Only redraw the required area

...and make it a bit easier to set the size and position of the clock

1 files changed, 30 insertions, 22 deletions

diff --git a/glitchyclock.c b/glitchyclock.c
index de34a30..0e15787 100644
--- a/glitchyclock.c
+++ b/glitchyclock.c
@@ -36,6 +36,11 @@ struct glitchyclock
 	int base_minutes;
 	int base_seconds;
 	int flag;
+
+	double clock_x;
+	double clock_y;
+	double clock_w;
+	double clock_h;
 };
 
 
@@ -90,6 +95,9 @@ struct glitch_cue cues[] = {
 	{ EOL, 0, 0, 0, 0 }
 };
 
+const double screen_w_frac = 0.2;    /* Fraction of screen width */
+const double screen_y_offset = 0.5;  /* Fraction of screen height */
+const double clock_aspect = 0.305;   /* Clock height divided by width */
 
 static double get_monotonic_seconds()
 {
@@ -116,11 +124,9 @@ static void run_cue(struct glitchyclock *gc)
 
 static gboolean draw_sig(GtkWidget *widget, cairo_t *cr, struct glitchyclock *gc)
 {
-	int w, h;
-	int lw, lh;
-	double sf;
+	double lw, lh;
+	int ilw, ilh;
 	PangoLayout *layout;
-	const double screen_w_frac = 0.2;
 	char timestr[64];
 	double seconds_elapsed, seconds_rounded;
 	double real_seconds_elapsed, real_seconds_rounded;
@@ -130,13 +136,12 @@ static gboolean draw_sig(GtkWidget *widget, cairo_t *cr, struct glitchyclock *gc
 	double duty;
 	const char *frozenstr = "vl:68";
 
-	w = gtk_widget_get_allocated_width(widget);
-	h = gtk_widget_get_allocated_height(widget);
-
 	/* Overall background */
 	cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
 	cairo_paint(cr);
 
+	cairo_translate(cr, gc->clock_x, gc->clock_y);
+
 	layout = pango_layout_new(gtk_widget_get_pango_context(widget));
 	pango_layout_set_alignment(layout, PANGO_ALIGN_CENTER);
 	pango_layout_set_font_description(layout, gc->fontdesc);
@@ -223,20 +228,13 @@ static gboolean draw_sig(GtkWidget *widget, cairo_t *cr, struct glitchyclock *gc
 	}
 
 	pango_layout_set_text(layout, "88:88", -1);
-
 	pango_cairo_update_layout(cr, layout);
-	pango_layout_get_size(layout, &lw, &lh);
+	pango_layout_get_size(layout, &ilw, &ilh);
+	lw = (double)ilw / PANGO_SCALE;
+	lh = (double)ilh / PANGO_SCALE;
+	cairo_scale(cr, gc->clock_w/lw, gc->clock_h/lh);
 
-	sf = (double)PANGO_SCALE*screen_w_frac*w/lw;
-	cairo_scale(cr, sf, sf);
 	pango_cairo_update_layout(cr, layout);
-
-	pango_layout_get_size(layout, &lw, &lh);
-	lw /= PANGO_SCALE;  lh /= PANGO_SCALE;
-	w /= sf;  h /= sf;
-	cairo_translate(cr, (w-lw)/2.0, h-lh-5*lh);
-	pango_cairo_update_layout(cr, layout);
-
 	cairo_set_source_rgb(cr, gc->brightness*0.10, 0.0, 0.0);
 	pango_cairo_show_layout(cr, layout);
 
@@ -248,13 +246,22 @@ static gboolean draw_sig(GtkWidget *widget, cairo_t *cr, struct glitchyclock *gc
 }
 
 
+static gboolean configure_sig(GtkWidget *da, GdkEventConfigure *event, struct glitchyclock *gc)
+{
+	gc->clock_w = screen_w_frac * event->width;
+	gc->clock_h = clock_aspect * gc->clock_w;
+	gc->clock_x = (event->width - gc->clock_w)/2.0;
+	gc->clock_y = event->height * screen_y_offset;
+
+	return FALSE;
+}
+
+
 static gboolean redraw_cb(gpointer data)
 {
-	gint w, h;
 	struct glitchyclock *gc = data;
-	w = gtk_widget_get_allocated_width(GTK_WIDGET(gc->da));
-	h = gtk_widget_get_allocated_height(GTK_WIDGET(gc->da));
-	gtk_widget_queue_draw_area(GTK_WIDGET(gc->da), 0, 0, w, h);
+	gtk_widget_queue_draw_area(GTK_WIDGET(gc->da), gc->clock_x, gc->clock_y,
+	                                               gc->clock_w, gc->clock_h);
 	return G_SOURCE_CONTINUE;
 }
 
@@ -317,6 +324,7 @@ int main(int argc, char *argv[])
 	gtk_widget_add_events(gc.da, GDK_KEY_PRESS_MASK | GDK_KEY_RELEASE_MASK);
 	g_signal_connect(G_OBJECT(gc.da), "draw", G_CALLBACK(draw_sig), &gc);
 	g_signal_connect(G_OBJECT(gc.da), "realize", G_CALLBACK(realise_sig), &gc);
+	g_signal_connect(G_OBJECT(gc.da), "configure-event", G_CALLBACK(configure_sig), &gc);
 
 	gtk_widget_grab_focus(GTK_WIDGET(gc.da));
 	gtk_widget_show_all(mainwindow);