Author Topic: GIMP 2.8.2 - Basic questions  (Read 56927 times)

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Offline TerraEsperZ

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Re: GIMP 2.8.2 - Basic questions
« Reply #15 on: September 19, 2012, 10:30:28 pm »
Thanks for all the responses, and sorry for not coming back to this thread sooner. I've been kept away from my computer for a couple of days.

I've been reading this thread with great interest all evening but I think for now I just need to try and get the hang of how GIMP handles everything. So far, "converting" a recent unfinished project into usable files to then combine in GIMP has been rather difficult and time-consuming, although I've finally gotten the hang of alpha transparency. Apparently (according to me and a few message boards), you can't directly edit the alpha channel but can circumvent this limitation by creating a layer mask which you *can* edit and then applying said layer mask which becomes the alpha channel. Why they make this so difficult while allowing you to move any layer or canvas around even without anything selected selection (and putting everything in place is really a bitch) is beyond me. I suspect that GIMP is perhaps unwittingly betraying his "by programmers for programmers" origins sometimes. God knows what little paid coding I did ended up with horribly unfathomable UIs.

So far, anything I can think of doing aside from transparencies and using layers to position sprites takes me less time on Paint and my other tools by several orders of magnitude. I'm not giving up on mastering this ugly beast, but I can tell that some of its quirks will probably never stop annoying me.

I'll report back later on whatever successes and/or failures and/or annoyances I run into.
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Mega Man: Powered Up (PSP)

Offline Maxim

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Re: GIMP 2.8.2 - Basic questions
« Reply #16 on: September 20, 2012, 01:15:01 am »
Ultimately it seems everyone prefers what they know and have got used to the workflow for - I have easy ways to do all of the above in Paint Shop Pro and I can name  a few things I think it can do more easily :) (flood fill with a repeating pattern, paste with colour coded transparency...). Gimp always seemed clunky to me, but I guess with time it'd become second nature.

Offline GSA

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Re: GIMP 2.8.2 - Basic questions
« Reply #17 on: September 20, 2012, 01:58:27 am »
Because there are now too many branching questions and I want to answer each one adequately, I'll make a different post to answer each one, alternating between interlocutors. Don't worry though, I'll get back to all questions eventually.

In this post, I answer Rekrul about the clone tool.

I just tried GIMP's clone tool and unless I didn't know how to work it, it didn't seem at all suitable for the job of erasing a cartoon eagle from in front of a 3-color US flag image.

There are different types of cartoons and I took a guess at what exactly you meant. I could have been wrong. It could be possible that the clone tool is not best suited for the particular image you are speaking of. It actually depends on the amount of high frequency data there is in your image. So, unless I see your image, I can't give you precise advice. (I don't know if there is noise in your image or if it's perfectly clean.)

Nevertheless, as the Wikipedia article on the clone tool states: "A typical use for the tool is in object removal – more colloquially, "airbrushing" or "photoshopping" out an unwanted part of the image." Hence, the clone tool is usually the designated tool for object removal.

The GIMP documentation is vague on how to use it. It says you need to Control-Click the source image, but doesn't tell you how to change the selection from the thumbnail sized circle that it defaults to.

In this case, you should have read the introduction of the tool section in the GIMP documentation as well. Most importantly, the section about the tool options dialog. By default, you will find these options just below the toolbox.

Of course, there is an option for the size of your brush there.

Also when pasting copies of it, it blends the edges with the surrounding image. I guess that's how it's supposed to work, but it's more suited to working with imperfections in photos, rather than limited color images.

In the aforementioned tool options dialog, you can choose your brush type. The default one is a circle with 50% hardness. That mean that the border of that circle is progressively more transparent. Hence the blending.

In your case, you don't want this. So, pick a brush with 100% hardness, either circle or square shaped.
Additionally, if it matters, you might want to check the "hard edge" box in the options. This will "pixel snap" your brush and disable the 1 pixel wide anti-aliasing around it.

Offline GSA

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Re: GIMP 2.8.2 - Basic questions
« Reply #18 on: September 20, 2012, 02:53:18 pm »
In this post, I answer TerraEsperZ about his last post. (Nodding at Maxim's last post along the way.)

