Meilleure façon de faire non-flickering, mises à jour graphiques segmenté dans Delphi?

le double tampon et les tactiques de dessin fantaisistes ne sont que la moitié de l'histoire. L'autre moitié, certains diraient la moitié la plus critique, est de limiter combien de votre contrôle est invalidé.

Dans vos commentaires, vous mentionnez que vous utilisez RedrawWindow(handle, @R, 0, rdw_Invalidate or rdw_Frame) . À quoi paramétrez-vous le rectangle R ? Si vous réglez cela sur votre zone client rect, alors vous redessinez toute la zone client de votre contrôle. Lors du défilement, seule une petite partie de vos besoins de contrôle pour être redessiné - la tranche au "bord de fuite" de la direction de défilement. Windows affichera le reste de l'écran zone client à l'écran pour déplacer les pixels existants dans la direction de défilement.

vérifiez également si vous avez mis vos options de fenêtre pour avoir besoin d'un nouveau dessin complet sur scroll. Je ne me souviens pas des noms des drapeaux, mais vous voulez qu'ils soient désactivés Pour que les actions de défilement n'invalident qu'une partie de votre zone client. Je crois que c'est la valeur par défaut de Windows.

même avec le matériel graphique accéléré, moins de travail est plus rapide que plus de travail. Obtenez votre invalider rects au minimum absolu et de réduire le nombre de pixels que vous poussez à travers le bus système.

C'est une question tout à fait ouverte. Beaucoup de conseils et de réponses ont déjà été donnés. Je voudrais en ajouter deux:

• Inclure csOpaque dans ControlStyle si vous peignez ClientRect pleinement,
• exclure CS_HREDRAW et CS_VREDRAW de Params.WindowClass.Style dans CreateParams .

puisque vous êtes particulièrement intéressé à dessiner sur TScrollingWinControl , je passe les dernières heures sur la réduction du code de une composante de planification de la mienne, pour obtenir seulement la peinture nécessaire et le code de défilement. Ce n'est qu'un exemple et en aucun cas entièrement fonctionnel ou voulu comme saint, mais il pourrait fournir une certaine inspiration:

unit Unit2;

interface

uses
  Classes, Controls, Windows, Messages, ComCtrls, Forms, Grids, Math, CommCtrl,
  SysUtils, StdCtrls, Graphics, Contnrs;

type
  TAwPlanGrid = class;

  TContainer = class(TWinControl)
  private
    procedure WMEraseBkgnd(var Message: TWMEraseBkgnd); message WM_ERASEBKGND;
  protected
    procedure CreateParams(var Params: TCreateParams); override;
    procedure PaintWindow(DC: HDC); override;
  public
    constructor Create(AOwner: TComponent); override;
  end;

  TScrollEvent = procedure(Sender: TControlScrollBar) of object;

  TScroller = class(TScrollingWinControl)
  private
    FOnScroll: TScrollEvent;
    procedure WMEraseBkgnd(var Message: TWMEraseBkgnd); message WM_ERASEBKGND;
  protected
    procedure CreateParams(var Params: TCreateParams); override;
    function DoMouseWheel(Shift: TShiftState; WheelDelta: Integer;
      MousePos: TPoint): Boolean; override;
    procedure DoScroll(AScrollBar: TControlScrollBar);
    property OnScroll: TScrollEvent read FOnScroll write FOnScroll;
  public
    constructor Create(AOwner: TComponent); override;
  end;

  TColumn = class(TCustomControl)
  private
    procedure WMEraseBkgnd(var Message: TWMEraseBkgnd); message WM_ERASEBKGND;
    procedure CMControlChange(var Message: TCMControlChange);
      message CM_CONTROLCHANGE;
  protected
    procedure Paint; override;
  public
    constructor Create(AOwner: TComponent); override;
  end;

  TTimeLineHeader = class(TCustomHeaderControl)
  protected
    procedure SectionResize(Section: THeaderSection); override;
  public
    constructor Create(AOwner: TComponent); override;
  end;

  TTimeLineGrid = class(TStringGrid)
  private
    FOnRowHeightsChanged: TNotifyEvent;
    FRowHeightsUpdating: Boolean;
  protected
    procedure Paint; override;
    procedure RowHeightsChanged; override;
    property OnRowHeightsChanged: TNotifyEvent read FOnRowHeightsChanged
      write FOnRowHeightsChanged;
  public
    constructor Create(AOwner: TComponent); override;
    function CanFocus: Boolean; override;
  end;

