为了好玩，我为你写了一个 ImageGrid 组件。
它只有一个垂直滚动条；调整控件的宽度会调整列数和行数。图像在内部列表中缓存为调整大小的位图，以及它们的文件名。
因为加载和重采样这些图像可能需要一些时间，具体取决于图像数量、分辨率以及您是否要使用 Graphics32 库来获得更好的重采样质量，因此该组件将加载过程委托给一个单独的线程，该线程（重新）运行关于设置列宽或行高，以及更改文件名或文件夹路径，组件尝试在其中查找要在 FileFormats 属性中提供的所有类型的图像。
特点：
- 在后台线程中创建图像缩略图并调整其大小，使用 GDI+ 库从文件名或使用 Graphics 32 库手动添加的图像
- 自动识别所有注册的图像文件格式
- 动画滚动
- 触摸屏支持通过拖动网格进行滚动
- 键盘支持选择拇指
- OwnerDraw 支持，例如为拇指添加标题
- 虚拟支持绕过自动创建拇指
属性和事件：
-
ColCount: 列数，只读
-
Count: 图片数量，只读
-
Images：在内部创建拇指的所有手动添加图像的列表
-
Items：所有文件名-缩略图或图像-缩略图组合的列表
-
RowCount: 行数，只读
-
Thumbs：所有内部创建的拇指列表
-
AutoHideScrollBar：当所有行都可见时隐藏滚动条
-
BorderStyle: 显示或隐藏主题边框
-
BorderWidth: 组件的外边距，在滚动条之外
-
CellAlignment：在单元格的左侧、中心或右侧对齐拇指
-
CellHeight: 单元格高度
-
CellLayout：在单元格的顶部、中间或底部对齐拇指
-
CellSpacing: 单元格间距
-
CellWidth: 单元格宽度
-
Color: 边框背景颜色和单元格间距
-
ColWidth: 列宽（等于单元格宽度加上单元格间距）
-
DefaultDrawing：默认绘制所有拇指
-
DesignPreview：在设计器中显示拇指
-
DragScroll：支持通过拖动网格来滚动网格
-
FileFormats: 过滤文件名的图片文件扩展名
-
FileNames: 包含所有文件名的列表
-
Folder: 组件试图查找所有图片文件的目录
-
ItemIndex: 选定单元格索引
-
MarkerColor：加载过程中临时拇指标记的颜色
-
MarkerStyle: 加载过程中临时拇指标记的样式
-
OnClickCell：点击单元格时触发
-
OnDrawCell: 绘制单元格时触发
-
OnMeasureThumb：在计算拇指大小时触发
-
OnProgress：当图像大小调整为拇指格式时触发
-
OnUnresolved：当无法创建拇指时触发，例如找不到文件名时
-
RetainUnresolvedItems：在列表中保留空拇指
-
RowHeight：行高（等于单元格高度加上单元格间距）
-
ParentBackground：在边框和单元格之间绘制父级的（主题）背景
-
Proportional：按比例调整图片大小
-
Sorted：文件名已排序
-
Stretch：将小图像拉伸到单元格大小
-
VirtualMode：防止自动创建拇指
-
WheelScrollLines: 鼠标滚轮滚动的行数
感谢：
代码太长，无法在此处发布，但开源项目可从GitHub server here 下载。这是界面部分：
unit AwImageGrid;
interface
{$DEFINE USE_GR32}
uses
Windows, Classes, SysUtils, Messages, Controls, Graphics, Forms, StdCtrls,
Grids, GDIPAPI, GDIPOBJ, RTLConsts, Math, Themes
{$IFDEF USE_GR32}, GR32, GR32_Resamplers {$ENDIF};
const
DefCellSpacing = 5;
DefCellWidth = 96;
DefCellHeight = 60;
DefColWidth = DefCellWidth + DefCellSpacing;
DefRowHeight = DefCellHeight + DefCellSpacing;
MinThumbSize = 4;
MinCellSize = 8;
type
PImageGridItem = ^TImageGridItem;
TImageGridItem = record
FFileName: TFileName;
FObject: TObject;
FImage: TGraphic;
FThumb: TBitmap;
end;
PImageGridItemList = ^TImageGridItemList;
TImageGridItemList = array[0..MaxListSize div 2] of TImageGridItem;
{ TImageGridItems
The managing object for holding filename-thumbnail or image-thumbnail
combinations in an array of TImageGridItem elements. When an item's image
changes, the item's thumb is freed. When an item's filename changes, then
the item's thumb is freed only if the item's image is unassigned. }
TImageGridItems = class(TStrings)
private
FCapacity: Integer;
FChanged: Boolean;
FCount: Integer;
FList: PImageGridItemList;
FOnChanged: TNotifyEvent;
FOnChanging: TNotifyEvent;
FOwnsObjects: Boolean;
FSorted: Boolean;
procedure ExchangeItems(Index1, Index2: Integer);
function GetImage(Index: Integer): TGraphic;
function GetThumb(Index: Integer): TBitmap;
procedure Grow;
procedure InsertItem(Index: Integer; const S: String; AObject: TObject;
AImage: TGraphic; AThumb: TBitmap);
procedure PutImage(Index: Integer; AImage: TGraphic);
procedure PutThumb(Index: Integer; AThumb: TBitmap);
procedure QuickSort(L, R: Integer);
procedure SetSorted(Value: Boolean);
protected
function CompareStrings(const S1, S2: String): Integer; override;
procedure Changed; virtual;
procedure Changing; virtual;
function Get(Index: Integer): String; override;
function GetCapacity: Integer; override;
function GetCount: Integer; override;
function GetObject(Index: Integer): TObject; override;
