[project @ 2002-05-04 19:57:18 by bursa]

Split box and layout modules from render.c.

svn path=/import/netsurf/; revision=13

1 files changed, 267 insertions, 0 deletions

diff --git a/render/layout.c b/render/layout.c
new file mode 100644
index 000000000..af0760362
--- /dev/null
+++ b/render/layout.c
@@ -0,0 +1,267 @@
+/**
+ * $Id: layout.c,v 1.1 2002/05/04 19:57:18 bursa Exp $
+ */
+
+#include <assert.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "libxml/HTMLparser.h"
+#include "css.h"
+#include "font.h"
+#include "box.h"
+#include "utils.h"
+
+/**
+ * internal functions
+ */
+
+signed long len(struct css_length * length, unsigned long em);
+
+unsigned long layout_block_children(struct box * box, unsigned long width);
+void layout_inline_container(struct box * box, unsigned long width);
+void layout_table(struct box * box, unsigned long width);
+
+
+/**
+ * convert a struct css_length to pixels
+ */
+
+signed long len(struct css_length * length, unsigned long em)
+{
+	switch (length->unit) {
+		case CSS_UNIT_EM: return length->value * em;
+		case CSS_UNIT_EX: return length->value * em * 0.6;
+		case CSS_UNIT_PX: return length->value;
+		case CSS_UNIT_IN: return length->value * 90.0;
+		case CSS_UNIT_CM: return length->value * 35.0;
+		case CSS_UNIT_MM: return length->value * 3.5;
+		case CSS_UNIT_PT: return length->value * 90.0 / 72.0;
+		case CSS_UNIT_PC: return length->value * 90.0 / 6.0;
+		default: return 0;
+	}
+	return 0;
+}
+
+/**
+ * layout algorithm
+ */
+
+void layout_block(struct box * box, unsigned long width)
+{
+	struct css_style * style = box->style;
+	switch (style->width.width) {
+		case CSS_WIDTH_AUTO:
+			box->width = width;
+			break;
+		case CSS_WIDTH_LENGTH:
+			box->width = len(&style->width.value.length, 10);
+			break;
+		case CSS_WIDTH_PERCENT:
+			box->width = width * style->width.value.percent / 100;
+			break;
+	}
+	box->height = layout_block_children(box, box->width);
+	switch (style->height.height) {
+		case CSS_HEIGHT_AUTO:
+			break;
+		case CSS_HEIGHT_LENGTH:
+			box->height = len(&style->height.length, 10);
+			break;
+	}
+}
+
+unsigned long layout_block_children(struct box * box, unsigned long width)
+{
+	struct box * c;
+	unsigned long y = 1;
+	
+	for (c = box->children; c != 0; c = c->next) {
+		switch (c->type) {
+			case BOX_BLOCK:
+				layout_block(c, width-4);
+				c->x = 2;
+				c->y = y;
+				y += c->height + 1;
+				break;
+			case BOX_INLINE_CONTAINER:
+				layout_inline_container(c, width-4);
+				c->x = 2;
+				c->y = y;
+				y += c->height + 1;
+				break;
+			case BOX_TABLE:
+				layout_table(c, width-4);
+				c->x = 2;
+				c->y = y;
+				y += c->height + 1;
+				break;
+			default:
+				die("block child not block, table, or inline container");
+		}
+	}
+	return y;
+}
+
+void layout_inline_container(struct box * box, unsigned long width)
+{
+	/* TODO: write this */
+	struct box * c;
+	unsigned long y = 1;
+	unsigned long x = 2;
+	const char * end;
+	struct box * new;
+
+	for (c = box->children; c != 0; ) {
+		c->width = font_split(0, c->font, c->text, width-2-x, &end)+1;
+		if (*end == 0) {
+			/* fits into this line */
+			c->x = x;
+			c->y = y;
+			c->height = 2;
+			x += c->width;
+			c = c->next;
+			continue;
+		}
+		if (end == c->text) {
+			/* doesn't fit at all: move down a line */
+			x = 2;
+			y += 3;
+			c->width = font_split(0, c->font, c->text, width-2-x, &end)+1;
+			if (end == c->text) end = strchr(c->text, ' ');
+			if (end == 0) end = c->text + 1;
+		}
+		/* split into two lines */ 
