Difference between revisions of "TImageList"
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SpeedButton1.GetBitmap(iIndex,spbTCNext.Glyph); | SpeedButton1.GetBitmap(iIndex,spbTCNext.Glyph); | ||
</syntaxhighlight> | </syntaxhighlight> | ||
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| + | == Multiple-resolution TImageList in Lazarus 1.9 and newer == | ||
| + | |||
| + | In Lazarus 1.9 the TImageList was rewritten to support multiple resolutions of one image. | ||
| + | |||
| + | [[File:ImageListEd-1.9.png]] | ||
| + | |||
| + | Set the Scaled property to True and the image list will automatically pick up the scaled image in your High-DPI aware LCL application. | ||
| + | |||
| + | === 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: font scaling problem Issue #32882. This change will be merged to 1.8.1 | ||
| + | * 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). | ||
| + | |||
| + | * The Add method scales the image to image list size. 1.8 behavior: | ||
== See also == | == See also == | ||
Revision as of 12:36, 3 February 2018
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TImageList 
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.
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.
Example with SpeedButton
Add images to the ImageBox like in the previous example and use:
SpeedButton1.GetBitmap(iIndex,spbTCNext.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.
Set the Scaled property to True and the image list will automatically pick up the scaled image in your High-DPI aware LCL application.
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: font scaling problem Issue #32882. This change will be merged to 1.8.1
- 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).
- The Add method scales the image to image list size. 1.8 behavior:
See also
