src/html.[ch]: Move under src/utils/

2 files changed, 791 insertions, 0 deletions

diff --git a/src/utils/html.c b/src/utils/html.c
new file mode 100644
index 0000000..47b2d7a
--- /dev/null
+++ b/src/utils/html.c
@@ -0,0 +1,703 @@
+/*
+ * HTML document generation
+ *
+ * Copyright (C) 2017  Patrick McDermott
+ *
+ * This file is part of Marquee.
+ *
+ * Marquee is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Marquee is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Marquee.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "html.h"
+
+#include <stdarg.h>
+#include <string.h>
+
+#include <glib.h>
+#include <gtk/gtk.h>
+
+static const gchar *styles =
+	/*
+	 * General styles
+	 */
+	"* {\n"
+		"margin: 6px;\n"
+		"padding: 0;\n"
+		"background: none;\n"
+		"border: 0 none;\n"
+	"}\n"
+	"html {\n"
+		"margin: 0;\n"
+	"}\n"
+	"body {\n"
+		"margin: 18px;\n"
+		"background-color: #AFAFAF;\n"
+		"font-family: sans-serif;\n"
+	"}\n"
+	"h1, h2, h3, h4, h5, h6, p {\n"
+		"text-align: center;\n"
+	"}\n"
+	/*
+	 * Horizontal notebook
+	 */
+	"div.notebook-h {\n"
+		"clear: left;\n"
+		"position: relative;\n"
+		"padding: 0;\n"
+	"}\n"
+	"div.notebook-h > input {\n"
+		"display: none;\n"
+	"}\n"
+	"div.notebook-h > label {\n"
+		"display: block;\n"
+		"background-color: #9F9F9F;\n"
+		"color: #5F5F5F;\n"
+		"float: left;\n"
+		"margin: 6px 3px 0 0;\n"
+		"border-width: 1px 1px 0 1px;\n"
+		"border-style: solid;\n"
+		"border-color: #8F8F8F;\n"
+		"border-radius: 3px 3px 0 0;\n"
+		"padding: 6px;\n"
+		"font-weight: bold;\n"
+		"position: relative;\n"
+		"top: 3px;\n"
+	"}\n"
+	"div.notebook-h > input:checked + label {\n"
+		"background-color: #CFCFCF;\n"
+		"color: #000000;\n"
+		"padding: 6px 6px 7px 6px;\n"
+		"border-color: #9F9F9F;\n"
+		"position: relative;\n"
+		"top: 0;\n"
+		"z-index: 1;\n"
+	"}\n"
+	"div.notebook-h > div {\n"
+		"display: none;\n"
+		"background-color: #CFCFCF;\n"
+		"clear: left;\n"
+		"border: 1px solid #9F9F9F;\n"
+		"border-radius: 0 0 3px 3px;\n"
+		"position: relative;\n"
+		"top: -1px;\n"
+		"margin: 0;\n"
+	"}\n"
+	/*
+	 * Vertical notebook
+	 */
+	"div.notebook-v {\n"
+		"position: relative;\n"
+		/* Why are these weird margin and padding numbers necessary? */
+		"margin: 6px 5px 6px 0;\n"
+		"padding: 6px 0 0 0;\n"
+	"}\n"
+	"div.notebook-v > input {\n"
+		"display: none;\n"
+	"}\n"
+	"div.notebook-v > label {\n"
+		"display: block;\n"
+		"background-color: #9F9F9F;\n"
+		"color: #5F5F5F;\n"
+		"float: left;\n"
+		"clear: left;\n"
+		"margin: 0 0 3px 6px;\n"
+		"border-width: 1px 0 1px 1px;\n"
+		"border-style: solid;\n"
+		"border-color: #8F8F8F;\n"
+		"border-radius: 3px 0 0 3px;\n"
+		"padding: 6px;\n"
+		"font-weight: bold;\n"
+		"position: relative;\n"
+		"left: 3px;\n"
+	"}\n"
+	"div.notebook-v > input:checked + label {\n"
+		"background-color: #CFCFCF;\n"
+		"color: #000000;\n"
+		"padding: 6px 7px 6px 6px;\n"
+		"border-color: #9F9F9F;\n"
+		"position: relative;\n"
+		"left: 0;\n"
+		"z-index: 1;\n"
+	"}\n"
+	"div.notebook-v > div {\n"
+		"display: none;\n"
+		"background-color: #CFCFCF;\n"
+		"border: 1px solid #9F9F9F;\n"
+		"border-radius: 0 3px 3px 0;\n"
