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delphi – 性能问题重新调整表单大小上的大量组件

发布时间：2020-12-15 04:32:23 所属栏目：大数据 来源：网络整理
导读：我觉得我的失败到目前为止在于搜索术语,因为这方面的信息必须很常见.在调整表单时,基本上我正在寻找常用的解决方案和最佳实践. 我有一个基于TScrollBox的组件的表单. ScrollBox包含在运行时动态添加的行.它们基本上是一个子组件.每个人都有左边的图像和右边
我觉得我的失败到目前为止在于搜索术语,因为这方面的信息必须很常见.在调整表单时,基本上我正在寻找常用的解决方案和最佳实践.

我有一个基于TScrollBox的组件的表单. ScrollBox包含在运行时动态添加的行.它们基本上是一个子组件.每个人都有左边的图像和右边的备忘录.基于图像的宽高比设置高度.在滚动框的大小调整后,循环设置触发行自身内部调整大小的行的宽度.如果高度已经改变,循环也会设置相对的顶部位置.

屏幕截图：

大约16行执行正常.我的目标是更接近32排,这是非常波动,可以钉在100％使用的核心.

我努力了：

>添加了一个支票,以防止在前一个尚未完成时启动新的调整大小.它回答了它是否发生,有时它.
>我试图阻止它每30ms更多地调整大小,这将允许每秒30帧的绘图.混合结果.
>将行基??础组件从TPanel更改为TWinControl.不知道使用小组是否有性能损失,但它是一种老习惯.
>有和没有双缓冲.

我想允许在调整大小期间进行行调整大小,作为预览图像的大小.这消除了在一些应用中是可接受的损失的一个明显的解决方案.

现在,该行内部的调整大小代码是完全动态的,并且基于每个图像的维度.我打算尝试的下一件事是基于集合中最大的图像基本指定纵横比,最大宽度/高度.这应该减少每行的数学量.但是,似乎问题更多的是调整大小事件和循环本身？

组件的完整单元代码：

unit rPBSSVIEW;

interface

uses
  Classes,Controls,Forms,ExtCtrls,StdCtrls,Graphics,SysUtils,rPBSSROW,Windows,Messages;

type
  TPBSSView = class(TScrollBox)
  private    
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    procedure ResizeRows(Sender: TObject);
    procedure AddRow(FileName: String);
    procedure FillRow(Row: Integer; ImageStream: TMemoryStream);
  end;

var
  PBSSrow: Array of TPBSSRow;
  Resizingn: Boolean;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('Standard',[TScrollBox]);
end;

procedure TPBSSView.AddRow(FileName: String);
begin
  SetLength(PBSSrow,(Length(PBSSrow) + 1));
  PBSSrow[Length(PBSSrow)-1] := TPBSSRow.create(self);
  With PBSSrow[Length(PBSSrow)-1] do
  begin
    Left := 2;
    if (Length(PBSSrow)-1) = 0 then Top := 2 else Top := ((PBSSRow[Length(PBSSRow) - 2].Top + PBSSRow[Length(PBSSRow) - 2].Height) + 2);
    Width := (inherited ClientWidth - 4);
    Visible := True;
    Parent := Self;
    PanelLeft.Caption := FileName;
  end;
end;

procedure TPBSSView.FillRow(Row: Integer; ImageStream: TMemoryStream);
begin
  PBSSRow[Row].LoadImageFromStream(ImageStream);
end;

procedure TPBSSView.ResizeRows(Sender: TObject);
var
  I,X: Integer;
begin
  if Resizingn then exit
  else
  begin
      Resizingn := True;
      HorzScrollBar.Visible := False;
      X := (inherited ClientWidth - 4);
      if Length(PBSSrow) > 0 then
      for I := 0 to Length(PBSSrow) - 1 do
      Begin
        PBSSRow[I].Width := X; //Set Width
        if not (I = 0) then      //Move all next ones down.
          begin
            PBSSRow[I].Top := (PBSSRow[(I - 1)].Top + PBSSRow[(I - 1)].Height) + 2;
          end;
        Application.ProcessMessages;
      End;
    HorzScrollBar.Visible := True;
    Resizingn := False;
  end;
end;

constructor TPBSSView.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  OnResize := ResizeRows;
  DoubleBuffered := True;
  VertScrollBar.Tracking := True;
  Resizingn := False;
end;

destructor TPBSSView.Destroy;
begin
  inherited;
end;

end.

