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netsurf/render/layout.c
James Bursa e8ef816111 [project @ 2006-01-15 22:25:40 by bursa] 
Fix crash related to negative margins on inlines.

svn path=/import/netsurf/; revision=2021
2006-01-15 22:25:40 +00:00

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/*
* 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 Richard Wilson <info@tinct.net>
* Copyright 2006 James Bursa <bursa@users.sourceforge.net>
* Copyright 2003 Phil Mellor <monkeyson@users.sourceforge.net>
*/
/** \file
* HTML layout (implementation).
*
* Layout is carried out in two stages:
*
* - calculation of minimum / maximum box widths
* - layout (position and dimensions)
*
* In most cases the functions for the two stages are a corresponding pair
* layout_minmax_X() and layout_X().
*/
#define _GNU_SOURCE /* for strndup */
#include <assert.h>
#include <ctype.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "netsurf/css/css.h"
#include "netsurf/content/content.h"
#ifdef riscos
#include "netsurf/desktop/gui.h"
#endif
#include "netsurf/desktop/options.h"
#include "netsurf/render/box.h"
#include "netsurf/render/font.h"
#include "netsurf/render/layout.h"
#define NDEBUG
#include "netsurf/utils/log.h"
#include "netsurf/utils/talloc.h"
#include "netsurf/utils/utils.h"
#define AUTO INT_MIN
static void layout_minmax_block(struct box *block);
static void layout_block_find_dimensions(int available_width, struct box *box);
static int layout_solve_width(int available_width, int width,
int margin[4], int padding[4], int border[4]);
static void layout_float_find_dimensions(int available_width,
struct css_style *style, struct box *box);
static void layout_find_dimensions(int available_width,
struct css_style *style,
int margin[4], int padding[4], int border[4]);
static int layout_clear(struct box *fl, css_clear clear);
static void find_sides(struct box *fl, int y0, int y1,
int *x0, int *x1, struct box **left, struct box **right);
static void layout_minmax_inline_container(struct box *inline_container);
static int line_height(struct css_style *style);
static bool layout_line(struct box *first, int width, int *y,
int cx, int cy, struct box *cont, bool indent,
struct content *content, struct box **next_box);
static struct box *layout_minmax_line(struct box *first, int *min, int *max);
static int layout_text_indent(struct css_style *style, int width);
static bool layout_float(struct box *b, int width, struct content *content);
static void place_float_below(struct box *c, int width, int cx, int y,
struct box *cont);
static bool layout_table(struct box *box, int available_width,
struct content *content);
static void layout_minmax_table(struct box *table);
static void layout_move_children(struct box *box, int x, int y);
static void calculate_mbp_width(struct css_style *style, unsigned int side,
int *fixed, float *frac);
static void layout_position_relative(struct box *root);
static void layout_compute_relative_offset(struct box *box, int *x, int *y);
/**
* Calculate positions of boxes in a document.
*
* \param doc content of type CONTENT_HTML
* \param width available width
* \param height available height
* \return true on success, false on memory exhaustion
*/
bool layout_document(struct content *content, int width, int height)
{
bool ret;
struct box *doc = content->data.html.layout;
assert(content->type == CONTENT_HTML);
layout_minmax_block(doc);
layout_block_find_dimensions(width, doc);
doc->x = doc->margin[LEFT] + doc->border[LEFT];
doc->y = doc->margin[TOP] + doc->border[TOP];
width -= doc->margin[LEFT] + doc->border[LEFT] + doc->padding[LEFT] +
doc->padding[RIGHT] + doc->border[RIGHT] +
doc->margin[RIGHT];
if (width < 0)
width = 0;
doc->width = width;
ret = layout_block_context(doc, content);
/* make <html> and <body> fill available height */
if (doc->y + doc->padding[TOP] + doc->height + doc->padding[BOTTOM] +
doc->border[BOTTOM] + doc->margin[BOTTOM] <
height) {
doc->height = height - (doc->y + doc->padding[TOP] +
doc->padding[BOTTOM] + doc->border[BOTTOM] +
doc->margin[BOTTOM]);
if (doc->children)
doc->children->height = doc->height -
(doc->children->margin[TOP] +
doc->children->border[TOP] +
doc->children->padding[TOP] +
doc->children->padding[BOTTOM] +
doc->children->border[BOTTOM] +
doc->children->margin[BOTTOM]);
}
layout_position_relative(doc);
layout_calculate_descendant_bboxes(doc);
return ret;
}
/**
* Layout a block formatting context.
*
* \param block BLOCK, INLINE_BLOCK, or TABLE_CELL to layout.
* \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, struct content *content)
{
struct box *box;
int cx;
int cy;
int max_pos_margin = 0;
int max_neg_margin = 0;
int y;
struct box *margin_box;
assert(block->type == BOX_BLOCK ||
block->type == BOX_INLINE_BLOCK ||
block->type == BOX_TABLE_CELL);
gui_multitask();
block->float_children = 0;
if (block->object) {
if (block->object->type == CONTENT_HTML) {
box = block->object->data.html.layout;
box->width = block->width;
box->height = AUTO;
if (!layout_block_context(box, block->object))
return false;
block->height = box->height;
layout_calculate_descendant_bboxes(box);
block->object->width = box->descendant_x1;
block->object->height = box->descendant_y1;
} else {
}
return true;
}
box = margin_box = block->children;
cx = 0;
cy = block->padding[TOP];
if (box)
box->y = block->padding[TOP];
while (box) {
assert(box->type == BOX_BLOCK || box->type == BOX_TABLE ||
box->type == BOX_INLINE_CONTAINER);
assert(margin_box);
/* Tables are laid out before being positioned, because the
* position depends on the width which is calculated in
* table layout. Blocks and inline containers are positioned
* before being laid out, because width is not dependent on
* content, and the position is required during layout for
* correct handling of floats.
*/
if (box->type == BOX_BLOCK || box->object)
layout_block_find_dimensions(box->parent->width, box);
else if (box->type == BOX_TABLE) {
if (!layout_table(box, box->parent->width, content))
return false;
layout_solve_width(box->parent->width, box->width,
box->margin, box->padding, box->border);
}
/* Position box: horizontal. */
box->x = box->parent->padding[LEFT] + box->margin[LEFT] +
box->border[LEFT];
cx += box->x;
/* Position box: top margin. */
if (max_pos_margin < box->margin[TOP])
max_pos_margin = box->margin[TOP];
else if (max_neg_margin < -box->margin[TOP])
max_neg_margin = -box->margin[TOP];
/* Clearance. */
y = 0;
if (box->style && box->style->clear != CSS_CLEAR_NONE)
y = layout_clear(block->float_children,
box->style->clear);
if (box->type != BOX_BLOCK || y ||
box->border[TOP] || box->padding[TOP]) {
margin_box->y += max_pos_margin - max_neg_margin;
cy += max_pos_margin - max_neg_margin;
max_pos_margin = max_neg_margin = 0;
margin_box = 0;
box->y += box->border[TOP];
cy += box->border[TOP];
if (cy < y) {
box->y += y - cy;
cy = y;
}
}
LOG(("box %p, cx %i, cy %i", box, cx, cy));
/* Layout (except tables). */
if (box->object) {
if (box->object->type == CONTENT_HTML) {
box->object->data.html.layout->width =
box->width;
if (!layout_block_context(box->object->
data.html.layout, box->object))
return false;
box->height = box->object->
data.html.layout->height;
/* + margins etc. */
} else {
/* this case handled already in
* layout_block_find_dimensions() */
}
} else if (box->type == BOX_INLINE_CONTAINER) {
box->width = box->parent->width;
if (!layout_inline_container(box, box->width, block,
cx, cy, content))
return false;
} else if (box->type == BOX_TABLE) {
/* Move down to avoid floats if necessary. */
int x0, x1;
struct box *left, *right;
y = cy;
while (1) {
x0 = cx;
x1 = cx + box->parent->width;
find_sides(block->float_children, y,
y + box->height,
&x0, &x1, &left, &right);
if (box->width <= x1 - x0)
break;
if (!left && !right)
break;
else if (!left)
y = right->y + right->height + 1;
else if (!right)
y = left->y + left->height + 1;
else if (left->y + left->height <
right->y + right->height)
y = left->y + left->height + 1;
else
y = right->y + right->height + 1;
}
box->x += x0 - cx;
cx = x0;
box->y += y - cy;
cy = y;
}
/* Advance to next box. */
if (box->type == BOX_BLOCK && !box->object && box->children) {
y = box->padding[TOP];
box = box->children;
box->y = y;
cy += y;
if (!margin_box) {
max_pos_margin = max_neg_margin = 0;
margin_box = box;
}
continue;
} else if (box->type == BOX_BLOCK || box->object)
cy += box->padding[TOP];
if (box->type == BOX_BLOCK && box->height == AUTO)
box->height = 0;
cy += box->height + box->padding[BOTTOM] + box->border[BOTTOM];
max_pos_margin = max_neg_margin = 0;
if (max_pos_margin < box->margin[BOTTOM])
max_pos_margin = box->margin[BOTTOM];
else if (max_neg_margin < -box->margin[BOTTOM])
max_neg_margin = -box->margin[BOTTOM];
if (!box->next) {
do {
cx -= box->x;
y = box->y + box->padding[TOP] + box->height +
box->padding[BOTTOM] +
box->border[BOTTOM];
box = box->parent;
if (box == block)
break;
if (box->height == AUTO)
box->height = y - box->padding[TOP];
cy += box->padding[BOTTOM] +
box->border[BOTTOM];
if (max_pos_margin < box->margin[BOTTOM])
max_pos_margin = box->margin[BOTTOM];
else if (max_neg_margin < -box->margin[BOTTOM])
max_neg_margin = -box->margin[BOTTOM];
} while (box != block && !box->next);
if (box == block)
break;
}
cx -= box->x;
y = box->y + box->padding[TOP] + box->height +
box->padding[BOTTOM] + box->border[BOTTOM];
box = box->next;
box->y = y;
margin_box = box;
}
/* Increase height to contain any floats inside (CSS 2.1 10.6.7). */
for (box = block->float_children; box; box = box->next_float) {
y = box->y + box->height + box->padding[BOTTOM] +
box->border[BOTTOM] + box->margin[BOTTOM];
if (cy < y)
cy = y;
}
if (block->height == AUTO)
block->height = cy - block->padding[TOP];
return true;
}
/**
* Calculate minimum and maximum width of a block.
