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authorJames Bursa <james@netsurf-browser.org>2010-09-16 02:04:38 +0000
committerJames Bursa <james@netsurf-browser.org>2010-09-16 02:04:38 +0000
commit81842e9a4d512fb573aff7d538a798130968c943 (patch)
tree005177ce37e72319b5f3d61c6d090560bd28852d
parentea203a6dd8a241d33e4bd1a6b076006cac715776 (diff)
downloadlibcss-81842e9a4d512fb573aff7d538a798130968c943.tar.gz
libcss-81842e9a4d512fb573aff7d538a798130968c943.tar.bz2
LibCSS API documentation, part 1, along with a simple example.
svn path=/trunk/libcss/; revision=10783
-rw-r--r--docs/API281
-rw-r--r--examples/example1.c579
2 files changed, 860 insertions, 0 deletions
diff --git a/docs/API b/docs/API
new file mode 100644
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--- /dev/null
+++ b/docs/API
@@ -0,0 +1,281 @@
+Using the LibCSS API
+====================
+
+This document explains how to use LibCSS. In addition to this document, please
+see the examples and the headers (found in /usr/local/include/libcss or a
+similar location). Experience with C is assumed.
+
+Using the library consists of the following general steps:
+
+1. Initialize the library.
+2. Load one or more CSS files.
+3. Use the Selection API to determine styles.
+4. Use the computed styles.
+5. Shut down the library.
+
+Please see example1.c for a demonstration of these steps.
+
+
+Initialize the library
+----------------------
+
+The library is initialized using css_initialise():
+
+ css_initialise("Aliases", myrealloc, 0);
+
+The first argument is the pathname of an Aliases file, which maps character
+encoding names to their canonical form. For an example, see test/data/Aliases.
+
+The 2nd argument is an allocation function. All allocations required by library
+initialization will be made by calling this function. It takes the same
+arguments as realloc(); a pointer and a size. If pointer is NULL a new block is
+being requested. If size is 0 the block should be freed. Otherwise an existing
+block is being resized. In many cases this function can simply call realloc().
+
+The allocation function also takes a private data pointer, which is the third
+argument to css_initialise(). This is not used by LibCSS but may be used to
+communicate context to the allocation function.
+
+The allocation function pointer and private data pointer are arguments to many
+LibCSS functions and work in the same way.
+
+css_initialise() returns a css_error value. It is CSS_OK if everything worked,
+and an error code otherwise. The error codes are defined in libcss/errors.h.
+
+Many LibCSS functions return a css_error value. Checking the return value of
+every call that does is advised, for example:
+
+ css_error code;
+ code = css_initialise("../test/data/Aliases", myrealloc, 0);
+ if (code != CSS_OK) {
+ fprintf(stderr, "ERROR: css_initialise failed: %s\n",
+ css_error_to_string(code));
+ exit(EXIT_FAILURE);
+ }
+
+LibCSS depends on LibWapcaplet. This must be initialized before LibCSS. For
+example:
+
+ lwc_code = lwc_initialise(myrealloc, NULL, 0);
+ if (lwc_code != lwc_error_ok)
+ ...
+
+
+Load one or more CSS files
+--------------------------
+
+A stylesheet is represented by the opaque type css_stylesheet. To create one,
+use css_stylesheet_create(), for example:
+
+ css_stylesheet *sheet;
+ code = css_stylesheet_create(CSS_LEVEL_DEFAULT, "UTF-8", "", NULL,
+ false, false, myrealloc, 0, resolve_url, 0, &sheet);
+ if (code != CSS_OK)
+ ...
+
+The arguments are as follows:
+
+ css_language_level level
+ Which version of CSS the stylesheet should be treated as. It currently has
+ no effect and is reserved for future use. The recommended value is
+ CSS_LEVEL_DEFAULT.
+
+ const char *charset
+ The encoding of the stylesheet data, or NULL if LibCSS should attempt to
+ detect it. If the encoding is known, for example from the Content-Type
+ header or a file attribute, then it should be supplied here.