procedure Put(Index: Integer; const S: String); override;
procedure PutObject(Index: Integer; AObject: TObject); override;
procedure PutThumbSilently(Index: Integer; AThumb: TBitmap); virtual;
procedure SetCapacity(Value: Integer); override;
procedure SetUpdateState(Updating: Boolean); override;
public
function Add(const S: String): Integer; override;
function AddImage(const S: String; AImage: TGraphic): Integer; virtual;
function AddItem(const S: String; AObject: TObject; AImage: TGraphic;
AThumb: TBitmap): Integer; virtual;
function AddObject(const S: String; AObject: TObject): Integer; override;
function AddThumb(const S: String; AThumb: TBitmap): Integer; virtual;
procedure AddStrings(Strings: TStrings); override;
procedure Assign(Source: TPersistent); override;
procedure Clear; override;
procedure ClearThumbs; virtual;
procedure Delete(Index: Integer); override;
destructor Destroy; override;
procedure Exchange(Index1, Index2: Integer); override;
function IndexOf(const S: String): Integer; override;
procedure Insert(Index: Integer; const S: String); override;
procedure InsertObject(Index: Integer; const S: String;
AObject: TObject); override;
function Find(const S: String; var Index: Integer): Boolean;
procedure Sort; virtual;
property FileNames[Index: Integer]: String read Get write Put;
property Images[Index: Integer]: TGraphic read GetImage write PutImage;
property OnChanged: TNotifyEvent read FOnChanged write FOnChanged;
property OnChanging: TNotifyEvent read FOnChanging write FOnChanging;
property OwnsObjects: Boolean read FOwnsObjects write FOwnsObjects;
property Sorted: Boolean read FSorted write SetSorted;
property Thumbs[Index: Integer]: TBitmap read GetThumb write PutThumb;
end;
{ TBorderControl
A control with a system drawn border following the current theme, and an
additional margin as implemented by TWinControl.BorderWidth. }
TBorderControl = class(TCustomControl)
private
FBorderStyle: TBorderStyle;
procedure SetBorderStyle(Value: TBorderStyle);
procedure WMNCPaint(var Message: TWMNCPaint); message WM_NCPAINT;
procedure CMCtl3DChanged(var Message: TMessage); message CM_CTL3DCHANGED;
protected
procedure CreateParams(var Params: TCreateParams); override;
function TotalBorderWidth: Integer; virtual;
public
constructor Create(AOwner: TComponent); override;
property BorderStyle: TBorderStyle read FBorderStyle write SetBorderStyle
default bsSingle;
property BorderWidth;
end;
{ TAnimRowScroller
A scroll box with a vertical scroll bar and vertically stacked items with a
fixed row height. Scrolling with the scroll bar is animated alike Windows'
own default list box control. Scrolling is also possible by dragging the
content with the left mouse button. }
TAnimRowScroller = class(TBorderControl)
private
FAutoHideScrollBar: Boolean;
FDragScroll: Boolean;
FDragScrolling: Boolean;
FDragSpeed: Single;
FDragStartPos: Integer;
FPrevScrollPos: Integer;
FPrevTick: Cardinal;
FRow: Integer;
FRowCount: Integer;
FRowHeight: Integer;
FScrollingPos: Integer;
FScrollPos: Integer;
FWheelScrollLines: Integer;
procedure Drag;
function IsWheelScrollLinesStored: Boolean;
procedure Scroll;
procedure SetAutoHideScrollBar(Value: Boolean);
procedure SetRow(Value: Integer);
procedure SetRowCount(Value: Integer);
procedure SetScrollPos(Value: Integer; Animate, Snap: Boolean);
procedure UpdateScrollBar;
procedure WMVScroll(var Message: TWMVScroll); message WM_VSCROLL;
