER_STYLE_NONE) + /* spec unclear: following Mozilla */ + border[i].width = 0; + else + border[i].width = FIXTOINT(css_unit_len2device_px( + style, unit_len_ctx, + value, unit)); + + /* Special case for border-collapse: make all borders + * on table/table-row-group/table-row zero width. */ + if (css_computed_border_collapse(style) == + CSS_BORDER_COLLAPSE_COLLAPSE && + (box->type == BOX_TABLE || + box->type == BOX_TABLE_ROW_GROUP || + box->type == BOX_TABLE_ROW)) + border[i].width = 0; + } + } +} + +#endif |