*
* \param block box of type BLOCK, INLINE_BLOCK, or TABLE_CELL
* \post block->min_width and block->max_width filled in,
* 0 <= block->min_width <= block->max_width
*/
void layout_minmax_block(struct box *block)
{
struct box *child;
int min = 0, max = 0;
int extra_fixed = 0;
float extra_frac = 0;
assert(block->type == BOX_BLOCK ||
block->type == BOX_INLINE_BLOCK ||
block->type == BOX_TABLE_CELL);
/* check if the widths have already been calculated */
if (block->max_width != UNKNOWN_MAX_WIDTH)
return;
if (block->object) {
if (block->object->type == CONTENT_HTML) {
layout_minmax_block(block->object->data.html.layout);
min = block->object->data.html.layout->min_width;
max = block->object->data.html.layout->max_width;
} else {
min = max = block->object->width;
}
} else {
/* recurse through children */
for (child = block->children; child; child = child->next) {
switch (child->type) {
case BOX_BLOCK:
layout_minmax_block(child);
break;
case BOX_INLINE_CONTAINER:
layout_minmax_inline_container(child);
break;
case BOX_TABLE:
layout_minmax_table(child);
break;
default:
assert(0);
}
assert(child->max_width != UNKNOWN_MAX_WIDTH);
if (min < child->min_width)
min = child->min_width;
if (max < child->max_width)
max = child->max_width;
}
}
if (max < min) {
box_dump(block, 0);
assert(0);
}
/* fixed width takes priority */
if (block->type != BOX_TABLE_CELL &&
block->style->width.width == CSS_WIDTH_LENGTH)
min = max = css_len2px(&block->style->width.value.length,
block->style);
/* add margins, border, padding to min, max widths */
calculate_mbp_width(block->style, LEFT, &extra_fixed, &extra_frac);
calculate_mbp_width(block->style, RIGHT, &extra_fixed, &extra_frac);
if (extra_fixed < 0)
extra_fixed = 0;
if (extra_frac < 0)
extra_frac = 0;
if (1.0 <= extra_frac)
extra_frac = 0.9;
block->min_width = (min + extra_fixed) / (1.0 - extra_frac);
block->max_width = (max + extra_fixed) / (1.0 - extra_frac);
assert(0 <= block->min_width && block->min_width <= block->max_width);
}
/**
* Compute dimensions of box, margins, paddings, and borders for a block-level
* element.
*
* See CSS 2.1 10.3.3, 10.3.4, 10.6.2, and 10.6.3.
*/
void layout_block_find_dimensions(int available_width, struct box *box)
{
int width;
int *margin = box->margin;
int *padding = box->padding;
int *border = box->border;
struct css_style *style = box->style;
/* calculate box width */
switch (style->width.width) {
case CSS_WIDTH_LENGTH:
width = css_len2px(&style->width.value.length, style);
break;
case CSS_WIDTH_PERCENT:
width = available_width *
style->width.value.percent / 100;
break;
case CSS_WIDTH_AUTO:
default:
width = AUTO;
break;
}
/* height */
switch (style->height.height) {
case CSS_HEIGHT_LENGTH:
box->height = css_len2px(&style->height.length, style);
break;
case CSS_HEIGHT_AUTO:
default:
box->height = AUTO;
break;
}
if (box->object && box->object->type != CONTENT_HTML) {
/* block-level replaced element, see 10.3.4 and 10.6.2 */
if (width == AUTO && box->height == AUTO) {
width = box->object->width;
box->height = box->object->height;
} else if (width == AUTO) {
if (box->object->height)
width = box->object->width *
(float) box->height /
box->object->height;
else
width = box->object->width;
} else if (box->height == AUTO) {
if (box->object->width)
box->height = box->object->height *
(float) width /
box->object->width;
else
box->height = box->object->height;
}
}
layout_find_dimensions(available_width, style, margin, padding, border);
box->width = layout_solve_width(available_width, width, margin,
padding, border);
if (style->overflow == CSS_OVERFLOW_SCROLL ||
style->overflow == CSS_OVERFLOW_AUTO) {
/* make space for scrollbars */
box->width -= SCROLLBAR_WIDTH;
box->padding[RIGHT] += SCROLLBAR_WIDTH;
box->padding[BOTTOM] += SCROLLBAR_WIDTH;
}
if (margin[TOP] == AUTO)
margin[TOP] = 0;
if (margin[BOTTOM] == AUTO)
margin[BOTTOM] = 0;
}
/**
* Solve the width constraint as given in CSS 2.1 section 10.3.3.
*/
int layout_solve_width(int available_width, int width,
int margin[4], int padding[4], int border[4])
{
if (width == AUTO) {
/* any other 'auto' become 0 */
if (margin[LEFT] == AUTO)
margin[LEFT] = 0;
if (margin[RIGHT] == AUTO)
margin[RIGHT] = 0;
width = available_width -
(margin[LEFT] + border[LEFT] + padding[LEFT] +
padding[RIGHT] + border[RIGHT] + margin[RIGHT]);
} else if (margin[LEFT] == AUTO && margin[RIGHT] == AUTO) {
/* make the margins equal, centering the element */
margin[LEFT] = margin[RIGHT] = (available_width -
(border[LEFT] + padding[LEFT] + width +
padding[RIGHT] + border[RIGHT])) / 2;
if (margin[LEFT] < 0) {
margin[RIGHT] += margin[LEFT];
margin[LEFT] = 0;
}
} else if (margin[LEFT] == AUTO) {
margin[LEFT] = available_width -
(border[LEFT] + padding[LEFT] + width +
padding[RIGHT] + border[RIGHT] + margin[RIGHT]);
} else {
/* margin-right auto or "over-constrained" */
margin[RIGHT] = available_width -
(margin[LEFT] + border[LEFT] + padding[LEFT] +
width + padding[RIGHT] + border[RIGHT]);
}
return width;
}
/**
* Position a box tree relatively
*/
void layout_position_relative(struct box *root)
{
struct box *box;
/**\todo ensure containing box is large enough after moving boxes */
if (!root)
return;
for (box = root->children; box; box = box->next) {
int x, y;
if (box->type == BOX_TEXT)
continue;
/* recurse first */
layout_position_relative(box);
/* Ignore things we're not interested in. */
if (!box->style || (box->style &&
box->style->position != CSS_POSITION_RELATIVE))
continue;
layout_compute_relative_offset(box, &x, &y);
box->x += x;
box->y += y;
/* Handle INLINEs - their "children" are in fact
* the sibling boxes between the INLINE and
* INLINE_END boxes */
if (box->type == BOX_INLINE && box->inline_end) {
struct box *b;
for (b = box->next; b && b != box->inline_end;
b = b->next) {
b->x += x;
b->y += y;
}
}
}
}
/**
* Compute a box's relative offset as per CSS 2.1 9.4.3
*/
void layout_compute_relative_offset(struct box *box, int *x, int *y)
{
int left = 0, right = 0, top = 0, bottom = 0;
assert(box && box->parent && box->style &&
box->style->position == CSS_POSITION_RELATIVE);
/* left */
if (box->style->pos[LEFT].pos == CSS_POS_PERCENT)
left = ((box->style->pos[LEFT].value.percent *
box->parent->width) / 100);
else if (box->style->pos[LEFT].pos == CSS_POS_LENGTH)
left = css_len2px(&box->style->pos[LEFT].value.length,
box->style);
/* right */
if (box->style->pos[RIGHT].pos == CSS_POS_PERCENT)
right = ((box->style->pos[RIGHT].value.percent *
box->parent->width) / 100);
else if (box->style->pos[RIGHT].pos == CSS_POS_LENGTH)
right = css_len2px(&box->style->pos[RIGHT].value.length,
box->style);
if (box->style->pos[LEFT].pos == CSS_POS_AUTO)
/* left is auto => computed = -right */
left = -right;
if (box->style->pos[RIGHT].pos == CSS_POS_AUTO)
/* right is auto => computed = -left */
right = -left;
if (box->style->pos[LEFT].pos != CSS_POS_AUTO &&
box->style->pos[RIGHT].pos != CSS_POS_AUTO) {
/* over constrained => examine direction property
* of containing block */
if (box->parent->style) {
if (box->parent->style->direction ==
CSS_DIRECTION_LTR)
/* left wins */
right = -left;
else if (box->parent->style->direction ==
CSS_DIRECTION_RTL)
/* right wins */
left = -right;
}
else {
/* no parent style, so assume LTR */
right = -left;
}
}
assert(left == -right);
/* top */
if (box->style->pos[TOP].pos == CSS_POS_PERCENT)
top = ((box->style->pos[TOP].value.percent *
box->parent->height) / 100);
else if (box->style->pos[TOP].pos == CSS_POS_LENGTH)
top = css_len2px(&box->style->pos[TOP].value.length,
box->style);
/* bottom */
if (box->style->pos[BOTTOM].pos == CSS_POS_PERCENT)
bottom = ((box->style->pos[BOTTOM].value.percent *
box->parent->height) / 100);
else if (box->style->pos[BOTTOM].pos == CSS_POS_LENGTH)
bottom = css_len2px(&box->style->pos[BOTTOM].value.length,
box->style);
if (box->style->pos[TOP].pos == CSS_POS_AUTO)
/* top is auto => computed = -bottom */
top = -bottom;
LOG(("%d,%d,%d,%d", left, right, top, bottom));
*x = left;
*y = top;
}
/**
* Compute dimensions of box, margins, paddings, and borders for a floating
* element.
