virtualtrees.pas

Last change: 2008-02-03 This is the source code of KCeasy。

    function GetPreviousVisibleColumn(Column: TColumnIndex): TColumnIndex;
    function GetVisibleColumns: TColumnsArray;
    function GetVisibleFixedWidth: Integer;
    function IsValidColumn(Column: TColumnIndex): Boolean;
    procedure LoadFromStream(const Stream: TStream; Version: Integer);
    procedure PaintHeader(DC: HDC; R: TRect; HOffset: Integer); virtual;
    procedure SaveToStream(const Stream: TStream);
    function TotalWidth: Integer;

    property ClickIndex: TColumnIndex read FClickIndex;
    property Items[Index: TColumnIndex]: TVirtualTreeColumn read GetItem write SetItem; default;
    property Header: TVTHeader read FHeader;
    property TrackIndex: TColumnIndex read FTrackIndex;
  end;

  TVirtualTreeColumnsClass = class of TVirtualTreeColumns;
  
  TVTHeaderStyle = (
    hsThickButtons,    // TButton look and feel
    hsFlatButtons,     // flatter look than hsThickButton, like an always raised flat TToolButton
    hsPlates,          // flat TToolButton look and feel (raise on hover etc.)
    hsXPStyle          // Windows XP style
  );

  TVTHeaderOption = (
    hoAutoResize,      // Adjust a column so that the header never exceeds the client width of the owner control.
    hoColumnResize,    // Resizing columns with the mouse is allowed.
    hoDblClickResize,  // Allows a column to resize itself to its largest entry.
    hoDrag,            // Dragging columns is allowed.
    hoHotTrack,        // Header captions are highlighted when mouse is over a particular column.
    hoOwnerDraw,       // Header items with the owner draw style can be drawn by the application via event.
    hoRestrictDrag,    // Header can only be dragged horizontally.
    hoShowHint,        // Show application defined header hint.
    hoShowImages,      // Show header images.
    hoShowSortGlyphs,  // Allow visible sort glyphs.
    hoVisible,         // Header is visible.
    hoAutoSpring       // Distribute size changes of the header to all columns, which are sizable and have the
                       // coAutoSpring option enabled. hoAutoResize must be enabled too.
  );
  TVTHeaderOptions = set of TVTHeaderOption;

  THeaderState = (
    hsAutoSizing,      // auto size chain is in progess, do not trigger again on WM_SIZE
    hsDragging,        // header dragging is in progress (only if enabled)
    hsDragPending,     // left button is down, user might want to start dragging a column
    hsLoading,         // The header currently loads from stream, so updates are not necessary.
    hsTracking,        // column resizing is in progress
    hsTrackPending     // left button is down, user might want to start resize a column
  );
  THeaderStates = set of THeaderState;

  TSortDirection = (
    sdAscending,
    sdDescending
  );

  // desribes what made a structure change event happen
  TChangeReason = (
    crIgnore,       // used as placeholder
    crAccumulated,  // used for delayed changes
    crChildAdded,   // one or more child nodes have been added
    crChildDeleted, // one or more child nodes have been deleted
    crNodeAdded,    // a node has been added
    crNodeCopied,   // a node has been duplicated
    crNodeMoved     // a node has been moved to a new place
  );