I've been reading this thread with great interest all evening but I think for now I just need to try and get the hang of how GIMP handles everything.

I'm glad to hear that you still have interest and that you don't want to kill me yet for recommending GIMP! :D

So far, "converting" a recent unfinished project into usable files to then combine in GIMP has been rather difficult and time-consuming,

Oh, I'm not sure you should have done that :o. Converting takes time and is probably inefficient. I think you should have finished your current project with your current tools and learned GIMP later.
But hey, let's see things on the bright side. You are learning!

Apparently (according to me and a few message boards), you can't directly edit the alpha channel but can circumvent this limitation by creating a layer mask which you *can* edit and then applying said layer mask which becomes the alpha channel.

Masks work, but there has to be some confusion here... because I never used masks. If you want to directly edit the alpha channel, you can! Either delete a selection or use the eraser tool.
Did you miss the tutorial image I attached here?

Why they make this so difficult while allowing you to move any layer or canvas around even without anything selected selection (and putting everything in place is really a bitch) is beyond me. I suspect that GIMP is perhaps unwittingly betraying his "by programmers for programmers" origins sometimes. God knows what little paid coding I did ended up with horribly unfathomable UIs.

I'm going to get lynched for saying this, but... If you think GIMP is unintuitive, just try Photoshop! You'd really know what "being lost" is. (By the way, normal people actually need to take a course to be able to use Photoshop...) But hey, Photoshop is recognized as being the best raster image manipulation software.

What you'll learn in GIMP works the same way in Photoshop, but GIMP is much more approachable for it's relative simplicity. Simple enough, actually, to make me believe that you won't need a course to learn GIMP.

So far, anything I can think of doing aside from transparencies and using layers to position sprites takes me less time on Paint and my other tools by several orders of magnitude. I'm not giving up on mastering this ugly beast, but I can tell that some of its quirks will probably never stop annoying me.

You know, transparencies and layers was the essential part of my recommendation of using GIMP. If you want to use MSPaint for the rest because that's what you are most used to, just do so. It may be the best thing to do if using multiple programs doesn't bother you.

Maxim just spoke about "pattern fill". Well, it's in GIMP as well. This is a pretty great feature that you should learn about too. Not only it would save you time when when you work on backgrounds, but it would have helped you greatly for your fancy borders in your Castlevania Legends Map. With pattern fill and grid snapping, it'd have taken about 1 min to generate all the borders of a map.

About Paint Shop Pro, it's good too if you can afford it. However, I don't think that it's better enough to be worth the price tag it has. (It's your call actually, you might want to try a demo.)

I'll report back later on whatever successes and/or failures and/or annoyances I run into.

You're welcome.

Offline Rekrul

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Re: GIMP 2.8.2 - Basic questions
« Reply #19 on: September 21, 2012, 04:49:03 am »
There are different types of cartoons and I took a guess at what exactly you meant. I could have been wrong. It could be possible that the clone tool is not best suited for the particular image you are speaking of. It actually depends on the amount of high frequency data there is in your image. So, unless I see your image, I can't give you precise advice. (I don't know if there is noise in your image or if it's perfectly clean.)

I've attached the image in question. I like to use it as a test for how easy an image program is to use. In my opinion, it shouldn't take more than a minute to completely erase the eagle, leaving the flag untouched.

Nevertheless, as the Wikipedia article on the clone tool states: "A typical use for the tool is in object removal – more colloquially, "airbrushing" or "photoshopping" out an unwanted part of the image." Hence, the clone tool is usually the designated tool for object removal.

I guess with the right options it can accomplish what I wanted to do, but it seems more suited to "airbrushing" small imperfections in a photo, rather than making large-scale changes.

The biggest problem is that you can't see the cloned copy of the image before you click the button. You have to rely on the dotted outline, which is hard to position precisely. For some reason, it never seems to work consistently. Sometimes I position the lower edge right on the edge of one of the stripes and it matches perfectly. Other times, I put it right on the edge and there's a one pixel offset. Even positioning the source box is a pain. It never seems to want to go right on the edge of a stripe, it's always one pixel above it or one pixel below it.

