Creating images with alpha channel using Graphic Converter

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quartex
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Creating images with alpha channel using Graphic Converter

Post by quartex »

To all artists who regularly create images with alpha channels:

I'm using graphic converter 5.2.1 for OS X and having a lot of trouble saving an image with an alpha channel. In graphics converter I choose "add alpha/mask channel" and then "show alpha/mask channel". Then i struggle to get the silhouette of the unit to match up with the actual picture. My problem it that when i save it as a .PNG file (one of the formats that is supposed to support alpha channels), when I open the .PNG file again, the alpha channel is gone. And likewise, these .png files appear as empty images in Wesnoth, as if the transparency was set to 100% (probably becuase they have no alpha channel).

Does anyone here use Graphic Converter? What am I doing wrong? I don't see any options like "save alpha channel when saving this file". I've almost figured out how to create and use alpha channels, but this is annoying.

Oh and is the default that black is 0% transparency and white is 100% transparency?

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Re: Creating images with alpha channel using Graphic Convert

Post by Elvish_Pillager »

quartex wrote:Does anyone here use Graphic Converter? What am I doing wrong?
I know of only one thing that causes this, which is that images creatd with "New image with clipboard" don't use the alpha properly.
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Re: Creating images with alpha channel using Graphic Convert

Post by Invisible Philosopher »

quartex wrote:To all artists who regularly create images with alpha channels:

I'm using graphic converter 5.2.1 for OS X and having a lot of trouble saving an image with an alpha channel. In graphics converter I choose "add alpha/mask channel" and then "show alpha/mask channel". Then i struggle to get the silhouette of the unit to match up with the actual picture. My problem it that when i save it as a .PNG file (one of the formats that is supposed to support alpha channels), when I open the .PNG file again, the alpha channel is gone. And likewise, these .png files appear as empty images in Wesnoth, as if the transparency was set to 100% (probably becuase they have no alpha channel).

Does anyone here use Graphic Converter? What am I doing wrong? I don't see any options like "save alpha channel when saving this file". I've almost figured out how to create and use alpha channels, but this is annoying.
With the version of GraphicConverter that I have (4.9.1), alpha channel only works properly with millions of colors.

Otherwise, I have no idea what isn't working.
Oh and is the default that black is 0% transparency and white is 100% transparency?
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quartex
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Post by quartex »

" With the version of GraphicConverter that I have (4.9.1), alpha channel only works properly with millions of colors. "

Hallelujah! Thank you very much! I didn't realize that it had to be a 32 bit file (which means it has millions of colors) in order to support alpha channels. You just made my day.

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Post by quartex »

So I created a .png file with an alpha channel. It looks exactly the same as all the other .png files Wesnoth uses. Except that when I try to use it in-game, it doesn't appear. I realized it isn't that Wesnoth think's it's a transparent picture, it's that it doesn't display it at all, as if it's a broken link. (I checked twice, and I have the file location right) In the unit description window it doesn't even display an empty space for the picture. The only difference I can see in file formats is that OS X think the other images are "Portable Network Graphics Images" and this is a .PNG file. I'm trying to get Pickslide's Sentinel artwork to work in the game, he posted it on the forums a while ago as one big file, instead of seperate files for each animation. Does this image appear in other people's copies of Wesnoth? Can anyone tell what's wrong with it?

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Post by Elvish_Pillager »

quartex wrote:I'm trying to get Pickslide's Sentinel artwork to work in the game
Please elaborate. What are you trying to do with it?
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Post by quartex »

I'm trying to create a new elven sentinel unit using his artwork.

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Post by Elvish_Pillager »

quartex wrote:I'm trying to create a new elven sentinel unit using his artwork.
For use where?
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Re: Creating images with alpha channel using Graphic Convert

Post by scott »

quartex wrote:What am I doing wrong?
Not using The GIMP. Seriously, I save as .png, 'OK', 'OK', and everything's great.

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Post by quartex »

Well since it doesn't seem to be very likely that it is going to be incorportate into the official release, I'm thinking of putting the unit into a user campaign I was working on.

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Post by Sangel »

Interesting. While I use Graphic Converter v4.4 for Mac OS X, I don't experience this problem - though alpha masks do seem to get corrupted easily while working on an image, so you do have to be careful.

I suggest you give this a try: Work on the image as a PICT file with alpha mask. Then, after saving the final copy as a PICT, open it up and do a Save As .png - does this produce an image Wesnoth can use?
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quartex
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Post by quartex »

Sangel, I wa susing 4.4, I just downloaded 5.2.1 (the newest version) and found that it's a lot nicer, although they both seem to have the same functionality. I'll try working in PICT or use GIMP and see if it makes a difference.

quartex
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Re: Creating images with alpha channel using Graphic Convert

Post by quartex »

scott wrote:
quartex wrote:What am I doing wrong?
Not using The GIMP. Seriously, I save as .png, 'OK', 'OK', and everything's great.
Installing GIMP on OS X doesn't seem like a trivial problem. Some of us are better at running applications under Xdarwin or X11 than others. Still it looks like a great open-source graphics program.

Sangel, if you edit a unit file and put the above image into Wesnoth's images folder, does my image show up ingame in your copy of Wesnoth? I'm not sure if it is a problem with my build (although I suppose we're all using scotts 0.8.2 build) or with the graphics file.

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Post by Christophe33 »

I'm usually using graphic converter (4.9 for the moment) to add a proper alpha channel after doing the image in photoshop. Before that I problem like the one you described. For any reason, the photoshop version of png doesn't work well in BfW (I have a old photoshop). What I do is open the image saved in png and usually select the hex border with the transparency wand then choose "make alpha channel from transparency", then save as png with the option "interlaced->no, filter->automatic". The option setting seems important to get a png that is accepted by BfW.
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Post by MadMax »

I do know that for the alpha channel to work, the image has to be in RGB.
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