  TTimeLine = class(TContainer)
  private
    FHeader: TTimeLineHeader;
  protected
    TimeLineGrid: TTimeLineGrid;
  public
    constructor Create(AOwner: TComponent); override;
  end;

  THighwayHeader = class(TCustomHeaderControl)
  private
    FSectionWidth: Integer;
    procedure SetSectionWidth(Value: Integer);
  protected
    function CreateSection: THeaderSection; override;
    procedure SectionResize(Section: THeaderSection); override;
    property SectionWidth: Integer read FSectionWidth write SetSectionWidth;
  public
    procedure AddSection(const AText: String);
    constructor Create(AOwner: TComponent); override;
  end;

  THighwayScroller = class(TScroller)
  private
    procedure WMHScroll(var Message: TWMScroll); message WM_HSCROLL;
    procedure WMPaint(var Message: TWMPaint); message WM_PAINT;
    procedure WMVScroll(var Message: TWMScroll); message WM_VSCROLL;
  protected
    procedure PaintWindow(DC: HDC); override;
    procedure Resize; override;
  public
    constructor Create(AOwner: TComponent); override;
  end;

  THighwayColumn = class(TColumn)
  end;

  THighwayColumns = class(TObject)
  private
    FHeight: Integer;
    FItems: TList;
    FParent: TWinControl;
    FWidth: Integer;
    function Add: THighwayColumn;
    function GetItem(Index: Integer): THighwayColumn;
    procedure SetHeight(Value: Integer);
    procedure SetWidth(Value: Integer);
  protected
    property Height: Integer read FHeight write SetHeight;
    property Items[Index: Integer]: THighwayColumn read GetItem; default;
    property Parent: TWinControl read FParent write FParent;
    property Width: Integer read FWidth write SetWidth;
  public
    constructor Create;
    destructor Destroy; override;
  end;

  THighway = class(TContainer)
  private
    procedure HeaderSectionResized(HeaderControl: TCustomHeaderControl;
      Section: THeaderSection);
  protected
    Columns: THighwayColumns;
    Header: THighwayHeader;
    Scroller: THighwayScroller;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
  end;

  TParkingHeader = class(TCustomHeaderControl)
  protected
    procedure SectionResize(Section: THeaderSection); override;
    procedure SetParent(AParent: TWinControl); override;
  public
    constructor Create(AOwner: TComponent); override;
  end;

  TParkingScroller = class(TScroller)
  public
    constructor Create(AOwner: TComponent); override;
  end;

  TParkingColumn = class(TColumn)
  private
    FItemHeight: Integer;
    procedure SetItemHeight(Value: Integer);
  protected
    function CanAutoSize(var NewWidth, NewHeight: Integer): Boolean; override;
  public
    constructor Create(AOwner: TComponent); override;
    property ItemHeight: Integer read FItemHeight write SetItemHeight;
  end;

  TParking = class(TContainer)
  protected
    Column: TParkingColumn;
    Header: TParkingHeader;
    Scroller: TParkingScroller;
    procedure PaintWindow(DC: HDC); override;
    procedure Resize; override;
  public
    constructor Create(AOwner: TComponent); override;
  end;

  TPlanItem = class(TGraphicControl)
  protected
    procedure Paint; override;
  public
    constructor Create(AOwner: TComponent); override;
  end;

  TPlanItems = class(TList)
  public
    procedure DayHeightChanged(OldDayHeight, NewDayHeight: Integer);
  end;

  TAwPlanGrid = class(TContainer)
  private
    FDayHeight: Integer;
    FHighway: THighway;
    FParking: TParking;
    FPlanItems: TPlanItems;
    FTimeLine: TTimeLine;
    function GetColWidth: Integer;
    procedure HighwayScrolled(Sender: TControlScrollBar);
    procedure SetColWidth(Value: Integer);
    procedure SetDayHeight(Value: Integer);
    procedure TimeLineRowHeightsChanged(Sender: TObject);
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    procedure MouseWheelHandler(var Message: TMessage); override;
    procedure Test;
    property ColWidth: Integer read GetColWidth;
    property DayHeight: Integer read FDayHeight;
  end;

function GradientFill(DC: HDC; Vertex: PTriVertex; NumVertex: ULONG;
  Mesh: Pointer; NumMesh, Mode: ULONG): BOOL; stdcall; overload;
  external msimg32 name 'GradientFill';

implementation

function Round2(Value, Rounder: Integer): Integer;
begin
  if Rounder = 0 then Result := Value
  else Result := (Value div Rounder) * Rounder;
end;