*/
void layout_float_find_dimensions(int available_width,
struct css_style *style, struct box *box)
{
int scrollbar_width = (style->overflow == CSS_OVERFLOW_SCROLL ||
style->overflow == CSS_OVERFLOW_AUTO) ?
SCROLLBAR_WIDTH : 0;
layout_find_dimensions(available_width, style,
box->margin, box->padding, box->border);
if (box->margin[LEFT] == AUTO)
box->margin[LEFT] = 0;
if (box->margin[RIGHT] == AUTO)
box->margin[RIGHT] = 0;
/* calculate box width */
switch (style->width.width) {
case CSS_WIDTH_LENGTH:
box->width = css_len2px(&style->width.value.length,
style);
break;
case CSS_WIDTH_PERCENT:
box->width = available_width *
style->width.value.percent / 100;
break;
case CSS_WIDTH_AUTO:
default:
box->width = AUTO;
break;
}
/* height */
switch (style->height.height) {
case CSS_HEIGHT_LENGTH:
box->height = css_len2px(&style->height.length,
style);
break;
case CSS_HEIGHT_AUTO:
default:
box->height = AUTO;
break;
}
box->padding[RIGHT] += scrollbar_width;
box->padding[BOTTOM] += scrollbar_width;
if (box->object && box->object->type != CONTENT_HTML) {
/* floating replaced element, see 10.3.6 and 10.6.2 */
if (box->width == AUTO && box->height == AUTO) {
box->width = box->object->width;
box->height = box->object->height;
} else if (box->width == AUTO)
box->width = box->object->width * (float) box->height /
box->object->height;
else if (box->height == AUTO)
box->height = box->object->height * (float) box->width /
box->object->width;
} else if (box->width == AUTO) {
/* CSS 2.1 section 10.3.5 */
if (box->min_width < available_width)
box->width = available_width;
else
box->width = box->min_width;
if (box->max_width < box->width)
box->width = box->max_width;
box->width -= box->margin[LEFT] + box->border[LEFT] +
box->padding[LEFT] + box->padding[RIGHT] +
box->border[RIGHT] + box->margin[RIGHT];
} else {
box->width -= scrollbar_width;
}
if (box->margin[TOP] == AUTO)
box->margin[TOP] = 0;
if (box->margin[BOTTOM] == AUTO)
box->margin[BOTTOM] = 0;
}
/**
* Calculate size of margins, paddings, and borders.
*
* \param available_width width of containing block
* \param style style giving margins, paddings, and borders
* \param margin[4] filled with margins, may be NULL
* \param padding[4] filled with paddings
* \param border[4] filled with border widths
*/
void layout_find_dimensions(int available_width,
struct css_style *style,
int margin[4], int padding[4], int border[4])
{
unsigned int i;
for (i = 0; i != 4; i++) {
if (margin) {
switch (style->margin[i].margin) {
case CSS_MARGIN_LENGTH:
margin[i] = css_len2px(&style->margin[i].
value.length, style);
break;
case CSS_MARGIN_PERCENT:
margin[i] = available_width *
style->margin[i].value.percent / 100;
break;
case CSS_MARGIN_AUTO:
default:
margin[i] = AUTO;
break;
}
}
switch (style->padding[i].padding) {
case CSS_PADDING_PERCENT:
padding[i] = available_width *
style->padding[i].value.percent / 100;
break;
case CSS_PADDING_LENGTH:
default:
padding[i] = css_len2px(&style->padding[i].
value.length, style);
break;
}
if (style->border[i].style == CSS_BORDER_STYLE_HIDDEN ||
style->border[i].style == CSS_BORDER_STYLE_NONE)
/* spec unclear: following Mozilla */
border[i] = 0;
else
border[i] = css_len2px(&style->border[i].
width.value, style);
}
}
/**
* Find y coordinate which clears all floats on left and/or right.
*
* \param fl first float in float list
* \param clear type of clear
* \return y coordinate relative to ancestor box for floats
*/
int layout_clear(struct box *fl, css_clear clear)
{
int y = 0;
for (; fl; fl = fl->next_float) {
if ((clear == CSS_CLEAR_LEFT || clear == CSS_CLEAR_BOTH) &&
fl->type == BOX_FLOAT_LEFT)
if (y < fl->y + fl->height + 1)
y = fl->y + fl->height + 1;
if ((clear == CSS_CLEAR_RIGHT || clear == CSS_CLEAR_BOTH) &&
fl->type == BOX_FLOAT_RIGHT)
if (y < fl->y + fl->height + 1)
y = fl->y + fl->height + 1;
}
return y;
}
/**
* Find left and right edges in a vertical range.
*
* \param fl first float in float list
* \param y0 start of y range to search
* \param y1 end of y range to search
* \param x0 start left edge, updated to available left edge
* \param x1 start right edge, updated to available right edge
* \param left returns float on left if present
* \param right returns float on right if present
*/
void find_sides(struct box *fl, int y0, int y1,
int *x0, int *x1, struct box **left, struct box **right)
{
int fy0, fy1, fx0, fx1;
LOG(("y0 %i, y1 %i, x0 %i, x1 %i", y0, y1, *x0, *x1));
*left = *right = 0;
for (; fl; fl = fl->next_float) {
fy0 = fl->y;
fy1 = fl->y + fl->height;
if (y0 <= fy1 && fy0 <= y1) {
if (fl->type == BOX_FLOAT_LEFT) {
fx1 = fl->x + fl->width;
if (*x0 < fx1) {
*x0 = fx1;
*left = fl;
}
} else if (fl->type == BOX_FLOAT_RIGHT) {
fx0 = fl->x;
if (fx0 < *x1) {
*x1 = fx0;
*right = fl;
}
}
}
}
LOG(("x0 %i, x1 %i, left %p, right %p", *x0, *x1, *left, *right));
}
/**
* Layout lines of text or inline boxes with floats.
*
* \param box inline container
* \param width horizontal space available
* \param cont ancestor box which defines horizontal space, for floats
* \param cx box position relative to cont
* \param cy box position relative to cont
* \param content memory pool for any new boxes
* \return true on success, false on memory exhaustion
*/
bool layout_inline_container(struct box *inline_container, int width,
struct box *cont, int cx, int cy, struct content *content)
{
bool first_line = true;
struct box *c, *next;
int y = 0;
assert(inline_container->type == BOX_INLINE_CONTAINER);
LOG(("inline_container %p, width %i, cont %p, cx %i, cy %i",
inline_container, width, cont, cx, cy));
for (c = inline_container->children; c; ) {
LOG(("c %p", c));
if (!layout_line(c, width, &y, cx, cy + y, cont, first_line,
content, &next))
return false;
c = next;
first_line = false;
}
inline_container->width = width;
inline_container->height = y;
return true;
}
/**
* Calculate minimum and maximum width of an inline container.
