Resizing Texture Patches

[BobertThe3rd]

So I've been resizing texture patches for a while now, when not all resolutions are available. However, I'm not sure if I am doing it the "best" way I possible could. So my question is, what is the best resizing method, using GIMP?Keep in mind that since I am doing this on released patches, I do not have access to the PSDs, and so can't use the absolute best method of scaling the vectors. This questions is for both downscaling and upscaling. Currently I am using the cubic method to both downscale and upscale, and doing nothing else. I have heard in some of Han's threads that he uses filtering in addition to the scaling. Also I would like to know what the standards are for various image types. I know, for example, that GUIs are 256x256 for 16x, 512x512 for 32x, and 1024x1024 for anything greater and items and blocks are the size the number references. However, for things like GUI buttons (on a separate sheet from the GUI), overlays, mobs, particles, etc. Things seem to be less cut and dry.


So specifically I want to know:

* What method to use to downscale/upscale

* What additional techniques, if any, should I apply

* Is it better to just leave lower resolution patches be themselves in a high resolution pack

* How can I get a batch operation to ignore png offsets in patches that have been unstitched

* What are the "standards" for the sizes of various types of images.

If you don't have an answer for GIMP, but do have an answer for Photoshop/Creative Suite, then go ahead and post it anyway, as GIMP usually has most of the same operations, they just require translation. Do not post anything that requires a PSD or XCF as I will typically not have access to those. Maybe this could become a staple resource if a good, comprehensive answer is given. Thanks in advance.

[HanFox]

Well down the list:

• - Downscaling: Sphax recommends Bilinear (sometimes just called Linear). I use Cubic (sometimes called Bicubic).
  - Upscaling: Never ever upscale. All you do is destroy the image. If it isn't available in a higher resolution it will need to be redrawn at a higher resolution.
• As far as GIMP goes I'm not sure if you use the same trick as in PhotoShop of readjusting the pixels until there's no transparency around the edges. Though, I'm pretty sure the resizing action from PhotoShop will work on rasterized pngs. Push comes to shove I can try and set you up with ImageMagick, but it's not exactly "entry level" due to being command based and requiring batch files.
• Yes, leave the lower resolution ones in higher packs because of above about upscaling.
• Not quite sure I understand what you mean about png offsets?
• There are no standards. Since everything now is unstitched and more modders are moving towards having seperate elements for their GUIs I generally leave everything in its respective resolution. So a 512x patch would have 512x GUI elements (but the GUI itself is still 1024x1024). Other people work off the old point of fact that GUIs are only ever technically 64x due to only being 4 times bigger than vanilla/16x, so they leave elements in 64x

On the note of reading about me mentioning thresholds, that's the alpha threshold. Where Sphax and other PhotoShop users run the action to remove transparent pixel or make them solid via certain masks and whatever the action actually does (I never looked at it. PS is evil ). I just use ImageMagick to detect the transparency percentage of the pixels and everything under 50% is removed and everything above it is made solid.

[BobertThe3rd]

In reference to the png offsets, it is actually mostly in your patches I come across them. When you unstitch a grid of textures using the filter to automatically cut them up, it saves their offset in the grid, when GIMP opens these images and sees an offset, it asks the user if they want to ignore or apply the offset before ever opening the image, because batch operations in GIMP are essentially going through the same motions a user would, batch resizes fail on these images due to them not being opened all the way, as of yet I haven't found a batch operation for interacting with popups like that. Note that I am using the Bimp plugin with Gimp to get the batch operations.

[HanFox]

Oh, I can actually remove all the offsets with ImageMagick

If you give me a zip with what you're working on I can batch remove the offsets if you like.

[BobertThe3rd]

You mean all of FTB Unleashed? *facepalm* I may download ImageMagick myself, I am a programmer and a linux user, command line arguments don't scare me :p

[HanFox]

Yes, all of FTB Unleashed... I wrote a little php/cli program that keeps file structure as it works.

It's BADLY written and incomplete, but you can have it if you like.