// Layout:
//
// - PlanGrid
//   - TimeLine         - Highway            - Parking
//     - TimeLineHeader   - HighwayHeader      - ParkingHeader
//     - TimeLineGrid     - HighwayScroller    - ParkingScroller
//                          - HighwayColumns     - ParkingColumn
//                            - PlanItems          - PlanItems

const
  DaysPerWeek = 5;
  MaxParkingWidth = 300;
  MinColWidth = 50;
  MinDayHeight = 40;
  MinParkingWidth = 60;
  DefTimeLineWidth = 85;
  DividerColor = "151900920"99A8AC;
  DefColWidth = 100;
  DefDayHeight = 48;
  DefWeekCount = 20;

{ TContainer }

constructor TContainer.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  ControlStyle := [csOpaque];
end;

procedure TContainer.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);
  with Params.WindowClass do
    Style := Style and not (CS_HREDRAW or CS_VREDRAW);
end;

procedure TContainer.PaintWindow(DC: HDC);
begin
  { Eat inherited }
end;

procedure TContainer.WMEraseBkgnd(var Message: TWMEraseBkgnd);
begin
  Message.Result := 1;
end;

{ TScroller }

constructor TScroller.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  ControlStyle := [csOpaque];
  HorzScrollBar.Tracking := True;
  VertScrollBar.Tracking := True;
end;

procedure TScroller.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);
  with Params.WindowClass do
    Style := Style and not (CS_HREDRAW or CS_VREDRAW);
end;

function TScroller.DoMouseWheel(Shift: TShiftState; WheelDelta: Integer;
  MousePos: TPoint): Boolean;
var
  Delta: Integer;
begin
  with VertScrollBar do
  begin
    Delta := Increment;
    if WheelDelta > 0 then
      Delta := -Delta;
    if ssCtrl in Shift then
      Delta := DaysPerWeek * Delta;
    Position := Min(Round2(Range - ClientHeight, Increment), Position + Delta);
  end;
  DoScroll(VertScrollBar);
  Result := True;
end;

procedure TScroller.DoScroll(AScrollBar: TControlScrollBar);
begin
  if Assigned(FOnScroll) then
    FOnScroll(AScrollBar);
end;

procedure TScroller.WMEraseBkgnd(var Message: TWMEraseBkgnd);
begin
  Message.Result := 1;
end;

{ TColumn }

procedure TColumn.CMControlChange(var Message: TCMControlChange);
begin
  inherited;
  if Message.Inserting then
    Message.Control.Width := Width;
end;

constructor TColumn.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  ControlStyle := [csOpaque];
end;

procedure TColumn.Paint;
type
  PTriVertex = ^TTriVertex;
  TTriVertex = packed record
    X: DWORD;
    Y: DWORD;
    Red: WORD;
    Green: WORD;
    Blue: WORD;
    Alpha: WORD;
  end;
var
  Vertex: array[0..1] of TTriVertex;
  GRect: TGradientRect;
begin
  Vertex[0].X := 0;
  Vertex[0].Y := Canvas.ClipRect.Top;
  Vertex[0].Red := $DD00;
  Vertex[0].Green := $DD00;
  Vertex[0].Blue := $DD00;
  Vertex[0].Alpha := 0;
  Vertex[1].X := Width;
  Vertex[1].Y := Canvas.ClipRect.Bottom;
  Vertex[1].Red := $FF00;
  Vertex[1].Green := $FF00;
  Vertex[1].Blue := $FF00;
  Vertex[1].Alpha := 0;
  GRect.UpperLeft := 0;
  GRect.LowerRight := 1;
  GradientFill(Canvas.Handle, @Vertex, 2, @GRect, 1, GRADIENT_FILL_RECT_H);
end;

procedure TColumn.WMEraseBkgnd(var Message: TWMEraseBkgnd);
begin
  Message.Result := 1;
end;

