overlay: introduce overlay.redraw_needed

Set on window resize, clear on draw_overlay() return.

Used in combination with sample_interval check to gate HZ redraw.

Will be used to gate redraw of process monitors heirarchy as well,
in a subsequent commit.

2 files changed, 20 insertions, 19 deletions

diff --git a/src/overlay.c b/src/overlay.c
index e223d08..d53a864 100644
--- a/src/overlay.c
+++ b/src/overlay.c
@@ -542,13 +542,9 @@ static void draw_overlay(vwm_t *vwm, vwm_xwindow_t *xwin, vmon_proc_t *proc, int
 	/* IOWait and Idle % @ row 0 */
 	draw_bars(vwm, xwin, *row, iowait_delta, total_delta, idle_delta, total_delta);
 
-	/* here's where the Idle/IOWait row drawing concludes */
-	if (1 /* FIXME TODO compositing_mode*/) {
+	/* only draw the \/\/\ and HZ if necessary */
+	if (xwin->overlay.redraw_needed || prev_sampling_interval != sampling_interval) {
 		snprintf(str, sizeof(str), "\\/\\/\\    %2iHz %n", (int)(sampling_interval < 0 ? 0 : 1 / sampling_intervals[sampling_interval]), &str_len);
-		/* TODO: I clear and redraw this row every time, which is unnecessary, small optimization would be to only do so when:
-		 * - overlay resized, and then constrain the clear to the affected width
-		 * - Hz changed
-		 */
 		XRenderFillRectangle(vwm->display, PictOpSrc, xwin->overlay.text_picture, &overlay_trans_color,
 			0, 0,					/* dst x, y */
 			xwin->attrs.width, OVERLAY_ROW_HEIGHT);	/* dst w, h */
@@ -562,6 +558,8 @@ static void draw_overlay(vwm_t *vwm, vwm_xwindow_t *xwin, vmon_proc_t *proc, int
 
 	draw_overlay_rest(vwm, xwin, proc, depth, row);
 
+	xwin->overlay.redraw_needed = 0;
+
 	return;
 }
 
@@ -585,6 +583,8 @@ static void maintain_overlay(vwm_t *vwm, vwm_xwindow_t *xwin)
 	 * For now, the monitors will just be a little latent in window resizes which is pretty harmless artifact.
 	 */
 
+	if (xwin->attrs.width != xwin->overlay.width || xwin->attrs.height != xwin->overlay.height) xwin->overlay.redraw_needed = 1;
+
 	/* if the window is larger than the overlays currently are, enlarge them */
 	if (xwin->attrs.width > xwin->overlay.width || xwin->attrs.height > xwin->overlay.height) {
 		vwm_overlay_t	existing;
diff --git a/src/overlay.h b/src/overlay.h
index 94e2dca..dd60319 100644
--- a/src/overlay.h
+++ b/src/overlay.h
@@ -9,19 +9,20 @@ typedef struct _vwm_xwindow_t vwm_xwindow_t;
 
 /* everything needed by the per-window overlay's context */
 typedef struct _vwm_overlay_t {
-	Pixmap			text_pixmap;		/* pixmap for overlayed text (kept around for XDrawText usage) */
-	Picture			text_picture;		/* picture representation of text_pixmap */
-	Picture			shadow_picture;		/* text shadow layer */
-	Picture			grapha_picture;		/* graph A layer */
-	Picture			graphb_picture;		/* graph B layer */
-	Picture			tmp_picture;		/* 1 row worth of temporary picture space */
-	Picture			picture;		/* overlay picture derived from the pixmap, for render compositing */
-	int			width;			/* current width of the overlay */
-	int			height;			/* current height of the overlay */
-	int			phase;			/* current position within the (horizontally scrolling) graphs */
-	int			heirarchy_end;		/* row where the process heirarchy currently ends */
-	int			snowflakes_cnt;		/* count of snowflaked rows (reset to zero to truncate snowflakes display) */
-	int			gen_last_composed;	/* the last composed vmon generation */
+	Pixmap	text_pixmap;		/* pixmap for overlayed text (kept around for XDrawText usage) */
+	Picture	text_picture;		/* picture representation of text_pixmap */
+	Picture	shadow_picture;		/* text shadow layer */
+	Picture	grapha_picture;		/* graph A layer */
+	Picture	graphb_picture;		/* graph B layer */
+	Picture	tmp_picture;		/* 1 row worth of temporary picture space */
+	Picture	picture;		/* overlay picture derived from the pixmap, for render compositing */
+	int	width;			/* current width of the overlay */
+	int	height;			/* current height of the overlay */
+	int	phase;			/* current position within the (horizontally scrolling) graphs */
+	int	heirarchy_end;		/* row where the process heirarchy currently ends */
+	int	snowflakes_cnt;		/* count of snowflaked rows (reset to zero to truncate snowflakes display) */
+	int	gen_last_composed;	/* the last composed vmon generation */
+	int	redraw_needed;		/* if a redraw is required (like when the window is resized...) */
 } vwm_overlay_t;
 
 int vwm_overlay_xwin_composed_height(vwm_t *vwm, vwm_xwindow_t *xwin);