Legacy ImageMagick Discussions Archive

Well, to round out this discussion, pre-multiplied alpha seems to be just the trick I was looking for. Thanks for that link! The video was helpful as a starting point, but I actually learned about the more useful technical aspects of the format at the link below. It's nothing a naive Google search ...

No, if the image is displayed at native resolution without the need for resampling then it appears fine even in OpenGL. Scaling the image via IM does not yield artifacts. Also, I think I got confused earlier when I suggested using Photoshop — more recent tests indicate that no artifacts appear when s ...

Is the OP getting similar results to this? http://blender.stackexchange.com/questions/1625/edging-alpha-texture-viewport-blender For example in 3D work textures using transparency can have straight alpha or premultiplied alpha as a render option. A video http://vimeo.com/11064139 *cross posted 8 ...

The problem is only you can see the red halo or do you have an example that anyone can see with most viewers. I've spent a little more time digging into the details, and believe I've finally discovered a perfectly logical explanation for the effects I've been seeing. I printed out the decoded image ...

Your red.png image is an 8-bit palette png with alpha channel. Oddly, the background color is red and not rgb(27,28,38). In fact all your images have the same histogram. Only the background color parameter is different. . Right, that's because I actually created red.png from black.png by changing ...

Curiously, the red background halo still appears when rendered in my pipeline, but the "interior" pixels (those which were originally opaque in red.png) appear at their proper color and at 50% opacity. This strikes my as wholly weird. What makes those other semi-opaque pixels near the boundaries ...

I know I've been long winded already, but I have one more detail of potential interest. I wanted to make it clear that my pipeline does not render everything with a 1 bit alpha. In fact, it's not even rendering these test images with 1 bit alpha. I created a variant of red.png in which the alpha ...

... then a cure would seem to be: convert bad.png -background Black -alpha background good.png Partial success! I've confirmed that this does indeed restore a value of "none" to "Alpha:". Unfortunately, now that I know more, it doesn't completely solve my problem. It's possible that ImageMagick can ...

First in palette indexed images (images with a limited table of colors), one color is used to denote transparency. This is the 'alpha color', or transparent index. GIF is famous for this style of image storage, but PNG can also do this. However by only having one color to hold alpha, the ...

Thanks for the replies, but unfortunately I'm still rather confused. Here are the results of the logo manipulations: $ identify -verbose logo_black.png | grep -Ei "(transparent|alpha)" Transparent color: black $ identify -verbose logo_white.png | grep -Ei "(transparent|alpha)" alpha: 1-bit Alpha ...

Hey all. I've got two 8-bit RGB PNG images that are nearly identical, exported with different versions of Adobe Illustrator. When I run "identify -verbose" on these images, they differ notably in an "Alpha" key which follows the general "Image Statistics" section in the output. I can't make good ...