Fix up empty region checks in canvas operations

We rely on not passing on empty rects to the drawing operations by
checking for empty regions and exiting early. However the checks
were wrongly using pixman_region32_n_rects(region) == 0, whereas
we should be using pixman_region32_not_empty().

2 files changed, 10 insertions, 10 deletions

diff --git a/common/cairo_canvas.c b/common/cairo_canvas.c
index 9e29e17a..770ca4ff 100644
--- a/common/cairo_canvas.c
+++ b/common/cairo_canvas.c
@@ -675,7 +675,7 @@ static void canvas_draw_text(SpiceCanvas *spice_canvas, SpiceRect *bbox, SpiceCl
 
     canvas_clip_pixman(&canvas->base, &dest_region, clip);
 
-    if (pixman_region32_n_rects(&dest_region) == 0) {
+    if (!pixman_region32_not_empty(&dest_region)) {
         touch_brush(&canvas->base, &text->fore_brush);
         touch_brush(&canvas->base, &text->back_brush);
         pixman_region32_fini(&dest_region);
diff --git a/common/canvas_base.c b/common/canvas_base.c
index beedae95..aecc56e2 100644
--- a/common/canvas_base.c
+++ b/common/canvas_base.c
@@ -1976,7 +1976,7 @@ static void canvas_draw_fill(SpiceCanvas *spice_canvas, SpiceRect *bbox, SpiceCl
                                  ROP_INPUT_BRUSH,
                                  ROP_INPUT_DEST);
 
-    if (rop == SPICE_ROP_NOOP || pixman_region32_n_rects(&dest_region) == 0) {
+    if (rop == SPICE_ROP_NOOP || !pixman_region32_not_empty(&dest_region)) {
         touch_brush(canvas, &fill->brush);
         pixman_region32_fini(&dest_region);
         return;
@@ -2007,7 +2007,7 @@ static void canvas_draw_copy(SpiceCanvas *spice_canvas, SpiceRect *bbox, SpiceCl
                                  ROP_INPUT_SRC,
                                  ROP_INPUT_DEST);
 
-    if (rop == SPICE_ROP_NOOP || pixman_region32_n_rects(&dest_region) == 0) {
+    if (rop == SPICE_ROP_NOOP || !pixman_region32_not_empty(&dest_region)) {
         canvas_touch_image(canvas, copy->src_bitmap);
         pixman_region32_fini(&dest_region);
         return;
@@ -2120,7 +2120,7 @@ static void canvas_draw_alpha_blend(SpiceCanvas *spice_canvas, SpiceRect *bbox,
     canvas_clip_pixman(canvas, &dest_region, clip);
 
     if (alpha_blend->alpha == 0 ||
-        pixman_region32_n_rects(&dest_region) == 0) {
+        !pixman_region32_not_empty(&dest_region)) {
         canvas_touch_image(canvas, alpha_blend->src_bitmap);
         pixman_region32_fini(&dest_region);
         return;
@@ -2177,7 +2177,7 @@ static void canvas_draw_opaque(SpiceCanvas *spice_canvas, SpiceRect *bbox, Spice
                                  ROP_INPUT_BRUSH,
                                  ROP_INPUT_SRC);
 
-    if (rop == SPICE_ROP_NOOP || pixman_region32_n_rects(&dest_region) == 0) {
+    if (rop == SPICE_ROP_NOOP || !pixman_region32_not_empty(&dest_region)) {
         canvas_touch_image(canvas, opaque->src_bitmap);
         touch_brush(canvas, &opaque->brush);
         pixman_region32_fini(&dest_region);
@@ -2231,7 +2231,7 @@ static void canvas_draw_blend(SpiceCanvas *spice_canvas, SpiceRect *bbox, SpiceC
                                  ROP_INPUT_SRC,
                                  ROP_INPUT_DEST);
 
-    if (rop == SPICE_ROP_NOOP || pixman_region32_n_rects(&dest_region) == 0) {
+    if (rop == SPICE_ROP_NOOP || !pixman_region32_not_empty(&dest_region)) {
         canvas_touch_image(canvas, blend->src_bitmap);
         pixman_region32_fini(&dest_region);
         return;
@@ -2305,7 +2305,7 @@ static void canvas_draw_blackness(SpiceCanvas *spice_canvas, SpiceRect *bbox, Sp
     canvas_mask_pixman(canvas, &dest_region, &blackness->mask,
                        bbox->left, bbox->top);
 
-    if (pixman_region32_n_rects(&dest_region) == 0) {
+    if (!pixman_region32_not_empty(&dest_region)) {
         pixman_region32_fini (&dest_region);
         return;
     }
@@ -2334,7 +2334,7 @@ static void canvas_draw_whiteness(SpiceCanvas *spice_canvas, SpiceRect *bbox, Sp
     canvas_mask_pixman(canvas, &dest_region, &whiteness->mask,
                        bbox->left, bbox->top);
 
-    if (pixman_region32_n_rects(&dest_region) == 0) {
+    if (!pixman_region32_not_empty(&dest_region)) {
         pixman_region32_fini(&dest_region);
         return;
     }
@@ -2362,7 +2362,7 @@ static void canvas_draw_invers(SpiceCanvas *spice_canvas, SpiceRect *bbox, Spice
     canvas_mask_pixman(canvas, &dest_region, &invers->mask,
                        bbox->left, bbox->top);
 
-    if (pixman_region32_n_rects(&dest_region) == 0) {
+    if (!pixman_region32_not_empty(&dest_region)) {
         pixman_region32_fini(&dest_region);
         return;
     }
@@ -2677,7 +2677,7 @@ static void canvas_draw_stroke(SpiceCanvas *spice_canvas, SpiceRect *bbox,
 
     canvas_clip_pixman(canvas, &gc.dest_region, clip);
 
-    if (pixman_region32_n_rects(&gc.dest_region) == 0) {
+    if (!pixman_region32_not_empty(&gc.dest_region)) {
         touch_brush(canvas, &stroke->brush);
         pixman_region32_fini(&gc.dest_region);
         return;