Allow decoration authors to pass custom geometry

Author: tarek-y-ismail

examples/miral-shell/decoration/decoration.cpp

@@ -291,7 +291,13 @@ auto resize_edge_rect(
     case mir_resize_edge_north:
     {
         auto rect = window_state.titlebar_rect();
-        rect.size.height = window_state.bottom_border_height();
+
+        // Cap the resize edge to half of the titlebar height
+        auto bottom_height = window_state.bottom_border_height();
+        auto top_height = window_state.titlebar_height();
+        auto const min_titlebar_drag_height = top_height / 2;
+
+        rect.size.height = std::min(min_titlebar_drag_height, bottom_height);
         return rect;
     }
 
@@ -369,10 +375,22 @@ void UserDecoration::focused()
 auto UserDecoration::create_manager(mir::Server& server)
     -> std::shared_ptr<miral::DecorationManagerAdapter>
 {
+    using namespace mir::geometry;
+    // Shared between all decorations.
+    auto const custom_geometry = std::make_shared<StaticGeometry>(StaticGeometry{
+        .titlebar_height = Height{24},
+        .side_border_width = geom::Width{6},
+        .bottom_border_height = geom::Height{6},
+        .resize_corner_input_size = geom::Size{16, 16},
+        .button_width = geom::Width{24},
+        .padding_between_buttons = geom::Width{6},
+    });
+
     return miral::DecorationBasicManager(
                server,
-               [](auto, auto)
+               [custom_geometry](auto, auto)
                {
+
                    auto decoration = std::make_shared<UserDecoration>();
                    auto decoration_adapter = std::make_shared<miral::DecorationAdapter>(
                        decoration->redraw_notifier(),
@@ -456,9 +474,9 @@ auto UserDecoration::create_manager(mir::Server& server)
                            decoration->input_manager.update_window_state(*window_state);
                        });
 
+                   decoration_adapter->set_custom_geometry(custom_geometry);
+
                    return decoration_adapter;
                })
         .to_adapter();
 }
-
-// TODO User defined static_geometry?

include/miral/miral/decoration_adapter.h

@@ -22,11 +22,11 @@
 // TODO one more layer of indirection
 #include "mir/geometry/forward.h"
 #include "mir/geometry/size.h"
-#include "mir/geometry/point.h"
 #include "mir_toolkit/common.h"
 
 #include "miral/decoration_basic_manager.h"
 #include "miral/decoration_manager_builder.h"
+#include "miral/decoration_window_state.h"
 
 #include <functional>
 #include <glm/gtc/constants.hpp>
@@ -260,6 +260,8 @@ struct DecorationAdapter
         std::function<void(ms::Surface const* window_surface, std::string const& /*name*/)> window_renamed,
         std::function<void(std::shared_ptr<WindowState>)> update_decoration_window_state);
 
+    void set_custom_geometry(std::shared_ptr<StaticGeometry> geometry);
+
     std::shared_ptr<msd::Decoration> to_decoration() const;
 
     void init(

include/miral/miral/decoration_window_state.h

@@ -23,6 +23,7 @@
 #include "mir/geometry/point.h"
 #include "mir/geometry/size.h"
 #include "mir_toolkit/common.h"
+#include <memory>
 
 namespace mir::scene { class Surface; }
 
@@ -48,16 +49,12 @@ struct StaticGeometry
                                                    ///< surface is considered a resize corner)
     geometry::Width const button_width;            ///< The width of window control buttons
     geometry::Width const padding_between_buttons; ///< The gep between titlebar buttons
-    geometry::Height const title_font_height;      ///< Height of the text used to render the window title
-    geometry::Point const title_font_top_left;     ///< Where to render the window title
-    geometry::Displacement const icon_padding;     ///< Padding inside buttons around icons
-    geometry::Width const icon_line_width;         ///< Width for lines in button icons
 };
 
 class WindowState
 {
 public:
-    WindowState(StaticGeometry const& static_geometry, ms::Surface const* surface);
+    WindowState(std::shared_ptr<StaticGeometry> const& static_geometry, ms::Surface const* surface);
 
     auto window_size() const -> geometry::Size;
     auto focused_state() const -> MirWindowFocusState;
@@ -85,7 +82,7 @@ class WindowState
     WindowState(WindowState const&) = delete;
     WindowState& operator=(WindowState const&) = delete;
 
-    StaticGeometry const static_geometry; // TODO: this can be shared between all instance of a decoration
+    std::shared_ptr<StaticGeometry> const static_geometry; // TODO: this can be shared between all instance of a decoration
     geometry::Size const window_size_;
     BorderType const border_type_;
     MirWindowFocusState const focus_state_;

src/miral/decoration_adapter.cpp

@@ -196,10 +196,6 @@ StaticGeometry const default_geometry{
     geom::Size{16, 16},       // resize_corner_input_size
     geom::Width{24},          // button_width
     geom::Width{6},           // padding_between_buttons
-    geom::Height{14},         // title_font_height
-    geom::Point{8, 2},        // title_font_top_left
-    geom::Displacement{5, 5}, // icon_padding
-    geom::Width{1},           // detail_line_width
 };
 
 miral::Renderer::Renderer(
@@ -445,10 +441,13 @@ struct miral::DecorationAdapter::Impl : public msd::Decoration
                               window_state_updated(window_surface);
                               window_renamed(args...);
                               on_update_decoration_window_state(window_state);
-                          }}
+                          }},
+        geometry{std::make_shared<StaticGeometry>(default_geometry)} // I could use a default parameter, but I don't like those...
     {
     }
 