+
+ const char *url
+ The URL that the stylesheet was retrieved from. LibCSS uses this along with
+ the resolve function (see below) to convert relative URLs in the stylesheet
+ (e.g. imports, background images) to absolute URLs. If the stylesheet has
+ no URL, use "".
+
+ const char *title
+ This is intended for the stylesheet title (for example from the <link> tag).
+ The title is not used by LibCSS but may be retrieved using
+ css_stylesheet_get_title(). May be NULL if there is no title.
+
+ bool allow_quirks
+
+
+ bool inline_style
+
+
+ css_allocator_fn alloc
+ void *alloc_pw
+
+
+ css_url_resolution_fn resolve
+ void *resolve_pw
+
+
+ css_stylesheet **stylesheet
+ Updated with the newly created stylesheet object.
+
+Once the stylesheet has been created, CSS source data can be added to it. LibCSS
+parses the data into internal structures. Only data in memory is supported; you
+must handle reading from files or the network if required. Data is added using
+css_stylesheet_append_data(), for example:
+
+ code = css_stylesheet_append_data(sheet, data, length);
+ if (code != CSS_OK && code != CSS_NEEDDATA)
+ ...
+
+The second argument is a pointer to a buffer containing some CSS to be parsed,
+with length in bytes given in the 3rd argument.
+
+This function may be called repeatedly with more data from the same stylesheet,
+for example as data arrives over the network.
+
+The return value may be CSS_NEEDDATA instead of CSS_OK. This indicates that more
+data may be expected. The two states can be treated identically.
+
+When all the data has been supplied, css_stylesheet_data_done() completes the
+processing:
+
+ code = css_stylesheet_data_done(sheet);
+ if (code != CSS_OK)
+ ...
+
+The stylesheet is now in memory and ready for further use.
+
+
+Use the Selection API to determine styles
+-----------------------------------------
+
+The Selection API is currently the only way to get information about styles from
+stylesheets that have been loaded. It takes a document node as input and returns
+the computed style that applies to that node. For example, it can be used to
+answer the question "What style should this <h1> element have?"
+
+CSS selectors can be complex and apply to certain arrangments of elements within
+a document tree. Therefore LibCSS has to be able to navigate your document tree
+and read attributes of it to determine if a style applies. It does this through
+a series of functions that you supply. In this way LibCSS is independent of the
+representation of the document. For example, with the style rule:
+
+ table h2 { color: red; }
+
+when requesting the style for an h2 element node, LibCSS will search its
+ancestors for a table element to determine if this style applies.
+
+The first step in using the Selection API is creating a selection context. This
+is a list of the stylesheets to be used. A context is created using
+css_select_ctx_create():
+
+ css_select_ctx *select_ctx;
+ code = css_select_ctx_create(myrealloc, 0, &select_ctx);
+ if (code != CSS_OK)
+ ...
+
+Stylesheets are added to the context using css_select_ctx_append_sheet():
+
+ code = css_select_ctx_append_sheet(select_ctx, sheet, CSS_ORIGIN_AUTHOR,
+ CSS_MEDIA_ALL);
+ if (code != CSS_OK)
+ ...
+
+When adding a stylesheet, the origin and media can be specified. These are used
+in the computation of styles as defined in the CSS specification.
+
+Alternatively stylesheets may be added using css_select_ctx_insert_sheet().
+
+After the context has been prepared, an empty computed style is created:
+
+ css_computed_style *style;
+ code = css_computed_style_create(myrealloc, 0, &style);
+ if (code != CSS_OK)
+ ...
+
+The style is then determined for a document node using css_select_style():
+
+ code = css_select_style(select_ctx, element_node, 0,
+ CSS_MEDIA_SCREEN, NULL, style,
+ &select_handler, 0);
+ if (code != CSS_OK)
+ ...
+
+The arguments are as follows:
+
+ css_select_ctx *ctx
+ The selection context, as described above.