+		"position: relative;\n"
+		"left: -1px;\n"
+		"margin: 0;\n"
+		"overflow: hidden;\n"
+	"}\n"
+	/*
+	 * Form elements
+	 */
+	"form {\n"
+		"margin: 0;\n"
+	"}\n"
+	"form input, form select {\n"
+		"border: 1px solid #9F9F9F;\n"
+		"border-radius: 3px;\n"
+		"background-color: #EFEFEF;\n"
+		"padding: 6px;\n"
+		"color: #000000;\n"
+		"transition: all 250ms ease-in-out 0s;\n"
+		"-moz-transition: all 250ms ease-in-out 0s;\n"
+		"-wekbit-transition: all 250ms ease-in-out 0s;\n"
+		"-o-transition: all 250ms ease-in-out 0s;\n"
+	"}\n"
+	"div.dialog-buttonbox {\n"
+		"margin: 0;\n"
+		"float: right;\n"
+	"}\n"
+	"form label {\n"
+		"display: block;\n"
+	"}\n"
+	"form label span {\n"
+		"display: inline-block;\n"
+		"width: calc(50% - 6px);\n"
+		"text-align: right;\n"
+	"}\n"
+	"form input[type=submit], form input[type=reset] {\n"
+		"background-color: #DFDFDF;\n"
+	"}\n"
+	"form input:hover, form select:hover,\n"
+	"form input:focus, form select:focus {\n"
+		"border: 1px solid #4F8FCF;\n"
+		"outline: 0;\n"
+	"}\n"
+	"form input[type=submit]:hover, form input[type=reset]:hover,\n"
+	"form input[type=submit]:focus, form input[type=reset]:focus {\n"
+		"background-color: #EFEFEF;\n"
+	"}\n"
+	"iframe {\n"
+		"width: calc(100% - 12px);\n"
+		"height: 400px;\n"
+	"}\n"
+	;
+
+gchar *
+mq_html_document(const gchar *title, ...)
+{
+	gsize    len;
+	va_list  ap;
+	gchar   *child;
+	gchar   *document;
+	gchar   *ptr;
+
+	/* Calculate length. */
+	len = strlen("<!doctype html>\n<html dir=\"");
+	len += 3;  /* "ltr" or "rtl" */
+	len += strlen("\">\n<head>\n<meta charset=\"utf-8\">\n<title>");
+	len += strlen(title);
+	len += strlen("</title>\n<style>\n");
+	len += strlen(styles);
+	len += strlen("</style>\n</head>\n<body>\n");
+	va_start(ap, title);
+	while ((child = va_arg(ap, gchar *))) {
+		len += strlen(child);
+	}
+	va_end(ap);
+	len += strlen("</body>\n</html>\n");
+	++len;  /* NUL byte */
+
+	/* Build string. */
+	document = g_new(gchar, len);
+	ptr = g_stpcpy(document, "<!doctype html>\n<html dir=\"");
+	ptr = g_stpcpy(ptr, gtk_widget_get_default_direction() ==
+		GTK_TEXT_DIR_RTL ? "rtl" : "ltr");
+	ptr = g_stpcpy(ptr, "\">\n<head>\n<meta charset=\"utf-8\">\n<title>");
+	ptr = g_stpcpy(ptr, title);
+	ptr = g_stpcpy(ptr, "</title>\n<style>\n");
+	ptr = g_stpcpy(ptr, styles);
+	ptr = g_stpcpy(ptr, "</style>\n</head>\n<body>\n");
+	va_start(ap, title);
+	while ((child = va_arg(ap, gchar *))) {
+		ptr = g_stpcpy(ptr, child);
+		g_free(child);
+	}
+	va_end(ap);
+	ptr = g_stpcpy(ptr, "</body>\n</html>\n");  /* g_stpcpy() adds NUL. */
+
+	return document;
+}
+
+#define TEXT_ELEMENT(ELEM) \
+	gchar * \
+	mq_html_##ELEM(const gchar *text) \
+	{ \
+		return g_strconcat("<" #ELEM ">", text, "</" #ELEM ">\n", \
+			NULL); \
+	} \
+	gchar * \
+	mq_html_##ELEM##_free(gchar *text) \
+	{ \
+		gchar *e; \
+		e = g_strconcat("<" #ELEM ">", text, "</" #ELEM ">\n", NULL); \
+		g_free(text); \
+		return e; \
+	}
+TEXT_ELEMENT(h1)
+TEXT_ELEMENT(h2)
+TEXT_ELEMENT(h3)
+TEXT_ELEMENT(h4)
+TEXT_ELEMENT(h5)
+TEXT_ELEMENT(h6)
+TEXT_ELEMENT(p)
+#undef TEXT_ELEMENT
+
+gchar *
+mq_html_list(const gchar *type, GDestroyNotify destroy, ...)
