Flex: Modify an embedded icon and use it in a button

apache-flexflashiconsimage

Just that, if you embed an icon:

[Embed(source='icons/checkmark.png')]
private static var CheckMark:Class;

You end up with a dynamic class. You can pretty easily assign the icon to a button at runtime by calling the setStyle method:

var btn:Button = new Button();
btn.setStyle("icon", CheckMark);

But what if you wanted to alter the icon at runtime, like changing it's alpha value or even redrawing pixels, before assigning it to the button?

So far I can't find a satisfactory answer…

Best Answer

This is the only answer I could find that seemed close: Dynamic Icons (example with View Source)

His solution involves a custom "DynamicIcon" class which is used in the button's icon setting, and a custom Button class which adds one method to the Button class to draw dynamic icons.

The end result is that you are able to send BitmapData to the DynamicIcon class, which will show up in the button. So, embed your image, instantiate your asset class, get the bitmapasset and modify it however you need to and send the bitmapData to the icon.

It's an interesting problem and it seems like there should be an easier solution, but this works without a lot of hassle.

Related Solutions

Apache – Flex combobox custom icon

The "properties" are actually styles on ComboBase: upSkin, downSkin, overSkin, disabledSkin.

The default is ComboBoxArrowSkin--take a look at the source code to get more details about overriding or customizing it.

Delphi – Populate an imagelist with icons at runtime ‘destroys’ transparency

To support alpha transparency, you need to create the image list and populate it at runtime:

function AddIconFromResource(ImageList: TImageList; ResID: Integer): Integer;
var
  Icon: TIcon;
begin
  Icon := TIcon.Create;
  try
    Icon.LoadFromResourceID(HInstance, ResID);
    Result := ImageList.AddIcon(Icon);
  finally
    Icon.Free;
  end;
end;

function AddPngFromResource(ImageList: TImageList; ResID: Integer): Integer;
var
  Png: TPngGraphic;
  ResStream: TStream;
  Bitmap: TBitmap;
begin
  ResStream := nil;
  Png := nil;
  Bitmap := nil;
  try
    ResStream := TResourceStream.CreateFromID(HInstance, ResID, RT_RCDATA);
    Png := TPNGGraphic.Create;
    Png.LoadFromStream(ResStream);
    FreeAndNil(ResStream);
    Bitmap := TBitmap.Create;
    Bitmap.Assign(Png);
    FreeAndNil(Png);
    Result := ImageList.Add(Bitmap, nil);              
  finally
    Bitmap.Free;
    ResStream.Free;
    Png.Free;
  end;
end;

// this could be e.g. in the form's or datamodule's OnCreate event
begin
  // create the imagelist
  ImageList := TImageList.Create(Self);
  ImageList.Name := 'ImageList';
  ImageList.DrawingStyle := dsTransparent;
  ImageList.Handle := ImageList_Create(ImageList.Width, ImageList.Height, ILC_COLOR32 or ILC_MASK, 0, ImageList.AllocBy);
  // populate the imagelist with png images from resources
  AddPngFromResource(ImageList, ...);
  // or icons
  AddIconFromResource(ImageList, ...);

end;

Best Answer

Related Solutions

Apache – Flex combobox custom icon

Delphi – Populate an imagelist with icons at runtime ‘destroys’ transparency

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