Change plot routine to take a drawing_area as argument

Previously we passed in width and height and the routine itself decided to
keep 5% margin around each edge - oddly doing this with double precision,
even though this is all integer coordinates.

Instead we are now passing in a drawing_area. We are kind of abusing the
cairo_rectangle_int_t data type here - but it seemed silly to redefine a
new data type for this.
Width and height give the size of the TOTAL drawing area (as before).
x and y give the offset from the edges - so the EFFECTIVE drawing area is
width-2x and height-2y
This is in preparation for adding tooltips - those need to know the
coordinate offsets from the edges - so having this hard coded inside the
plot function didn't make sense anymore.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 8 insertions, 5 deletions

diff --git a/gtk-gui.c b/gtk-gui.c
index ee3ad2ef1..a5728e2c8 100644
--- a/gtk-gui.c
+++ b/gtk-gui.c
@@ -674,18 +674,21 @@ static gboolean expose_event(GtkWidget *widget, GdkEventExpose *event, gpointer
 {
 	struct dive *dive = current_dive;
 	struct graphics_context gc = { .printer = 0 };
-	int w,h;
+	static cairo_rectangle_int_t drawing_area;
 
-	w = widget->allocation.width;
-	h = widget->allocation.height;
+	/* the drawing area gives TOTAL width * height - x,y is used as the topx/topy offset
+	 * so effective drawing area is width-2x * height-2y */
+	drawing_area.width = widget->allocation.width;
+	drawing_area.height = widget->allocation.height;
+	drawing_area.x = drawing_area.width / 20.0;
+	drawing_area.y = drawing_area.height / 20.0;
 
 	gc.cr = gdk_cairo_create(widget->window);
 	set_source_rgb(&gc, 0, 0, 0);
 	cairo_paint(gc.cr);
 
 	if (dive)
-		plot(&gc, w, h, dive);
-
+		plot(&gc, &drawing_area, dive);
 	cairo_destroy(gc.cr);
 
 	return FALSE;