+{
+	gsize    len;
+	va_list  ap;
+	gchar   *child;
+	gchar   *list;
+	gchar   *ptr;
+
+	/* TODO: Doesn't support specification of <ol> list types. */
+
+	/* Calculate length. */
+	len = strlen("<ul>\n");
+	va_start(ap, destroy);
+	while ((child = va_arg(ap, gchar *))) {
+		len += strlen("<li>\n");
+		len += strlen(child);
+		len += strlen("</li>\n");
+	}
+	va_end(ap);
+	len += strlen("</ul>\n");
+	++len;  /* NUL byte */
+
+	/* Build string. */
+	list = g_new(gchar, len);
+	if (type && type[0]) {
+		ptr = g_stpcpy(list, "<ol>\n");
+	} else {
+		ptr = g_stpcpy(list, "<ul>\n");
+	}
+	va_start(ap, destroy);
+	while ((child = va_arg(ap, gchar *))) {
+		ptr = g_stpcpy(ptr, "<li>\n");
+		ptr = g_stpcpy(ptr, child);
+		if (destroy) {
+			destroy(child);
+		}
+		ptr = g_stpcpy(ptr, "</li>\n");
+	}
+	va_end(ap);
+	ptr = g_stpcpy(ptr, "</ul>\n");  /* g_stpcpy() adds the NUL. */
+
+	return list;
+}
+
+gchar *
+mq_html_list_v(const gchar *type, gchar **children)
+{
+	gsize  len;
+	gsize  i;
+	gchar *list;
+	gchar *ptr;
+
+	/* TODO: Doesn't support specification of <ol> list types. */
+
+	/* Calculate length. */
+	len = strlen("<ul>\n");
+	for (i = 0; children && children[i]; ++i) {
+		len += strlen("<li>\n");
+		len += strlen(children[i]);
+		len += strlen("</li>\n");
+	}
+	len += strlen("</ul>\n");
+	++len;  /* NUL byte */
+
+	/* Build string. */
+	list = g_new(gchar, len);
+	if (type && type[0]) {
+		ptr = g_stpcpy(list, "<ol>\n");
+	} else {
+		ptr = g_stpcpy(list, "<ul>\n");
+	}
+	for (i = 0; children && children[i]; ++i) {
+		ptr = g_stpcpy(ptr, "<li>\n");
+		ptr = g_stpcpy(ptr, children[i]);
+		ptr = g_stpcpy(ptr, "</li>\n");
+	}
+	ptr = g_stpcpy(ptr, "</ul>\n");  /* g_stpcpy() adds the NUL. */
+
+	return list;
+}
+
+gchar *
+mq_html_container(const gchar *element, ...)
+{
+	gsize    len;
+	va_list  ap;
+	gchar   *child;
+	gchar   *container;
+	gchar   *ptr;
+
+	/* Calculate length. */
+	len = strlen("<");
+	len += strlen(element);
+	len += strlen(">\n");
+	va_start(ap, element);
+	while ((child = va_arg(ap, gchar *))) {
+		len += strlen(child);
+	}
+	va_end(ap);
+	len += strlen("</");
+	len += strlen(element);
+	len += strlen(">\n");
+	++len;  /* NUL byte */
+
+	/* Build string. */
+	container = g_new(gchar, len);
+	ptr = g_stpcpy(container, "<");
+	ptr = g_stpcpy(ptr, element);
+	ptr = g_stpcpy(ptr, ">\n");
+	va_start(ap, element);
+	while ((child = va_arg(ap, gchar *))) {
+		ptr = g_stpcpy(ptr, child);
+		g_free(child);
+	}
+	va_end(ap);
+	ptr = g_stpcpy(ptr, "</");
+	ptr = g_stpcpy(ptr, element);
+	ptr = g_stpcpy(ptr, ">\n");  /* g_stpcpy() adds the NUL. */
+
+	return container;
+}
+
+gchar *
+mq_html_notebook(gboolean vertical, const gchar *name, guint current_page, ...)