{ TTimeLineHeader }

constructor TTimeLineHeader.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  ControlStyle := [csOpaque];
  DoubleBuffered := True;
  Sections.Add;
  Sections[0].MinWidth := 40;
  Sections[0].Width := DefTimeLineWidth;
  Sections[0].MaxWidth := DefTimeLineWidth;
  Sections[0].Text := '2011';
end;

procedure TTimeLineHeader.SectionResize(Section: THeaderSection);
begin
  if HasParent then
    Parent.Width := Section.Width;
  inherited SectionResize(Section);
end;

{ TTimeLineGrid }

function TTimeLineGrid.CanFocus: Boolean;
begin
  Result := False;
end;

constructor TTimeLineGrid.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Align := alCustom;
  Anchors := [akTop, akRight, akBottom];
  BorderStyle := bsNone;
  ColCount := 2;
  ColWidths[0] := 85;
  ControlStyle := [csOpaque];
  FixedCols := 1;
  FixedRows := 0;
  GridLineWidth := 0;
  Options := [goFixedHorzLine, goRowSizing];
  ScrollBars := ssNone;
  TabStop := False;
  Cells[0, 4] := 'Drag day height';
end;

procedure TTimeLineGrid.Paint;
begin
  inherited Paint;
  with Canvas do
    if ClipRect.Right >= Width - 1 then
    begin
      Pen.Color := DividerColor;
      MoveTo(Width - 1, ClipRect.Top);
      LineTo(Width - 1, ClipRect.Bottom);
    end;
end;

procedure TTimeLineGrid.RowHeightsChanged;
begin
  inherited RowHeightsChanged;
  if Assigned(FOnRowHeightsChanged) and (not FRowHeightsUpdating) then
    try
      FRowHeightsUpdating := True;
      FOnRowHeightsChanged(Self);
    finally
      FRowHeightsUpdating := False;
    end;
end;

{ TTimeLine }

constructor TTimeLine.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Align := alLeft;
  Width := DefTimeLineWidth;
  Height := 100;
  FHeader := TTimeLineHeader.Create(Self);
  FHeader.Parent := Self;
  TimeLineGrid := TTimeLineGrid.Create(Self);
  TimeLineGrid.RowCount := DefWeekCount * DaysPerWeek;
  TimeLineGrid.SetBounds(0, FHeader.Height, Width, Height - FHeader.Height);
  TimeLineGrid.Parent := Self;
end;

{ THighwayHeader }

procedure THighwayHeader.AddSection(const AText: String);
begin
  with THeaderSection(Sections.Add) do
    Text := AText;
end;

constructor THighwayHeader.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Align := alCustom;
  Anchors := [akLeft, akTop, akRight];
  ControlStyle := [csOpaque];
  DoubleBuffered := True;
  FullDrag := False;
end;

function THighwayHeader.CreateSection: THeaderSection;
begin
  Result := THeaderSection.Create(Sections);
  Result.MinWidth := MinColWidth;
  Result.Width := FSectionWidth;
end;

procedure THighwayHeader.SectionResize(Section: THeaderSection);
begin
  SectionWidth := Section.Width;
  inherited SectionResize(Section);
end;

procedure THighwayHeader.SetSectionWidth(Value: Integer);
var
  i: Integer;
begin
  if FSectionWidth <> Value then
  begin
    FSectionWidth := Value;
    for i := 0 to Sections.Count - 1 do
      Sections[i].Width := FSectionWidth;
  end;
end;

{ THighwayScroller }

constructor THighwayScroller.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Align := alCustom;
  Anchors := [akLeft, akTop, akRight, akBottom];
  ControlStyle := [csOpaque];
end;

procedure THighwayScroller.PaintWindow(DC: HDC);
begin
  if ControlCount > 0 then
    ExcludeClipRect(DC, 0, 0, ControlCount * Controls[0].Width,
      Controls[0].Height);
  FillRect(DC, ClientRect, Brush.Handle);
end;

procedure THighwayScroller.Resize;
begin
  with VertScrollBar do
    Position := Round2(Position, Increment);
  DoScroll(HorzScrollBar);
  DoScroll(VertScrollBar);
  inherited Resize;
end;

procedure THighwayScroller.WMHScroll(var Message: TWMScroll);
begin
  inherited;
  DoScroll(HorzScrollBar);
end;

procedure THighwayScroller.WMPaint(var Message: TWMPaint);
begin
  ControlState := ControlState + [csCustomPaint];
  inherited;
  ControlState := ControlState - [csCustomPaint];
end;

procedure THighwayScroller.WMVScroll(var Message: TWMScroll);
var
  NewPos: Integer;
begin
  NewPos := Round2(Message.Pos, VertScrollBar.Increment);
  Message.Pos := NewPos;
  inherited;
  with VertScrollBar do
    if Position <> NewPos then
      Position := Round2(Position, Increment);
  DoScroll(VertScrollBar);
end;