+    void set_custom_geometry(std::shared_ptr<StaticGeometry> geometry);
+
     void init(
         std::shared_ptr<ms::Surface> window_surface,
         std::shared_ptr<ms::Surface> decoration_surface,
@@ -495,6 +494,8 @@ struct miral::DecorationAdapter::Impl : public msd::Decoration
     std::function<void(ms::Surface const* window_surface, mir::geometry::Size const& /*window_size*/)>
         on_window_resized_to;
     std::function<void(ms::Surface const* window_surface, std::string const& /*name*/)> on_window_renamed;
+
+    std::shared_ptr<StaticGeometry> geometry;
 };
 
 miral::DecorationAdapter::DecorationAdapter(
@@ -602,6 +603,16 @@ void miral::DecorationAdapter::Impl::update()
     renderer->update_render_submit(window_state);
 }
 
+void miral::DecorationAdapter::set_custom_geometry(std::shared_ptr<StaticGeometry> geometry)
+{
+    impl->set_custom_geometry(geometry);
+}
+
+void miral::DecorationAdapter::Impl::set_custom_geometry(std::shared_ptr<StaticGeometry> geometry)
+{
+    this->geometry = geometry;
+}
+
 void miral::DecorationAdapter::Impl::init(
     std::shared_ptr<ms::Surface> window_surface,
     std::shared_ptr<ms::Surface> decoration_surface,
@@ -613,7 +624,7 @@ void miral::DecorationAdapter::Impl::init(
     this->shell = shell;
     this->session = window_surface->session().lock();
     this->decoration_surface = decoration_surface;
-    this->window_state = std::make_shared<WindowState>(default_geometry, window_surface.get());
+    this->window_state = std::make_shared<WindowState>(geometry, window_surface.get());
 
     renderer = std::make_unique<Renderer>(window_surface, buffer_allocator, render_titlebar, render_left_border, render_right_border, render_bottom_border);
     input_adapter = std::make_unique<InputResolverAdapter>(
@@ -640,7 +651,7 @@ void miral::DecorationAdapter::Impl::init(
 
 void miral::DecorationAdapter::Impl::window_state_updated(std::shared_ptr<ms::Surface> const window_surface)
 {
-    window_state = std::make_shared<WindowState>(default_geometry, window_surface.get());
+    window_state = std::make_shared<WindowState>(geometry, window_surface.get());
 }
 
 miral::DecorationAdapter::DecorationAdapter::Impl::~Impl()

src/miral/decoration_window_state.cpp

@@ -64,7 +64,7 @@ auto border_type_for(MirWindowType type, MirWindowState state) -> BorderType
     return {};
 }
 
-WindowState::WindowState(StaticGeometry const& static_geometry, ms::Surface const* surface) :
+WindowState::WindowState(std::shared_ptr<StaticGeometry> const& static_geometry, ms::Surface const* surface) :
     static_geometry{static_geometry},
     window_size_{surface->window_size()},
     border_type_{border_type_for(surface->type(), surface->state())},
@@ -84,7 +84,7 @@ auto WindowState::titlebar_height() const -> geometry::Height
     {
     case BorderType::Full:
     case BorderType::Titlebar:
-        return static_geometry.titlebar_height;
+        return static_geometry->titlebar_height;
     case BorderType::None:
         return geometry::Height{0};
     }
@@ -98,7 +98,7 @@ auto WindowState::side_border_width() const -> geometry::Width
     switch(border_type_)
     {
     case BorderType::Full:
-        return static_geometry.side_border_width;
+        return static_geometry->side_border_width;
     case BorderType::Titlebar:
     case BorderType::None:
         return geometry::Width{0};
@@ -117,7 +117,7 @@ auto WindowState::bottom_border_height() const -> geometry::Height
     switch(border_type_)
     {
     case BorderType::Full:
-        return static_geometry.bottom_border_height;
+        return static_geometry->bottom_border_height;
     case BorderType::Titlebar:
     case BorderType::None:
         return geometry::Height{0};
@@ -176,12 +176,12 @@ auto WindowState::window_name() const -> std::string
 
 auto WindowState::geometry() const -> StaticGeometry
 {
-    return static_geometry;
+    return *static_geometry;
 }
 
 auto WindowState::resize_corner_input_size() const -> geometry::Size
 {
-    return static_geometry.resize_corner_input_size;
+    return static_geometry->resize_corner_input_size;
 }
 
 auto WindowState::border_type() const -> BorderType

src/miral/symbols.map

@@ -535,6 +535,7 @@ global:
     miral::DecorationAdapter::DecorationAdapter*;
     miral::DecorationAdapter::init*;
     miral::DecorationAdapter::redraw_notifier*;
+    miral::DecorationAdapter::set_custom_geometry*;
     miral::DecorationAdapter::to_decoration*;
     miral::DecorationAdapter::update*;
     miral::DecorationBasicManager::DecorationBasicManager*;