I don't think there's currently a way to make a loaded bitmap have an alpha channel only if the source stream has one.
You could use 'unknown/mask, which should create a mask bitmap only if the source stream has an alpha channel, but at the expense of parsing the file an extra time. At Fri, 9 Sep 2016 19:07:24 -0700 (PDT), Lehi Toskin wrote: > Is there a way to detect if an image has a transparency/alpha channel? I've > been looking around and `(send bmp has-alpha-channel?)` really only works if > `bmp` has been loaded or created specifically with an alpha channel. What I > want to know is if a given path-string has such properties, not if the bitmap > object does. -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