{ THighwayColumns }

function THighwayColumns.Add: THighwayColumn;
var
  Index: Integer;
begin
  Result := THighwayColumn.Create(nil);
  Index := FItems.Add(Result);
  Result.SetBounds(Index * FWidth, 0, FWidth, FHeight);
  Result.Parent := FParent;
end;

constructor THighwayColumns.Create;
begin
  FItems := TObjectList.Create(True);
end;

destructor THighwayColumns.Destroy;
begin
  FItems.Free;
  inherited Destroy;
end;

function THighwayColumns.GetItem(Index: Integer): THighwayColumn;
begin
  Result := FItems[Index];
end;

procedure THighwayColumns.SetHeight(Value: Integer);
var
  i: Integer;
begin
  if FHeight <> Value then
  begin
    FHeight := Value;
    for i := 0 to FItems.Count - 1 do
      Items[i].Height := FHeight;
  end;
end;

procedure THighwayColumns.SetWidth(Value: Integer);
var
  i: Integer;
begin
  if FWidth <> Value then
  begin
    FWidth := Max(MinColWidth, Value);
    for i := 0 to FItems.Count - 1 do
      with Items[i] do
        SetBounds(Left + (FWidth - Width) * i, 0, FWidth, FHeight);
  end;
end;

{ THighway }

constructor THighway.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Align := alClient;
  Width := 100;
  Height := 100;
  Header := THighwayHeader.Create(Self);
  Header.SetBounds(0, 0, Width, Header.Height);
  Header.OnSectionResize := HeaderSectionResized;
  Header.Parent := Self;
  Scroller := THighwayScroller.Create(Self);
  Scroller.SetBounds(0, Header.Height, Width, Height - Header.Height);
  Scroller.Parent := Self;
  Columns := THighwayColumns.Create;
  Columns.Parent := Scroller;
end;

destructor THighway.Destroy;
begin
  Columns.Free;
  inherited Destroy;
end;

procedure THighway.HeaderSectionResized(HeaderControl: TCustomHeaderControl;
  Section: THeaderSection);
begin
  Columns.Width := Section.Width;
  Scroller.HorzScrollBar.Increment := Columns.Width;
  Header.Left := -Scroller.HorzScrollBar.Position;
end;

{ TParkingHeader }

const
  BlindWidth = 2000;

constructor TParkingHeader.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Align := alCustom;
  Anchors := [akLeft, akTop, akRight];
  ControlStyle := [csOpaque];
  DoubleBuffered := True;
  Sections.Add;
  Sections[0].Width := BlindWidth;
  Sections.Add;
  Sections[1].AutoSize := True;
  Sections[1].Text := 'Parked';
end;

procedure TParkingHeader.SectionResize(Section: THeaderSection);
begin
  if (Section.Index = 0) and HasParent then
  begin
    Parent.Width := Max(MinParkingWidth,
      Min(Parent.Width - Section.Width + BlindWidth, MaxParkingWidth));
    Section.Width := BlindWidth;
    Sections[1].Width := Parent.Width - 2;
  end;
  inherited SectionResize(Section);
end;

procedure TParkingHeader.SetParent(AParent: TWinControl);
begin
  inherited SetParent(AParent);
  if HasParent then
  begin
    SetBounds(-BlindWidth + 2, 0, BlindWidth + Parent.Width, Height);
    Sections[1].Width := Parent.Width - 2;
  end;
end;

{ TParkingScroller }

constructor TParkingScroller.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Align := alCustom;
  Anchors := [akLeft, akTop, akRight, akBottom];
  ControlStyle := [csOpaque];
  HorzScrollBar.Visible := False;
  VertScrollBar.Increment := DefDayHeight;
end;

