setalpha() ??

setalpha() ??

Postby Romeo » Wed Feb 24, 2016 5:26 pm

I'am testing the testimg.prg and found a SetAlpha() function, but i dont know how to use it.

any help about this function ?

tks
Romeo
 
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Re: setalpha() ??

Postby ukoenig » Thu Feb 25, 2016 11:45 am

Romeo ,

a Alphablended Image is needed, in case You want to show a SHADOW
To show a simple background transparent, You can use a normal color
SetAlpha( .F. ) shows the transparent-area of a ALPHAblended image as a BLACK color
I don't know any reason to use it.
But You can use something like :
if IsAlpha( aTemp[ n ][ 1 ] )
to detect, if a image includes a alpha-channel

Image

Very useful to download PIXELFORMER

Some links
viewtopic.php?f=3&t=23687&p=127412#p127412
viewtopic.php?f=3&t=17288&p=89855&hilit=pixelformer#p89855

A alphablended image ( BMP or PNG ) is used to show a shadow and a transparent level of a color ( yellow ).

Image

A non alphablended image uses the background-color to be transparent.

Image

best regards
Uwe :D
Last edited by ukoenig on Thu Feb 25, 2016 8:05 pm, edited 5 times in total.
Since 1995 ( the first release of FW 1.9 )
i work with FW.
If you have any questions about special functions, maybe i can help.
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Re: setalpha() ??

Postby Romeo » Thu Feb 25, 2016 3:00 pm

many many tks
R
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Location: Milan (Italy)

Re: setalpha() ??

Postby Antonio Linares » Thu Feb 25, 2016 6:23 pm

Uwe,

many thanks
regards, saludos

Antonio Linares
www.fivetechsoft.com
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