Create transparent PNG

General
1

I have a transparent PNG. If I save this to a BLOB field, retrieve it and display again, the transparency is gone. It should be possible to create a mask and recreate the transparency. How to do this?

2

Did you save it and load it as it png?

3

As type Picture…

4

https://documentation.xojo.com/api/graphics/picture.html#picture-todata

What are the prameters that you use?
Png should keep transparency…

 Var picData as String = myPic.ToData(Picture.Formats.png)

Save picData to db and read back should be exactly the same…

5

Use that code. Still transparency gone, turned into black, that is.

6

Black ok probably something is different here ill have a look how we do this.

Edit:
Do you use a canvas to draw the picture to?

7

Edit:
Do you use a canvas to draw the picture to?

It’s an PNG that the user selects; first time displays in a canvas. Then it gets stored in a table. After retrieval it is displayed in a Toolbar as icon.

8

Extract the image file directly from the table and save it to disk, check if the image has transparency or if you save it withouth.

As a good practice, store pictures, keep the orifginal data in a variable, from the file that the user choosed, then save this in the table instead of compressing again the picture in xojo

9

Picture.ToData returns a MemoryBlock. A string has an encoding. May it happen that the encoding destroyes some bytes into the picture data?

10

Maybe… haven’t tested that.