LibGUI: Rewrite layout system in terms of min and max sizes

This patch removes size policies and preferred sizes, and replaces them
with min-size and max-size for each widget.

Box layout now works in 3 passes:

    1) Set all items (widgets/spacers) to their min-size
    2) Distribute remaining space evenly, respecting max-size
    3) Place widgets one after the other, adding spacing in between

I've also added convenience helpers for setting a fixed size (which is
the same as setting min-size and max-size to the same value.)

This significantly reduces the verbosity of widget layout and makes GML
a bit more pleasant to write, too. :^)

9 files changed, 23 insertions, 43 deletions

diff --git a/DevTools/HackStudio/Debugger/DisassemblyWidget.cpp b/DevTools/HackStudio/Debugger/DisassemblyWidget.cpp
index 893d8dac82..9602d90392 100644
--- a/DevTools/HackStudio/Debugger/DisassemblyWidget.cpp
+++ b/DevTools/HackStudio/Debugger/DisassemblyWidget.cpp
@@ -48,11 +48,9 @@ DisassemblyWidget::DisassemblyWidget()
 
     m_top_container = add<GUI::Widget>();
     m_top_container->set_layout<GUI::HorizontalBoxLayout>();
-    m_top_container->set_size_policy(GUI::SizePolicy::Fill, GUI::SizePolicy::Fixed);
-    m_top_container->set_preferred_size(0, 20);
+    m_top_container->set_fixed_height(20);
 
     m_function_name_label = m_top_container->add<GUI::Label>("");
-    m_function_name_label->set_size_policy(GUI::SizePolicy::Fill, GUI::SizePolicy::Fill);
 
     m_disassembly_view = add<GUI::TableView>();
 
diff --git a/DevTools/HackStudio/EditorWrapper.cpp b/DevTools/HackStudio/EditorWrapper.cpp
index e2f51cfbc5..c21396f251 100644
--- a/DevTools/HackStudio/EditorWrapper.cpp
+++ b/DevTools/HackStudio/EditorWrapper.cpp
@@ -40,21 +40,18 @@ EditorWrapper::EditorWrapper()
     set_layout<GUI::VerticalBoxLayout>();
 
     auto& label_wrapper = add<GUI::Widget>();
-    label_wrapper.set_size_policy(GUI::SizePolicy::Fill, GUI::SizePolicy::Fixed);
-    label_wrapper.set_preferred_size(0, 14);
+    label_wrapper.set_fixed_height(14);
     label_wrapper.set_fill_with_background_color(true);
     label_wrapper.set_layout<GUI::HorizontalBoxLayout>();
     label_wrapper.layout()->set_margins({ 2, 0, 2, 0 });
 
     m_filename_label = label_wrapper.add<GUI::Label>("(Untitled)");
     m_filename_label->set_text_alignment(Gfx::TextAlignment::CenterLeft);
-    m_filename_label->set_size_policy(GUI::SizePolicy::Fill, GUI::SizePolicy::Fixed);
-    m_filename_label->set_preferred_size(0, 14);
+    m_filename_label->set_fixed_height(14);
 
     m_cursor_label = label_wrapper.add<GUI::Label>("(Cursor)");
     m_cursor_label->set_text_alignment(Gfx::TextAlignment::CenterRight);
-    m_cursor_label->set_size_policy(GUI::SizePolicy::Fill, GUI::SizePolicy::Fixed);
-    m_cursor_label->set_preferred_size(0, 14);
+    m_cursor_label->set_fixed_height(14);
 
     m_editor = add<Editor>();
     m_editor->set_ruler_visible(true);
diff --git a/DevTools/HackStudio/FindInFilesWidget.cpp b/DevTools/HackStudio/FindInFilesWidget.cpp
index 8491379013..7c823ed42b 100644
--- a/DevTools/HackStudio/FindInFilesWidget.cpp
+++ b/DevTools/HackStudio/FindInFilesWidget.cpp
@@ -138,15 +138,12 @@ FindInFilesWidget::FindInFilesWidget()
 
     auto& top_container = add<Widget>();
     top_container.set_layout<GUI::HorizontalBoxLayout>();
-    top_container.set_size_policy(GUI::SizePolicy::Fill, GUI::SizePolicy::Fixed);
-    top_container.set_preferred_size(0, 20);
+    top_container.set_fixed_height(20);
 
     m_textbox = top_container.add<GUI::TextBox>();
-    m_textbox->set_size_policy(GUI::SizePolicy::Fill, GUI::SizePolicy::Fill);
 
     m_button = top_container.add<GUI::Button>("Find in files");
-    m_button->set_size_policy(GUI::SizePolicy::Fixed, GUI::SizePolicy::Fill);
-    m_button->set_preferred_size(100, 0);
+    m_button->set_fixed_width(100);
 
     m_result_view = add<GUI::TableView>();
 
