9

我觉得到目前为止我的失败在于搜索词，因为这方面的信息必须非常普遍。基本上，我正在寻找在调整表单大小时对多个组件执行调整大小的通用解决方案和最佳实践。

我有一个带有基于TScrollBox. ScrollBox 包含在运行时动态添加的行。它们基本上是一个子组件。每个人在左边都有一个图像，在右边有一个备忘录。高度是根据图像的宽度和纵横比设置的。在调整滚动框的大小时，循环设置行的宽度，触发行自己的内部调整大小。如果高度发生变化，循环还会设置相对顶部位置。

截屏：

在此处输入图像描述

大约 16 行表现良好。我的目标是接近 32 行，这非常不稳定，并且可以将核心固定在 100% 的使用率。

我努力了：

  • 添加了一项检查以防止在前一个尚未完成时开始新的调整大小。它会回答是否发生并且有时会发生。
  • 我尝试阻止它比每 30 毫秒更频繁地调整大小，这将允许每秒绘制 30 帧。结果好坏参半。
  • 将行基础组件从 TPanel 更改为 TWinControl。不确定使用面板是否会降低性能，但这是一个旧习惯。
  • 有和没有双重缓冲。

我想允许在调整大小期间进行行大小调整，以预览图像在行中的大小。这消除了一个明显的解决方案，该解决方案在某些应用程序中是可接受的损失。

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尺寸。接下来我打算尝试根据集合中最大的图像基本上指定纵横比、最大宽度/高度。这应该会减少每行的数学量。但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.

行代码：

unit rPBSSROW;

interface

uses
  Classes, Controls, Forms, ExtCtrls, StdCtrls, Graphics, 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(0,0,100,100);
    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(2,5,5,2);
    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.
4

2 回答 2

11

一些提示：

  • TWinControl已经是一个容器，您不需要在其中添加另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，或者在我下面的示例控件中TCustomControl，
  • 由于所有其他面板都无法识别（边框和斜面被禁用），完全松开它们并将其TMemo直接放在行控件上，
  • SetSubComponent仅用于设计时使用。你不需要它。也不是Register这件事的程序。
  • 将全局行数组放在类定义中，否则多个TPBSSView控件将使用同一个数组！
  • TWinControl已经跟踪了它的所有子控件，所以无论如何您都不需要数组，请参见下面的示例，
  • 利用该Align属性使您免于手动重新对齐，
  • 如果备忘录控件仅用于显示文本，则将其删除并自己绘制文本。

试试这个：

unit PBSSView;

interface

uses
  Windows, Messages, Classes, Controls, SysUtils, Graphics, ExtCtrls, StdCtrls,
  Forms, 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, 0, ImageWidth, ImageHeight), FGraphic);
  SetRect(R, ImageWidth, 0, 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, Width, 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, Width, 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.

截屏

如果这仍然表现不佳，那么可能有多种其他增强功能。

更新：

  • 通过覆盖/拦截WM_ERASEBKGND（PaintWindow对于版本 < XE2 的拦截）消除闪烁，
  • 通过使用DisableAlign和获得更好的性能EnableAlign。
于 2013-05-15T15:35:24.253 回答
3

我不知道这是否会产生重大影响，而是分别设置 PBSSRow[I].Width 和 PBSSRow[I].Top ，而是调用 PBSSRow[I].SetBounds 。这将为您节省该 SubComponent 的一个 Resize 事件。

于 2013-05-15T15:48:07.253 回答