*
* \param inline_container box of type INLINE_CONTAINER
* \post inline_container->min_width and inline_container->max_width filled in,
* 0 <= inline_container->min_width <= inline_container->max_width
*/
void layout_minmax_inline_container(struct box *inline_container)
{
struct box *child;
int line_min = 0, line_max = 0;
int min = 0, max = 0;
assert(inline_container->type == BOX_INLINE_CONTAINER);
/* check if the widths have already been calculated */
if (inline_container->max_width != UNKNOWN_MAX_WIDTH)
return;
for (child = inline_container->children; child; ) {
child = layout_minmax_line(child, &line_min, &line_max);
if (min < line_min)
min = line_min;
if (max < line_max)
max = line_max;
}
inline_container->min_width = min;
inline_container->max_width = max;
assert(0 <= inline_container->min_width &&
inline_container->min_width <=
inline_container->max_width);
}
/**
* Calculate line height from a style.
*/
int line_height(struct css_style *style)
{
float font_len;
assert(style);
assert(style->line_height.size == CSS_LINE_HEIGHT_LENGTH ||
style->line_height.size == CSS_LINE_HEIGHT_ABSOLUTE ||
style->line_height.size == CSS_LINE_HEIGHT_PERCENT);
/* take account of minimum font size option */
if ((font_len = css_len2px(&style->font_size.value.length, 0)) <
option_font_min_size * 9.0 / 72.0)
font_len = option_font_min_size * 9.0 / 72.0;
switch (style->line_height.size) {
case CSS_LINE_HEIGHT_LENGTH:
return css_len2px(&style->line_height.value.length,
style);
case CSS_LINE_HEIGHT_ABSOLUTE:
return style->line_height.value.absolute * font_len;
case CSS_LINE_HEIGHT_PERCENT:
default:
return style->line_height.value.percent * font_len
/ 100.0;
}
}
/**
* Position a line of boxes in inline formatting context.
*
* \param first box at start of line
* \param width available width
* \param y coordinate of top of line, updated on exit to bottom
* \param cx coordinate of left of line relative to cont
* \param cy coordinate of top of line relative to cont
* \param cont ancestor box which defines horizontal space, for floats
* \param indent apply any first-line indent
* \param next_box updated to first box for next line, or 0 at end
* \param content memory pool for any new boxes
* \return true on success, false on memory exhaustion
*/
bool layout_line(struct box *first, int width, int *y,
int cx, int cy, struct box *cont, bool indent,
struct content *content, struct box **next_box)
{
int height, used_height;
int x0 = 0;
int x1 = width;
int x, h, x_previous;
struct box *left;
struct box *right;
struct box *b;
struct box *split_box = 0;
struct box *d;
struct box *br_box = 0;
bool move_y = false;
int space_before = 0, space_after = 0;
unsigned int inline_count = 0;
unsigned int i;
LOG(("first %p, first->text '%.*s', width %i, y %i, cx %i, cy %i",
first, (int) first->length, first->text, width,
*y, cx, cy));
/* find sides at top of line */
x0 += cx;
x1 += cx;
find_sides(cont->float_children, cy, cy, &x0, &x1, &left, &right);
x0 -= cx;
x1 -= cx;
/* get minimum line height from containing block */
used_height = height = line_height(first->parent->parent->style);
if (x1 < x0)
x1 = x0;
/* pass 1: find height of line assuming sides at top of line: loop
* body executed at least once
* keep in sync with the loop in layout_minmax_line() */
for (x = 0, b = first; x <= x1 - x0 && b != 0; b = b->next) {
assert(b->type == BOX_INLINE || b->type == BOX_INLINE_BLOCK ||
b->type == BOX_FLOAT_LEFT ||
b->type == BOX_FLOAT_RIGHT ||
b->type == BOX_BR || b->type == BOX_TEXT ||
b->type == BOX_INLINE_END);
x += space_after;
if (b->type == BOX_BR)
break;
if (b->type == BOX_FLOAT_LEFT || b->type == BOX_FLOAT_RIGHT)
continue;
if (b->type == BOX_INLINE_BLOCK) {
if (b->width == UNKNOWN_WIDTH)
if (!layout_float(b, width, content))
return false;
/** \todo should margin be included? spec unclear */
h = b->border[TOP] + b->padding[TOP] + b->height +
b->padding[BOTTOM] + b->border[BOTTOM];
if (height < h)
height = h;
x += b->margin[LEFT] + b->border[LEFT] +
b->padding[LEFT] + b->width +
b->padding[RIGHT] + b->border[RIGHT] +
b->margin[RIGHT];
space_after = 0;
continue;
}
if (b->type == BOX_INLINE) {
/* calculate borders, margins, and padding */
layout_find_dimensions(width, b->style,
b->margin, b->padding, b->border);
for (i = 0; i != 4; i++)
if (b->margin[i] == AUTO)
b->margin[i] = 0;
x += b->margin[LEFT] + b->border[LEFT] +
b->padding[LEFT];
if (b->inline_end) {
b->inline_end->margin[RIGHT] = b->margin[RIGHT];
b->inline_end->padding[RIGHT] =
b->padding[RIGHT];
b->inline_end->border[RIGHT] =
b->border[RIGHT];
} else {
x += b->padding[RIGHT] + b->border[RIGHT] +
b->margin[RIGHT];
}
} else if (b->type == BOX_INLINE_END) {
b->width = 0;
if (b->space) {
/** \todo optimize out */
nsfont_width(b->style, " ", 1, &space_after);
} else {
space_after = 0;
}
x += b->padding[RIGHT] + b->border[RIGHT] +
b->margin[RIGHT];
continue;
}
if (!b->object && !b->gadget) {
/* inline non-replaced, 10.3.1 and 10.6.1 */
b->height = line_height(b->style ? b->style :
b->parent->parent->style);
if (height < b->height)
height = b->height;
if (!b->text) {
b->width = 0;
space_after = 0;
continue;
}
if (b->width == UNKNOWN_WIDTH)
/** \todo handle errors */
nsfont_width(b->style, b->text, b->length,
&b->width);
x += b->width;
if (b->space)
/** \todo optimize out */
nsfont_width(b->style, " ", 1, &space_after);
else
space_after = 0;
continue;
}
space_after = 0;
/* inline replaced, 10.3.2 and 10.6.2 */
assert(b->style);
/* calculate box width */
switch (b->style->width.width) {
case CSS_WIDTH_LENGTH:
b->width = css_len2px(&b->style->width.value.