diff --git a/DevTools/HackStudio/Git/GitWidget.cpp b/DevTools/HackStudio/Git/GitWidget.cpp
index 265eb6f98c..95ef6928ec 100644
--- a/DevTools/HackStudio/Git/GitWidget.cpp
+++ b/DevTools/HackStudio/Git/GitWidget.cpp
@@ -54,16 +54,14 @@ GitWidget::GitWidget(const LexicalPath& repo_root)
 
     auto& refresh_button = unstaged_header.add<GUI::Button>();
     refresh_button.set_icon(Gfx::Bitmap::load_from_file("/res/icons/16x16/reload.png"));
-    refresh_button.set_preferred_size({ 16, 16 });
-    refresh_button.set_size_policy(GUI::SizePolicy::Fixed, GUI::SizePolicy::Fixed);
+    refresh_button.set_fixed_size(16, 16);
     refresh_button.set_tooltip("refresh");
     refresh_button.on_click = [this](int) { refresh(); };
 
     auto& unstaged_label = unstaged_header.add<GUI::Label>();
     unstaged_label.set_text("Unstaged");
 
-    unstaged_header.set_size_policy(GUI::SizePolicy::Fill, GUI::SizePolicy::Fixed);
-    unstaged_header.set_preferred_size(0, 20);
+    unstaged_header.set_fixed_height(20);
     m_unstaged_files = unstaged.add<GitFilesView>(
         [this](const auto& file) { stage_file(file); },
         Gfx::Bitmap::load_from_file("/res/icons/16x16/plus.png").release_nonnull());
@@ -80,16 +78,14 @@ GitWidget::GitWidget(const LexicalPath& repo_root)
 
     auto& commit_button = staged_header.add<GUI::Button>();
     commit_button.set_icon(Gfx::Bitmap::load_from_file("/res/icons/16x16/commit.png"));
-    commit_button.set_preferred_size({ 16, 16 });
-    commit_button.set_size_policy(GUI::SizePolicy::Fixed, GUI::SizePolicy::Fixed);
+    commit_button.set_fixed_size(16, 16);
     commit_button.set_tooltip("commit");
     commit_button.on_click = [this](int) { commit(); };
 
     auto& staged_label = staged_header.add<GUI::Label>();
     staged_label.set_text("Staged");
 
-    staged_header.set_size_policy(GUI::SizePolicy::Fill, GUI::SizePolicy::Fixed);
-    staged_header.set_preferred_size(0, 20);
+    staged_header.set_fixed_height(20);
     m_staged_files = staged.add<GitFilesView>(
         [this](const auto& file) { unstage_file(file); },
         Gfx::Bitmap::load_from_file("/res/icons/16x16/minus.png").release_nonnull());
diff --git a/DevTools/HackStudio/HackStudioWidget.cpp b/DevTools/HackStudio/HackStudioWidget.cpp
index e373664110..588c3ee80b 100644
--- a/DevTools/HackStudio/HackStudioWidget.cpp
+++ b/DevTools/HackStudio/HackStudioWidget.cpp
@@ -100,8 +100,7 @@ HackStudioWidget::HackStudioWidget(const String& path_to_project)
     auto& outer_splitter = add<GUI::HorizontalSplitter>();
 
     auto& left_hand_splitter = outer_splitter.add<GUI::VerticalSplitter>();
-    left_hand_splitter.set_size_policy(GUI::SizePolicy::Fixed, GUI::SizePolicy::Fill);
-    left_hand_splitter.set_preferred_size(150, 0);
+    left_hand_splitter.set_fixed_width(150);
     create_project_tree_view(left_hand_splitter);
     m_project_tree_view_context_menu = create_project_tree_view_context_menu();
 
@@ -494,8 +493,8 @@ NonnullRefPtr<GUI::Action> HackStudioWidget::create_add_terminal_action()
 
 void HackStudioWidget::reveal_action_tab(GUI::Widget& widget)
 {
-    if (m_action_tab_widget->preferred_size().height() < 200)
-        m_action_tab_widget->set_preferred_size(0, 200);
+    if (m_action_tab_widget->min_height() < 200)
+        m_action_tab_widget->set_fixed_height(200);
     m_action_tab_widget->set_active_widget(&widget);
 }
 
@@ -617,7 +616,7 @@ void HackStudioWidget::run(TerminalWrapper& wrapper)
 
 void HackStudioWidget::hide_action_tabs()
 {
-    m_action_tab_widget->set_preferred_size(0, 24);
+    m_action_tab_widget->set_fixed_height(24);
 };
 
 Project& HackStudioWidget::project()
@@ -673,7 +672,7 @@ void HackStudioWidget::create_form_editor(GUI::Widget& parent)
     m_form_inner_container = parent.add<GUI::Widget>();
     m_form_inner_container->set_layout<GUI::HorizontalBoxLayout>();
     auto& form_widgets_toolbar = m_form_inner_container->add<GUI::ToolBar>(Orientation::Vertical, 26);
-    form_widgets_toolbar.set_preferred_size(38, 0);
+    form_widgets_toolbar.set_fixed_width(38);
 