  TVTHeader = class(TPersistent)
  private
    FOwner: TBaseVirtualTree;
    FColumns: TVirtualTreeColumns;
    FHeight: Cardinal;
    FFont: TFont;
    FParentFont: Boolean;
    FOptions: TVTHeaderOptions;
    FStates: THeaderStates;            // used to keep track of internal states the header can enter
    FLeftTrackPos: Integer;            // left border of this column to quickly calculate its width on resize
    FStyle: TVTHeaderStyle;            // button style
    FBackground: TColor;
    FAutoSizeIndex: TColumnIndex;
    FPopupMenu: TPopupMenu;
    FMainColumn: TColumnIndex;         // the column which holds the tree
    FImages: TCustomImageList;
    FImageChangeLink: TChangeLink;     // connections to the image list to get notified about changes
    FSortColumn: TColumnIndex;
    FSortDirection: TSortDirection;
    FTrackStart: TPoint;               // client coordinates of the tracking start point
    FDragStart: TPoint;                // initial mouse drag position
    FDragImage: TVTDragImage;          // drag image management during header drag
    FLastWidth: Integer;               // Used to adjust spring columns. This is the width of all visible columns,
                                       // not the header rectangle.
    procedure FontChanged(Sender: TObject);
    function GetMainColumn: TColumnIndex;
    function GetUseColumns: Boolean;
    procedure SetAutoSizeIndex(Value: TColumnIndex);
    procedure SetBackground(Value: TColor);
    procedure SetColumns(Value: TVirtualTreeColumns);
    procedure SetFont(const Value: TFont);
    procedure SetHeight(Value: Cardinal);
    procedure SetImages(const Value: TCustomImageList);
    procedure SetMainColumn(Value: TColumnIndex);
    procedure SetOptions(Value: TVTHeaderOptions);
    procedure SetParentFont(Value: Boolean);
    procedure SetSortColumn(Value: TColumnIndex);
    procedure SetSortDirection(const Value: TSortDirection);
    procedure SetStyle(Value: TVTHeaderStyle);
  protected
    function CanWriteColumns: Boolean; virtual;
    procedure ChangeScale(M, D: Integer); virtual;
    function DetermineSplitterIndex(P: TPoint): Boolean; virtual;
    procedure DragTo(P: TPoint);
    function GetColumnsClass: TVirtualTreeColumnsClass; virtual;
    function GetOwner: TPersistent; override;
    function GetShiftState: TShiftState;
    function HandleHeaderMouseMove(var Message: TWMMouseMove): Boolean;
    function HandleMessage(var Message: TMessage): Boolean; virtual;
    procedure ImageListChange(Sender: TObject);
    procedure PrepareDrag(P, Start: TPoint);
    procedure ReadColumns(Reader: TReader);
    procedure RecalculateHeader; virtual;
    procedure UpdateMainColumn;
    procedure UpdateSpringColumns;
    procedure WriteColumns(Writer: TWriter);
  public
    constructor Create(AOwner: TBaseVirtualTree); virtual;
    destructor Destroy; override;

    procedure Assign(Source: TPersistent); override;
    procedure AutoFitColumns(Animated: Boolean = True);
    function InHeader(P: TPoint): Boolean; virtual;
    procedure Invalidate(Column: TVirtualTreeColumn; ExpandToRight: Boolean = False);
    procedure LoadFromStream(const Stream: TStream); virtual;
    procedure RestoreColumns;
    procedure SaveToStream(const Stream: TStream); virtual;

    property DragImage: TVTDragImage read FDragImage;
    property States: THeaderStates read FStates;
    property Treeview: TBaseVirtualTree read FOwner;
    property UseColumns: Boolean read GetUseColumns;
  published
    property AutoSizeIndex: TColumnIndex read FAutoSizeIndex write SetAutoSizeIndex;
    property Background: TColor read FBackground write SetBackground default clBtnFace;
    property Columns: TVirtualTreeColumns read FColumns write SetColumns stored False; // Stored by the owner tree to
                                                                                       // support VFI.
    property Font: TFont read FFont write SetFont;
    property Height: Cardinal read FHeight write SetHeight default 17;
    property Images: TCustomImageList read FImages write SetImages;
    property MainColumn: TColumnIndex read GetMainColumn write SetMainColumn default 0;
    property Options: TVTHeaderOptions read FOptions write SetOptions default [hoColumnResize, hoDrag, hoShowSortGlyphs];
    property ParentFont: Boolean read FParentFont write SetParentFont default False;
    property PopupMenu: TPopupMenu read FPopupMenu write FPopUpMenu;
    property SortColumn: TColumnIndex read FSortColumn write SetSortColumn default NoColumn;
    property SortDirection: TSortDirection read FSortDirection write SetSortDirection default sdAscending;
    property Style: TVTHeaderStyle read FStyle write SetStyle default hsThickButtons;
  end;

  TVTHeaderClass = class of TVTHeader;

  // Communication interface between a tree editor and the tree itself (declared as using stdcall in case it
  // is implemented in a (C/C++) DLL). The GUID is not nessecary in Delphi but important for BCB users
  // to allow QueryInterface and _uuidof calls.
  IVTEditLink = interface
    ['{2BE3EAFA-5ACB-45B4-9D9A-B58BCC496E17}']
    function BeginEdit: Boolean; stdcall;                  // Called when editing actually starts.
    function CancelEdit: Boolean; stdcall;                 // Called when editing has been cancelled by the tree.
    function EndEdit: Boolean; stdcall;                    // Called when editing has been finished by the tree.
    function PrepareEdit(Tree: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex): Boolean; stdcall;
                                                           // Called after creation to allow a setup.
    function GetBounds: TRect; stdcall;                    // Called to get the current size of the edit window
                                                           // (only important if the edit resizes itself).
    procedure ProcessMessage(var Message: TMessage); stdcall;
                                                           // Used to forward messages to the edit window(s)-
    procedure SetBounds(R: TRect); stdcall;                // Called to place the editor.
  end;

