From b485f458fcc428b1440c1fcd01be30fea30a1684 Mon Sep 17 00:00:00 2001
From: Thomas White <taw@physics.org>
Date: Tue, 4 Jun 2019 23:31:41 +0200
Subject: Add cursor

---
 src/nanolight.c | 47 +++++++++++++++++++++++++++++++++++------------
 src/nanolight.h |  3 +++
 2 files changed, 38 insertions(+), 12 deletions(-)

diff --git a/src/nanolight.c b/src/nanolight.c
index e597e68..2ed51ce 100644
--- a/src/nanolight.c
+++ b/src/nanolight.c
@@ -105,8 +105,8 @@ static gboolean draw_sig(GtkWidget *widget, cairo_t *cr, struct nanolight *nl)
 	int i;
 	PangoContext *pc;
 	PangoFontDescription *fontdesc;
-	PangoLayout *layout;
 	double x, y;
+	PangoRectangle cursor;
 
 	w = gtk_widget_get_allocated_width(widget);
 	h = gtk_widget_get_allocated_height(widget);
@@ -143,15 +143,23 @@ static gboolean draw_sig(GtkWidget *widget, cairo_t *cr, struct nanolight *nl)
 	}
 
 	/* Command line */
-	layout = pango_layout_new(pc);
-	fontdesc = pango_font_description_from_string("Comfortaa Bold 16");
-	pango_layout_set_text(layout, nl->cmdline, -1);
-	pango_layout_set_alignment(layout, PANGO_ALIGN_LEFT);
-	pango_layout_set_font_description(layout, fontdesc);
+	pango_layout_set_text(nl->layout, nl->cmdline, -1);
 	cairo_set_source_rgb(cr, 1.0, 1.0, 1.0);
-	cairo_move_to(cr, 0.0, h - OVERALL_BORDER*2 - 20.0);
-	pango_cairo_show_layout(cr, layout);
-	g_object_unref(layout);
+	cairo_save(cr);
+	cairo_translate(cr, 0.0, h - OVERALL_BORDER*2 - 20.0);
+	cairo_move_to(cr, 0.0, 0.0);
+	pango_cairo_show_layout(cr, nl->layout);
+	pango_layout_get_cursor_pos(nl->layout, nl->cursor_idx, &cursor, NULL);
+	x = pango_units_to_double(cursor.x);
+	y = pango_units_to_double(cursor.y);
+	h = pango_units_to_double(cursor.height);
+	cairo_move_to(cr, x, y);
+	cairo_line_to(cr, x, y+h);
+	cairo_set_line_width(cr, 3.0);
+	cairo_set_line_cap(cr, CAIRO_LINE_CAP_ROUND);
+	cairo_set_source_rgb(cr, 0.8, 0.4, 0.4);
+	cairo_stroke(cr);
+	cairo_restore(cr);
 
 	return FALSE;
 }
@@ -196,6 +204,7 @@ static void execute_command(struct nanolight *nl)
 {
 	if ( command_run(nl->cmdline, nl) == 0 ) {
 		nl->cmdline[0] = '\0';
+		nl->cursor_idx = 0;
 	}
 	redraw(nl);
 }
@@ -206,17 +215,21 @@ static gboolean im_commit_sig(GtkIMContext *im, gchar *str, struct nanolight *nl
 	size_t cmd_len = strlen(nl->cmdline);
 	if ( cmd_len+strlen(str) > 1023 ) return FALSE;
 	strcat(nl->cmdline, str);
+	nl->cursor_idx += strlen(str);
 	redraw(nl);
 	return FALSE;
 }
 
 
-static void delete_char(char *str)
+static size_t delete_char(char *str)
 {
 	char *last;
-	if ( str[0] == '\0' ) return;
+	size_t len;
+	if ( str[0] == '\0' ) return 0;
 	last = g_utf8_find_prev_char(str, str+strlen(str));
+	len = strlen(last);
 	last[0] = '\0';
+	return len;
 }
 
 
@@ -246,12 +259,13 @@ static gboolean key_press_sig(GtkWidget *da, GdkEventKey *event, struct nanoligh
 
 		case GDK_KEY_Escape :
 		nl->cmdline[0] = '\0';
+		nl->cursor_idx = 0;
 		redraw(nl);
 		claim = 1;
 		break;
 
 		case GDK_KEY_BackSpace :
-		delete_char(nl->cmdline);
+		nl->cursor_idx -= delete_char(nl->cmdline);
 		claim = 1;
 		redraw(nl);
 		break;
@@ -266,6 +280,8 @@ static gboolean key_press_sig(GtkWidget *da, GdkEventKey *event, struct nanoligh
 static gint realise_sig(GtkWidget *da, struct nanolight *nl)
 {
 	GdkWindow *win = gtk_widget_get_window(da);
+	PangoContext *pc;
+	PangoFontDescription *fontdesc;
 
 	/* Keyboard and input method stuff */
 	nl->im_context = gtk_im_multicontext_new();
@@ -274,6 +290,12 @@ static gint realise_sig(GtkWidget *da, struct nanolight *nl)
 	g_signal_connect(G_OBJECT(nl->im_context), "commit", G_CALLBACK(im_commit_sig), nl);
 	g_signal_connect(G_OBJECT(da), "key-press-event", G_CALLBACK(key_press_sig), nl);
 
+	pc = gtk_widget_get_pango_context(da);
+	nl->layout = pango_layout_new(pc);
+	fontdesc = pango_font_description_from_string("Comfortaa Bold 16");
+	pango_layout_set_alignment(nl->layout, PANGO_ALIGN_LEFT);
+	pango_layout_set_font_description(nl->layout, fontdesc);
+
 	return FALSE;
 }
 
@@ -339,6 +361,7 @@ int main(int argc, char *argv[])
 	nl.n_fixtures = 0;
 	nl.max_fixtures = 0;
 	nl.cmdline[0] = '\0';
+	nl.cursor_idx = 0;
 
 	create_fixture(&nl, &cls, "mh1", 1);
 	create_fixture(&nl, &cls, "mh2", 52);
diff --git a/src/nanolight.h b/src/nanolight.h
index 9e6f19e..5c08cd7 100644
--- a/src/nanolight.h
+++ b/src/nanolight.h
@@ -72,7 +72,10 @@ struct nanolight
 	GtkWidget *da;
 
 	double fixture_width;
+
 	char cmdline[1024];
+	int cursor_idx;
+	PangoLayout *layout;
 };
 
 
-- 
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