swaybar: fix sep block width for mixed scales

When there are outputs with mixed scales, it was possible for swaybar to
alter `block->separator_block_width` for an output with a higher scale,
and use the changed value for a lower scale output. This caused there to
be larger than normal separation between blocks on the lower scale
outputs. The issue is more obvious the larger the scale difference
between the highest scale output and the lowest scale output.

This fixes the issue by using a local variable that is originally set to
`block->separator_block_width` for rendering, but if it needs to be
increased, the local variable is the only thing touched.

swaybar/render.c

@@ -163,6 +163,7 @@ static uint32_t render_status_block(cairo_t *cairo,
 	}
 
 	int sep_width, sep_height;
+	int sep_block_width = block->separator_block_width;
 	if (!edge) {
 		if (config->sep_symbol) {
 			get_text_size(cairo, config->font, &sep_width, &sep_height, NULL,
@@ -172,11 +173,11 @@ static uint32_t render_status_block(cairo_t *cairo,
 			if (output->height < _ideal_surface_height) {
 				return _ideal_surface_height;
 			}
-			if (sep_width > block->separator_block_width) {
-				block->separator_block_width = sep_width + margin * 2;
+			if (sep_width > sep_block_width) {
+				sep_block_width = sep_width + margin * 2;
 			}
 		}
-		*x -= block->separator_block_width;
+		*x -= sep_block_width;
 	} else {
 		*x -= margin;
 	}
@@ -261,16 +262,14 @@ static uint32_t render_status_block(cairo_t *cairo,
 			cairo_set_source_u32(cairo, config->colors.separator);
 		}
 		if (config->sep_symbol) {
-			offset = pos + (block->separator_block_width - sep_width) / 2;
+			offset = pos + (sep_block_width - sep_width) / 2;
 			cairo_move_to(cairo, offset, height / 2.0 - sep_height / 2.0);
 			pango_printf(cairo, config->font, output->scale, false,
 					"%s", config->sep_symbol);
 		} else {
 			cairo_set_line_width(cairo, 1);
-			cairo_move_to(cairo,
-					pos + block->separator_block_width / 2, margin);
-			cairo_line_to(cairo,
-					pos + block->separator_block_width / 2, height - margin);
+			cairo_move_to(cairo, pos + sep_block_width / 2, margin);
+			cairo_line_to(cairo, pos + sep_block_width / 2, height - margin);
 			cairo_stroke(cairo);
 		}
 	}