fix(compositor): honor explicit output layout coordinates

#84

Author: Ly-sec

src/compositor/noctalia_compositor.c

@@ -630,73 +630,25 @@ static int layout_extents_max_x(struct greeter_server* server) {
 
 static bool layout_output_at(struct greeter_output* output, int layout_x, int layout_y);
 
-struct configured_layout_entry {
-  struct greeter_output* output;
-  struct greeter_output_placement cfg;
-};
-
-static int compare_configured_layout_entry(const void* a, const void* b) {
-  const struct configured_layout_entry* ea = a;
-  const struct configured_layout_entry* eb = b;
-  if (ea->cfg.y != eb->cfg.y) {
-    return ea->cfg.y - eb->cfg.y;
-  }
-  if (ea->cfg.x != eb->cfg.x) {
-    return ea->cfg.x - eb->cfg.x;
-  }
-  return strcmp(ea->cfg.name, eb->cfg.name);
-}
-
 static void layout_outputs_from_config(struct greeter_server* server) {
-  struct configured_layout_entry entries[16];
-  size_t count = 0;
   for (size_t i = 0; i < server->output_placement_count; ++i) {
     const struct greeter_output_placement* cfg = &server->output_placements[i];
     struct greeter_output* output = output_by_name(server, cfg->name);
     if (output == NULL) {
       wlr_log(WLR_INFO, "output_layout: '%s' not connected", cfg->name);
       continue;
     }
-    entries[count].output = output;
-    entries[count].cfg = *cfg;
-    ++count;
-  }
-  if (count == 0) {
-    return;
-  }
-
-  qsort(entries, count, sizeof(entries[0]), compare_configured_layout_entry);
-
-  int row_cfg_y = entries[0].cfg.y;
-  int layout_x = 0;
-  int layout_y = 0;
-  int row_max_effective_height = 0;
-  for (size_t i = 0; i < count; ++i) {
-    if (i > 0 && entries[i].cfg.y != row_cfg_y) {
-      layout_y += row_max_effective_height;
-      layout_x = 0;
-      row_cfg_y = entries[i].cfg.y;
-      row_max_effective_height = 0;
-    }
-
-    if (!layout_output_at(entries[i].output, layout_x, layout_y)) {
+    if (!layout_output_at(output, cfg->x, cfg->y)) {
       continue;
     }
 
     int effective_width = 0;
     int effective_height = 0;
-    wlr_output_effective_resolution(entries[i].output->wlr_output, &effective_width, &effective_height);
+    wlr_output_effective_resolution(output->wlr_output, &effective_width, &effective_height);
     wlr_log(
-        WLR_INFO, "greeter output: %s at (%d,%d) (configured %s:%d,%d; effective %dx%d)", entries[i].cfg.name, layout_x,
-        layout_y, entries[i].cfg.name, entries[i].cfg.x, entries[i].cfg.y, effective_width, effective_height
+        WLR_INFO, "greeter output: %s at (%d,%d) (effective %dx%d)", cfg->name, cfg->x, cfg->y, effective_width,
+        effective_height
     );
-
-    if (effective_height > row_max_effective_height) {
-      row_max_effective_height = effective_height;
-    }
-    if (effective_width > 0) {
-      layout_x += effective_width;
-    }
   }
 
   int fallback_x = layout_extents_max_x(server);

src/wayland/wayland_client.cpp

@@ -84,73 +84,26 @@ namespace {
     return -1;
   }
 
-  [[nodiscard]] std::optional<WaylandOutputLayout> chainedLayoutForOutput(
-      const WaylandOutputInfo& output, const std::vector<greeter::GreeterOutputPlacement>& layout,
-      const std::vector<WaylandOutputInfo>& outputs
-  ) {
+  [[nodiscard]] std::optional<WaylandOutputLayout>
+  chainedLayoutForOutput(const WaylandOutputInfo& output, const std::vector<greeter::GreeterOutputPlacement>& layout) {
     if (layout.empty()) {
       return std::nullopt;
     }
 
-    std::vector<const greeter::GreeterOutputPlacement*> ordered;
-    ordered.reserve(layout.size());
     for (const auto& placement : layout) {
-      ordered.push_back(&placement);
-    }
-    std::sort(
-        ordered.begin(), ordered.end(),
-        [](const greeter::GreeterOutputPlacement* lhs, const greeter::GreeterOutputPlacement* rhs) {
-          if (lhs->y != rhs->y) {
-            return lhs->y < rhs->y;
-          }
-          if (lhs->x != rhs->x) {
-            return lhs->x < rhs->x;
-          }
-          return lhs->name < rhs->name;
-        }
-    );
-
-    int32_t rowConfigY = ordered.front()->y;
-    int32_t layoutX = 0;
-    int32_t layoutY = 0;
-    int32_t rowMaxLogicalHeight = 0;
-    for (const greeter::GreeterOutputPlacement* placement : ordered) {
-      const WaylandOutputInfo* out = nullptr;
-      for (const auto& candidate : outputs) {
-        if (candidate.done && candidate.name == placement->name) {
-          out = &candidate;
-          break;
-        }
-      }
-      if (out == nullptr) {
+      if (placement.name != output.name) {
         continue;
       }
-
-      const auto logical = logicalSizeForOutputInfo(*out);
+      const auto logical = logicalSizeForOutputInfo(output);
       if (!logical) {
-        continue;
-      }
-
-      if (placement != ordered.front() && placement->y != rowConfigY) {
-        layoutY += rowMaxLogicalHeight;
-        layoutX = 0;
-        rowConfigY = placement->y;
-        rowMaxLogicalHeight = 0;
-      }
-
-      if (out->output == output.output) {
-        return WaylandOutputLayout{
-            .x = layoutX,
-            .y = layoutY,
-            .width = logical->first,
-            .height = logical->second,
-        };
-      }
-
-      if (static_cast<int32_t>(logical->second) > rowMaxLogicalHeight) {
-        rowMaxLogicalHeight = static_cast<int32_t>(logical->second);
+        return std::nullopt;
       }
-      layoutX += static_cast<int32_t>(logical->first);
+      return WaylandOutputLayout{
+          .x = placement.x,
+          .y = placement.y,
+          .width = logical->first,
+          .height = logical->second,
+      };
     }
 
     return std::nullopt;
@@ -536,7 +489,7 @@ std::optional<WaylandOutputLayout> WaylandClient::layoutForOutput(const WaylandO
   int32_t y = output.y;
   if (!allReadyOutputsShareOrigin(m_outputs)) {
     // Compositor layout coordinates already account for greeter output scale.
-  } else if (const auto chained = chainedLayoutForOutput(output, m_outputLayout, m_outputs)) {
+  } else if (const auto chained = chainedLayoutForOutput(output, m_outputLayout)) {
     x = chained->x;
     y = chained->y;
     kLog.info(