From eac5162294d022c1f62bf9d6e429e3451b2a091d Mon Sep 17 00:00:00 2001
From: Aki <please@ignore.pl>
Date: Mon, 13 Sep 2021 21:54:06 +0200
Subject: Added stupid hovering support

---
 text.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 52 insertions(+), 3 deletions(-)

diff --git a/text.c b/text.c
index 187c301..24cfb3e 100644
--- a/text.c
+++ b/text.c
@@ -37,6 +37,8 @@ struct State
 {
 	int width;
 	int height;
+	int pointer_x;
+	int pointer_y;
 	xcb_connection_t * c;
 	xcb_screen_t * s;
 	xcb_visualtype_t * v;
@@ -50,6 +52,7 @@ enum Actions
 	ACTION_REDRAW = 1 << 0,
 	ACTION_ARRANGE = 1 << 1,
 	ACTION_CLOSE = 1 << 2,
+	ACTION_POINTER = 1 << 3,
 };
 
 struct Layout
@@ -100,9 +103,9 @@ int main(int argc, const char ** argv)
 		int actions = handle(&state, e);  // Obviously, right now this may have at most one action.
 		if (ACTION_CLOSE & actions)
 			break;
-		if (ACTION_ARRANGE & actions)
+		if ((ACTION_ARRANGE | ACTION_POINTER) & actions)  // TODO: Separate implementation for pointer.
 			arrange(&state, &layout, body);
-		if (ACTION_REDRAW & actions)
+		if ((ACTION_REDRAW | ACTION_POINTER) & actions)
 			draw(&state, &layout);
 	}
 	finalize(&state, &layout);
@@ -122,7 +125,8 @@ int setup(struct State * state)
 	const uint32_t mask = XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK;
 	const uint32_t values[] = {
 		state->s->white_pixel,
-		XCB_EVENT_MASK_EXPOSURE | XCB_EVENT_MASK_KEY_PRESS | XCB_EVENT_MASK_STRUCTURE_NOTIFY,
+		XCB_EVENT_MASK_EXPOSURE | XCB_EVENT_MASK_KEY_PRESS | XCB_EVENT_MASK_STRUCTURE_NOTIFY |
+			XCB_EVENT_MASK_POINTER_MOTION,
 	};
 	xcb_create_window(
 		state->c, XCB_COPY_FROM_PARENT, state->w, state->s->root, 0, 0, initial_width, initial_height, 0,
@@ -131,6 +135,8 @@ int setup(struct State * state)
 	state->ctx = cairo_create(state->surface);
 	xcb_map_window(state->c, state->w);
 	xcb_flush(state->c);
+	state->pointer_x = 0;
+	state->pointer_y = 0;
 	return 0;
 }
 
@@ -158,6 +164,13 @@ int handle(struct State * state, xcb_generic_event_t * e)
 	case XCB_EXPOSE:
 		actions |= ACTION_REDRAW;
 		break;
+	case XCB_MOTION_NOTIFY:
+		;
+		actions |= ACTION_POINTER;
+		xcb_motion_notify_event_t * motion = (xcb_motion_notify_event_t *) e;
+		state->pointer_x = motion->event_x;
+		state->pointer_y = motion->event_y;
+		break;
 	case XCB_CONFIGURE_NOTIFY:
 		;
 		actions |= ACTION_ARRANGE;
@@ -191,6 +204,38 @@ xcb_visualtype_t * find_visual(xcb_screen_t * screen)
 }
 
 
+PangoAttribute * find_link_under(PangoLayout * layout, PangoAttrList * attrs, int x, int y)
+{
+	int index;
+	int trailing;
+	int found = pango_layout_xy_to_index(layout, x * PANGO_SCALE, y * PANGO_SCALE, &index, &trailing);
+	PangoAttribute * attr = NULL;
+	if (!found)
+		return NULL;
+	PangoAttrIterator * iter = pango_attr_list_get_iterator(attrs);
+	for (int next = TRUE; next; next = pango_attr_iterator_next(iter))
+	{
+		attr = pango_attr_iterator_get(iter, PANGO_ATTR_FOREGROUND);
+		if (NULL == attr)
+			continue;
+		int start, end;
+		pango_attr_iterator_range(iter, &start, &end);
+		if (start > index || index > end)
+		{
+			attr = NULL;
+			continue;
+		}
+		attr = pango_attr_foreground_new(0xffff, 0x0000, 0x0000);
+		attr->start_index = start;
+		attr->end_index = end;
+		goto done;
+	}
+done:
+	pango_attr_iterator_destroy(iter);
+	return attr;
+}
+
+
 void arrange(struct State * state, struct Layout * layout, union Command body[])
 {
 	if (NULL == layout->desc)
@@ -224,6 +269,10 @@ void arrange(struct State * state, struct Layout * layout, union Command body[])
 			pango_attr_list_change(attrs, attr);
 			break;
 		case COMMAND_BLOCK:
+			;
+			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_attr_list_unref(attrs);
 			attrs = pango_attr_list_new();
-- 
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