+{
+	gsize    name_len;
+	gsize    len;
+	va_list  ap;
+	gsize    i;
+	gchar   *child;
+	gchar   *tab_label;
+	gchar   *i_str;
+	gchar   *notebook;
+	gchar   *ptr;
+
+	/* Calculate length. */
+	name_len = strlen(name);
+	len = strlen("<div class=\"notebook-") + 1 + strlen("\">\n");
+	va_start(ap, current_page);
+	i = 0;
+	while ((child = va_arg(ap, gchar *)) &&
+			(tab_label = va_arg(ap, gchar *))) {
+		i_str = g_strdup_printf("%zu", i);
+		len += strlen("<input id=\"_tab_");
+		len += name_len;
+		len += strlen("_");
+		len += strlen(i_str);
+		/* len += (gsize) log10(i) + 1; */
+		len += strlen("\" type=\"radio\"");
+		if (i == current_page) {
+			len += strlen(" checked=\"checked\"");
+		}
+		len += strlen(" name=\"_tabs\"></input>\n");
+		len += strlen("<label for=\"_tab_");
+		len += name_len;
+		len += strlen("_");
+		len += strlen(i_str);
+		/* len += (gsize) log10(i) + 1; */
+		len += strlen("\">");
+		len += strlen(tab_label);
+		len += strlen("</label>\n");
+		++i;
+	}
+	va_end(ap);
+	va_start(ap, current_page);
+	while ((child = va_arg(ap, gchar *)) &&
+			(tab_label = va_arg(ap, gchar *))) {
+		i_str = g_strdup_printf("%zu", i);
+		len += strlen("<div id=\"_tab-page_");
+		len += name_len;
+		len += strlen("_");
+		len += strlen(i_str);
+		len += strlen("\">\n");
+		len += strlen(child);
+		len += strlen("</div>\n<style>\ndiv.notebook-") + 1;
+		len += strlen(" > input#_tab_");
+		len += name_len;
+		len += strlen("_");
+		len += strlen(i_str);
+		len += strlen(":checked ~ div#_tab-page_");
+		len += name_len;
+		len += strlen("_");
+		len += strlen(i_str);
+		len += strlen(" {\ndisplay: block;\n}\n</style>\n");
+	}
+	va_end(ap);
+	len += strlen("</div>\n");
+	++len;  /* NUL byte */
+
+	/* Build string. */
+	notebook = g_new(gchar, len);
+	ptr = g_stpcpy(notebook, "<div class=\"notebook-");
+	ptr = g_stpcpy(ptr, vertical ? "v" : "h");
+	ptr = g_stpcpy(ptr, "\">\n");
+	va_start(ap, current_page);
+	i = 0;
+	while ((child = va_arg(ap, gchar *)) &&
+			(tab_label = va_arg(ap, gchar *))) {
+		i_str = g_strdup_printf("%zu", i);
+		ptr = g_stpcpy(ptr, "<input id=\"_tab_");
+		ptr = g_stpcpy(ptr, name);
+		ptr = g_stpcpy(ptr, "_");
+		ptr = g_stpcpy(ptr, i_str);
+		ptr = g_stpcpy(ptr, "\" type=\"radio\"");
+		if (i == current_page) {
+			ptr = g_stpcpy(ptr, " checked=\"checked\"");
+		}
+		ptr = g_stpcpy(ptr, " name=\"_tabs\"></input>\n");
+		ptr = g_stpcpy(ptr, "<label for=\"_tab_");
+		ptr = g_stpcpy(ptr, name);
+		ptr = g_stpcpy(ptr, "_");
+		ptr = g_stpcpy(ptr, i_str);
+		ptr = g_stpcpy(ptr, "\">");
+		ptr = g_stpcpy(ptr, tab_label);
+		ptr = g_stpcpy(ptr, "</label>\n");
+		g_free(i_str);
+		++i;
+	}
+	va_end(ap);
+	va_start(ap, current_page);
+	i = 0;
+	while ((child = va_arg(ap, gchar *)) &&
+			(tab_label = va_arg(ap, gchar *))) {
+		i_str = g_strdup_printf("%zu", i);
+		ptr = g_stpcpy(ptr, "<div id=\"_tab-page_");
+		ptr = g_stpcpy(ptr, name);
+		ptr = g_stpcpy(ptr, "_");
+		ptr = g_stpcpy(ptr, i_str);
+		ptr = g_stpcpy(ptr, "\">\n");
