Fix #5643, #5064: rounding issues in floating-point -> integer conversions

Currently, various floating-point expressions involving
the coordinates of borders, titlebars and content surfaces
are directly assigned to integers, and so they are rounded
towards zero.

This results in off-by-one distances between these elements
when the signs of their coordinates differ.

Fixed by wrapping these expressions with a call to
floor before the assignment.

2 files changed, 19 insertions, 19 deletions

diff --git a/sway/desktop/output.c b/sway/desktop/output.c
index 691a285d..7871a136 100644
--- a/sway/desktop/output.c
+++ b/sway/desktop/output.c
@@ -105,8 +105,8 @@ static bool get_surface_box(struct surface_iterator_data *data,
                 data->rotation);
 
         struct wlr_box box = {
-                .x = data->ox + _sx,
-                .y = data->oy + _sy,
+                .x = floor(data->ox + _sx),
+                .y = floor(data->oy + _sy),
                 .width = sw,
                 .height = sh,
         };
diff --git a/sway/desktop/render.c b/sway/desktop/render.c
index f314db73..20832cc4 100644
--- a/sway/desktop/render.c
+++ b/sway/desktop/render.c
@@ -346,8 +346,8 @@ static void render_view(struct sway_output *output, pixman_region32_t *damage,
         if (state->border_left) {
                 memcpy(&color, colors->child_border, sizeof(float) * 4);
                 premultiply_alpha(color, con->alpha);
-                box.x = state->x;
-                box.y = state->content_y;
+                box.x = floor(state->x);
+                box.y = floor(state->content_y);
                 box.width = state->border_thickness;
                 box.height = state->content_height;
                 scale_box(&box, output_scale);
@@ -365,8 +365,8 @@ static void render_view(struct sway_output *output, pixman_region32_t *damage,
                         memcpy(&color, colors->child_border, sizeof(float) * 4);
                 }
                 premultiply_alpha(color, con->alpha);
-                box.x = state->content_x + state->content_width;
-                box.y = state->content_y;
+                box.x = floor(state->content_x + state->content_width);
+                box.y = floor(state->content_y);
                 box.width = state->border_thickness;
                 box.height = state->content_height;
                 scale_box(&box, output_scale);
@@ -380,8 +380,8 @@ static void render_view(struct sway_output *output, pixman_region32_t *damage,
                         memcpy(&color, colors->child_border, sizeof(float) * 4);
                 }
                 premultiply_alpha(color, con->alpha);
-                box.x = state->x;
-                box.y = state->content_y + state->content_height;
+                box.x = floor(state->x);
+                box.y = floor(state->content_y + state->content_height);
                 box.width = state->width;
                 box.height = state->border_thickness;
                 scale_box(&box, output_scale);
@@ -662,8 +662,8 @@ static void render_top_border(struct sway_output *output,
         // Child border - top edge
         memcpy(&color, colors->child_border, sizeof(float) * 4);
         premultiply_alpha(color, con->alpha);
-        box.x = state->x;
-        box.y = state->y;
+        box.x = floor(state->x);
+        box.y = floor(state->y);
         box.width = state->width;
         box.height = state->border_thickness;
         scale_box(&box, output_scale);
@@ -718,8 +718,8 @@ static void render_containers_linear(struct sway_output *output,
                         }
 
                         if (state->border == B_NORMAL) {
-                                render_titlebar(output, damage, child, state->x,
-                                                state->y, state->width, colors,
+                                render_titlebar(output, damage, child, floor(state->x),
+                                                floor(state->y), state->width, colors,
                                                 title_texture, marks_texture);
                         } else if (state->border == B_PIXEL) {
                                 render_top_border(output, damage, child, colors);
@@ -773,7 +773,7 @@ static void render_containers_tabbed(struct sway_output *output,
                         marks_texture = child->marks_unfocused;
                 }
 
-                int x = cstate->x + tab_width * i;
+                int x = floor(cstate->x + tab_width * i);
 
                 // Make last tab use the remaining width of the parent
                 if (i == parent->children->length - 1) {
@@ -886,8 +886,8 @@ static void render_container(struct sway_output *output,
         struct parent_data data = {
                 .layout = con->current.layout,
                 .box = {
-                        .x = con->current.x,
-                        .y = con->current.y,
+                        .x = floor(con->current.x),
+                        .y = floor(con->current.y),
                         .width = con->current.width,
                         .height = con->current.height,
                 },
@@ -903,8 +903,8 @@ static void render_workspace(struct sway_output *output,
         struct parent_data data = {
                 .layout = ws->current.layout,
                 .box = {
-                        .x = ws->current.x,
-                        .y = ws->current.y,
+                        .x = floor(ws->current.x),
+                        .y = floor(ws->current.y),
                         .width = ws->current.width,
                         .height = ws->current.height,
                 },
@@ -938,8 +938,8 @@ static void render_floating_container(struct sway_output *soutput,
                 }
 
                 if (con->current.border == B_NORMAL) {
-                        render_titlebar(soutput, damage, con, con->current.x,
-                                        con->current.y, con->current.width, colors,
+                        render_titlebar(soutput, damage, con, floor(con->current.x),
+                                        floor(con->current.y), con->current.width, colors,
                                         title_texture, marks_texture);
                 } else if (con->current.border == B_PIXEL) {
                         render_top_border(soutput, damage, con, colors);