+
+ void *node
+ A pointer to the document node for which the style is required. This is a
+ void pointer and may therefore be of any desired type. LibCSS can not use it
+ directly; instead it gets information about it through the functions given
+ in the handler argument, described below. Usually this will be a node in a
+ document tree.
+
+ uint32_t pseudo_element
+
+ uint64_t media
+ The media that the style should apply to. The computed style will only
+ consider stylesheets or @media blocks that include this media. See the CSS
+ specification for more details.
+
+ const css_stylesheet *inline_style
+
+ css_computed_style *result
+ Updated to the computed style for the node.
+
+ css_select_handler *handler
+ This is a table of functions that are used to get information from and to
+ navigate the document tree, in order to determine if a CSS selector matches
+ the document node. Further details are below.
+
+ void *pw
+ A private data pointer that is passed to each of the handler functions.
+
+The types of the handler functions that need to be supplied and the definition
+of css_select_handler are given in libcss/select.h. The functions all have the
+following in common:
+
+ * the first argument is the private data pointer that was the last argument to
+ css_select_style()
+
+ * the second argument is the document node that is being queried is some way
+
+ * the last one or two arguments are pointers that must be updated with the
+ required information
+
+ * the return value is a css_error and should be CSS_OK if everything worked and
+ an error code otherwise
+
+For example, the node_name function, which determines the element name of a
+node, could be this:
+
+ css_error node_name(void *pw, void *n, lwc_string **name)
+ {
+ my_document_node *node = n;
+ *name = lwc_string_ref(node->name);
+ return CSS_OK;
+ }
+
+where my_document_node is your document tree node type (e.g. a struct of some
+sort).
+
+
+Use the computed styles
+-----------------------
+
+After the style has been computed by css_select_style() the CSS properties can
+finally be retrieved. This is done using the property accessor functions
+declared in libcss/computed.h.
+
+Note that although struct css_computed_style is declared in computed.h, its
+members must not be used directly. The accessors carry out various additional
+work to read the properties correctly.
+
+For example, the css_computed_color() accessor retrieves the color property:
+
+ uint8_t color_type;
+ css_color color_shade;
+ color_type = css_computed_color(style, &color_shade);
+
+In this case color_type can be CSS_COLOR_INHERIT or CSS_COLOR_COLOR. In the
+latter case, color_shade contains the actual color in RRGGBBAA format. Together
+these two variables encode the possible values for the property given by the
+CSS specification.
+
diff --git a/examples/example1.c b/examples/example1.c
new file mode 100644
index 0000000..8690e0a
--- /dev/null
+++ b/examples/example1.c
@@ -0,0 +1,579 @@
+/*
+ * LibCSS - example1.c
+ *
+ * Compile this using a command such as:
+ * gcc -g -W -Wall -o example1 example1.c `pkg-config --cflags --libs libcss`
+ */
+
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+
+/* The entire API is available through this header. */
+#include <libcss/libcss.h>
+
+
+/* This macro is used to silence compiler warnings about unused function
+ * arguments. */
+#define UNUSED(x) ((x) = (x))
+
+
+/* Function declarations. */
+static void *myrealloc(void *ptr, size_t len, void *pw);