+		ptr = g_stpcpy(ptr, child);
+		g_free(child);
+		ptr = g_stpcpy(ptr, "</div>\n<style>\ndiv.notebook-");
+		ptr = g_stpcpy(ptr, vertical ? "v" : "h");
+		ptr = g_stpcpy(ptr, " > input#_tab_");
+		ptr = g_stpcpy(ptr, name);
+		ptr = g_stpcpy(ptr, "_");
+		ptr = g_stpcpy(ptr, i_str);
+		ptr = g_stpcpy(ptr, ":checked ~ div#_tab-page_");
+		ptr = g_stpcpy(ptr, name);
+		ptr = g_stpcpy(ptr, "_");
+		ptr = g_stpcpy(ptr, i_str);
+		ptr = g_stpcpy(ptr, " {\ndisplay: block;\n}\n</style>\n");
+		++i;
+	}
+	va_end(ap);
+	ptr = g_stpcpy(ptr, "</div>\n");  /* g_stpcpy() adds the NUL. */
+
+	return notebook;
+}
+
+gchar *
+mq_html_form(const gchar *submit_label, const gchar *reset_label, ...)
+{
+	gsize    len;
+	va_list  ap;
+	gchar   *child;
+	gchar   *form;
+	gchar   *ptr;
+
+	/* Calculate length. */
+	len = strlen("<form>\n");
+	va_start(ap, reset_label);
+	while ((child = va_arg(ap, gchar *))) {
+		len += strlen(child);
+	}
+	va_end(ap);
+	len += strlen("<div class=\"dialog-buttonbox\">\n") +
+		strlen("<input type=\"reset\" value=\"") + strlen(reset_label) +
+		strlen("\">\n<input type=\"submit\" value=\"") +
+		strlen(submit_label) + strlen("\">\n</div>\n") +
+		strlen("</form>\n");
+	++len;  /* NUL byte */
+
+	/* Build string. */
+	form = g_new(gchar, len);
+	ptr = g_stpcpy(form, "<form>\n");
+	va_start(ap, reset_label);
+	while ((child = va_arg(ap, gchar *))) {
+		ptr = g_stpcpy(ptr, child);
+		g_free(child);
+	}
+	va_end(ap);
+	ptr = g_stpcpy(ptr, "<div class=\"dialog-buttonbox\">\n");
+	ptr = g_stpcpy(ptr, "<input type=\"reset\" value=\"");
+	ptr = g_stpcpy(ptr, reset_label);
+	ptr = g_stpcpy(ptr, "\">\n<input type=\"submit\" value=\"");
+	ptr = g_stpcpy(ptr, submit_label);
+	ptr = g_stpcpy(ptr, "\">\n</div>\n");
+	ptr = g_stpcpy(ptr, "</form>\n");  /* g_stpcpy() adds the NUL. */
+
+	return form;
+}
+
+gchar *
+mq_html_input_text(const gchar *name, const gchar *label, const gchar *value)
+{
+	return g_strdup_printf("<label for=\"%s\">\n<span>%s:</span>\n"
+		"<input type=\"text\" name=\"%s\" id=\"%s\" value=\"%s\">\n"
+		"</label>\n",
+		name, label, name, name, value ? value : "");
+}
+
+gchar *
+mq_html_input_number_i(const gchar *name, const gchar *label,
+	gint min, gint step, gint max, gint value)
+{
+	return g_strdup_printf("<label for=\"%s\">\n<span>%s:</span>\n"
+		"<input type=\"number\" name=\"%s\" id=\"%s\""
+		" min=\"%d\" step=\"%d\" max=\"%d\" value=\"%d\">\n"
+		"</label>\n",
+		name, label, name, name, min, step, max, value);
+}
+
+gchar *
+mq_html_input_number_d(const gchar *name, const gchar *label,
+	gdouble min, gdouble step, gdouble max, gdouble value)
+{
+	return g_strdup_printf("<label for=\"%s\">\n<span>%s:</span>\n"
+		"<input type=\"number\" name=\"%s\" id=\"%s\""
+		" min=\"%f\" step=\"%f\" max=\"%f\" value=\"%f\">\n"
+		"</label>\n",
+		name, label, name, name, min, step, max, value);
+}
+
+gchar *
+mq_html_input_radio(const gchar *name, const gchar *label, gboolean checked)
+{
+	return g_strdup_printf("<label for=\"%s\">\n<span>%s:</span>\n"
