Is TImage empty

[Squall_FF8 1]

Hey Guys,

I have TImage that in run-time I can load with png or jpg.
1. How to check is the TImage empty (aka no image loaded?

2. How to erase the loaded image? (when an image is loaded)

[Remy Lebeau 1586]

2 hours ago, Squall_FF8 said:

1. How to check is the TImage empty (aka no image loaded?

Check the TImage.Picture.Graphic and TGraphic.Empty properties:

if (Image1.Picture.Graphic = nil) or Image.Picture.Graphic.Empty then

2 hours ago, Squall_FF8 said:

2. How to erase the loaded image? (when an image is loaded)

You can assign nil to the TImage.Picture property:

Image1.Picture := nil;
// same as:
// Image1.Picture.Assign(nil);

Or to its Graphic property:

Image1.Picture.Graphic := nil;

 

Edited 36 minutes ago by Remy Lebeau

[Squall_FF8 1]

Thank you @Remy Lebeau!

 

BTW do you know, why Image1.Picture.Bitmap.Empty clears the image? It is suppose the return a value, not to destroy an image

[Uwe Raabe 2140]

If Image1.Picture.Graphic is not of type TBitmap, referencing Image1.Picture.Bitmap will clear the current content and create an empty TBitmap.

[Remy Lebeau 1586]

Yes, and this is documented behavior:

https://docwiki.embarcadero.com/Libraries/en/Vcl.Graphics.TPicture.Bitmap

Quote

Use Bitmap to reference the picture object when it contains a bitmap. If Bitmap is referenced when the picture contains a Metafile or Icon graphic, the graphic won't be converted (Types of Graphic Objects). Instead, the original contents of the picture are discarded and Bitmap returns a new, blank bitmap.

Where it says "a Metafile or Icon graphic", it really means "any non-Bitmap graphic" instead.

 

Use the TPicture.Graphic property when you need to access as-is whatever TGraphic descendant is currently loaded in the TPicture.  Use the TPicture.Bitmap property instead when you specifically need a TBitmap.

Edited 27 minutes ago by Remy Lebeau