+static css_error resolve_url(void *pw,
+ const char *base, lwc_string *rel, lwc_string **abs);
+static void die(const char *text, css_error code);
+static css_error node_name(void *pw, void *node,
+ lwc_string **name);
+static css_error node_classes(void *pw, void *node,
+ lwc_string ***classes, uint32_t *n_classes);
+static css_error node_id(void *pw, void *node,
+ lwc_string **id);
+static css_error named_ancestor_node(void *pw, void *node,
+ lwc_string *name,
+ void **ancestor);
+static css_error named_parent_node(void *pw, void *node,
+ lwc_string *name,
+ void **parent);
+static css_error named_sibling_node(void *pw, void *node,
+ lwc_string *name,
+ void **sibling);
+static css_error parent_node(void *pw, void *node, void **parent);
+static css_error sibling_node(void *pw, void *node, void **sibling);
+static css_error node_has_name(void *pw, void *node,
+ lwc_string *name,
+ bool *match);
+static css_error node_has_class(void *pw, void *node,
+ lwc_string *name,
+ bool *match);
+static css_error node_has_id(void *pw, void *node,
+ lwc_string *name,
+ bool *match);
+static css_error node_has_attribute(void *pw, void *node,
+ lwc_string *name,
+ bool *match);
+static css_error node_has_attribute_equal(void *pw, void *node,
+ lwc_string *name,
+ lwc_string *value,
+ bool *match);
+static css_error node_has_attribute_dashmatch(void *pw, void *node,
+ lwc_string *name,
+ lwc_string *value,
+ bool *match);
+static css_error node_has_attribute_includes(void *pw, void *node,
+ lwc_string *name,
+ lwc_string *value,
+ bool *match);
+static css_error node_is_first_child(void *pw, void *node, bool *match);
+static css_error node_is_link(void *pw, void *node, bool *match);
+static css_error node_is_visited(void *pw, void *node, bool *match);
+static css_error node_is_hover(void *pw, void *node, bool *match);
+static css_error node_is_active(void *pw, void *node, bool *match);
+static css_error node_is_focus(void *pw, void *node, bool *match);
+static css_error node_is_lang(void *pw, void *node,
+ lwc_string *lang, bool *match);
+static css_error node_presentational_hint(void *pw, void *node,
+ uint32_t property, css_hint *hint);
+static css_error ua_default_for_property(void *pw, uint32_t property,
+ css_hint *hint);
+static css_error compute_font_size(void *pw, const css_hint *parent,
+ css_hint *size);
+
+/* Table of function pointers for the LibCSS Select API. */
+static css_select_handler select_handler = {
+ node_name,
+ node_classes,
+ node_id,
+ named_ancestor_node,
+ named_parent_node,
+ named_sibling_node,
+ parent_node,
+ sibling_node,
+ node_has_name,
+ node_has_class,
+ node_has_id,
+ node_has_attribute,
+ node_has_attribute_equal,
+ node_has_attribute_dashmatch,
+ node_has_attribute_includes,
+ node_is_first_child,
+ node_is_link,
+ node_is_visited,
+ node_is_hover,
+ node_is_active,
+ node_is_focus,
+ node_is_lang,
+ node_presentational_hint,
+ ua_default_for_property,
+ compute_font_size
+};
+
+
+int main(int argc, char **argv)
+{
+ lwc_error lwc_code;
+ css_error code;
+ css_stylesheet *sheet;
+ size_t size;
+ const char data[] = "h1 { color: red } "
+ "h4 { color: #321; } "
+ "h4, h5 { color: #123456; ";
+ css_select_ctx *select_ctx;
+ uint32_t count;
+ unsigned int hh;
+
+ UNUSED(argc);
+ UNUSED(argv);
+
+ /* initialise libwapcaplet (required by libcss) */
+ lwc_code = lwc_initialise(myrealloc, NULL, 0);
+ if (lwc_code != lwc_error_ok) {
+ fprintf(stderr, "lwc_initialise: %i\n", lwc_code);
+ return 1;
+ }
+
+ /* initialise libcss */