+		"<input type=\"radio\" name=\"%s\" id=\"%s\"%s>\n</label>\n",
+		name, label, name, name, checked ? " checked=\"checked\"" : "");
+}
+
+gchar *
+mq_html_input_checkbox(const gchar *name, const gchar *label, gboolean checked)
+{
+	/*
+	 * Values of "checkbox"-type <input>s that are not checked are not sent
+	 * in queries with form submissions.  The "about:preferences"
+	 * query-handling code doesn't handle any preferences that aren't
+	 * submitted in the query, so values need to be submitted for unchecked
+	 * "checkbox"-type <input>s in order for unchecking to have any effect.
+	 *
+	 * This function returns two <input>s: one of type "hidden" with a value
+	 * of "off" and one of type "checkbox".  If the "checkbox"-type <input>
+	 * is checked, both <input> values will be submitted in the query, with
+	 * the value of the "checkbox"-type <input> last.  Otherwise, only the
+	 * "off" value of the "hidden"-type <input> will be submitted.
+	 *
+	 * The query-parsing code for "about"-scheme resources iterates through
+	 * each "key=value" pair in order, inserting each pair into a
+	 * GHashTable.  When keys collide, g_hash_table_insert() replaces the
+	 * previous value with the new value.  Thus, the value of the
+	 * "checkbox"-type <input> will override that of the "hidden"-type
+	 * <input> when the former <input> is checked.
+	 */
+
+	return g_strdup_printf("<label for=\"%s\">\n<span>%s:</span>\n"
+		"<input type=\"hidden\" name=\"%s\" value=\"off\">\n"
+		"<input type=\"checkbox\" name=\"%s\" id=\"%s\"%s>\n</label>\n",
+		name, label, name, name, name,
+		checked ? " checked=\"checked\"" : "");
+}
+
+gchar *
+mq_html_input_select(const gchar *name, const gchar *label,
+	const gchar *selected,
+	GDestroyNotify destroy_value, GDestroyNotify destroy_label, ...)
+{
+	gsize    len;
+	va_list  ap;
+	gchar   *option_value;
+	gchar   *option_label;
+	gchar   *select;
+	gchar   *ptr;
+
+	g_assert(selected && selected[0]);  /* Would cause buffer overflow */
+
+	/* Calculate length. */
+	len = strlen("<label for=\"");
+	len += strlen(name);
+	len += strlen("\">\n<span>");
+	len += strlen(label);
+	len += strlen(":</span>\n<select name=\"");
+	len += strlen(name);
+	len += strlen("\" id=\"");
+	len += strlen(name);
+	len += strlen("\">\n");
+	va_start(ap, destroy_label);
+	while ((option_value = va_arg(ap, gchar *)) && (option_label =
+				va_arg(ap, gchar *))) {
+		len += strlen("<option value=\"");
+		len += strlen(option_value);
+		len += strlen("\"");
+		len += strlen(">");
+		len += strlen(option_label);
+		len += strlen("</option>\n");
+	}
+	va_end(ap);
+	len += strlen(" selected=\"selected\"");
+	len += strlen("</select>\n</label>\n");
+	++len;  /* NUL byte */
+
+	/* Build string. */
+	select = g_new(gchar, len);
+	ptr = g_stpcpy(select, "<label for=\"");
+	ptr = g_stpcpy(ptr, name);
+	ptr = g_stpcpy(ptr, "\">\n<span>");
+	ptr = g_stpcpy(ptr, label);
+	ptr = g_stpcpy(ptr, ":</span>\n<select name=\"");
+	ptr = g_stpcpy(ptr, name);