行号：

unit rPBSSROW;

interface

uses
  Classes,pngimage,SysUtils;

type
  TPBSSRow = class(TWinControl)
  private
    FImage: TImage;
    FPanel: TPanel;
    FMemo: TMemo;
    FPanelLeft: TPanel;
    FPanelRight: TPanel;
    FImageWidth: Integer;
    FImageHeight: Integer;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    procedure MyPanelResize(Sender: TObject);
    procedure LeftPanelResize(Sender: TObject);
  published
    procedure LoadImageFromStream(ImageStream: TMemoryStream);
    property Image: TImage read FImage;
    property Panel: TPanel read FPanel;
    property PanelLeft: TPanel read FPanelLeft;
    property PanelRight: TPanel read FPanelRight;
  end;

procedure Register;    

implementation

procedure Register;
begin
  RegisterComponents('Standard',[TWinControl]);
end;

procedure TPBSSRow.MyPanelResize(Sender: TObject);
begin
  if (Width - 466) <= FImageWidth then FPanelLeft.Width := (Width - 466)
else FPanelLeft.Width := FImageWidth;
  FPanelRight.Width := (Width - FPanelLeft.Width);
end;

procedure TPBSSRow.LeftPanelResize(Sender: TObject);
var
  AspectRatio: Extended;
begin
  FPanelRight.Left := (FPanelLeft.Width);
  //Enforce Info Minimum Height or set Height
  if FImageHeight > 0 then  AspectRatio := (FImageHeight/FImageWidth) else
  AspectRatio := 0.4;
  if (Round(AspectRatio * FPanelLeft.Width)) >= 212 then
  begin
    Height := (Round(AspectRatio * FPanelLeft.Width));
    FPanelLeft.Height := Height;
    FPanelRight.Height := Height;
  end
  else
  begin
    Height :=212;
    FPanelLeft.Height := Height;
    FPanelRight.Height := Height;
  end;
  if Fimage.Height >= FImageHeight then FImage.Stretch := False else Fimage.Stretch := True;
  if Fimage.Width >= FImageWidth then FImage.Stretch := False else Fimage.Stretch := True;
end;

procedure TPBSSRow.LoadImageFromStream(ImageStream: TMemoryStream);
var
  P: TPNGImage;
  n: Integer;
begin
  P := TPNGImage.Create;
  ImageStream.Position := 0;
  P.LoadFromStream(ImageStream);
  FImage.Picture.Assign(P);
  FImageWidth := P.Width;
  FImageHeight := P.Height;
end;

constructor TPBSSRow.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
    BevelInner := bvNone;
    BevelOuter := bvNone;
    BevelKind :=  bkNone;
    Color := clWhite;
    OnResize := MyPanelResize;
    DoubleBuffered := True;
  //Left Panel for Image
  FPanelLeft := TPanel.Create(Self);
  with FPanelLeft do
  begin
    SetSubComponent(true);
    Align := alLeft;
    Parent := Self;
    //SetBounds(0,100,100);
    ParentBackground := False;
    Color := clBlack;
    Font.Color := clLtGray;
    Constraints.MinWidth := 300;
    BevelInner := bvNone;
    BevelOuter := bvNone;
    BevelKind :=  bkNone;
    BorderStyle := bsNone;
    OnResize := LeftPanelResize;
  end;
  //Image for left panel
  FImage := TImage.Create(Self);
  FImage.SetSubComponent(true);
  FImage.Align := alClient;
  FImage.Parent := FPanelLeft;
  FImage.Center := True;
  FImage.Stretch := True;
  FImage.Proportional := True;
  //Right Panel for Info
  FPanelRight := TPanel.Create(Self);
  with FPanelRight do
  begin
    SetSubComponent(true);
    Parent := Self;
    Padding.SetBounds(2,5,2);
    BevelInner := bvNone;
    BevelOuter := bvNone;
    BevelKind :=  bkNone;
    BorderStyle := bsNone;
    Color := clLtGray;
  end;

  //Create Memo in Right Panels
  FMemo := TMemo.create(self);
  with FMemo do
  begin
    SetSubComponent(true);
    Parent := FPanelRight;
    Align := alClient;
    BevelOuter := bvNone;
    BevelInner := bvNone;
    BorderStyle := bsNone;
    Color := clLtGray;
  end;

end;

destructor TPBSSRow.Destroy;
begin
  inherited;
end;

end.

解决方法

几个提示：

> TWinControl已经是一个容器,你不需要另外一个面板来添加控件
>您不需要TImage组件来查看图形,也可以使用TPaintBox,或者在下面的示例控件中,TCustomControl,
>由于您的所有其他面板都不可识别(边框和斜面被禁用),完全松开它们,并将TMemo直接放在行控件上,
> SetSubComponent仅用于设计时间的使用.你不需要它也不是注册程序.
将全局行数组放在类定义中,否则多个TPBSSView控件将使用相同的数组！
> TWinControl已经跟踪了它的所有子控件,所以你不需要数组,看我下面的例子,
>使用Align属性来保存您手动重新对齐,
>如果备忘录控件仅用于显示文本,则将其删除并自行绘制文本.