length, b->style);
break;
case CSS_WIDTH_PERCENT:
b->width = width *
b->style->width.value.percent /
100;
break;
case CSS_WIDTH_AUTO:
default:
b->width = AUTO;
break;
}
/* height */
switch (b->style->height.height) {
case CSS_HEIGHT_LENGTH:
b->height = css_len2px(&b->style->height.length,
b->style);
break;
case CSS_HEIGHT_AUTO:
default:
b->height = AUTO;
break;
}
if (b->object) {
if (b->width == AUTO && b->height == AUTO) {
b->width = b->object->width;
b->height = b->object->height;
} else if (b->width == AUTO) {
if (b->object->height)
b->width = b->object->width *
(float) b->height /
b->object->height;
else
b->width = b->object->width;
} else if (b->height == AUTO) {
if (b->object->width)
b->height = b->object->height *
(float) b->width /
b->object->width;
else
b->height = b->object->height;
}
} else {
/* form control with no object */
if (b->width == AUTO)
b->width = 0;
if (b->height == AUTO)
b->height = line_height(b->style ? b->style :
b->parent->parent->style);
}
if (b->object && b->object->type == CONTENT_HTML &&
b->width != b->object->available_width) {
content_reformat(b->object, b->width, b->height);
if (b->style->height.height == CSS_HEIGHT_AUTO)
b->height = b->object->height;
}
if (height < b->height)
height = b->height;
x += b->width;
}
/* find new sides using this height */
x0 = cx;
x1 = cx + width;
find_sides(cont->float_children, cy, cy + height, &x0, &x1,
&left, &right);
x0 -= cx;
x1 -= cx;
if (indent)
x0 += layout_text_indent(first->parent->parent->style, width);
if (x1 < x0)
x1 = x0;
space_after = space_before = 0;
/* pass 2: place boxes in line: loop body executed at least once */
for (x = x_previous = 0, b = first; x <= x1 - x0 && b; b = b->next) {
if (b->type == BOX_INLINE || b->type == BOX_INLINE_BLOCK ||
b->type == BOX_TEXT ||
b->type == BOX_INLINE_END) {
assert(b->width != UNKNOWN_WIDTH);
x_previous = x;
x += space_after;
b->x = x;
if ((b->type == BOX_INLINE && !b->inline_end) ||
b->type == BOX_INLINE_BLOCK) {
b->x += b->margin[LEFT] + b->border[LEFT];
x = b->x + b->padding[LEFT] + b->width +
b->padding[RIGHT] +
b->border[RIGHT] +
b->margin[RIGHT];
} else if (b->type == BOX_INLINE) {
b->x += b->margin[LEFT] + b->border[LEFT];
x = b->x + b->padding[LEFT] + b->width;
} else if (b->type == BOX_INLINE_END) {
x += b->padding[RIGHT] + b->border[RIGHT] +
b->margin[RIGHT];
} else {
x += b->width;
}
space_before = space_after;
if (b->object)
space_after = 0;
else if (b->text || b->type == BOX_INLINE_END) {
space_after = 0;
if (b->space)
/** \todo handle errors, optimize */
nsfont_width(b->style, " ", 1,
&space_after);
} else
space_after = 0;
split_box = b;
move_y = true;
inline_count++;
/* fprintf(stderr, "layout_line: '%.*s' %li %li\n", b->length, b->text, xp, x); */
} else if (b->type == BOX_BR) {
b->x = x;
b->width = 0;
br_box = b;
b = b->next;
split_box = 0;
move_y = true;
break;
} else {
/* float */
LOG(("float %p", b));
d = b->children;
d->float_children = 0;
/* css_dump_style(b->style); */
if (!layout_float(d, width, content))
return false;
d->x = d->margin[LEFT] + d->border[LEFT];
d->y = d->margin[TOP] + d->border[TOP];
b->width = d->margin[LEFT] + d->border[LEFT] +
d->padding[LEFT] + d->width +
d->padding[RIGHT] + d->border[RIGHT] +
d->margin[RIGHT];
b->height = d->margin[TOP] + d->border[TOP] +
d->padding[TOP] + d->height +
d->padding[BOTTOM] + d->border[BOTTOM] +
d->margin[BOTTOM];
if (b->width < (x1 - x0) - x || (left == 0 && right == 0 && x == 0)) {
/* fits next to this line, or this line is empty with no floats */
if (b->type == BOX_FLOAT_LEFT) {
b->x = cx + x0;
x0 += b->width;
left = b;
} else {
b->x = cx + x1 - b->width;
x1 -= b->width;
right = b;
}
b->y = cy;
/* fprintf(stderr, "layout_line: float fits %li %li, edges %li %li\n", */
/* b->x, b->y, x0, x1); */
} else {
/* doesn't fit: place below */
place_float_below(b, width, cx, cy + height + 1, cont);
/* fprintf(stderr, "layout_line: float doesn't fit %li %li\n", b->x, b->y); */
}
if (cont->float_children == b) {
LOG(("float %p already placed", b));
box_dump(cont, 0);
assert(0);
}
b->next_float = cont->float_children;
cont->float_children = b;
split_box = 0;
}
}
if (x1 - x0 < x && split_box) {
/* the last box went over the end */
unsigned int i;
size_t space = 0;
int w;
struct box * c2;
x = x_previous;
if ((split_box->type == BOX_INLINE ||
split_box->type == BOX_TEXT) &&
!split_box->object &&
!split_box->gadget && split_box->text) {
for (i = 0; i != split_box->length &&
split_box->text[i] != ' '; i++)
;
if (i != split_box->length)
space = i;
}
/* space != 0 implies split_box->text != 0 */
if (space == 0)
w = split_box->width;
else
/** \todo handle errors */
nsfont_width(split_box->style, split_box->text,
space, &w);
LOG(("splitting: split_box %p, space %zu, w %i, left %p, "
"right %p, inline_count %u",
split_box, space, w, left, right,
inline_count));
if ((space == 0 || x1 - x0 <= x + space_before + w) &&
!left && !right && inline_count == 1) {
/* first word doesn't fit, but no floats and first
on line so force in */
if (space == 0) {
/* only one word in this box or not text */
b = split_box->next;
} else {
/* cut off first word for this line */
c2 = talloc_memdup(content, split_box,
sizeof *c2);
if (!c2)
return false;
c2->text = talloc_strndup(content,
split_box->text + space + 1,
split_box->length -(space + 1));
if (!c2->text)
return false;
c2->length = split_box->length - (space + 1);
c2->width = UNKNOWN_WIDTH;
c2->clone = 1;
split_box->length = space;
split_box->width = w;
split_box->space = 1;
c2->next = split_box->next;
split_box->next = c2;
c2->prev = split_box;
if (c2->next)
c2->next->prev = c2;
else
c2->parent->last = c2;
b = c2;
}
x += space_before + w;
/* fprintf(stderr, "layout_line: overflow, forcing\n"); */
} else if (space == 0 || x1 - x0 <= x + space_before + w) {
/* first word doesn't fit, but full width not
available so leave for later */
b = split_box;
/* fprintf(stderr, "layout_line: overflow, leaving\n"); */
} else {
/* fit as many words as possible */
assert(space != 0);
/** \todo handle errors */
nsfont_split(split_box->style,
split_box->text, split_box->length,
x1 - x0 - x - space_before, &space, &w);
LOG(("'%.*s' %i %zu %i", (int) split_box->length,
split_box->text, x1 - x0, space, w));
/* assert(space == split_box->length || split_box->text[space] = ' '); */
if (space == 0)
space = 1;
if (space != split_box->length) {
c2 = talloc_memdup(content, split_box,
sizeof *c2);
if (!c2)
return false;
c2->text = talloc_strndup(content,
split_box->text + space + 1,
split_box->length -(space + 1));
if (!c2->text)
return false;
c2->length = split_box->length - (space + 1);
c2->width = UNKNOWN_WIDTH;
c2->clone = 1;
split_box->length = space;
split_box->width = w;
split_box->space = 1;
c2->next = split_box->next;
split_box->next = c2;
c2->prev = split_box;
if (c2->next)
c2->next->prev = c2;
else
c2->parent->last = c2;
b = c2;
}
x += space_before + w;
/* fprintf(stderr, "layout_line: overflow, fit\n"); */
}
move_y = true;
}
/* set positions */
switch (first->parent->parent->style->text_align) {
case CSS_TEXT_ALIGN_RIGHT: x0 = x1 - x; break;
case CSS_TEXT_ALIGN_CENTER: x0 = (x0 + (x1 - x)) / 2; break;
default: break; /* leave on left */
}
for (d = first; d != b; d = d->next) {
if (d->type == BOX_INLINE || d->type == BOX_INLINE_BLOCK ||
d->type == BOX_BR || d->type == BOX_TEXT ||
d->type == BOX_INLINE_END) {
d->x += x0;
d->y = *y - d->padding[TOP];
}
if ((d->type == BOX_INLINE && (d->object || d->gadget)) ||
d->type == BOX_INLINE_BLOCK) {
h = d->border[TOP] + d->padding[TOP] + d->height +
d->padding[BOTTOM] + d->border[BOTTOM];
if (used_height < h)
used_height = h;
}
}
assert(b != first || (move_y && 0 < used_height && (left || right)));
/* handle clearance for br */
if (br_box && br_box->style->clear != CSS_CLEAR_NONE) {
int clear_y = layout_clear(cont->float_children,
br_box->style->clear);
if (used_height < clear_y - cy)
used_height = clear_y - cy;
}
if (move_y)
*y += used_height;
*next_box = b;
return true;
}
/**
* Calculate minimum and maximum width of a line.
*
* \param first a box in an inline container
* \param line_min updated to minimum width of line starting at first
* \param line_max updated to maximum width of line starting at first
* \return first box in next line, or 0 if no more lines
* \post 0 <= *line_min <= *line_max
*/
struct box *layout_minmax_line(struct box *first,
int *line_min, int *line_max)
{
int min = 0, max = 0, width, height, fixed;
float frac;
size_t i, j;
struct box *b;
/* corresponds to the pass 1 loop in layout_line() */
for (b = first; b; b = b->next) {
assert(b->type == BOX_INLINE || b->type == BOX_INLINE_BLOCK ||
b->type == BOX_FLOAT_LEFT ||
b->type == BOX_FLOAT_RIGHT ||
b->type == BOX_BR || b->type == BOX_TEXT ||
b->type == BOX_INLINE_END);
LOG(("%p: min %i, max %i", b, min, max));
if (b->type == BOX_BR) {
b = b->next;
break;
}
if (b->type == BOX_FLOAT_LEFT || b->type == BOX_FLOAT_RIGHT) {
assert(b->children);
if (b->children->type == BOX_BLOCK)
layout_minmax_block(b->children);
else
layout_minmax_table(b->children);
b->min_width = b->children->min_width;
b->max_width = b->children->max_width;
if (min < b->min_width)
min = b->min_width;
max += b->max_width;
continue;
}
if (b->type == BOX_INLINE_BLOCK) {
layout_minmax_block(b);
if (min < b->min_width)
min = b->min_width;
max += b->max_width;
continue;
}
if (b->type == BOX_INLINE) {
fixed = frac = 0;
calculate_mbp_width(b->style, LEFT, &fixed, &frac);
if (!b->inline_end)
calculate_mbp_width(b->style, RIGHT,
&fixed, &frac);
if (0 < fixed)
max += fixed;
/* \todo update min width, consider fractional extra */
} else if (b->type == BOX_INLINE_END) {
fixed = frac = 0;
calculate_mbp_width(b->inline_end->style, RIGHT,
&fixed, &frac);
if (0 < fixed)
max += fixed;
if (b->next && b->space) {
nsfont_width(b->style, " ", 1, &width);
max += width;
}
continue;
}
if (!b->object && !b->gadget) {
/* inline non-replaced, 10.3.1 and 10.6.1 */
if (!b->text)
continue;
if (b->width == UNKNOWN_WIDTH)
/** \todo handle errors */
nsfont_width(b->style, b->text, b->length,
&b->width);
max += b->width;
if (b->next && b->space) {
nsfont_width(b->style, " ", 1, &width);
max += width;
}
/* min = widest word */
i = 0;
do {
for (j = i; j != b->length &&
b->text[j] != ' '; j++)
;
nsfont_width(b->style, b->text + i,
j - i, &width);
if (min < width)
min = width;
i = j + 1;
} while (j != b->length);
continue;
}
/* inline replaced, 10.3.2 and 10.6.2 */
assert(b->style);
/* calculate box width */
switch (b->style->width.width) {
case CSS_WIDTH_LENGTH:
width = css_len2px(&b->style->width.value.
