Programmatically import image as PNG with ALPHA channel

[Paolo]

Hello,

Is there a way to programmatically import an image as png with alpha channel, without showing up the import dialog as in:

def vs.ImportImageFileN(filePath, importPt, mode):
    return HANDLE

I am aware of:

def vs.ImportImageFile(filePath, importPt):
    return HANDLE

but I am wondering if there is a way to force the default import preferences (JPEG) as PNG with ALPHA channel.

 

This is needed in my perspective rectifier plugin, where a new image (PNG with ALPHA) is created and imported on the fly.

 

[JBenghiat]

I don’t believe there is a way to do this without the SDK.

If these are bitmaps in the drawing, though, setting the fill to none (in vs set the FPat to 0), will make all white pixels transparent and may do the trick. 

[Paolo]

Thank you JBenghiat, it works!

Even importing a PNG (with alpha) as JPEG, it maintains its transparency. It appears filled with white, but IT CAN BE set to fill none!

I was (for years) convinced that JPEGs couldn't have alpha channels, but I was wrong 🤔

 

[JBenghiat]

It’s not really an alpha channel, just simply treating white pixels as transparent. Vectorworks has actually had this feature for bitmaps for years, even before importing PNG was an option. 

[Paolo]

If all white pixels become transparent, well, this is not so good.

In the PNG with alpha there could be white pixels that must remain opaque!

 

I have to test it…

I fear, in the end, I have to show up the import dialog to the user, instructing him to choose PNG with ALPHA option…