backend: clarify how scaling affect other blit arguments

And fixes inconsistencies when setting these arguments with a scaling factor. Fixes #1264 Signed-off-by: Yuxuan Shui <[email protected]>
yshui · May 21, 2024 · 94faacb · 94faacb
1 parent ff9de51
commit 94faacb
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Showing 7 changed files with 112 additions and 16 deletions.
diff --git a/src/backend/backend.h b/src/backend/backend.h
@@ -128,13 +128,13 @@ struct backend_blit_args {
 	/// Scale factor for the horizontal and vertical direction (X for horizontal,
 	/// Y for vertical).
 	vec2 scale;
-	/// Corner radius of the source image. The corners of
+	/// Corner radius of the source image BEFORE scaling. The corners of
 	/// the source image will be rounded.
 	double corner_radius;
-	/// Effective size of the source image, set where the corners
+	/// Effective size of the source image BEFORE scaling, set where the corners
 	/// of the image are.
 	ivec2 effective_size;
-	/// Border width of the source image. This is used with
+	/// Border width of the source image BEFORE scaling. This is used with
 	/// `corner_radius` to create a border for the rounded corners.
 	/// Setting this has no effect if `corner_radius` is 0.
 	int border_width;

diff --git a/src/backend/xrender/xrender.c b/src/backend/xrender/xrender.c
@@ -302,8 +302,8 @@ static bool xrender_blit(struct backend_base *base, ivec2 origin,
 	bool has_alpha = inner->has_alpha || args->opacity != 1;
 	auto const tmpw = to_u16_checked(inner->size.width);
 	auto const tmph = to_u16_checked(inner->size.height);
-	auto const tmpew = to_u16_checked(args->effective_size.width);
-	auto const tmpeh = to_u16_checked(args->effective_size.height);
+	auto const tmpew = to_u16_saturated(args->effective_size.width * args->scale.x);
+	auto const tmpeh = to_u16_saturated(args->effective_size.height * args->scale.y);
 	const xcb_render_color_t dim_color = {
 	    .red = 0, .green = 0, .blue = 0, .alpha = (uint16_t)(0xffff * args->dim)};
 
@@ -346,8 +346,25 @@ static bool xrender_blit(struct backend_base *base, ivec2 origin,
 		auto tmp_pict = x_create_picture_with_pictfmt(
 		    xd->base.c, inner->size.width, inner->size.height, pictfmt, depth, 0, NULL);
 
-		x_set_picture_clip_region(xd->base.c, tmp_pict, to_i16_checked(-origin.x),
-		                          to_i16_checked(-origin.y), args->target_mask);
+		vec2 inverse_scale = (vec2){
+		    .x = 1.0 / args->scale.x,
+		    .y = 1.0 / args->scale.y,
+		};
+		if (vec2_eq(args->scale, SCALE_IDENTITY)) {
+			x_set_picture_clip_region(
+			    xd->base.c, tmp_pict, to_i16_checked(-origin.x),
+			    to_i16_checked(-origin.y), args->target_mask);
+		} else {
+			// We need to scale the target_mask back so it's in the source's
+			// coordinate space.
+			scoped_region_t source_mask_region;
+			pixman_region32_init(&source_mask_region);
+			pixman_region32_copy(&source_mask_region, args->target_mask);
+			region_scale_ceil(&source_mask_region, origin, inverse_scale);
+			x_set_picture_clip_region(
+			    xd->base.c, tmp_pict, to_i16_checked(-origin.x),
+			    to_i16_checked(-origin.y), &source_mask_region);
+		}
 		// Copy source -> tmp
 		xcb_render_composite(xd->base.c->c, XCB_RENDER_PICT_OP_SRC, inner->pict,
 		                     XCB_NONE, tmp_pict, 0, 0, 0, 0, 0, 0, tmpw, tmph);
@@ -398,6 +415,10 @@ static bool xrender_blit(struct backend_base *base, ivec2 origin,
 		}
 
