Following Bert's advice, I see that HaloMorph overrides #drawSubmorphsOn: and calls its Canvas using asAlphaBlendingCanvas. That seems like a good place to start.<br><br>I tried subclassing ImageMorph and adding this method:
<br><br> drawOn: aCanvas<br> ^ super drawOn: (aCanvas asAlphaBlendingCanvas: alphaValue).<br><br>Unfortunately, it didn't display anything at all. I tried alpha values of 0.5 and 1.0. If I remove the alpha blending stuff, and simply call:
<br><br> ^ super drawOn: aCanvas.<br><br>it works like a normal ImageMorph, so at least I know it isn't broken someplace else.<br><br>Any suggestions on how to get asAlphaBlendingCanvas to blend some alphas?<br><br>
<br><br><br><div><span class="gmail_quote">On 4/23/07, <b class="gmail_sendername">Steven Greenberg</b> <<a href="mailto:greenbes@puzzlingevidence.net">greenbes@puzzlingevidence.net</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Thanks for the pointer! I didn't try that code in the workspace, but if you enable "haloTransitions" using the Preferences browser then the halos fade in and out.<br><br> Thanks,<br> Steve<div><span class="e" id="q_1121d285e36c650a_1">
<br><br><br><br>
<div><span class="gmail_quote">On 4/22/07, <b class="gmail_sendername">Bert Freudenberg</b> <<a href="mailto:bert@freudenbergs.de" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">bert@freudenbergs.de
</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br>On Apr 23, 2007, at 0:44 , Steven Greenberg wrote:<br><br>> I have a PNG image that I'd like to display fading out. I tried<br>> the BitBlt method suggested by "Team RAR" to fade the image, but I
<br>
> can't make it work.<br>><br>> The image loads properly from a file and displays fine as an<br>> ImageMorph. I have been able to use a TransformationMorph to<br>> rotate and scale it, and PNG transparency is working properly.
<br>><br>> Is the "Team RAR" BitBlt method the only way, or are there<br>> alternatives?<br>><br>> I'm running a 3.9 image, and my display depth is set to 32 bits.<br>><br><br>Normally you would just use an alpha-blending canvas. See HaloMorph
<br>fadeIn/fadeOut and draw methods. To try those halos, enable this:<br><br> Preferences enable: #haloTransitions<br><br>Now when I tried then the halo icons do not actually show until alpha<br>is one. No idea why that is.
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