protected
procedure CreateWnd; override;
function DoMouseWheel(Shift: TShiftState; WheelDelta: Integer;
MousePos: TPoint): Boolean; override;
procedure DrawFocusRect; virtual;
procedure MouseDown(Button: TMouseButton; Shift: TShiftState; X,
Y: Integer); override;
procedure MouseMove(Shift: TShiftState; X, Y: Integer); override;
procedure MouseUp(Button: TMouseButton; Shift: TShiftState; X,
Y: Integer); override;
procedure Resize; override;
procedure SetRowHeight(Value: Integer); virtual;
procedure WndProc(var Message: TMessage); override;
property AutoHideScrollBar: Boolean read FAutoHideScrollBar
write SetAutoHideScrollBar default True;
property Row: Integer read FRow write SetRow default -1;
property RowCount: Integer read FRowCount write SetRowCount;
property RowHeight: Integer read FRowHeight write SetRowHeight
default DefRowHeight;
property DragScroll: Boolean read FDragScroll write FDragScroll
default True;
property DragScrolling: Boolean read FDragScrolling;
property ScrollingPos: Integer read FScrollingPos;
property WheelScrollLines: Integer read FWheelScrollLines
write FWheelScrollLines stored IsWheelScrollLinesStored;
public
constructor Create(AOwner: TComponent); override;
procedure MouseWheelHandler(var Message: TMessage); override;
function Scrolling: Boolean;
end;
{ TCustomImageGrid
The base class of an image grid. It shows images from left to right, then
from top to bottom. The number of columns is determined by the width of the
control, possibly resulting in a vertical scroll bar. The coord size is set
by ColWidth and RowHeight, being the sum of CellWidth resp. CellHeight plus
CellSpacing. Each cell shows a thumb of the corresponding image. The control
automatically starts a thumbs generating background thread when an image's
graphic, filename or its cell size is changed. Before every such change, any
previously created thread is terminated. Combine multiple changes by calling
Items.BeginUpdate/Items.EndUpdate to prevent the thread from being recreated
repeatedly. }
TCustomImageGrid = class;
TPath = type String;
TDrawCellEvent = procedure(Sender: TCustomImageGrid; Index, ACol,
ARow: Integer; R: TRect) of object;
TImageEvent = procedure(Sender: TCustomImageGrid; Index: Integer) of object;
TMeasureThumbEvent = procedure(Sender: TCustomImageGrid; Index: Integer;
var AThumbWidth, AThumbHeight: Integer) of object;
TCustomImageGrid = class(TAnimRowScroller)
private
FCellAlignment: TAlignment;
FCellLayout: TTextLayout;
FCellSpacing: Integer;
FColCount: Integer;
FColWidth: Integer;
FDefaultDrawing: Boolean;
FDesignPreview: Boolean;
FFileFormats: TStrings;
FFolder: TPath;
FItemIndex: Integer;
FItems: TImageGridItems;
FMarkerColor: TColor;
FMarkerStyle: TPenStyle;
FOnClickCell: TImageEvent;
FOnDrawCell: TDrawCellEvent;
FOnMeasureThumb: TMeasureThumbEvent;
FOnProgress: TImageEvent;
FOnUnresolved: TImageEvent;
FProportional: Boolean;
FRetainUnresolvedItems: Boolean;
FStretch: Boolean;
FThumbsGenerator: TThread;
FVirtualMode: Boolean;
procedure DeleteUnresolvedItems;
procedure FileFormatsChanged(Sender: TObject);
function GetCellHeight: Integer;
function GetCellWidth: Integer;
function GetCount: Integer;
function GetFileNames: TStrings;
function GetImage(Index: Integer): TGraphic;
function GetRowCount: Integer;
function GetSorted: Boolean;
function GetThumb(Index: Integer): TBitmap;
function IsFileNamesStored: Boolean;
procedure ItemsChanged(Sender: TObject);
procedure ItemsChanging(Sender: TObject);
procedure Rearrange;
procedure SetCellAlignment(Value: TAlignment);
procedure SetCellHeight(Value: Integer);
procedure SetCellLayout(Value: TTextLayout);
procedure SetCellSpacing(Value: Integer);
procedure SetCellWidth(Value: Integer);
procedure SetColWidth(Value: Integer);
procedure SetDefaultDrawing(Value: Boolean);
procedure SetDesignPreview(Value: Boolean);
procedure SetFileFormats(Value: TStrings);
procedure SetFileNames(Value: TStrings);
procedure SetFolder(Value: TPath);
procedure SetImage(Index: Integer; Value: TGraphic);
procedure SetItemIndex(Value: Integer);
procedure SetItems(Value: TImageGridItems);
procedure SetMarkerColor(Value: TColor);
procedure SetMarkerStyle(Value: TPenStyle);
procedure SetProportional(Value: Boolean);
procedure SetRetainUnresolvedItems(Value: Boolean);
procedure SetSorted(Value: Boolean);
procedure SetStretch(Value: Boolean);
procedure SetThumb(Index: Integer; Value: TBitmap);
procedure SetVirtualMode(Value: Boolean);
procedure TerminateThumbsGenerator;
procedure ThumbsUpdated(Sender: TObject);
procedure UpdateThumbs;
procedure WMEraseBkgnd(var Message: TWMEraseBkgnd); message WM_ERASEBKGND;
procedure WMGetDlgCode(var Message: TWMGetDlgCode); message WM_GETDLGCODE;
procedure CMEnter(var Message: TCMEnter); message CM_ENTER;
procedure CMExit(var Message: TCMExit); message CM_EXIT;
protected
procedure ChangeScale(M, D: Integer); override;
procedure DoClickCell(Index: Integer); virtual;
procedure DoDrawCell(Index, ACol, ARow: Integer; R: TRect); virtual;
procedure DoMeasureThumb(Index: Integer; var AThumbWidth,
AThumbHeight: Integer); virtual;
procedure DoProgress(Index: Integer); virtual;
procedure DrawFocusRect; override;
procedure InvalidateItem(Index: Integer); virtual;
procedure KeyDown(var Key: Word; Shift: TShiftState); override;
procedure Loaded; override;
procedure MouseDown(Button: TMouseButton; Shift: TShiftState; X,
Y: Integer); override;
procedure MouseUp(Button: TMouseButton; Shift: TShiftState; X,
Y: Integer); override;
procedure Paint; override;
procedure Resize; override;
procedure SetRowHeight(Value: Integer); override;
property CellAlignment: TAlignment read FCellAlignment
write SetCellAlignment default taCenter;
property CellHeight: Integer read GetCellHeight write SetCellHeight
default DefCellHeight;
property CellLayout: TTextLayout read FCellLayout write SetCellLayout
default tlCenter;
property CellSpacing: Integer read FCellSpacing write SetCellSpacing
default DefCellSpacing;
property CellWidth: Integer read GetCellWidth write SetCellWidth
default DefCellWidth;
property ColCount: Integer read FColCount;
property ColWidth: Integer read FColWidth write SetColWidth
default DefColWidth;
property Count: Integer read GetCount;
property DefaultDrawing: Boolean read FDefaultDrawing
write SetDefaultDrawing default True;
property DesignPreview: Boolean read FDesignPreview write SetDesignPreview
default False;
property FileFormats: TStrings read FFileFormats write SetFileFormats;
property FileNames: TStrings read GetFileNames write SetFileNames
stored IsFileNamesStored;
property Folder: TPath read FFolder write SetFolder;
property Images[Index: Integer]: TGraphic read GetImage write SetImage;
property ItemIndex: Integer read FItemIndex write SetItemIndex default -1;
property Items: TImageGridItems read FItems write SetItems;
property MarkerColor: TColor read FMarkerColor write SetMarkerColor
default clGray;
property MarkerStyle: TPenStyle read FMarkerStyle write SetMarkerStyle
default psDash;
property OnClickCell: TImageEvent read FOnClickCell write FOnClickCell;
property OnDrawCell: TDrawCellEvent read FOnDrawCell write FOnDrawCell;
property OnMeasureThumb: TMeasureThumbEvent read FOnMeasureThumb
write FOnMeasureThumb;
property OnProgress: TImageEvent read FOnProgress write FOnProgress;
property OnUnresolved: TImageEvent read FOnUnresolved write FOnUnresolved;
property Proportional: Boolean read FProportional write SetProportional
default True;
property RetainUnresolvedItems: Boolean read FRetainUnresolvedItems
write SetRetainUnresolvedItems default False;
property RowCount: Integer read GetRowCount;
property Sorted: Boolean read GetSorted write SetSorted default False;
property Stretch: Boolean read FStretch write SetStretch default False;
property Thumbs[Index: Integer]: TBitmap read GetThumb write SetThumb;
property VirtualMode: Boolean read FVirtualMode write SetVirtualMode
default False;
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
function CellRect(Index: Integer): TRect;
function CoordFromIndex(Index: Integer): TGridCoord;
procedure Clear; virtual;
function MouseToIndex(X, Y: Integer): Integer;
procedure ScrollInView(Index: Integer);
procedure SetCellSize(ACellWidth, ACellHeight: Integer);
procedure SetCoordSize(AColWidth, ARowHeight: Integer);
property ParentBackground default False;
public
property TabStop default True;
end;
TAwImageGrid = class(TCustomImageGrid)
public
property ColCount;
property Count;
property Images;
property Items;
property RowCount;
property Thumbs;
published
property Align;
property Anchors;
property AutoHideScrollBar;
property BorderStyle;
property BorderWidth;
property CellAlignment;
property CellHeight;
property CellLayout;
property CellSpacing;
property CellWidth;
property ClientHeight;
property ClientWidth;
property Color;
property ColWidth;
property Constraints;
property Ctl3D;
property DefaultDrawing;
property DesignPreview;
property DragCursor;
property DragKind;
property DragMode;
property DragScroll;
property Enabled;
property FileFormats;
property FileNames;
property Folder;
property ItemIndex;
property MarkerColor;
property MarkerStyle;
property OnCanResize;
property OnClick;
property OnClickCell;
property OnConstrainedResize;
property OnContextPopup;
property OnDblClick;
property OnDockDrop;
property OnDockOver;
property OnDragDrop;
property OnDragOver;
property OnDrawCell;
property OnEndDock;
property OnEndDrag;
property OnEnter;
property OnExit;
property OnGetSiteInfo;
property OnKeyDown;
property OnKeyPress;
property OnKeyUp;
property OnMeasureThumb;
property OnMouseDown;
property OnMouseMove;
property OnMouseUp;
property OnMouseWheel;
property OnMouseWheelDown;
property OnMouseWheelUp;
property OnProgress;
property OnResize;
property OnStartDock;
property OnStartDrag;
property OnUnDock;
property OnUnresolved;
property ParentBackground;
property RetainUnresolvedItems;
property RowHeight;
property ParentColor;
property ParentCtl3D;
property ParentShowHint;
property PopupMenu;
property Proportional;
property ShowHint;
property Sorted;
property Stretch;
property TabOrder;
property TabStop;
property VirtualMode;
property Visible;
property WheelScrollLines;
end;