     GUI::ActionGroup tool_actions;
     tool_actions.set_exclusive(true);
@@ -710,8 +709,7 @@ void HackStudioWidget::create_form_editor(GUI::Widget& parent)
     m_form_editor_widget = form_editor_inner_splitter.add<FormEditorWidget>();
 
     auto& form_editing_pane_container = form_editor_inner_splitter.add<GUI::VerticalSplitter>();
-    form_editing_pane_container.set_size_policy(GUI::SizePolicy::Fixed, GUI::SizePolicy::Fill);
-    form_editing_pane_container.set_preferred_size(190, 0);
+    form_editing_pane_container.set_fixed_width(190);
     form_editing_pane_container.set_layout<GUI::VerticalBoxLayout>();
 
     auto add_properties_pane = [&](auto& text, auto& pane_widget) {
@@ -721,8 +719,7 @@ void HackStudioWidget::create_form_editor(GUI::Widget& parent)
         label.set_fill_with_background_color(true);
         label.set_text_alignment(Gfx::TextAlignment::CenterLeft);
         label.set_font(Gfx::Font::default_bold_font());
-        label.set_size_policy(GUI::SizePolicy::Fill, GUI::SizePolicy::Fixed);
-        label.set_preferred_size(0, 16);
+        label.set_fixed_height(16);
         wrapper.add_child(pane_widget);
     };
 
@@ -803,14 +800,13 @@ void HackStudioWidget::create_action_tab(GUI::Widget& parent)
 {
     m_action_tab_widget = parent.add<GUI::TabWidget>();
 
-    m_action_tab_widget->set_size_policy(GUI::SizePolicy::Fill, GUI::SizePolicy::Fixed);
-    m_action_tab_widget->set_preferred_size(0, 24);
+    m_action_tab_widget->set_fixed_height(24);
     m_action_tab_widget->on_change = [this](auto&) {
         on_action_tab_change();
 
         static bool first_time = true;
         if (!first_time)
-            m_action_tab_widget->set_preferred_size(0, 200);
+            m_action_tab_widget->set_fixed_height(200);
         first_time = false;
     };
 
diff --git a/DevTools/HackStudio/Locator.cpp b/DevTools/HackStudio/Locator.cpp
index f207df2985..50c16fde1e 100644
--- a/DevTools/HackStudio/Locator.cpp
+++ b/DevTools/HackStudio/Locator.cpp
@@ -69,8 +69,7 @@ private:
 Locator::Locator()
 {
     set_layout<GUI::VerticalBoxLayout>();
-    set_size_policy(GUI::SizePolicy::Fill, GUI::SizePolicy::Fixed);
-    set_preferred_size(0, 20);
+    set_fixed_height(20);
     m_textbox = add<GUI::TextBox>();
     m_textbox->on_change = [this] {
         update_suggestions();
diff --git a/DevTools/Inspector/main.cpp b/DevTools/Inspector/main.cpp
index 0591313f80..2e30792068 100644
--- a/DevTools/Inspector/main.cpp
+++ b/DevTools/Inspector/main.cpp
@@ -128,8 +128,7 @@ int main(int argc, char** argv)
     auto& tree_view = splitter.add<GUI::TreeView>();
     tree_view.set_model(remote_process.object_graph_model());
     tree_view.set_activates_on_selection(true);
-    tree_view.set_size_policy(GUI::SizePolicy::Fixed, GUI::SizePolicy::Fill);
-    tree_view.set_preferred_size(286, 0);
+    tree_view.set_fixed_width(286);
 
     auto& properties_tree_view = splitter.add<GUI::TreeView>();
     properties_tree_view.set_editable(true);
diff --git a/DevTools/Profiler/ProfileTimelineWidget.cpp b/DevTools/Profiler/ProfileTimelineWidget.cpp
index 025af2c5f9..bbaf38973f 100644
--- a/DevTools/Profiler/ProfileTimelineWidget.cpp
+++ b/DevTools/Profiler/ProfileTimelineWidget.cpp
@@ -33,8 +33,7 @@ ProfileTimelineWidget::ProfileTimelineWidget(Profile& profile)
 {
     set_background_color(Color::White);
     set_fill_with_background_color(true);
-    set_size_policy(GUI::SizePolicy::Fill, GUI::SizePolicy::Fixed);
-    set_preferred_size(0, 80);
+    set_fixed_height(80);
 }
 
 ProfileTimelineWidget::~ProfileTimelineWidget()
diff --git a/DevTools/Profiler/main.cpp b/DevTools/Profiler/main.cpp
index 38f3ebc3ee..fb157979e8 100644
--- a/DevTools/Profiler/main.cpp
+++ b/DevTools/Profiler/main.cpp
@@ -176,8 +176,7 @@ static bool prompt_to_stop_profiling(pid_t pid, const String& process_name)
     });
 
     auto& stop_button = widget.add<GUI::Button>("Stop");
-    stop_button.set_size_policy(GUI::SizePolicy::Fixed, GUI::SizePolicy::Fixed);
-    stop_button.set_preferred_size(140, 22);
+    stop_button.set_fixed_size(140, 22);
     stop_button.on_click = [&](auto) {
         GUI::Application::the()->quit();
     };