+ code = css_initialise("../test/data/Aliases", myrealloc, 0);
+ if (code != CSS_OK)
+ die("css_initialise", code);
+
+
+ /* create a stylesheet */
+ code = css_stylesheet_create(CSS_LEVEL_DEFAULT, "UTF-8", "", NULL,
+ false, false, myrealloc, 0, resolve_url, 0, &sheet);
+ if (code != CSS_OK)
+ die("css_stylesheet_create", code);
+ code = css_stylesheet_size(sheet, &size);
+ if (code != CSS_OK)
+ die("css_stylesheet_size", code);
+ printf("created stylesheet, size %zu\n", size);
+
+
+ /* parse some CSS source */
+ code = css_stylesheet_append_data(sheet, (const uint8_t *) data,
+ sizeof data);
+ if (code != CSS_OK && code != CSS_NEEDDATA)
+ die("css_stylesheet_append_data", code);
+ code = css_stylesheet_data_done(sheet);
+ if (code != CSS_OK)
+ die("css_stylesheet_data_done", code);
+ code = css_stylesheet_size(sheet, &size);
+ if (code != CSS_OK)
+ die("css_stylesheet_size", code);
+ printf("appended data, size now %zu\n", size);
+
+
+ /* prepare a selection context containing the stylesheet */
+ code = css_select_ctx_create(myrealloc, 0, &select_ctx);
+ if (code != CSS_OK)
+ die("css_select_ctx_create", code);
+ code = css_select_ctx_append_sheet(select_ctx, sheet, CSS_ORIGIN_AUTHOR,
+ CSS_MEDIA_ALL);
+ if (code != CSS_OK)
+ die("css_select_ctx_append_sheet", code);
+ code = css_select_ctx_count_sheets(select_ctx, &count);
+ if (code != CSS_OK)
+ die("css_select_ctx_count_sheets", code);
+ printf("created selection context with %i sheets\n", count);
+
+
+ /* select style for each of h1 to h6 */
+ for (hh = 1; hh != 7; hh++) {
+ css_computed_style *style;
+ char element[20];
+ lwc_string *element_name;
+ uint8_t color_type;
+ css_color color_shade;
+
+ /* in this very simple example our "document tree" is just one
+ * node and is in fact a libwapcaplet string containing the
+ * element name */
+ snprintf(element, sizeof element, "h%i", hh);
+ lwc_intern_string(element, strlen(element), &element_name);
+
+ code = css_computed_style_create(myrealloc, 0, &style);
+ if (code != CSS_OK)
+ die("css_computed_style_create", code);
+ code = css_select_style(select_ctx, element_name, 0,
+ CSS_MEDIA_SCREEN, NULL, style,
+ &select_handler, 0);
+ if (code != CSS_OK)
+ die("css_select_style", code);
+
+ color_type = css_computed_color(style, &color_shade);
+ if (color_type == CSS_COLOR_INHERIT)
+ printf("color of h%i is 'inherit'\n", hh);
+ else
+ printf("color of h%i is %x\n", hh, color_shade);
+
+ code = css_computed_style_destroy(style);
+ if (code != CSS_OK)
+ die("css_computed_style_destroy", code);
+ }
+
+
+ /* free everything and shut down libcss */
+ code = css_select_ctx_destroy(select_ctx);
+ if (code != CSS_OK)
+ die("css_select_ctx_destroy", code);
+ code = css_stylesheet_destroy(sheet);
+ if (code != CSS_OK)
+ die("css_stylesheet_destroy", code);
+ code = css_finalise(myrealloc, 0);
+ if (code != CSS_OK)
+ die("css_finalise", code);
+
+
+ return 0;
+}
+
+
+void *myrealloc(void *ptr, size_t len, void *pw)
+{
+ UNUSED(pw);
+ /*printf("myrealloc(%p, %zu)\n", ptr, len);*/
+
+ return realloc(ptr, len);
+}
+
+
+css_error resolve_url(void *pw,
+ const char *base, lwc_string *rel, lwc_string **abs)
+{
+ UNUSED(pw);
+ UNUSED(base);
+
+ /* About as useless as possible */
+ *abs = lwc_string_ref(rel);
+
+ return CSS_OK;
+}
+
+
+void die(const char *text, css_error code)
+{
+ fprintf(stderr, "ERROR: %s: %i: %s\n",
+ text, code, css_error_to_string(code));
+ exit(EXIT_FAILURE);
+}
+
+
+
+/* Select handlers. Our "document tree" is actually just a single node, which is
