Option not to enlarge thumbnail about bgrabitmap HOT 9 OPEN

That would be handy indeed. I am also not sure how to make it elegant. The pointer parameter is indeed a way to have it optionally returned.

Another option is a record or object in return of GetThumbnail functions with Bitmap and FileInfo

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And another option for AOptions is public variable in BGRAThumbnail unit, so there will be no need to initialize it and pass it, like those CheckersColor variables. So it will be initialized on initialization with default parameters.

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Good idea.

There are indeed lots of parameters already and using an enum could help.

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Would you like the thumbnail image to be smaller or keep it the same size and pad with empty pixels?

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Something like that?

type
  TBGRAThumbnailOptions = record
    BackColor: TBGRAPixel;  //default background
    Checkers: boolean;      //draw checkers to represent the transparent background of the image
    Enlarge: boolean;       //enlarge source image if smaller than the expected thumbnail size
    Pad: boolean;           //pad the thumbnail with BackColor to make it the expected size
  end; 

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Not sure what Pad means. Width and Height could be there as well.

Here is early implementation. I moved I moved dimension check to InternalGetBitmapThumbnail, as GetStremThumbnail wouldn't work for all files. All AOptions functions are overload functions located below of original for compatibility with older code.

QuickInfo is not quite implemented. Still thinking around it. May be other way or other record type. Just to optionally return original resolution as well, so can be used alongside thumbnail if needed without additional access to picture file. Will think on this tomorrow.

https://pastebin.com/e6Hvf0pj

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About Pad, for now it would be set to True. When you ask for a thumbnail of size 128x128, then if the image is 128x64, then there will be unused pixels in the square 128x128 and they will be set to the BackColor. In other word the content is padded with this color.

But as you ask for images not to be enlarged, then you might for example just want to reduce the resolution, but not pad it with pixels. If the source image is 256x128, it would become 128x64 and not 128x128.

I moved I moved dimension check to InternalGetBitmapThumbnail, as GetStremThumbnail wouldn't work for all files.

I am not sure I understand

All AOptions functions are overload functions located below of original for compatibility with older code.

I agree that overload is a way to preserve compatibility. The functions that contains the actual code will be those that have the AOptions parameter, while the others functions will call the former. So that code is not duplicated and that all options are handled.

QuickInfo is not quite implemented. Still thinking around it. May be other way or other record type. Just to optionally return original resolution as well, so can be used alongside thumbnail if needed without additional access to picture file. Will think on this tomorrow.

That would be handy indeed. I am also not sure how to make it elegant. The pointer parameter is indeed a way to have it optionally returned.

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I am not sure I understand

if AOptions.Enlarge = False section is in InternalGetBitmapThumbnail, rather than GetStreamThumbnail, as I was suggesting above, as not not every AReader is TBGRAImageReader

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if AOptions.Enlarge = False section is in InternalGetBitmapThumbnail, rather than GetStreamThumbnail, as I was suggesting above, as not not every AReader is TBGRAImageReader

Not sure I see why. Enlarging can be done on any format.

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