DBImage.OnGetPicture transparency

rbuser

Hi,

My program has a couple png images in a timagelist and I want to give the
user a way to use these images
I created a passthru function that can be called from
DBImage.OnGetPicture().

The problem is alpha transparency for the png images is lost.
It seems normal mask transparency works. What am I missing?

class function TRapDrawContactCategoryIcon.GetSignature: String;
begin
Result := 'procedure DrawContactCategoryIcon(const APicture: TPicture;
const AImageIndex: integer; const ASmallIcons: boolean);';
end;

procedure TRapDrawContactCategoryIcon.ExecuteFunction(aParams:
TraParamList);
var Picture: TPicture;
ImageIndex: integer;
SmallIcons: boolean;
begin
GetParamValue( 0, Picture );
GetParamValue( 1, ImageIndex );
GetParamValue( 2, SmallIcons );

if Assigned(Picture) or (ImageIndex < 0) or
(ImageIndex >= DMResource.imgEvent.Count)
then begin
Picture.Bitmap.Transparent := True;
if SmallIcons
then DMResource.imgEventSmall.GetImage(ImageIndex, Picture.Bitmap)
else DMResource.imgEvent.GetImage(ImageIndex, Picture.Bitmap);
end;
end;


Using RB11.08

Regards,
Jeroen.

nicocizik

Hi Jeroen,

Are you able to see the image correctly if you use Delphi instead of
RAP? What happens if you simply load the image into a TppImage
component manually? If you would like, you can send me the image you
are trying to view and I can try to recreate the problem here on my machine.


Regards,

Nico Cizik
Digital Metaphors
http://www.digital-metaphors.com

rbuser

Hi Nico,

I did test it with Delphi and TImage with the same results.
I managed to get the desired result using some classes from DevExpress.
There the code:

uses dxGDIPlusClasses;

procedure TDMResource.GetPNGImage(const AImageList: TcxImageList; const
AItemIndex: integer; const APicture: TPicture);
var srcBmp: TcxAlphaBitmap;
PNG: TdxPNGImage;
begin
if Assigned(APicture) and Assigned(AImageList)
then begin
srcBmp := TcxAlphaBitmap.Create;
PNG := TdxPNGImage.Create;
try
AImageList.GetImage(AItemIndex, srcBmp);
PNG.SetBitmap(srcBmp);
APicture.Assign(PNG);
finally
srcBmp.Free;
PNG.Free;
end;
end;
end;