  // Indicates in the OnUpdating event what state the tree is currently in.
  TVTUpdateState = (
    usBegin,       // The tree just entered the update state (BeginUpdate call for the first time).
    usBeginSynch,  // The tree just entered the synch update state (BeginSynch call for the first time).
    usSynch,       // Begin/EndSynch has been called but the tree did not change the update state.
    usUpdate,      // Begin/EndUpdate has been called but the tree did not change the update state.
    usEnd,         // The tree just left the update state (EndUpdate called for the last level).
    usEndSynch     // The tree just left the synch update state (EndSynch called for the last level).
  );

  // Used during owner draw of the header to indicate which drop mark for the column must be drawn.
  TVTDropMarkMode = (
    dmmNone,
    dmmLeft,
    dmmRight
  );

  // This structure carries all important information about header painting and is used in the advanced header painting.
  THeaderPaintInfo = record
    TargetCanvas: TCanvas;
    Column: TVirtualTreeColumn;
    PaintRectangle: TRect;
    TextRectangle: TRect;
    IsHoverIndex,
    IsDownIndex,
    IsEnabled,
    ShowHeaderGlyph,
    ShowSortGlyph,
    ShowRightBorder: Boolean;
    DropMark: TVTDropMarkMode;
    GlyphPos,
    SortGlyphPos: TPoint;
  end;

  // These elements are used both to query the application, which of them it wants to draw itself and to tell it during
  // painting, which elements must be drawn during the advanced custom draw events.
  THeaderPaintElements = set of (
    hpeBackground,
    hpeDropMark,
    hpeHeaderGlyph,
    hpeSortGlyph,
    hpeText
  );

  // Various events must be handled at different places than they were initiated or need
  // a persistent storage until they are reset.
  TVirtualTreeStates = set of (
    tsCancelHintAnimation,    // Set when a new hint is about to show but an old hint is still being animated.
    tsChangePending,          // A selection change is pending.
    tsCheckPropagation,       // Set during automatic check state propagation.
    tsCollapsing,             // A full collapse operation is in progress.
    tsToggleFocusedSelection, // Node selection was modifed using Ctrl-click. Change selection state on next mouse up.
    tsClearPending,           // Need to clear the current selection on next mouse move.
    tsClipboardFlushing,      // Set during flushing the clipboard to avoid freeing the content.
    tsCopyPending,            // Indicates a pending copy operation which needs to be finished.
    tsCutPending,             // Indicates a pending cut operation which needs to be finished.
    tsDrawSelPending,         // Multiselection only. User held down the left mouse button on a free
                              // area and might want to start draw selection.
    tsDrawSelecting,          // Multiselection only. Draw selection has actually started.
    tsEditing,                // Indicates that an edit operation is currently in progress.
    tsEditPending,            // An mouse up start edit if dragging has not started.
    tsExpanding,              // A full expand operation is in progress.
    tsHint,                   // Set when our hint is visible or soon will be.
    tsInAnimation,            // Set if the tree is currently in an animation loop.
    tsIncrementalSearching,   // Set when the user starts incremental search.
    tsIncrementalSearchPending, // Set in WM_KEYDOWN to tell to use the char in WM_CHAR for incremental search.
    tsIterating,              // Set when IterateSubtree is currently in progress.
    tsKeyCheckPending,        // A check operation is under way, initiated by a key press (space key). Ignore mouse.
    tsLeftButtonDown,         // Set when the left mouse button is down.
    tsMouseCheckPending,      // A check operation is under way, initiated by a mouse click. Ignore space key.
    tsMiddleButtonDown,       // Set when the middle mouse button is down.
    tsNeedScale,              // On next ChangeScale scale the default node height.
    tsNeedRootCountUpdate,    // Set if while loading a root node count is set.
    tsOLEDragging,            // OLE dragging in progress.
    tsOLEDragPending,         // User has requested to start delayed dragging.
    tsPainting,               // The tree is currently painting itself.
    tsRightButtonDown,        // Set when the right mouse button is down.
    tsPopupMenuShown,         // The user clicked the right mouse button, which might cause a popup menu to appear.
    tsScrolling,              // Set when autoscrolling is active.
    tsScrollPending,          // Set when waiting for the scroll delay time to elapse.
    tsSizing,                 // Set when the tree window is being resized. This is used to prevent recursive calls
                              // due to setting the