 		set_picture_scale(xd->base.c, tmp_pict, args->scale);
+		// Transformations don't affect the picture's clip region, so we need to
+		// set it again
+		x_set_picture_clip_region(xd->base.c, tmp_pict, to_i16_checked(-origin.x),
+		                          to_i16_checked(-origin.y), args->target_mask);
 
 		xcb_render_composite(xd->base.c->c, XCB_RENDER_PICT_OP_OVER, tmp_pict,
 		                     mask_pict, target->pict, 0, 0, mask_pict_dst_x,

diff --git a/src/renderer/command_builder.c b/src/renderer/command_builder.c
@@ -96,6 +96,8 @@ command_for_shadow(struct layer *layer, struct backend_command *cmd,
                    const struct win_option *wintype_options,
                    const struct x_monitors *monitors, const struct backend_command *end) {
 	auto w = layer->win;
+	auto shadow_size_scaled = vec2_as(
+	    vec2_floor(vec2_scale(ivec2_as(layer->shadow.size), layer->shadow_scale)));
 	if (!w->shadow) {
 		return 0;
 	}
@@ -105,8 +107,8 @@ command_for_shadow(struct layer *layer, struct backend_command *cmd,
 	pixman_region32_clear(&cmd->target_mask);
 	pixman_region32_union_rect(&cmd->target_mask, &cmd->target_mask,
 	                           layer->shadow.origin.x, layer->shadow.origin.y,
-	                           (unsigned)layer->shadow.size.width,
-	                           (unsigned)layer->shadow.size.height);
+	                           (unsigned)shadow_size_scaled.width,
+	                           (unsigned)shadow_size_scaled.height);
 	log_trace("Calculate shadow for %#010x (%s)", w->base.id, w->name);
 	log_region(TRACE, &cmd->target_mask);
 	if (!wintype_options[w->window_type].full_shadow) {

diff --git a/src/renderer/layout.c b/src/renderer/layout.c
@@ -49,8 +49,7 @@ static bool layer_from_window(struct layer *out_layer, struct managed_win *w, iv
 	out_layer->window.origin =
 	    vec2_as((vec2){.x = w->g.x + win_animatable_get(w, WIN_SCRIPT_OFFSET_X),
 	                   .y = w->g.y + win_animatable_get(w, WIN_SCRIPT_OFFSET_Y)});
-	out_layer->window.size = vec2_as((vec2){.width = w->widthb * out_layer->scale.x,
-	                                        .height = w->heightb * out_layer->scale.y});
+	out_layer->window.size = vec2_as((vec2){.width = w->widthb, .height = w->heightb});
 	out_layer->crop.origin = vec2_as((vec2){
 	    .x = win_animatable_get(w, WIN_SCRIPT_CROP_X),
 	    .y = win_animatable_get(w, WIN_SCRIPT_CROP_Y),
@@ -70,16 +69,19 @@ static bool layer_from_window(struct layer *out_layer, struct managed_win *w, iv
 		                   .y = w->g.y + w->shadow_dy +
 		                        win_animatable_get(w, WIN_SCRIPT_SHADOW_OFFSET_Y)});
 		out_layer->shadow.size =
-		    vec2_as((vec2){.width = w->shadow_width * out_layer->shadow_scale.x,
-		                   .height = w->shadow_height * out_layer->shadow_scale.y});
+		    vec2_as((vec2){.width = w->shadow_width, .height = w->shadow_height});
 	} else {
 		out_layer->shadow.origin = (ivec2){};
 		out_layer->shadow.size = (ivec2){};
 		out_layer->shadow_scale = SCALE_IDENTITY;
 	}
 
+	struct ibox window_scaled = {
+	    .origin = out_layer->window.origin,
+	    .size = ivec2_scale_floor(out_layer->window.size, out_layer->scale),
+	};
 	struct ibox screen = {.origin = {0, 0}, .size = size};
-	if (!ibox_overlap(out_layer->window, screen) || !ibox_overlap(out_layer->crop, screen)) {
+	if (!ibox_overlap(window_scaled, screen) || !ibox_overlap(out_layer->crop, screen)) {
 		goto out;
 	}
 

diff --git a/src/renderer/layout.h b/src/renderer/layout.h
@@ -29,9 +29,9 @@ struct layer {
 	struct managed_win *win;
 	/// Damaged region of this layer, in screen coordinates
 	region_t damaged;
-	/// Window rectangle in screen coordinates.
+	/// Window rectangle in screen coordinates, before it's scaled.
 	struct ibox window;
-	/// Shadow rectangle in screen coordinates.
+	/// Shadow rectangle in screen coordinates, before it's scaled.
 	struct ibox shadow;
 	/// Scale of the window. The origin of scaling is the top left corner of the
 	/// window.

