From 80722aeda0df83efa844e72e44b94c2d7f676b74 Mon Sep 17 00:00:00 2001
From: Aki <please@ignore.pl>
Date: Tue, 14 Sep 2021 22:31:01 +0200
Subject: Added custom pango attribute to store uri

---
 text.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 63 insertions(+), 7 deletions(-)

diff --git a/text.c b/text.c
index 24cfb3e..256e804 100644
--- a/text.c
+++ b/text.c
@@ -28,8 +28,9 @@ union Command
 	} block;
 	struct {
 		int type;
-		int position;
-		int length;
+		int start;
+		int end;
+		const char * uri;
 	} span;
 };
 
@@ -65,20 +66,29 @@ struct Layout
 int setup(struct State *);
 void finalize(struct State *, struct Layout *);
 int handle(struct State *, xcb_generic_event_t *);
+xcb_visualtype_t * find_visual(xcb_screen_t *);
+PangoAttribute * find_link_under(PangoLayout *, PangoAttrList *, int, int);
 void arrange(struct State *, struct Layout *, union Command[]);
 void draw(struct State *, struct Layout *);
-xcb_visualtype_t * find_visual(xcb_screen_t *);
+PangoAttribute * attr_hyperlink_new(const char *);
+PangoAttribute * attr_string_copy(const PangoAttribute *);
+void attr_string_destroy(PangoAttribute *);
+gboolean attr_string_equal(const PangoAttribute *, const PangoAttribute *);
+PangoAttribute * attr_string_new(const PangoAttrClass *, const char *);
 
 static const int MARGIN = 20;
 static const char * const FONT = "Serif 16";
+static PangoAttrType PANGO_CUSTOM_ATTR_HYPERLINK;
+static PangoAttrClass hyperlink_klass;  // TODO: Separate almost-pango-internals somewhere to minimize clutter.
 
 #define _BLOCK(_txt) {.block = {.type = COMMAND_BLOCK, .length = sizeof(_txt) - 1, .data = _txt}}
 union Command body[] = {
-	{.span = {.type = COMMAND_SPAN, .position = 28, .length = 11}},
+	{.span = {.type = COMMAND_SPAN, .start = 28, .end = 39, .uri = "https://ignore.pl/consectetur"}},
 	_BLOCK(
 		"Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam auctor porta eros at tempus. Aliquam "
 		"elementum lectus id mi fermentum, non consectetur urna lobortis."
 	),
+	{.span = {.type = COMMAND_SPAN, .start = 10, .end = 19, .uri = "https://ignore.pl/dignissim"}},
 	_BLOCK("Phasellus dignissim rhoncus magna at imperdiet."),
 	{.type = COMMAND_DONE},
 };
@@ -89,6 +99,13 @@ int main(int argc, const char ** argv)
 {
 	(void) argc;
 	(void) argv;
+	PANGO_CUSTOM_ATTR_HYPERLINK = pango_attr_type_register("hyperlink");
+	hyperlink_klass = (PangoAttrClass){
+		PANGO_CUSTOM_ATTR_HYPERLINK,
+		attr_string_copy,
+		attr_string_destroy,
+		attr_string_equal,
+	};
 	struct State state;
 	if (-1 == setup(&state))
 	{
@@ -264,8 +281,12 @@ void arrange(struct State * state, struct Layout * layout, union Command body[])
 		case COMMAND_SPAN:
 			;
 			PangoAttribute * attr = pango_attr_foreground_new(0x0000, 0x0000, 0xffff);
-			attr->start_index = c->span.position;
-			attr->end_index = c->span.position + c->span.length;
+			attr->start_index = c->span.start;
+			attr->end_index = c->span.end;
+			pango_attr_list_change(attrs, attr);
+			attr = attr_hyperlink_new(c->span.uri);
+			attr->start_index = c->span.start;
+			attr->end_index = c->span.end;
 			pango_attr_list_change(attrs, attr);
 			break;
 		case COMMAND_BLOCK:
@@ -273,7 +294,7 @@ void arrange(struct State * state, struct Layout * layout, union Command body[])
 			attr = find_link_under(layout->v[i], attrs, state->pointer_x - MARGIN, state->pointer_y - MARGIN);
 			if (NULL != attr)
 				pango_attr_list_change(attrs, attr);
-			pango_layout_set_attributes(layout->v[i], attrs);  // TODO-maybe: Don't reset everything?
+			pango_layout_set_attributes(layout->v[i], attrs);
 			pango_attr_list_unref(attrs);
 			attrs = pango_attr_list_new();
 			pango_layout_set_font_description(layout->v[i], layout->desc);
@@ -309,3 +330,38 @@ void draw(struct State * state, struct Layout * layout)
 	cairo_surface_flush(state->surface);
 	xcb_flush(state->c);
 }
+
+
+PangoAttribute * attr_hyperlink_new(const char * uri)
+{
+	return attr_string_new(&hyperlink_klass, uri);
+}
+
+
+PangoAttribute * attr_string_copy(const PangoAttribute * src)
+{
+	return attr_string_new(src->klass, ((PangoAttrString *) src)->value);
+}
+
+
+void attr_string_destroy(PangoAttribute * attr)
+{
+	PangoAttrString * str = (PangoAttrString *) attr;
+	g_free(str->value);
+	g_slice_free(PangoAttrString, str);
+}
+
+
+gboolean attr_string_equal(const PangoAttribute * lhs, const PangoAttribute * rhs)
+{
+	return 0 == strcmp(((PangoAttrString *) lhs)->value, ((PangoAttrString *) rhs)->value);
+}
+
+
+PangoAttribute * attr_string_new(const PangoAttrClass * klass, const char * uri)
+{
+	PangoAttrString * str = g_slice_new(PangoAttrString);
+	pango_attribute_init(&str->attr, klass);
+	str->value = g_strdup(uri);
+	return (PangoAttribute *) str;
+}
-- 
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