+ * a libwapcaplet string containing the element name. Therefore all the
+ * functions below except those getting or testing the element name return empty
+ * data or false attributes. */
+css_error node_name(void *pw, void *n, lwc_string **name)
+{
+ lwc_string *node = n;
+ UNUSED(pw);
+ *name = lwc_string_ref(node);
+ return CSS_OK;
+}
+
+css_error node_classes(void *pw, void *n,
+ lwc_string ***classes, uint32_t *n_classes)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ *classes = NULL;
+ *n_classes = 0;
+ return CSS_OK;
+}
+
+css_error node_id(void *pw, void *n, lwc_string **id)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ *id = NULL;
+ return CSS_OK;
+}
+
+css_error named_ancestor_node(void *pw, void *n,
+ lwc_string *name,
+ void **ancestor)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ UNUSED(name);
+ *ancestor = NULL;
+ return CSS_OK;
+}
+
+css_error named_parent_node(void *pw, void *n,
+ lwc_string *name,
+ void **parent)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ UNUSED(name);
+ *parent = NULL;
+ return CSS_OK;
+}
+
+css_error named_sibling_node(void *pw, void *n,
+ lwc_string *name,
+ void **sibling)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ UNUSED(name);
+ *sibling = NULL;
+ return CSS_OK;
+}
+
+css_error parent_node(void *pw, void *n, void **parent)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ *parent = NULL;
+ return CSS_OK;
+}
+
+css_error sibling_node(void *pw, void *n, void **sibling)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ *sibling = NULL;
+ return CSS_OK;
+}
+
+css_error node_has_name(void *pw, void *n,
+ lwc_string *name,
+ bool *match)
+{
+ lwc_string *node = n;
+ UNUSED(pw);
+ assert(lwc_string_caseless_isequal(node, name, match) == lwc_error_ok);
+ return CSS_OK;
+}
+
+css_error node_has_class(void *pw, void *n,
+ lwc_string *name,
+ bool *match)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ UNUSED(name);
+ *match = false;
+ return CSS_OK;
+}
+
+css_error node_has_id(void *pw, void *n,
+ lwc_string *name,
+ bool *match)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ UNUSED(name);
+ *match = false;
+ return CSS_OK;
+}
+
+css_error node_has_attribute(void *pw, void *n,
+ lwc_string *name,
+ bool *match)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ UNUSED(name);
+ *match = false;
+ return CSS_OK;
+}
+
+css_error node_has_attribute_equal(void *pw, void *n,
+ lwc_string *name,
+ lwc_string *value,
+ bool *match)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ UNUSED(name);
+ UNUSED(value);
+ *match = false;
+ return CSS_OK;
+}
+
+css_error node_has_attribute_dashmatch(void *pw, void *n,
+ lwc_string *name,
+ lwc_string *value,
+ bool *match)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ UNUSED(name);
+ UNUSED(value);
+ *match = false;
+ return CSS_OK;
+}
+
+css_error node_has_attribute_includes(void *pw, void *n,
+ lwc_string *name,
+ lwc_string *value,
+ bool *match)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ UNUSED(name);
+ UNUSED(value);
+ *match = false;
+ return CSS_OK;
+}
+
+css_error node_is_first_child(void *pw, void *n, bool *match)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ *match = false;
+ return CSS_OK;
+}
+
+css_error node_is_link(void *pw, void *n, bool *match)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ *match = false;
+ return CSS_OK;
+}
+
+css_error node_is_visited(void *pw, void *n, bool *match)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ *match = false;