diff --git a/src/types.h b/src/types.h
@@ -62,6 +62,13 @@ struct ibox {
 
 static const vec2 SCALE_IDENTITY = {1.0, 1.0};
 
+static inline vec2 ivec2_as(ivec2 a) {
+	return (vec2){
+	    .x = a.x,
+	    .y = a.y,
+	};
+}
+
 static inline ivec2 ivec2_add(ivec2 a, ivec2 b) {
 	return (ivec2){
 	    .x = a.x + b.x,
@@ -95,6 +102,27 @@ static inline ivec2 vec2_as(vec2 a) {
 	};
 }
 
+static inline vec2 vec2_add(vec2 a, vec2 b) {
+	return (vec2){
+	    .x = a.x + b.x,
+	    .y = a.y + b.y,
+	};
+}
+
+static inline vec2 vec2_ceil(vec2 a) {
+	return (vec2){
+	    .x = ceil(a.x),
+	    .y = ceil(a.y),
+	};
+}
+
+static inline vec2 vec2_floor(vec2 a) {
+	return (vec2){
+	    .x = floor(a.x),
+	    .y = floor(a.y),
+	};
+}
+
 static inline bool vec2_eq(vec2 a, vec2 b) {
 	return a.x == b.x && a.y == b.y;
 }
@@ -128,5 +156,15 @@ static inline bool ibox_eq(struct ibox a, struct ibox b) {
 	return ivec2_eq(a.origin, b.origin) && ivec2_eq(a.size, b.size);
 }
 
+static inline ivec2 ivec2_scale_ceil(ivec2 a, vec2 scale) {
+	vec2 scaled = vec2_scale(ivec2_as(a), scale);
+	return vec2_as(vec2_ceil(scaled));
+}
+
+static inline ivec2 ivec2_scale_floor(ivec2 a, vec2 scale) {
+	vec2 scaled = vec2_scale(ivec2_as(a), scale);
+	return vec2_as(vec2_floor(scaled));
+}
+
 #define MARGIN_INIT                                                                      \
 	{ 0, 0, 0, 0 }
diff --git a/src/utils.h b/src/utils.h
@@ -140,6 +140,39 @@ safe_isinf(double a) {
 		(uint32_t) __to_tmp;                                                     \
 	})
 
+static inline uint16_t u64_to_u16_saturated(uint64_t val) {
+	if (val > UINT16_MAX) {
+		return UINT16_MAX;
+	}
+	return (uint16_t)val;
+}
+static inline uint16_t double_to_u16_saturated(double val) {
+	BUG_ON(safe_isnan(val));
+	if (val < 0) {
+		return 0;
+	}
+	if (val > UINT16_MAX) {
+		return UINT16_MAX;
+	}
+	return (uint16_t)val;
+}
+static inline uint16_t i64_to_u16_saturated(int64_t val) {
+	if (val < 0) {
+		return 0;
+	}
+	if (val > UINT16_MAX) {
+		return UINT16_MAX;
+	}
+	return (uint16_t)val;
+}
+
+#define to_u16_saturated(val)                                                            \
+	_Generic((val),                                                                  \
+	    double: double_to_u16_saturated(val),                                        \
+	    float: double_to_u16_saturated((double)(val)),                               \
+	    uint64_t: u64_to_u16_saturated(val),                                         \
+	    default: i64_to_u16_saturated((int64_t)(val)))
+
 static inline int32_t double_to_i32_saturated(double val) {
 	BUG_ON(safe_isnan(val));
 	if (val < INT32_MIN) {