Basically, you're working double-blind; You can't tell exactly how the source box is aligned (do you put the outline on the pixels you want, or is the line outside the pixels?), and you can't tell how the copy is aligned until you stamp it down.

In this case, the copy function is better suited to erasing the eagle, except that when filling in the stars, the outline around the floating copy keeps getting in the way, making it hard to tell when I have the stars lined up properly. It looks right, but then I stamp it down and discover that there's a slight mismatch that was hidden by the border, so I have to undo it and try again.

It's just so much easier when you can move the actual copy in real time without a border to get in the way or without having to press CTRL-V every time you want another copy.

Plus, why can't you scroll an iamge with the arrow keys? Virtually every other program with a scrollable display allows the use of the arrow keys, but not GIMP. So I go into the prefs, find the shortcuts section, open the View options, find the ones for scroll left/right/up/down, click one and it says to enter new accelerator. I press the arrow keys and nothing happens. Back to the help file. To define shortcuts, there's a special option you have to check in the prefs. Why??? If I'm going to the shortcuts window, it's a good bet that I want to configure them! So I check the Dynamic shortcuts option, go back to the shortcut prefs, click the option for scrolling, it says to enter new accelerator, I press the arrow keys and it still does nothing! Why do they have an option to change the shortcuts if you're not actually allowed to change the shortcuts???

Offline TerraEsperZ

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Re: GIMP 2.8.2 - Basic questions
« Reply #20 on: September 21, 2012, 08:54:30 pm »
I'll report back later on whatever successes and/or failures and/or annoyances I run into.

You're welcome.

I hope I didn't sound ungrateful there because that wasn't my intention at all. Just poking some fun at myself for not being very adaptable ;).

Anyway, I just wanted to chime in a bit more and thank you for suggesting GIMP to me. Right now, it looks somewhat improbable that I'll ever switch completely from MS Paint to it but it's already being useful for my The Final Fantasy Legend project. I've been slowly separating all the layers of the maps I've done so far not because it's really needed, but rather because I just love turning them on and off depending on what I want to show. Also, once I've moved on to the last few remaining maps, placing sprites and labels will be a lot easier than before.

I also have no problem using multiple programs, if it saves me time. And so far, GIMP definitely feels easier and more powerful than Paint Shop Pro 8 so the later will most likely be retired as far as I'm concerned.
« Last Edit: September 21, 2012, 08:54:46 pm by TerraEsperZ »
Current project:
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Offline GSA

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Re: GIMP 2.8.2 - Basic questions
« Reply #21 on: September 21, 2012, 11:47:13 pm »
In this post, I answer Rekrul about arrow keys in GIMP. (Note: I am only able to provide slow drop by drop answers as I'm very busy these days. I'm sorry.)

Plus, why can't you scroll an image with the arrow keys? Virtually every other program with a scrollable display allows the use of the arrow keys, but not GIMP.

Scrolling with arrow keys? Oh, you are so old school! :D

Actually, scrolling is much less efficient with arrows than what GIMP offers. In GIMP, you scroll by holding [either the middle mouse button or spacebar] and moving the mouse!

Really, it's so much faster that I wouldn't go back to old programs where I can't scroll with the mouse.

So I go into the prefs, find the shortcuts section, open the View options, find the ones for scroll left/right/up/down, click one and it says to enter new accelerator. I press the arrow keys and nothing happens. Back to the help file. To define shortcuts, there's a special option you have to check in the prefs. Why??? If I'm going to the shortcuts window, it's a good bet that I want to configure them! So I check the Dynamic shortcuts option, go back to the shortcut prefs, click the option for scrolling, it says to enter new accelerator, I press the arrow keys and it still does nothing! Why do they have an option to change the shortcuts if you're not actually allowed to change the shortcuts???

I don't know *everything* about GIMP, but I think some keys are not configurable because they have multiple functions. For instance, you can't change what "left click" does. Same goes for arrow keys; you can't configure them. (And I don't see why anyone would want to remap arrow keys.)

