backend: invert color and dim doesn't need reg_op

We only ever invert color of or dim the entire image, so just remove the
ability to do region based inversion and dimming. Making implementing
image_op easier.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/backend/backend.c

@@ -203,14 +203,12 @@ void paint_all_new(session_t *ps, win *const t, bool ignore_damage) {
 			                          &reg_bound_local);
 
 			// A region covers the entire window
-			region_t reg_win;
-			pixman_region32_init_rect(&reg_win, 0, 0, w->g.width, w->g.height);
 			auto new_img = ps->backend_data->ops->copy(
 			    ps->backend_data, w->win_image, &reg_visible_local);
 			if (w->invert_color) {
 				ps->backend_data->ops->image_op(
-				    ps->backend_data, IMAGE_OP_INVERT_COLOR, new_img,
+				    ps->backend_data, IMAGE_OP_INVERT_COLOR_ALL, new_img,
-				    &reg_win, &reg_visible_local, NULL);
+				    NULL, &reg_visible_local, NULL);
 			}
 			if (w->dim) {
 				double dim_opacity = ps->o.inactive_dim;
@@ -218,7 +216,7 @@ void paint_all_new(session_t *ps, win *const t, bool ignore_damage) {
 					dim_opacity *= w->opacity;
 				}
 				ps->backend_data->ops->image_op(
-				    ps->backend_data, IMAGE_OP_DIM, new_img, &reg_win,
+				    ps->backend_data, IMAGE_OP_DIM_ALL, new_img, NULL,
 				    &reg_visible_local, (double[]){dim_opacity});
 			}
 			if (w->frame_opacity != 1) {
@@ -236,7 +234,6 @@ void paint_all_new(session_t *ps, win *const t, bool ignore_damage) {
 			ps->backend_data->ops->compose(ps->backend_data, new_img, w->g.x,
 			                               w->g.y, &reg_paint, &reg_visible);
 			ps->backend_data->ops->release_image(ps->backend_data, new_img);
-			pixman_region32_fini(&reg_win);
 			pixman_region32_fini(&reg_visible_local);
 			pixman_region32_fini(&reg_bound_local);
 		}

src/backend/backend.h

@@ -23,10 +23,10 @@ typedef struct backend_base {
 } backend_t;
 
 enum image_operations {
-	// Invert the color of the image
+	// Invert the color of the entire image, `reg_op` ignored
-	IMAGE_OP_INVERT_COLOR,
+	IMAGE_OP_INVERT_COLOR_ALL,
-	// Dim the image, argument is the percentage
+	// Dim the entire image, argument is the percentage. `reg_op` ignored
-	IMAGE_OP_DIM,
+	IMAGE_OP_DIM_ALL,
 	// Multiply the alpha channel by the argument
 	IMAGE_OP_APPLY_ALPHA,
 	// Same as APPLY_ALPHA, but `reg_op` is ignored and the operation applies to the

src/backend/xrender.c

@@ -351,15 +351,10 @@ static bool image_op(backend_t *base, enum image_operations op, void *image,
 	}
 
 	pixman_region32_init(&reg);
-	pixman_region32_intersect(&reg, (region_t *)reg_op, (region_t *)reg_visible);
-	if (!pixman_region32_not_empty(&reg)) {
-		pixman_region32_fini(&reg);
-		return true;
-	}
 
 	switch (op) {
-	case IMAGE_OP_INVERT_COLOR:
+	case IMAGE_OP_INVERT_COLOR_ALL:
-		x_set_picture_clip_region(base->c, img->pict, 0, 0, &reg);
+		x_set_picture_clip_region(base->c, img->pict, 0, 0, reg_visible);
 		if (img->has_alpha) {
 			auto tmp_pict =
 			    x_create_picture_with_visual(base->c, base->root, img->width,
@@ -383,8 +378,8 @@ static bool image_op(backend_t *base, enum image_operations op, void *image,
 			                     0, 0, 0, 0, img->width, img->height);
 		}
 		break;
-	case IMAGE_OP_DIM:
+	case IMAGE_OP_DIM_ALL:
-		x_set_picture_clip_region(base->c, img->pict, 0, 0, &reg);
+		x_set_picture_clip_region(base->c, img->pict, 0, 0, reg_visible);
 		dim_opacity = *(double *)arg;
 
 		xcb_render_color_t color = {
@@ -402,6 +397,12 @@ static bool image_op(backend_t *base, enum image_operations op, void *image,
 		                           color, 1, &rect);
 		break;
 	case IMAGE_OP_APPLY_ALPHA:
+		assert(reg_op);
+		pixman_region32_intersect(&reg, (region_t *)reg_op, (region_t *)reg_visible);
+		if (!pixman_region32_not_empty(&reg)) {
+			break;
+		}
+
 		alpha_multiplier = *(double *)arg;
 		if (alpha_multiplier == 1) {
 			break;