Search found 7 matches

by Claghorn
2012-08-18T12:04:11-07:00
Forum: Users
Topic: Convert grayscale image to black plus transparency?
Replies: 16
Views: 22303

Re: Convert grayscale image to black plus transparency?

Thanks for the analysis. That does appear to finally get closer to gimp, but I guess I'll stick with gimp for now since the images I get with it look more like the original (maybe the 256 versus 183 issue).
by Claghorn
2012-08-18T08:54:06-07:00
Forum: Users
Topic: Convert grayscale image to black plus transparency?
Replies: 16
Views: 22303

Re: Convert grayscale image to black plus transparency?

That's still not working like gimp. I don't have the original image to compose with in an ebook, I've just got a single .png file with transparency which will wind up being displayed on a solid background. If you look at my updated web page with all the gimp examples, you'll see exactly what I want....
by Claghorn
2012-08-17T22:13:33-07:00
Forum: Users
Topic: Convert grayscale image to black plus transparency?
Replies: 16
Views: 22303

Re: Convert grayscale image to black plus transparency?

I can't decrypt that, but it looks like the "probably what I want" is merging the wheat background in, and that is most definitely not what I want. Wheat is just one example, anyone could select any background they want in their ebook reader. I want to stop the process where I can capture a .png fil...
by Claghorn
2012-08-17T14:26:09-07:00
Forum: Users
Topic: Convert grayscale image to black plus transparency?
Replies: 16
Views: 22303

Re: Convert grayscale image to black plus transparency?

I have discovered that the color to alpha function in gimp does exactly what I want. See the bottom of this web page:

http://home.comcast.net/~tomhorsley/game/calibre.html
by Claghorn
2012-08-17T12:31:28-07:00
Forum: Users
Topic: Convert grayscale image to black plus transparency?
Replies: 16
Views: 22303

Re: Convert grayscale image to black plus transparency?

Technique 2 works perfectly, but unfortunately I can't use it because the background color is a preference set in the book reader long after the book is created. Technique 1 produces the same disappearing light background problem my original attempt had. For instance, forgetting wheat for a moment, ...
by Claghorn
2012-08-17T10:40:53-07:00
Forum: Users
Topic: Convert grayscale image to black plus transparency?
Replies: 16
Views: 22303

Re: Convert grayscale image to black plus transparency?

Here's a fair use safe clip from the title page of my (legally purchased) Game Of Thrones ebook: http://home.comcast.net/~tomhorsley/images/sample-gray.jpeg This is a completely opaque grayscale jpeg image. What I want is the same image with transparency instead of whiteness so that if it is display...
by Claghorn
2012-08-17T04:38:13-07:00
Forum: Users
Topic: Convert grayscale image to black plus transparency?
Replies: 16
Views: 22303

Convert grayscale image to black plus transparency?

I'm trying to fiddle with the .jpg images used to decorate chapter headers and such in an epub book. They look fine with a white background, but if you want to change your default background color or use a pattern, they look horrible, turning into visually jarring rectangles on the page. What I'd li...