loginDialog: allocate children manually

The login screen is pretty custom full screen container and the standard
layout managers aren't really a good fit for the kind of layout that's
happening. This will be even more problematic with upcoming changes
to login banners, so we need to switch techniques.

This commit moves login dialog over to using a custom allocate handler
that has specific domain knowledge of the parts of the login screen
and where they go.

https://bugzilla.gnome.org/show_bug.cgi?id=703972

diff --git a/js/gdm/loginDialog.js b/js/gdm/loginDialog.js
index a40dc258bfe9998f44727071affcc294ce3d5ca3..640d1c78c900ea1ce305a49a7730e1e19fded327 100644 (file)
--- a/js/gdm/loginDialog.js
+++ b/js/gdm/loginDialog.js
@@ -364,12 +364,12 @@ const LoginDialog = new Lang.Class({
     Name: 'LoginDialog',
 
     _init: function(parentActor) {
-        this.actor = new St.Widget({ accessible_role: Atk.Role.WINDOW,
-                                     layout_manager: new Clutter.BinLayout(),
-                                     style_class: 'login-dialog',
-                                     visible: false });
+        this.actor = new Shell.GenericContainer({ style_class: 'login-dialog',
+                                                  visible: false });
+        this.actor.get_accessible().set_role(Atk.Role.WINDOW);
 
         this.actor.add_constraint(new Layout.MonitorConstraint({ primary: true }));
+        this.actor.connect('allocate', Lang.bind(this, this._onAllocate));
         this.actor.connect('destroy', Lang.bind(this, this._onDestroy));
         parentActor.add_child(this.actor);
 
@@ -405,8 +405,6 @@ const LoginDialog = new Lang.Class({
         this._userSelectionBox = new St.BoxLayout({ style_class: 'login-dialog-user-selection-box',
                                                     x_align: Clutter.ActorAlign.CENTER,
                                                     y_align: Clutter.ActorAlign.CENTER,
-                                                    x_expand: true,
-                                                    y_expand: true,
                                                     vertical: true,
                                                     visible: false });
         this.actor.add_child(this._userSelectionBox);
@@ -452,9 +450,7 @@ const LoginDialog = new Lang.Class({
 
         this._logoBin = new St.Widget({ style_class: 'login-dialog-logo-bin',
                                         x_align: Clutter.ActorAlign.CENTER,
-                                        y_align: Clutter.ActorAlign.END,
-                                        x_expand: true,
-                                        y_expand: true });
+                                        y_align: Clutter.ActorAlign.END });
         this.actor.add_child(this._logoBin);
         this._updateLogo();
 
@@ -485,6 +481,86 @@ const LoginDialog = new Lang.Class({
                                                              Lang.bind(this, this._updateDisableUserList));
     },
 
+    _getLogoBinAllocation: function (dialogBox) {
+        let actorBox = new Clutter.ActorBox();
+
+        let [minWidth, minHeight, natWidth, natHeight] = this._logoBin.get_preferred_size();
+        let centerX = dialogBox.x1 + (dialogBox.x2 - dialogBox.x1) / 2;
+
+        actorBox.x1 = centerX - natWidth / 2;
+        actorBox.y1 = dialogBox.y2 - natHeight;
+        actorBox.x2 = actorBox.x1 + natWidth;
+        actorBox.y2 = actorBox.y1 + natHeight;
+
+        return actorBox;
+    },
+
+    _getCenterActorAllocation: function (dialogBox, actor) {
+        let actorBox = new Clutter.ActorBox();
+
+        let [minWidth, minHeight, natWidth, natHeight] = actor.get_preferred_size();
+        let centerX = dialogBox.x1 + (dialogBox.x2 - dialogBox.x1) / 2;
+        let centerY = dialogBox.y1 + (dialogBox.y2 - dialogBox.y1) / 2;
+
+        actorBox.x1 = centerX - natWidth / 2;
+        actorBox.y1 = centerY - natHeight / 2;
+        actorBox.x2 = actorBox.x1 + natWidth;
+        actorBox.y2 = actorBox.y1 + natHeight;
+
+        return actorBox;
+    },
+
+    _onAllocate: function (actor, dialogBox, flags) {
+        let dialogHeight = dialogBox.y2 - dialogBox.y1;
+
+        // First find out what space the children require
+        let authPromptAllocation = null;
+        if (this._authPrompt.actor.visible)
+            authPromptAllocation = this._getCenterActorAllocation(dialogBox, this._authPrompt.actor);
+
+        let userSelectionAllocation = null;
+        let userSelectionHeight = 0;
+        if (this._userSelectionBox.visible) {
+            userSelectionAllocation = this._getCenterActorAllocation(dialogBox, this._userSelectionBox);
+            userSelectionHeight = userSelectionAllocation.y2 - userSelectionAllocation.y1;
+        }
+
+        let logoAllocation = null;
+        let logoHeight = 0;
+        if (this._logoBin.visible) {
+            logoAllocation = this._getLogoBinAllocation(dialogBox);
+            logoHeight = logoAllocation.y2 - logoAllocation.y1;
+        }
+
+        // Then figure out what extra space we can hand out
+        let leftOverYSpace = dialogHeight - userSelectionHeight - logoHeight;
+        if (leftOverYSpace > 0) {
+            if (userSelectionAllocation) {
+                let topExpansion = leftOverYSpace / 2;
+
+                // Don't ever expand more than we have space for
+                if (userSelectionAllocation.y1 - topExpansion < 0)
+                    topExpansion = userSelectionAllocation.y1;
+
+                // Always expand the bottom the same as the top since it's centered
+                let bottomExpansion = topExpansion;
+
+                userSelectionAllocation.y1 -= topExpansion;
+                userSelectionAllocation.y2 += bottomExpansion;
+            }
+        }
+
+        // Finally hand out the allocations
+        if (authPromptAllocation)
+            this._authPrompt.actor.allocate(authPromptAllocation, flags);
+
+        if (userSelectionAllocation)
+            this._userSelectionBox.allocate(userSelectionAllocation, flags);
+
+        if (logoAllocation)
+            this._logoBin.allocate(logoAllocation, flags);
+    },
+
     _ensureUserListLoaded: function() {
         if (!this._userManager.is_loaded) {
             this._userManagerLoadedId = this._userManager.connect('notify::is-loaded',