length, b->style);
if (width < 0)
width = 0;
break;
case CSS_WIDTH_PERCENT:
/*b->width = width *
b->style->width.value.percent /
100;
break;*/
case CSS_WIDTH_AUTO:
default:
width = AUTO;
break;
}
/* height */
switch (b->style->height.height) {
case CSS_HEIGHT_LENGTH:
height = css_len2px(&b->style->height.length,
b->style);
break;
case CSS_HEIGHT_AUTO:
default:
height = AUTO;
break;
}
if (b->object) {
if (width == AUTO && height == AUTO) {
width = b->object->width;
} else if (width == AUTO) {
if (b->object->height)
width = b->object->width *
(float) height /
b->object->height;
else
width = b->object->width;
}
} else {
/* form control with no object */
if (width == AUTO)
width = 0;
}
if (min < width)
min = width;
max += width;
}
/* \todo first line text-indent */
*line_min = min;
*line_max = max;
LOG(("line_min %i, line_max %i", min, max));
assert(b != first);
assert(0 <= *line_min && *line_min <= *line_max);
return b;
}
/**
* Calculate the text-indent length.
*
* \param style style of block
* \param width width of containing block
* \return length of indent
*/
int layout_text_indent(struct css_style *style, int width)
{
switch (style->text_indent.size) {
case CSS_TEXT_INDENT_LENGTH:
return css_len2px(&style->text_indent.value.length,
style);
case CSS_TEXT_INDENT_PERCENT:
return width * style->text_indent.value.percent / 100;
default:
return 0;
}
}
/**
* Layout the contents of a float or inline block.
*
* \param b float or inline block box
* \param width available width
* \param content memory pool for any new boxes
* \return true on success, false on memory exhaustion
*/
bool layout_float(struct box *b, int width, struct content *content)
{
layout_float_find_dimensions(width, b->style, b);
if (b->type == BOX_TABLE) {
if (!layout_table(b, width, content))
return false;
if (b->margin[LEFT] == AUTO)
b->margin[LEFT] = 0;
if (b->margin[RIGHT] == AUTO)
b->margin[RIGHT] = 0;
} else
return layout_block_context(b, content);
return true;
}
/**
* Position a float in the first available space.
*
* \param c float box to position
* \param width available width
* \param cx x coordinate relative to cont to place float right of
* \param y y coordinate relative to cont to place float below
* \param cont ancestor box which defines horizontal space, for floats
*/
void place_float_below(struct box *c, int width, int cx, int y,
struct box *cont)
{
int x0, x1, yy = y;
struct box * left;
struct box * right;
LOG(("c %p, width %i, cx %i, y %i, cont %p", c, width, cx, y, cont));
do {
y = yy;
x0 = cx;
x1 = cx + width;
find_sides(cont->float_children, y, y, &x0, &x1, &left, &right);
if (left != 0 && right != 0) {
yy = (left->y + left->height <
right->y + right->height ?
left->y + left->height :
right->y + right->height) + 1;
} else if (left == 0 && right != 0) {
yy = right->y + right->height + 1;
} else if (left != 0 && right == 0) {
yy = left->y + left->height + 1;
}
} while (!((left == 0 && right == 0) || (c->width < x1 - x0)));
if (c->type == BOX_FLOAT_LEFT) {
c->x = x0;
} else {
c->x = x1 - c->width;
}
c->y = y;
}
/**
* 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,
struct content *content)
{
unsigned int columns = table->columns; /* total columns */
unsigned int i;
unsigned int *row_span;
int *excess_y;
int table_width, min_width = 0, max_width = 0;
int required_width = 0;
int x, remainder = 0, count = 0;
int table_height = 0;
int *xs; /* array of column x positions */
int auto_width;
int spare_width;
int relative_sum = 0;
int border_spacing_h = 0, border_spacing_v = 0;
int spare_height;
struct box *c;
struct box *row;
struct box *row_group;
struct box **row_span_cell;
struct column *col;
struct css_style *style = table->style;
assert(table->type == BOX_TABLE);
assert(style);
assert(table->children && table->children->children);
assert(columns);
/* allocate working buffers */
col = malloc(columns * sizeof col[0]);
excess_y = malloc(columns * sizeof excess_y[0]);
row_span = malloc(columns * sizeof row_span[0]);
row_span_cell = malloc(columns * sizeof row_span_cell[0]);
xs = malloc((columns + 1) * sizeof xs[0]);
if (!col || !xs || !row_span || !excess_y || !row_span_cell) {
free(col);
free(excess_y);
free(row_span);
free(row_span_cell);
free(xs);
return false;
}
memcpy(col, table->col, sizeof(col[0]) * columns);
/* find margins, paddings, and borders for table and cells */
layout_find_dimensions(available_width, style, table->margin,
table->padding, table->border);
for (row_group = table->children; row_group;
row_group = row_group->next) {
for (row = row_group->children; row; row = row->next) {
for (c = row->children; c; c = c->next) {
assert(c->style);
layout_find_dimensions(available_width,
c->style, 0,
c->padding, c->border);
if (c->style->overflow ==
CSS_OVERFLOW_SCROLL ||
c->style->overflow ==
CSS_OVERFLOW_AUTO) {
c->padding[RIGHT] += SCROLLBAR_WIDTH;
c->padding[BOTTOM] += SCROLLBAR_WIDTH;
}
}
}
}
/* border-spacing is used in the separated borders model */
if (style->border_collapse == CSS_BORDER_COLLAPSE_SEPARATE) {
border_spacing_h = css_len2px(&style->border_spacing.horz,
style);
border_spacing_v = css_len2px(&style->border_spacing.vert,
style);
}
/* find specified table width, or available width if auto-width */
switch (style->width.width) {
case CSS_WIDTH_LENGTH:
table_width = css_len2px(&style->width.value.length, style);
auto_width = table_width;
break;
case CSS_WIDTH_PERCENT:
table_width = ceil(available_width *
style->width.value.percent / 100);
auto_width = table_width;
break;
case CSS_WIDTH_AUTO:
default:
table_width = AUTO;
auto_width = available_width -
((table->margin[LEFT] == AUTO ? 0 :
table->margin[LEFT]) +
table->border[LEFT] +
table->padding[LEFT] +
table->padding[RIGHT] +
table->border[RIGHT] +
(table->margin[RIGHT] == AUTO ? 0 :
table->margin[RIGHT]));
break;
}
/* calculate width required by cells */
for (i = 0; i != columns; i++) {
LOG(("table %p, column %u: type %s, width %i, min %i, max %i",
table, i,
((const char *[]) {"UNKNOWN", "FIXED", "AUTO",
"PERCENT", "RELATIVE"})[col[i].type],
col[i].width, col[i].min, col[i].max));
if (col[i].type == COLUMN_WIDTH_FIXED) {
if (col[i].width < col[i].min)
col[i].width = col[i].max = col[i].min;
else
col[i].min = col[i].max = col[i].width;
required_width += col[i].width;
} else if (col[i].type == COLUMN_WIDTH_PERCENT) {
int width = col[i].width * auto_width / 100;
required_width += col[i].min < width ? width :
col[i].min;
} else
required_width += col[i].min;
LOG(("required_width %i", required_width));
}
required_width += (columns + 1) * border_spacing_h;
LOG(("width %i, min %i, max %i, auto %i, required %i",
table_width, table->min_width, table->max_width,
auto_width, required_width));
if (auto_width < required_width) {
/* table narrower than required width for columns:
* treat percentage widths as maximums */
for (i = 0; i != columns; i++) {
if (col[i].type == COLUMN_WIDTH_RELATIVE)
continue;
if (col[i].type == COLUMN_WIDTH_PERCENT) {
col[i].max = auto_width * col[i].width / 100;
if (col[i].max < col[i].min)
col[i].max = col[i].min;
}