{ TParkingColumn }

function TParkingColumn.CanAutoSize(var NewWidth, NewHeight: Integer): Boolean;
begin
  if HasParent then
    NewHeight := Max(Parent.Height, ControlCount * FItemHeight);
  Result := True;
end;

constructor TParkingColumn.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Align := alTop;
  AutoSize := True;
  FItemHeight := DefDayHeight;
end;

procedure TParkingColumn.SetItemHeight(Value: Integer);
var
  i: Integer;
begin
  if FItemHeight <> Value then
  begin
    FItemHeight := Value;
    for i := 0 to ControlCount - 1 do
      Controls[i].Height := FItemHeight;
    TScroller(Parent).VertScrollBar.Increment := FItemHeight;
  end;
end;

{ TParking }

constructor TParking.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Align := alRight;
  Width := 120;
  Height := 100;
  Header := TParkingHeader.Create(Self);
  Header.Parent := Self;
  Scroller := TParkingScroller.Create(Self);
  Scroller.SetBounds(1, Header.Height, Width, Height - Header.Height);
  Scroller.Parent := Self;
  Column := TParkingColumn.Create(Self);
  Column.Parent := Scroller;
end;

procedure TParking.PaintWindow(DC: HDC);
var
  R: TRect;
begin
  Brush.Color := DividerColor;
  SetRect(R, 0, Header.Height, 1, Height);
  FillRect(DC, R, Brush.Handle);
end;

procedure TParking.Resize;
begin
  Column.AdjustSize;
  inherited Resize;
end;

{ TPlanItem }

constructor TPlanItem.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Anchors := [akLeft, akTop, akRight];
  ControlStyle := [csOpaque];
  Color := Random(clWhite);
end;

procedure TPlanItem.Paint;
begin
  Canvas.Brush.Color := Color;
  Canvas.FillRect(Canvas.ClipRect);
end;

{ TPlanItems }

procedure TPlanItems.DayHeightChanged(OldDayHeight, NewDayHeight: Integer);
var
  i: Integer;
begin
  for i := 0 to Count - 1 do
    with TPlanItem(Items[i]) do
      if not (Parent is TParkingColumn) then
      begin
        Top := Trunc(Top * (NewDayHeight / OldDayHeight));
        Height := Trunc(Height * (NewDayHeight / OldDayHeight));
      end;
end;

{ TAwPlanGrid }

constructor TAwPlanGrid.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  ControlStyle := [csOpaque];
  TabStop := True;
  Width := 400;
  Height := 200;
  FTimeLine := TTimeLine.Create(Self);
  FTimeLine.TimeLineGrid.OnRowHeightsChanged := TimeLineRowHeightsChanged;
  FTimeLine.Parent := Self;
  FParking := TParking.Create(Self);
  FParking.Parent := Self;
  FHighway := THighway.Create(Self);
  FHighway.Scroller.OnScroll := HighwayScrolled;
  FHighway.Parent := Self;
  FPlanItems := TPlanItems.Create;
  SetColWidth(DefColWidth);
  SetDayHeight(DefDayHeight);
  FHighway.Columns.Height := DefWeekCount * DaysPerWeek * FDayHeight;
end;

destructor TAwPlanGrid.Destroy;
begin
  FPlanItems.Free;
  inherited Destroy;
end;

function TAwPlanGrid.GetColWidth: Integer;
begin
  Result := FHighway.Columns.Width;
end;

procedure TAwPlanGrid.HighwayScrolled(Sender: TControlScrollBar);
begin
  if Sender.Kind = sbVertical then
    FTimeLine.TimeLineGrid.TopRow := Sender.Position div FDayHeight
  else
  begin
    FHighway.Header.Left := -Sender.Position;
    FHighway.Header.Width := FHighway.Width + Sender.Position;
  end;
end;

procedure TAwPlanGrid.MouseWheelHandler(var Message: TMessage);
var
  X: Integer;
begin
  with Message do
  begin
    X := ScreenToClient(SmallPointToPoint(TCMMouseWheel(Message).Pos)).X;
    if X >= FParking.Left then
      Result := FParking.Scroller.Perform(CM_MOUSEWHEEL, WParam, LParam)
    else
      Result := FHighway.Scroller.Perform(CM_MOUSEWHEEL, WParam, LParam);
  end;
  if Message.Result = 0 then
    inherited MouseWheelHandler(Message);
end;

procedure TAwPlanGrid.SetColWidth(Value: Integer);
begin
  if ColWidth <> Value then
  begin
    FHighway.Columns.Width := Value;
    FHighway.Header.SectionWidth := ColWidth;
    FHighway.Scroller.HorzScrollBar.Increment := ColWidth;
  end;
end;