+ return CSS_OK;
+}
+
+css_error node_is_hover(void *pw, void *n, bool *match)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ *match = false;
+ return CSS_OK;
+}
+
+css_error node_is_active(void *pw, void *n, bool *match)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ *match = false;
+ return CSS_OK;
+}
+
+css_error node_is_focus(void *pw, void *n, bool *match)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ *match = false;
+ return CSS_OK;
+}
+
+css_error node_is_lang(void *pw, void *n,
+ lwc_string *lang,
+ bool *match)
+{
+ UNUSED(pw);
+ UNUSED(n);
+ UNUSED(lang);
+ *match = false;
+ return CSS_OK;
+}
+
+css_error node_presentational_hint(void *pw, void *node,
+ uint32_t property, css_hint *hint)
+{
+ UNUSED(pw);
+ UNUSED(node);
+ UNUSED(property);
+ UNUSED(hint);
+ return CSS_PROPERTY_NOT_SET;
+}
+
+css_error ua_default_for_property(void *pw, uint32_t property, css_hint *hint)
+{
+ UNUSED(pw);
+
+ if (property == CSS_PROP_COLOR) {
+ hint->data.color = 0x00000000;
+ hint->status = CSS_COLOR_COLOR;
+ } else if (property == CSS_PROP_FONT_FAMILY) {
+ hint->data.strings = NULL;
+ hint->status = CSS_FONT_FAMILY_SANS_SERIF;
+ } else if (property == CSS_PROP_QUOTES) {
+ /* Not exactly useful :) */
+ hint->data.strings = NULL;
+ hint->status = CSS_QUOTES_NONE;
+ } else if (property == CSS_PROP_VOICE_FAMILY) {
+ /** \todo Fix this when we have voice-family done */
+ hint->data.strings = NULL;
+ hint->status = 0;
+ } else {
+ return CSS_INVALID;
+ }
+
+ return CSS_OK;
+}
+
+css_error compute_font_size(void *pw, const css_hint *parent, css_hint *size)
+{
+ static css_hint_length sizes[] = {
+ { FLTTOFIX(6.75), CSS_UNIT_PT },
+ { FLTTOFIX(7.50), CSS_UNIT_PT },
+ { FLTTOFIX(9.75), CSS_UNIT_PT },
+ { FLTTOFIX(12.0), CSS_UNIT_PT },
+ { FLTTOFIX(13.5), CSS_UNIT_PT },
+ { FLTTOFIX(18.0), CSS_UNIT_PT },
+ { FLTTOFIX(24.0), CSS_UNIT_PT }
+ };
+ const css_hint_length *parent_size;
+
+ UNUSED(pw);
+
+ /* Grab parent size, defaulting to medium if none */
+ if (parent == NULL) {
+ parent_size = &sizes[CSS_FONT_SIZE_MEDIUM - 1];
+ } else {
+ assert(parent->status == CSS_FONT_SIZE_DIMENSION);
+ assert(parent->data.length.unit != CSS_UNIT_EM);
+ assert(parent->data.length.unit != CSS_UNIT_EX);
+ parent_size = &parent->data.length;
+ }
+
+ assert(size->status != CSS_FONT_SIZE_INHERIT);
+
+ if (size->status < CSS_FONT_SIZE_LARGER) {
+ /* Keyword -- simple */
+ size->data.length = sizes[size->status - 1];
+ } else if (size->status == CSS_FONT_SIZE_LARGER) {
+ /** \todo Step within table, if appropriate */
+ size->data.length.value =
+ FMUL(parent_size->value, FLTTOFIX(1.2));
+ size->data.length.unit = parent_size->unit;
+ } else if (size->status == CSS_FONT_SIZE_SMALLER) {
+ /** \todo Step within table, if appropriate */
+ size->data.length.value =
+ FMUL(parent_size->value, FLTTOFIX(1.2));
+ size->data.length.unit = parent_size->unit;
+ } else if (size->data.length.unit == CSS_UNIT_EM ||
+ size->data.length.unit == CSS_UNIT_EX) {
+ size->data.length.value =
+ FMUL(size->data.length.value, parent_size->value);
+
+ if (size->data.length.unit == CSS_UNIT_EX) {
+ size->data.length.value = FMUL(size->data.length.value,
+ FLTTOFIX(0.6));
+ }
+
+ size->data.length.unit = parent_size->unit;
+ } else if (size->data.length.unit == CSS_UNIT_PCT) {
+ size->data.length.value = FDIV(FMUL(size->data.length.value,
+ parent_size->value), FLTTOFIX(100));
+ size->data.length.unit = parent_size->unit;
+ }
+
+ size->status = CSS_FONT_SIZE_DIMENSION;
+
+ return CSS_OK;
+}
+
+