min_width += col[i].min;
max_width += col[i].max;
}
} else {
/* take percentages exactly */
for (i = 0; i != columns; i++) {
if (col[i].type == COLUMN_WIDTH_RELATIVE)
continue;
if (col[i].type == COLUMN_WIDTH_PERCENT) {
int width = auto_width * col[i].width / 100;
if (width < col[i].min)
width = col[i].min;
col[i].min = col[i].width = col[i].max = width;
col[i].type = COLUMN_WIDTH_FIXED;
}
min_width += col[i].min;
max_width += col[i].max;
}
}
/* allocate relative widths */
spare_width = auto_width;
for (i = 0; i != columns; i++) {
if (col[i].type == COLUMN_WIDTH_RELATIVE)
relative_sum += col[i].width;
else if (col[i].type == COLUMN_WIDTH_FIXED)
spare_width -= col[i].width;
else
spare_width -= col[i].min;
}
spare_width -= (columns + 1) * border_spacing_h;
if (relative_sum != 0) {
if (spare_width < 0)
spare_width = 0;
for (i = 0; i != columns; i++) {
if (col[i].type == COLUMN_WIDTH_RELATIVE) {
col[i].min = ceil(col[i].max =
(float) spare_width
* (float) col[i].width
/ relative_sum);
min_width += col[i].min;
max_width += col[i].max;
}
}
}
min_width += (columns + 1) * border_spacing_h;
max_width += (columns + 1) * border_spacing_h;
if (auto_width <= min_width) {
/* not enough space: minimise column widths */
for (i = 0; i < columns; i++) {
col[i].width = col[i].min;
}
table_width = min_width;
} else if (max_width <= auto_width) {
/* more space than maximum width */
if (table_width == AUTO) {
/* for auto-width tables, make columns max width */
for (i = 0; i < columns; i++) {
col[i].width = col[i].max;
}
table_width = max_width;
} else {
/* for fixed-width tables, distribute the extra space too */
unsigned int flexible_columns = 0;
for (i = 0; i != columns; i++)
if (col[i].type != COLUMN_WIDTH_FIXED)
flexible_columns++;
if (flexible_columns == 0) {
int extra = (table_width - max_width) / columns;
remainder = (table_width - max_width) - (extra * columns);
for (i = 0; i != columns; i++) {
col[i].width = col[i].max + extra;
count -= remainder;
if (count < 0) {
col[i].width++;
count += columns;
}
}
} else {
int extra = (table_width - max_width) / flexible_columns;
remainder = (table_width - max_width) - (extra * flexible_columns);
for (i = 0; i != columns; i++)
if (col[i].type != COLUMN_WIDTH_FIXED) {
col[i].width = col[i].max + extra;
count -= remainder;
if (count < 0) {
col[i].width++;
count += flexible_columns;
}
}
}
}
} else {
/* space between min and max: fill it exactly */
float scale = (float) (auto_width - min_width) /
(float) (max_width - min_width);
/* fprintf(stderr, "filling, scale %f\n", scale); */
for (i = 0; i < columns; i++) {
col[i].width = col[i].min + (int) (0.5 +
(col[i].max - col[i].min) * scale);
}
table_width = auto_width;
}
xs[0] = x = border_spacing_h;
for (i = 0; i != columns; i++) {
x += col[i].width + border_spacing_h;
xs[i + 1] = x;
row_span[i] = 0;
excess_y[i] = 0;
row_span_cell[i] = 0;
}
/* position cells */
table_height = border_spacing_v;
for (row_group = table->children; row_group;
row_group = row_group->next) {
int row_group_height = 0;
for (row = row_group->children; row; row = row->next) {
/* some sites use height="1" or similar
* to attempt to make cells as small as
* possible, so treat it as a minimum */
int row_height = (int) css_len2px(&row->style->
height.length, row->style);
/* we can't use this value currently as it is always
* the height of a line of text in the current style */
row_height = 0;
for (c = row->children; c; c = c->next) {
assert(c->style);
c->width = xs[c->start_column + c->columns] -
xs[c->start_column] -
border_spacing_h -
c->border[LEFT] -
c->padding[LEFT] -
c->padding[RIGHT] -
c->border[RIGHT];
c->float_children = 0;
c->height = AUTO;
if (!layout_block_context(c, content)) {
free(col);
free(excess_y);
free(row_span);
free(row_span_cell);
free(xs);
return false;
}
/* warning: c->descendant_y0 and c->descendant_y1 used as temporary
* storage until after vertical alignment is complete */
c->descendant_y0 = c->height;
c->descendant_y1 = c->padding[BOTTOM];
if (c->style->height.height ==
CSS_HEIGHT_LENGTH) {
/* some sites use height="1" or similar
* to attempt to make cells as small as
* possible, so treat it as a minimum */
int h = (int) css_len2px(&c->style->
height.length, c->style);
if (c->height < h)
c->height = h;
}
c->x = xs[c->start_column] + c->border[LEFT];
c->y = c->border[TOP];
for (i = 0; i != c->columns; i++) {
row_span[c->start_column + i] = c->rows;
excess_y[c->start_column + i] =
c->border[TOP] +
c->padding[TOP] +
c->height +
c->padding[BOTTOM] +
c->border[BOTTOM];
row_span_cell[c->start_column + i] = 0;
}
row_span_cell[c->start_column] = c;
c->padding[BOTTOM] = -border_spacing_v -
c->border[TOP] -
c->padding[TOP] -
c->height -
c->border[BOTTOM];
}
for (i = 0; i != columns; i++)
if (row_span[i] != 0)
row_span[i]--;
else
row_span_cell[i] = 0;
if (row->next || row_group->next) {
/* row height is greatest excess of a cell
* which ends in this row */
for (i = 0; i != columns; i++)
if (row_span[i] == 0 && row_height <
excess_y[i])
row_height = excess_y[i];
} else {
/* except in the last row */
for (i = 0; i != columns; i++)
if (row_height < excess_y[i])
row_height = excess_y[i];
}
for (i = 0; i != columns; i++) {
if (row_height < excess_y[i])
excess_y[i] -= row_height;
else
excess_y[i] = 0;
if (row_span_cell[i] != 0)
row_span_cell[i]->padding[BOTTOM] +=
row_height +
border_spacing_v;
}
row->x = 0;
row->y = row_group_height;
row->width = table_width;
row->height = row_height;
row_group_height += row_height + border_spacing_v;
}
row_group->x = 0;
row_group->y = table_height;
row_group->width = table_width;
row_group->height = row_group_height;
table_height += row_group_height;
}
/* perform vertical alignment */
for (row_group = table->children; row_group; row_group = row_group->next) {
for (row = row_group->children; row; row = row->next) {
for (c = row->children; c; c = c->next) {
/* unextended bottom padding is in c->descendant_y1, and unextended
* cell height is in c->descendant_y0 */
spare_height = (c->padding[BOTTOM] - c->descendant_y1) +
(c->height - c->descendant_y0);
switch (c->style->vertical_align.type) {
case CSS_VERTICAL_ALIGN_SUB:
case CSS_VERTICAL_ALIGN_SUPER:
case CSS_VERTICAL_ALIGN_TEXT_TOP:
case CSS_VERTICAL_ALIGN_TEXT_BOTTOM:
case CSS_VERTICAL_ALIGN_LENGTH:
case CSS_VERTICAL_ALIGN_PERCENT:
case CSS_VERTICAL_ALIGN_BASELINE:
/* todo: baseline alignment, for now just use ALIGN_TOP */
case CSS_VERTICAL_ALIGN_TOP:
break;
case CSS_VERTICAL_ALIGN_MIDDLE:
c->padding[TOP] += spare_height / 2;
c->padding[BOTTOM] -= spare_height / 2;
layout_move_children(c, 0, spare_height / 2);
break;
case CSS_VERTICAL_ALIGN_BOTTOM:
c->padding[TOP] += spare_height;
c->padding[BOTTOM] -= spare_height;
layout_move_children(c, 0, spare_height);
break;
case CSS_VERTICAL_ALIGN_NOT_SET:
case CSS_VERTICAL_ALIGN_INHERIT:
assert(0);
break;
}
}
}
}
free(col);
free(excess_y);
free(row_span);
free(row_span_cell);
free(xs);
table->width = table_width;
table->height = table_height;
return true;
}
/**
* Calculate minimum and maximum width of a table.