+	ptr = g_stpcpy(ptr, "\" id=\"");
+	ptr = g_stpcpy(ptr, name);
+	ptr = g_stpcpy(ptr, "\">\n");
+	va_start(ap, destroy_label);
+	while ((option_value = va_arg(ap, gchar *)) && (option_label =
+				va_arg(ap, gchar *))) {
+		ptr = g_stpcpy(ptr, "<option value=\"");
+		ptr = g_stpcpy(ptr, option_value);
+		ptr = g_stpcpy(ptr, "\"");
+		if (g_strcmp0(option_value, selected) == 0) {
+			ptr = g_stpcpy(ptr, " selected=\"selected\"");
+		}
+		ptr = g_stpcpy(ptr, ">");
+		ptr = g_stpcpy(ptr, option_label);
+		if (destroy_value) {
+			destroy_value(option_value);
+		}
+		if (destroy_label) {
+			destroy_label(option_label);
+		}
+		ptr = g_stpcpy(ptr, "</option>\n");
+	}
+	va_end(ap);
+	ptr = g_stpcpy(ptr, "</select>\n</label>\n");  /* g_stpcpy() adds NUL */
+
+	return select;
+}
+
+gchar *
+mq_html_input_iframe(const gchar *src)
+{
+	return g_strdup_printf("<iframe src=\"%s\"></iframe>", src);
+}
diff --git a/src/utils/html.h b/src/utils/html.h
new file mode 100644
index 0000000..92fe2ea
--- /dev/null
+++ b/src/utils/html.h
@@ -0,0 +1,88 @@
+/*
+ * HTML document generation
+ *
+ * Copyright (C) 2017  Patrick McDermott
+ *
+ * This file is part of Marquee.
+ *
+ * Marquee is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Marquee is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Marquee.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef MQ_HTML_H
+#define MQ_HTML_H
+
+#include <glib.h>
+
+gchar *
+mq_html_document(const gchar *title, ...) G_GNUC_NULL_TERMINATED;
+
+#define TEXT_ELEMENT(ELEM) \
+	gchar * \
+	mq_html_##ELEM(const gchar *text); \
+	gchar * \
+	mq_html_##ELEM##_free(gchar *text);
+TEXT_ELEMENT(h1)
+TEXT_ELEMENT(h2)
+TEXT_ELEMENT(h3)
+TEXT_ELEMENT(h4)
+TEXT_ELEMENT(h5)
+TEXT_ELEMENT(h6)
+TEXT_ELEMENT(p)
+#undef TEXT_ELEMENT
+
+gchar *
+mq_html_container(const gchar *element, ...) G_GNUC_NULL_TERMINATED;
+
+gchar *
+mq_html_list(const gchar *type, GDestroyNotify destroy, ...)
+	G_GNUC_NULL_TERMINATED;
+
+gchar *
+mq_html_list_v(const gchar *type, gchar **children);
+
+gchar *
+mq_html_notebook(gboolean vertical, const gchar *name, guint current_page, ...)
+	G_GNUC_NULL_TERMINATED;
+
+gchar *
+mq_html_form(const gchar *submit_label, const gchar *reset_label, ...)
+	G_GNUC_NULL_TERMINATED;
+
+gchar *
+mq_html_input_text(const gchar *name, const gchar *label, const gchar *value);
+
+gchar *
+mq_html_input_number_i(const gchar *name, const gchar *label,
+	gint min, gint step, gint max, gint value);
+
+gchar *
+mq_html_input_number_d(const gchar *name, const gchar *label,
+	gdouble min, gdouble step, gdouble max, gdouble value);
+
+gchar *
+mq_html_input_radio(const gchar *name, const gchar *label, gboolean checked);
+
+gchar *
+mq_html_input_checkbox(const gchar *name, const gchar *label, gboolean checked);
+
+gchar *
+mq_html_input_select(const gchar *name, const gchar *label,
+	const gchar *selected,
+	GDestroyNotify destroy_value, GDestroyNotify destroy_label, ...)
+	G_GNUC_NULL_TERMINATED;
+
+gchar *
+mq_html_input_iframe(const gchar *src);
+
+#endif