procedure TAwPlanGrid.SetDayHeight(Value: Integer);
var
  OldDayHeight: Integer;
begin
  if FDayHeight <> Value then
  begin
    OldDayHeight := FDayHeight;
    FDayHeight := Max(MinDayHeight, Round2(Value, 4));
    FTimeLine.TimeLineGrid.DefaultRowHeight := FDayHeight;
    FHighway.Columns.Height := DefWeekCount * DaysPerWeek * FDayHeight;
    FHighway.Scroller.VertScrollBar.Increment := FDayHeight;
    FPlanItems.DayHeightChanged(OldDayHeight, FDayHeight);
  end;
end;

procedure TAwPlanGrid.Test;
var
  i: Integer;
  PlanItem: TPlanItem;
begin
  Randomize;
  Anchors := [akLeft, akTop, akBottom, akRight];
  for i := 0 to 3 do
    FHighway.Columns.Add;
  FHighway.Header.AddSection('Drag col width');
  FHighway.Header.AddSection('Column 2');
  FHighway.Header.AddSection('Column 3');
  FHighway.Header.AddSection('Column 4');
  for i := 0 to 9 do
  begin
    PlanItem := TPlanItem.Create(Self);
    PlanItem.Parent := FParking.Column;
    PlanItem.Top := i * DefDayHeight;
    PlanItem.Height := DefDayHeight;
    FPlanItems.Add(PlanItem);
  end;
  for i := 0 to 3 do
  begin
    PlanItem := TPlanItem.Create(Self);
    PlanItem.Parent := FHighway.Columns[i];
    PlanItem.Top := (i + 3) * DefDayHeight;
    PlanItem.Height := DefDayHeight;
    FPlanItems.Add(PlanItem);
  end;
  SetFocus;
end;

procedure TAwPlanGrid.TimeLineRowHeightsChanged(Sender: TObject);
var
  iRow: Integer;
begin
  with FTimeLine.TimeLineGrid do
    for iRow := 0 to RowCount - 1 do
      if RowHeights[iRow] <> DefaultRowHeight then
      begin
        SetDayHeight(RowHeights[iRow]);
        Break;
      end;
end;

end.

code D'essai:

with TAwPlanGrid.Create(Self) do
begin
  SetBounds(10, 100, 600, 400);
  Parent := Self;
  Test;
end;

My 2 cts.

j'ai vu l'argument, et essayer de l'employer dans la pratique, que vous ne devriez jamais dessiner sur les mêmes pixels plus d'une fois.

Si vous dessinez un carré rouge sur un fond blanc puis vous peindre tout en blanc sauf lorsque le carré rouge , de "combler" le carré rouge:

il n'y a pas de clignotant, et vous faites moins d'opérations de dessin.

qui est un exemple extrême de invalider seulement ce que vous avez à , comme dthorp mentions . Si vous faites défiler un contrôle, utilisez ScrollWindow pour que le sous-système graphique déplace ce qui est déjà là, et puis juste remplissez le bit manquant en bas.

il va y avoir des moments où vous ont pour peindre le même pixels plusieurs fois; le texte ClearType est le meilleur exemple. Le rendu ClearType nécessite l'accès aux pixels ci - dessous-ce qui signifie que vous allez à avoir pour remplir une zone avec du blanc, puis dessiner votre texte dessus.

mais même cela peut généralement être atténué en mesurant le rects du texte que vous allez rendre, remplir clWhite partout autrement , puis avoir DrawText remplir zones de vide - à l'aide d'un blanc HBRUSH contexte:

mais cette astuce ne peut pas fonctionner lorsque vous dessinez du texte sur un gradient, ou du contenu existant arbitraire - il y aura donc flicker. Dans ce cas, vous devez doubler le tampon d'une façon ou d'une autre. (Bien que ne doublez pas la mémoire tampon si l'utilisateur est dans une session distante - clignoter est mieux que le dessin lent).

Bavardage Bonus : maintenant que j'ai expliqué pourquoi vous ne devriez pas doubler le contenu de la mémoire tampon lorsque l'utilisateur tourne sur le bureau distant (C'est-à-dire les services de Terminal), vous savez maintenant ce que cette option avancée D'Internet Explorer signifie, ce qu'elle fait, et pourquoi elle est désactivée par défaut: