Difference between revisions of "TImageList"

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(Undo revision 135581 by TyphonFinger (talk))
Tag: Undo
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[[File:combo.png]]
 
[[File:combo.png]]
  
== SpeedButton例子 ==
+
== Example with SpeedButton ==
  
 
Add images to the ImageList1 like in the previous example and use:
 
Add images to the ImageList1 like in the previous example and use:
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</syntaxhighlight>
 
</syntaxhighlight>
  
== Lazarus 1.9以及最新版本的高分辨率设置 ==
+
== Multiple-resolution TImageList in Lazarus 1.9 and newer ==
  
 
In Lazarus 1.9 the TImageList was rewritten to support multiple resolutions of one image.
 
In Lazarus 1.9 the TImageList was rewritten to support multiple resolutions of one image.
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Set the Scaled property to True and the image list will automatically pick up the scaled image in your High-DPI aware LCL application.
 
Set the Scaled property to True and the image list will automatically pick up the scaled image in your High-DPI aware LCL application.
  
=== 程序演示 ===
+
=== Demo applications ===
 
There are 2 demo applications in Lazarus sources:
 
There are 2 demo applications in Lazarus sources:
 
* examples/imagelist_highdpi_designtime
 
* examples/imagelist_highdpi_designtime
 
* examples/imagelist_highdpi_runtime
 
* examples/imagelist_highdpi_runtime
  
=== 影响兼容的修改 ===
+
=== Changes affecting backwards compatibility ===
==== 添加方法 ====
+
==== Add method ====
 
* Old behavior: the image got sliced if too big or extended if too small.
 
* Old behavior: the image got sliced if too big or extended if too small.
 
* New behavior: the image is scaled to all resolutions in the image list.
 
* New behavior: the image is scaled to all resolutions in the image list.
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* Remedy: use AddSliced (if the image consists of several icons to be added) or AddSlice (if one image from a custom rect has to be added - also rect outside the image is supported).
 
* Remedy: use AddSliced (if the image consists of several icons to be added) or AddSlice (if one image from a custom rect has to be added - also rect outside the image is supported).
  
==Lazarus 1.8以及更以前版本的DPI替代方案: 调整TImageList中图片大小==
+
==High-DPI alternative for Lazarus 1.8 and older: resize all images in TImageList==
  
 
This is useful for example for [[High DPI]] scaling to get icons with higher resolution for TActionList, TMainMenu and TToolBar.
 
This is useful for example for [[High DPI]] scaling to get icons with higher resolution for TActionList, TMainMenu and TToolBar.
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</syntaxhighlight>
 
</syntaxhighlight>
  
== 参考资料 ==
+
== See also ==
 
* [[doc:lcl//controls/timagelist.html|TImageList doc]]
 
* [[doc:lcl//controls/timagelist.html|TImageList doc]]
 
* [[TImage]]
 
* [[TImage]]
  
 
{{LCL Components}}
 
{{LCL Components}}

Revision as of 09:36, 26 April 2020

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TImageList timagelist.png is a component that provides a list of images that can be used within other components like TToolBar of TActionList.

Example with ComboBox

To use TImageList, drop an TImageList object onto the form. In this example we need six images.

All images must be the same size. If two sizes of image are to be used, then two TImageLists must be used.

Set the height and width of the images in the Object Inspector; In this case 50px wide by 18px high.

Set Style to csOwnerDrawFixed.

Double-click on the TImageList icon to open the TImageList editor. Make sure that the icons show correctly when selected. If they are smaller than expected, check the size in the Object Inspector <F11>. You may have to reload the images.

ImageListEd.png

Place a ComboBox on the form and name it cbSymbols.

In the FormCreate event enter:

 cbSymbols.Items.Clear;
 for I := 0 to 5 do
   cbSymbols.Items.Add('');
 cbSymbols.ItemIndex := 0;

This will write 6 blank entries, and select the first.

In the OnDrawItem event for cbSymbols place the following code:

procedure TMyForm.cbSymbolsDrawItem( 
  aControl: TWinControl;
  iIndex: Integer; 
  aRect: TRect; 
  aState: TOwnerDrawState );
var
  cnv: TCanvas;
begin
  if not (aControl is TComboBox) then exit;
  cnv := TComboBox( aControl ).Canvas;
  Imagelist1.Draw( cnv, aRect.Left+2, aRect.Top+2, iIndex );
end;

The adjustments (+2) are to center the image in the item, if necessary.

combo.png

Example with SpeedButton

Add images to the ImageList1 like in the previous example and use:

   ImageList1.GetBitmap(iIndex,SpeedButton1.Glyph);

Multiple-resolution TImageList in Lazarus 1.9 and newer

In Lazarus 1.9 the TImageList was rewritten to support multiple resolutions of one image.

ImageListEd-1.9.png

Every LCL control that supports ImageList has now a new [Images]Width property to decide what custom width at 96 PPI (100% scale) is to be used. Example: TToolBar.Images/ImageWidth, TListView.LargeImages/LargeImagesWidth.

Set the Scaled property to True and the image list will automatically pick up the scaled image in your High-DPI aware LCL application.

Demo applications

There are 2 demo applications in Lazarus sources:

  • examples/imagelist_highdpi_designtime
  • examples/imagelist_highdpi_runtime

Changes affecting backwards compatibility

Add method

  • Old behavior: the image got sliced if too big or extended if too small.
  • New behavior: the image is scaled to all resolutions in the image list.
  • Reason: Image List now supports multiple resolutions.
  • Remedy: use AddSliced (if the image consists of several icons to be added) or AddSlice (if one image from a custom rect has to be added - also rect outside the image is supported).

High-DPI alternative for Lazarus 1.8 and older: resize all images in TImageList

This is useful for example for High DPI scaling to get icons with higher resolution for TActionList, TMainMenu and TToolBar. Note: This may not work correctly with all widgetsets on all platforms. Note also: This code is not required for Laz 1.9+.

procedure ScaleImageList(ImgList: TImageList; NewWidth, NewHeight: Integer);
var
  TempImgList: TImageList;
  TempBmp1: TBitmap;
  TempBmp2: TBitmap;
  I: Integer;
begin
  TempImgList := TImageList.Create(nil);
  TempBmp1 := TBitmap.Create;
  TempBmp1.PixelFormat := pf32bit;
  TempBmp2 := TBitmap.Create;
  TempBmp2.PixelFormat := pf32bit;
  TempBmp2.SetSize(NewWidth, NewHeight);
  try
    TempImgList.Width := NewWidth;
    TempImgList.Height := NewHeight;

    for I := 0 to ImgList.Count - 1 do begin
      // Load image for given index to temporary bitmap
      ImgList.GetBitmap(I, TempBmp1);

      // Clear transparent image background
      TempBmp2.Canvas.Brush.Style := bsSolid;
      TempBmp2.Canvas.Brush.Color := TempBmp2.TransparentColor;
      TempBmp2.Canvas.FillRect(0, 0, TempBmp2.Width, TempBmp2.Height);

      // Stretch image to new size
      TempBmp2.Canvas.StretchDraw(Rect(0, 0, TempBmp2.Width, TempBmp2.Height), TempBmp1);
      TempImgList.Add(TempBmp2, nil);
    end;

    ImgList.Assign(TempImgList);
  finally
    TempImgList.Free;
    TempBmp1.Free;
    TempBmp2.Free;
  end;
end;

See also


LCL Components
Component Tab Components
Standard TMainMenu • TPopupMenu • TButton • TLabel • TEdit • TMemo • TToggleBox • TCheckBox • TRadioButton • TListBox • TComboBox • TScrollBar • TGroupBox • TRadioGroup • TCheckGroup • TPanel • TFrame • TActionList
Additional TBitBtn • TSpeedButton • TStaticText • TImage • TShape • TBevel • TPaintBox • TNotebook • TLabeledEdit • TSplitter • TTrayIcon • TControlBar • TFlowPanel • TMaskEdit • TCheckListBox • TScrollBox • TApplicationProperties • TStringGrid • TDrawGrid • TPairSplitter • TColorBox • TColorListBox • TValueListEditor
Common Controls TTrackBar • TProgressBar • TTreeView • TListView • TStatusBar • TToolBar • TCoolBar • TUpDown • TPageControl • TTabControl • THeaderControl • TImageList • TPopupNotifier • TDateTimePicker
Dialogs TOpenDialog • TSaveDialog • TSelectDirectoryDialog • TColorDialog • TFontDialog • TFindDialog • TReplaceDialog • TTaskDialog • TOpenPictureDialog • TSavePictureDialog • TCalendarDialog • TCalculatorDialog • TPrinterSetupDialog • TPrintDialog • TPageSetupDialog
Data Controls TDBNavigator • TDBText • TDBEdit • TDBMemo • TDBImage • TDBListBox • TDBLookupListBox • TDBComboBox • TDBLookupComboBox • TDBCheckBox • TDBRadioGroup • TDBCalendar • TDBGroupBox • TDBGrid • TDBDateTimePicker
Data Access TDataSource • TCSVDataSet • TSdfDataSet • TBufDataset • TFixedFormatDataSet • TDbf • TMemDataset
System TTimer • TIdleTimer • TLazComponentQueue • THTMLHelpDatabase • THTMLBrowserHelpViewer • TAsyncProcess • TProcessUTF8 • TProcess • TSimpleIPCClient • TSimpleIPCServer • TXMLConfig • TEventLog • TServiceManager • TCHMHelpDatabase • TLHelpConnector
Misc TColorButton • TSpinEdit • TFloatSpinEdit • TArrow • TCalendar • TEditButton • TFileNameEdit • TDirectoryEdit • TDateEdit • TTimeEdit • TCalcEdit • TFileListBox • TFilterComboBox • TComboBoxEx • TCheckComboBox • TButtonPanel • TShellTreeView • TShellListView • TXMLPropStorage • TINIPropStorage • TJSONPropStorage • TIDEDialogLayoutStorage • TMRUManager • TStrHolder
LazControls TCheckBoxThemed • TDividerBevel • TExtendedNotebook • TListFilterEdit • TListViewFilterEdit • TLvlGraphControl • TShortPathEdit • TSpinEditEx • TFloatSpinEditEx • TTreeFilterEdit • TExtendedTabControl •
RTTI TTIEdit • TTIComboBox • TTIButton • TTICheckBox • TTILabel • TTIGroupBox • TTIRadioGroup • TTICheckGroup • TTICheckListBox • TTIListBox • TTIMemo • TTICalendar • TTIImage • TTIFloatSpinEdit • TTISpinEdit • TTITrackBar • TTIProgressBar • TTIMaskEdit • TTIColorButton • TMultiPropertyLink • TTIPropertyGrid • TTIGrid
SQLdb TSQLQuery • TSQLTransaction • TSQLScript • TSQLConnector • TMSSQLConnection • TSybaseConnection • TPQConnection • TPQTEventMonitor • TOracleConnection • TODBCConnection • TMySQL40Connection • TMySQL41Connection • TMySQL50Connection • TMySQL51Connection • TMySQL55Connection • TMySQL56Connection • TMySQL57Connection • TSQLite3Connection • TIBConnection • TFBAdmin • TFBEventMonitor • TSQLDBLibraryLoader
Pascal Script TPSScript • TPSScriptDebugger • TPSDllPlugin • TPSImport_Classes • TPSImport_DateUtils • TPSImport_ComObj • TPSImport_DB • TPSImport_Forms • TPSImport_Controls • TPSImport_StdCtrls • TPSCustomPlugin
SynEdit TSynEdit • TSynCompletion • TSynAutoComplete • TSynMacroRecorder • TSynExporterHTML • TSynPluginSyncroEdit • TSynPasSyn • TSynFreePascalSyn • TSynCppSyn • TSynJavaSyn • TSynPerlSyn • TSynHTMLSyn • TSynXMLSyn • TSynLFMSyn • TSynDiffSyn • TSynUNIXShellScriptSyn • TSynCssSyn • TSynPHPSyn • TSynTeXSyn • TSynSQLSyn • TSynPythonSyn • TSynVBSyn • TSynAnySyn • TSynMultiSyn • TSynBatSyn • TSynIniSyn • TSynPoSyn
Chart TChart • TListChartSource • TRandomChartSource • TUserDefinedChartSource • TCalculatedChartSource • TDbChartSource • TChartToolset • TChartAxisTransformations • TChartStyles • TChartLegendPanel • TChartNavScrollBar • TChartNavPanel • TIntervalChartSource • TDateTimeIntervalChartSource • TChartListBox • TChartExtentLink • TChartImageList
IPro TIpFileDataProvider • TIpHtmlDataProvider • TIpHttpDataProvider • TIpHtmlPanel
Virtual Controls TVirtualDrawTree • TVirtualStringTree • TVTHeaderPopupMenu