*
* \param table box of type TABLE
* \post table->min_width and table->max_width filled in,
* 0 <= table->min_width <= table->max_width
*/
void layout_minmax_table(struct box *table)
{
unsigned int i, j;
int border_spacing_h = 0;
int table_min = 0, table_max = 0;
int extra_fixed = 0;
float extra_frac = 0;
struct column *col = table->col;
struct box *row_group, *row, *cell;
/* check if the widths have already been calculated */
if (table->max_width != UNKNOWN_MAX_WIDTH)
return;
/* start with 0 except for fixed-width columns */
for (i = 0; i != table->columns; i++) {
if (col[i].type == COLUMN_WIDTH_FIXED)
col[i].min = col[i].max = col[i].width;
else
col[i].min = col[i].max = 0;
}
/* border-spacing is used in the separated borders model */
if (table->style->border_collapse == CSS_BORDER_COLLAPSE_SEPARATE)
border_spacing_h = css_len2px(&table->style->
border_spacing.horz, table->style);
/* 1st pass: consider cells with colspan 1 only */
for (row_group = table->children; row_group; row_group =row_group->next)
for (row = row_group->children; row; row = row->next)
for (cell = row->children; cell; cell = cell->next) {
assert(cell->type == BOX_TABLE_CELL);
assert(cell->style);
if (cell->columns != 1)
continue;
layout_minmax_block(cell);
i = cell->start_column;
/* update column min, max widths using cell widths */
if (col[i].min < cell->min_width)
col[i].min = cell->min_width;
if (col[i].max < cell->max_width)
col[i].max = cell->max_width;
}
/* 2nd pass: cells which span multiple columns */
for (row_group = table->children; row_group; row_group =row_group->next)
for (row = row_group->children; row; row = row->next)
for (cell = row->children; cell; cell = cell->next) {
unsigned int flexible_columns = 0;
int min = 0, max = 0, fixed_width = 0, extra;
if (cell->columns == 1)
continue;
layout_minmax_block(cell);
i = cell->start_column;
/* find min width so far of spanned columns, and count
* number of non-fixed spanned columns and total fixed width */
for (j = 0; j != cell->columns; j++) {
min += col[i + j].min;
if (col[i + j].type == COLUMN_WIDTH_FIXED)
fixed_width += col[i + j].width;
else
flexible_columns++;
}
min += (cell->columns - 1) * border_spacing_h;
/* distribute extra min to spanned columns */
if (min < cell->min_width) {
if (flexible_columns == 0) {
extra = 1 + (cell->min_width - min) /
cell->columns;
for (j = 0; j != cell->columns; j++) {
col[i + j].min += extra;
if (col[i + j].max < col[i + j].min)
col[i + j].max = col[i + j].min;
}
} else {
extra = 1 + (cell->min_width - min) /
flexible_columns;
for (j = 0; j != cell->columns; j++) {
if (col[i + j].type !=
COLUMN_WIDTH_FIXED) {
col[i + j].min += extra;
if (col[i + j].max <
col[i + j].min)
col[i + j].max =
col[i + j].min;
}
}
}
}
/* find max width so far of spanned columns */
for (j = 0; j != cell->columns; j++)
max += col[i + j].max;
max += (cell->columns - 1) * border_spacing_h;
/* distribute extra max to spanned columns */
if (max < cell->max_width && flexible_columns) {
extra = 1 + (cell->max_width - max) / flexible_columns;
for (j = 0; j != cell->columns; j++)
if (col[i + j].type != COLUMN_WIDTH_FIXED)
col[i + j].max += extra;
}
}
for (i = 0; i != table->columns; i++) {
if (col[i].max < col[i].min) {
box_dump(table, 0);
assert(0);
}
table_min += col[i].min;
table_max += col[i].max;
}
/* fixed width takes priority, unless it is too narrow */
if (table->style->width.width == CSS_WIDTH_LENGTH) {
int width = css_len2px(&table->style->width.value.length,
table->style);
if (table_min < width)
table_min = width;
if (table_max < width)
table_max = width;
}
/* add margins, border, padding to min, max widths */
calculate_mbp_width(table->style, LEFT, &extra_fixed, &extra_frac);
calculate_mbp_width(table->style, RIGHT, &extra_fixed, &extra_frac);
if (1.0 <= extra_frac)
extra_frac = 0.9;
table->min_width = (table_min + extra_fixed) / (1.0 - extra_frac);
table->max_width = (table_max + extra_fixed) / (1.0 - extra_frac);
table->min_width += (table->columns + 1) * border_spacing_h;
table->max_width += (table->columns + 1) * border_spacing_h;
assert(0 <= table->min_width && table->min_width <= table->max_width);
}
/**
* Moves the children of a box by a specified amount
*
* \param box top of tree of boxes
* \param x the amount to move children by horizontally
* \param y the amount to move children by vertically
*/
void layout_move_children(struct box *box, int x, int y)
{
assert(box);
for (box = box->children; box; box = box->next) {
box->x += x;
box->y += y;
}
}
/**
* Determine width of margin, borders, and padding on one side of a box.
*
* \param style style to measure
* \param size side of box to measure
* \param fixed increased by sum of fixed margin, border, and padding
* \param frac increased by sum of fractional margin and padding
*/
void calculate_mbp_width(struct css_style *style, unsigned int side,
int *fixed, float *frac)
{
assert(style);
/* margin */
if (style->margin[side].margin == CSS_MARGIN_LENGTH)
*fixed += css_len2px(&style->margin[side].value.length, style);
else if (style->margin[side].margin == CSS_MARGIN_PERCENT)
*frac += style->margin[side].value.percent * 0.01;
/* border */
if (style->border[side].style != CSS_BORDER_STYLE_NONE)
*fixed += css_len2px(&style->border[side].width.value, style);
/* padding */
if (style->padding[side].padding == CSS_PADDING_LENGTH)
*fixed += css_len2px(&style->padding[side].value.length, style);
else if (style->padding[side].padding == CSS_PADDING_PERCENT)
*frac += style->padding[side].value.percent * 0.01;
}
/**
* Recursively calculate the descendant_[xy][01] values for a laid-out box tree.
*
* \param box tree of boxes to update
*/
void layout_calculate_descendant_bboxes(struct box *box)
{
struct box *child;
if (box->width == UNKNOWN_WIDTH /*||
box->width < 0 || box->height < 0*/) {
LOG(("%p has bad width or height", box));
while (box->parent)
box = box->parent;
box_dump(box, 0);
assert(0);
}
box->descendant_x0 = -box->border[LEFT];
box->descendant_y0 = -box->border[TOP];
box->descendant_x1 = box->padding[LEFT] + box->width +
box->padding[RIGHT] + box->border[RIGHT];
box->descendant_y1 = box->padding[TOP] + box->height +
box->padding[BOTTOM] + box->border[BOTTOM];
if (box->object) {
LOG(("%i %i %i %i",
box->descendant_x1, box->object->width,
box->descendant_y1, box->object->height));
if (box->descendant_x1 < box->object->width)
box->descendant_x1 = box->object->width;
if (box->descendant_y1 < box->object->height)
box->descendant_y1 = box->object->height;
return;
}
if (box->type == BOX_INLINE || box->type == BOX_TEXT)
return;
if (box->type == BOX_INLINE_END) {
box = box->inline_end;
for (child = box->next;
child && child != box->inline_end;
child = child->next) {
if (child->type == BOX_FLOAT_LEFT ||
child->type == BOX_FLOAT_RIGHT)
continue;
if (child->x + child->descendant_x0 - box->x <
box->descendant_x0)
box->descendant_x0 = child->x +
child->descendant_x0 - box->x;
if (box->descendant_x1 < child->x +
child->descendant_x1 - box->x)
box->descendant_x1 = child->x +
child->descendant_x1 - box->x;
if (child->y + child->descendant_y0 - box->y <
box->descendant_y0)
box->descendant_y0 = child->y +
child->descendant_y0 - box->y;
if (box->descendant_y1 < child->y +
child->descendant_y1 - box->y)
box->descendant_y1 = child->y +
child->descendant_y1 - box->y;
}
return;
}
for (child = box->children; child; child = child->next) {
if (child->type == BOX_FLOAT_LEFT ||
child->type == BOX_FLOAT_RIGHT)
continue;
layout_calculate_descendant_bboxes(child);
if (child->style &&
child->style->overflow != CSS_OVERFLOW_VISIBLE)
continue;
if (child->x + child->descendant_x0 < box->descendant_x0)
box->descendant_x0 = child->x + child->descendant_x0;
if (box->descendant_x1 < child->x + child->descendant_x1)
box->descendant_x1 = child->x + child->descendant_x1;
if (child->y + child->descendant_y0 < box->descendant_y0)
box->descendant_y0 = child->y + child->descendant_y0;
if (box->descendant_y1 < child->y + child->descendant_y1)
box->descendant_y1 = child->y + child->descendant_y1;
}
for (child = box->float_children; child; child = child->next_float) {
if (child->type != BOX_FLOAT_LEFT &&
child->type != BOX_FLOAT_RIGHT)
continue;
layout_calculate_descendant_bboxes(child);
if (child->x + child->descendant_x0 < box->descendant_x0)
box->descendant_x0 = child->x + child->descendant_x0;
if (box->descendant_x1 < child->x + child->descendant_x1)
box->descendant_x1 = child->x + child->descendant_x1;
if (child->y + child->descendant_y0 < box->descendant_y0)
box->descendant_y0 = child->y + child->descendant_y0;
if (box->descendant_y1 < child->y + child->descendant_y1)
box->descendant_y1 = child->y + child->descendant_y1;
}
}
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