+		c->x = x;
+		c->y = y;
+		c->height = 2;
+		x = 2;
+		y += 3;
+		new = memcpy(xcalloc(1, sizeof(struct box)), c, sizeof(struct box));
+		new->text = end + 1;
+		new->next = c->next;
+		c->next = new;
+		c = new;
+	}
+
+	box->width = width;
+	box->height = y + 3;
+}
+
+/**
+ * layout a table
+ *
+ * this is the fixed table layout algorithm,
+ * <http://www.w3.org/TR/REC-CSS2/tables.html#fixed-table-layout>
+ */
+
+void layout_table(struct box * table, unsigned long width)
+{
+	unsigned int columns;  /* total columns */
+	unsigned int auto_columns;  /* number of columns with auto width */
+	unsigned long table_width;
+	unsigned long used_width = 0;  /* width used by fixed or percent columns */
+	unsigned long auto_width;  /* width of each auto column (all equal) */
+	unsigned long extra_width = 0;  /* extra width for each column if table is wider than columns */
+	unsigned long x;
+	unsigned long y = 1;
+	unsigned long * xs;
+	unsigned int i;
+	struct box * c;
+	struct box * r;
+
+	assert(table->type == BOX_TABLE);
+
+	/* find table width */
+	switch (table->style->width.width) {
+		case CSS_WIDTH_LENGTH:
+			table_width = len(&table->style->width.value.length, 10);
+			break;
+		case CSS_WIDTH_PERCENT:
+			table_width = width * table->style->width.value.percent / 100;
+			break;
+		case CSS_WIDTH_AUTO:
+		default:
+			table_width = width;
+			break;
+	}
+
+	/* calculate column statistics */
+	for (columns = 0, auto_columns = 0, c = table->children->children;
+			c != 0; c = c->next) {
+		assert(c->type == BOX_TABLE_CELL);
+		switch (c->style->width.width) {
+			case CSS_WIDTH_LENGTH:
+				used_width += len(&c->style->width.value.length, 10);
+				break;
+			case CSS_WIDTH_PERCENT:
+				used_width += table_width * c->style->width.value.percent / 100;
+				break;
+			case CSS_WIDTH_AUTO:
+				auto_columns++;
+				break;
+		}
+		columns++;
+	}
+
+	if (auto_columns == 0 && table->style->width.width != CSS_WIDTH_AUTO)
+		extra_width = (table_width - used_width) / columns;
+	else if (auto_columns != 0)
+		auto_width = (table_width - used_width) / auto_columns;
+
+	/*printf("%i %i %i %i %i\n", table_width, columns, auto_columns, used_width, auto_width);*/
+	
+	/* find column widths */
+	xs = xcalloc(columns + 1, sizeof(*xs));
+	xs[0] = x = 0;
+	for (i = 1, c = table->children->children; c != 0; i++, c = c->next) {
+		switch (c->style->width.width) {
+			case CSS_WIDTH_LENGTH:
+				x += len(&c->style->width.value.length, 10) + extra_width;
+				break;
+			case CSS_WIDTH_PERCENT:
+				x += table_width * c->style->width.value.percent / 100 + extra_width;
+				break;
+			case CSS_WIDTH_AUTO:
+				x += auto_width;
+				break;
+		}
+		xs[i] = x;
+		printf("%i ", x);
+	}
+	printf("\n");
+
+	if (auto_columns == 0 && table->style->width.width == CSS_WIDTH_AUTO)
+		table_width = used_width;
+	
+	/* position cells */
+	for (r = table->children; r != 0; r = r->next) {
+		unsigned long height = 0;
+		for (i = 0, c = r->children; c != 0; i++, c = c->next) {
+			c->width = xs[i+1] - xs[i];
+			c->height = layout_block_children(c, c->width);
+			switch (c->style->height.height) {
+				case CSS_HEIGHT_AUTO:
+					break;
+				case CSS_HEIGHT_LENGTH:
+					c->height = len(&c->style->height.length, 10);
+					break;
+			}
+			c->x = xs[i];
+			c->y = 1;
+			if (c->height > height) height = c->height;
+		}
+		r->x = 0;
+		r->y = y;
+		r->width = table_width;
+		r->height = height + 2;
+		y += height + 3;
+	}
+
+	free(xs);
+	
+	table->width = table_width;
+	table->height = y;
+}
+