尝试这个开始：

unit PBSSView;

interface

uses
  Windows,Messages,Classes,PngImage;

type
  TPBSSRow = class(TCustomControl)
  private
    FGraphic: TPngImage;
    FStrings: TStringList;
    function ImageHeight: Integer; overload;
    function ImageHeight(ControlWidth: Integer): Integer; overload;
    function ImageWidth: Integer; overload;
    function ImageWidth(ControlWidth: Integer): Integer; overload;
    procedure WMEraseBkgnd(var Message: TWmEraseBkgnd); message WM_ERASEBKGND;
    procedure WMWindowPosChanging(var Message: TWMWindowPosChanging);
      message WM_WINDOWPOSCHANGING;
  protected
    procedure Paint; override;
    procedure RequestAlign; override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    procedure LoadImageFromStream(Stream: TMemoryStream);
    property Strings: TStringList read FStrings;
  end;

  TPBSSView = class(TScrollBox)
  private
    function GetRow(Index: Integer): TPBSSRow;
    procedure WMEnterSizeMove(var Message: TMessage); message WM_ENTERSIZEMOVE;
    procedure WMEraseBkgnd(var Message: TWmEraseBkgnd); message WM_ERASEBKGND;
    procedure WMExitSizeMove(var Message: TMessage); message WM_EXITSIZEMOVE;
  protected
    procedure PaintWindow(DC: HDC); override;
  public
    constructor Create(AOwner: TComponent); override;
    procedure AddRow(const FileName: TFileName);
    procedure FillRow(Index: Integer; ImageStream: TMemoryStream);
    property Rows[Index: Integer]: TPBSSRow read GetRow;
  end;

implementation

{ TPBSSRow }

constructor TPBSSRow.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Width := 300;
  Height := 50;
  FStrings := TStringList.Create;
end;

destructor TPBSSRow.Destroy;
begin
  FStrings.Free;
  FGraphic.Free;
  inherited Destroy;
end;

function TPBSSRow.ImageHeight: Integer;
begin
  Result := ImageHeight(Width);
end;

function TPBSSRow.ImageHeight(ControlWidth: Integer): Integer;
begin
  if (FGraphic <> nil) and not FGraphic.Empty then
    Result := Round(ImageWidth(ControlWidth) * FGraphic.Height / FGraphic.Width)
  else
    Result := Height;
end;

function TPBSSRow.ImageWidth: Integer;
begin
  Result := ImageWidth(Width);
end;

function TPBSSRow.ImageWidth(ControlWidth: Integer): Integer;
begin
  Result := ControlWidth div 2;
end;

procedure TPBSSRow.LoadImageFromStream(Stream: TMemoryStream);
begin
  FGraphic.Free;
  FGraphic := TPngImage.Create;
  Stream.Position := 0;
  FGraphic.LoadFromStream(Stream);
  Height := ImageHeight + Padding.Bottom;
end;

procedure TPBSSRow.Paint;
var
  R: TRect;
begin
  Canvas.StretchDraw(Rect(0,ImageWidth,ImageHeight),FGraphic);
  SetRect(R,Width,ImageHeight);
  Canvas.FillRect(R);
  Inc(R.Left,10);
  DrawText(Canvas.Handle,FStrings.Text,-1,R,DT_EDITCONTROL or
    DT_END_ELLIPSIS or DT_NOFULLWIDTHCHARBREAK or DT_NOPREFIX or DT_WORDBREAK);
  Canvas.FillRect(Rect(0,ImageHeight,Height));
end;

procedure TPBSSRow.RequestAlign;
begin
  {eat inherited}
end;

procedure TPBSSRow.WMEraseBkgnd(var Message: TWmEraseBkgnd);
begin
  Message.Result := 1;
end;

procedure TPBSSRow.WMWindowPosChanging(var Message: TWMWindowPosChanging);
begin
  inherited;
  if (FGraphic <> nil) and not FGraphic.Empty then
    Message.WindowPos.cy := ImageHeight(Message.WindowPos.cx) + Padding.Bottom;
end;

{ TPBSSView }

procedure TPBSSView.AddRow(const FileName: TFileName);
var
  Row: TPBSSRow;
begin
  Row := TPBSSRow.Create(Self);
  Row.Align := alTop;
  Row.Padding.Bottom := 2;
  Row.Parent := Self;
end;

constructor TPBSSView.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  VertScrollBar.Tracking := True;
end;

procedure TPBSSView.FillRow(Index: Integer; ImageStream: TMemoryStream);
begin
  Rows[Index].LoadImageFromStream(ImageStream);
end;

function TPBSSView.GetRow(Index: Integer): TPBSSRow;
begin
  Result := TPBSSRow(Controls[Index]);
end;

procedure TPBSSView.PaintWindow(DC: HDC);
begin
  {eat inherited}
end;

procedure TPBSSView.WMEnterSizeMove(var Message: TMessage);
begin
  if not AlignDisabled then
    DisableAlign;
  inherited;
end;

procedure TPBSSView.WMEraseBkgnd(var Message: TWmEraseBkgnd);
var
  DC: HDC;
begin
  DC := GetDC(Handle);
  try
    FillRect(DC,Rect(0,VertScrollBar.Range,Height),Brush.Handle);
  finally
    ReleaseDC(Handle,DC);
  end;
  Message.Result := 1;
end;

procedure TPBSSView.WMExitSizeMove(var Message: TMessage);
begin
  inherited;
  if AlignDisabled then
    EnableAlign;
end;

end.

如果仍然表现不佳,那么还有其他多项增强功能可能.

更新：

>通过覆盖/拦截WM_ERASEBKGND(并拦截版本< XE2的PaintWindow)来消除闪烁,
通过使用DisableAlign和EnableAlign来提高性能.

（编辑：李大同）

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