UiSurface

Remarks

A document is a tree; a surface is a place to show part of one. Until this existed the two were the same thing — one root, one size, one draw list — and a second window therefore meant a second document. It cannot: a panel dragged from the main window into a torn-off one has to keep its scroll offset, its selection and whatever the user has half-typed, and the only operation that preserves those is Reparent, which is within a document by construction. Making a window a surface rather than a document turns "move a panel to another window" into the reparent the docking host already performs.

⚠ Every surface after the first is an ordinary element under Root, and that is deliberate. It keeps one style tree, so a torn-off panel inherits the theme, matches the same stylesheets and resolves rem against the same root — and it keeps one focus, one pointer capture and one gesture recogniser, which is what lets a drag that starts in one window finish in another. What the surface root does not do is take part in its parent's flex layout: it is removed from the layout tree's child list and laid out on its own, against its own size.

⚠ DpiScale is per surface, because two windows are routinely on two displays. It is not a scale the document applies to anything — lengths stay in logical points everywhere above the renderer — it is the grid the finished layout is snapped to, so that a one-pixel border on a 2× display is one physical pixel rather than one and a half.

Fields and properties (10)

• public int Id

  What tells the surfaces of one document apart.

• public UiDocument Document

  The document it shows part of.

• public UiElement Root

  The element it is laid out from.

• public bool IsPrimary

  Whether this is the surface the document was created with.

• public float Width

  Its width in device-independent pixels.

• public float Height

  Its height.

• public float DpiScale

  How many physical pixels one device-independent one is here.

• public DrawList Drawing

  The commands the last draw produced for it.

• public bool IsRemoved

  Whether it has been taken out of the document.

• public LengthContext Metrics

  The lengths vw, vh and rem measure against here.

Used by (15)

• AdvancedFixtureVixen.Ui.Controls.Advanced.Tests
• DockingHostVixen.Ui.Controls.Advanced
• FakeWindowVixen.Ui.Controls.Advanced.Tests
• FakeWindowsVixen.Ui.Controls.Advanced.Tests
• IUiWindowVixen.Ui
• IUiWindowHostVixen.Ui
• PlatformInputVixen.Platform.Ui
• PlatformUiWindowVixen.Platform.Ui
• PlatformWindowHostVixen.Platform.Ui
• PlatformWindowHostTestsVixen.Platform.Ui.Tests
• SurfaceTestsVixen.Ui.Tests
• UiDocumentVixen.Ui
• UiElementVixen.Ui
• EditorHostVixen.Editor.Host
• EditorPaneVixen.Editor.Host