Krypton Workspace RTL

Overview

Issue #2383 adds logical right-to-left packing for KryptonWorkspace horizontal sequences. Nested navigator chrome already follows Control.RightToLeft via KryptonWorkspaceCell : KryptonNavigator. This work mirrors cell tiling, separator drag, and left/right drop insert without GDI-mirroring cell contents and without rewriting XML.

Package: Krypton.Workspace. Docking document areas (KryptonSpace : KryptonWorkspace) inherit the behaviour. Form-edge docking chrome is out of scope.

Architecture

Workspace layout is a tree of KryptonWorkspaceSequence / KryptonWorkspaceCell. Children order is the source of truth for persistence, designers, and KryptonDocumentGroupHelper.

RTL is a view transform applied only when packing a horizontal sequence:

  1. Star allocation (passes 1–4 of LayoutSequenceNonMaximized) still walks collection order.
  2. Pass #5 places items from client.Right when both RTL flags are set (WorkspaceRtlLayout.NextItem).
  3. Vertical sequences still pack top-to-bottom.
Form.RightToLeft + Form.RightToLeftLayout
        |
        v
KryptonWorkspace.RightToLeftLayout  (copied; no WS_EX_LAYOUTRTL)
        |
        v
CommonHelper.IsRightToLeftLayout(workspace)
        |
        +-- Horizontal pack from the right
        +-- Negate vertical-separator mouse delta
        +-- Swap Left/Right drop insert mapping

Do not set WS_EX_LAYOUTRTL on the workspace. That would GDI-mirror nested cells (the class of bugs tracked by #2103).

Public API

KryptonWorkspace.RightToLeftLayout

bool, default false. Named to match WinForms Form.RightToLeftLayout, not the Toolkit RightToLeftLayout enum.

Packing requires both:

  • RightToLeft == RightToLeft.Yes (usually inherited from the form)
  • RightToLeftLayout == true (copied from the parent Form on parent/handle change)

Setting only RightToLeft (text direction) does not reverse columns.

Drop and helpers

  • Physical left/right hot rects are unchanged. DragTargetWorkspaceEdge / DragTargetWorkspaceCellEdge swap Left/Right insert mapping when the gate is on, so a drop on the physical left still appears on the visual left.
  • KryptonDocumentGroupHelper.SplitActiveCell / MovePageToNewCell still insert after in Children order. Under RTL that collection-after cell is visually to the left of a horizontal split.

Usage

On a KryptonForm (or any Form):

form.RightToLeft = RightToLeft.Yes;
form.RightToLeftLayout = true;

The hosted KryptonWorkspace copies the layout flag and packs horizontal sequences from the right. Vertical stacks stay top-to-bottom. SaveLayoutToArray / LoadLayoutFromArray keep the same Children order.

Edge cases

  • Maximized cell: still fills the client; RTL packing does not apply while maximized.
  • Nested horizontal sequences: each horizontal sequence packs from the right of its allocated rect.
  • Separator drag: before/after remain collection neighbours; the X delta is negated so dragging toward the visual-right panel shrinks it (KryptonSplitContainer RTL).
  • Docking: document-area workspaces inherit this. Auto-hide / docked windows on the form edges are a separate Docking RTL topic.