Speaking of this, the arrow keys are used to move layers around. For instance, right after pasting something, you can move the "floating selection" one pixel at a time with arrows or faster with shift+arrows. It's quite useful to align stuff.
« Last Edit: September 21, 2012, 11:50:09 pm by GSA »

Offline Rekrul

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Re: GIMP 2.8.2 - Basic questions
« Reply #22 on: September 22, 2012, 01:32:11 am »
Scrolling with arrow keys? Oh, you are so old school! :D

Actually, scrolling is much less efficient with arrows than what GIMP offers. In GIMP, you scroll by holding [either the middle mouse button or spacebar] and moving the mouse!

Really, it's so much faster that I wouldn't go back to old programs where I can't scroll with the mouse.

I suppose so, it's just that it's so ingrained and intuitive that I can't help reaching for the arrow keys when I want to scroll.

I don't know *everything* about GIMP, but I think some keys are not configurable because they have multiple functions. For instance, you can't change what "left click" does. Same goes for arrow keys; you can't configure them. (And I don't see why anyone would want to remap arrow keys.)

Just as an experiment, I tried to remap CTRL-arrow and it told me that it was an invalid shortcut. However when pressing the arrow keys alone, absolutely nothing happens. I wish it would pop up a brief explanation so you're not left wondering. Like "We're sorry, but GIMP doesn't allow remapping that key".

Speaking of this, the arrow keys are used to move layers around. For instance, right after pasting something, you can move the "floating selection" one pixel at a time with arrows or faster with shift+arrows. It's quite useful to align stuff.

Yes, I agree. I've often wished that Ultimate Paint had the option to move things with some form of keyboard control. On the Amiga I used to use the keyboard equivalents for moving the mouse in some cases, just to get more precise control. I know I could turn on Mouse Keys, but it's always nicer when the program offers it. :)

Offline GSA

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Re: GIMP 2.8.2 - Basic questions
« Reply #23 on: October 14, 2012, 02:20:56 pm »
I'm back. It's been more than 3 weeks since my last post and I apologize for the delay but I had to take care of other things.

In this post, I answer Rekrul about...


About copy and paste.
OK, I just tried it again, following your instructions.

I made a square selection, pressed CTRL-C, then CTRL-V. The pointer changed to an anchor, but nothing else happened.
Let me stop you right there. It looks like nothing happened but if you looked at the layers dialog, you would have seen that your selection was copied in a "floating" layer (meaning that the operation was indeed successful). The pointer changing to an anchor means that you will anchor the selection if you click.

I clicked outside the selection and the box went away, but then I had to press CTRL-V again to make the copy appear.
You anchored the first floating selection and you pasted a new one. You could have used the first one instead.

Moved it to where I wanted, clicked outside the box and it pasted it.
When you press CTRL-V it pastes the selection. When you click outside the box, it anchors the selection. (Just to make sure you understand the terminology and what's going on.)

If I wanted to paste additional copies, I had to press CTRL-V again for each one.
If you paste a new copy, the previous one will be anchored automatically (saving some time). Doing multiple CTRL-V shouldn't be noticeably slower than Ultimate Paint "stamping" method assuming that you keep your left hand on CTRL-V and your right hand on the mouse/arrows the whole time.



About GIMP lacking an error message.
Just as an experiment, I tried to remap CTRL-arrow and it told me that it was an invalid shortcut. However when pressing the arrow keys alone, absolutely nothing happens. I wish it would pop up a brief explanation so you're not left wondering. Like "We're sorry, but GIMP doesn't allow remapping that key".
Not including every error message is generally a bad practice and this is a legitimate complaint from your part. However, I'd like you to keep in mind that GIMP is a free software made by a team of volunteers (anyone really). They don't have full time employees dedicated to QA testing and as such, it is expectable that they wouldn't think about every invalid use case.

I am not involved with GIMP development myself, but you could submit a bug report if it matters.



About multiple selections
Can Gimp allow you to make multiple, unconnected selections at the same time?
Yes. Hold [Shift] while making a new selection to add it to the previous selection. Hold [Ctrl] to subtract the new selection from the previous one. And more rarely needed, hold [Shift]+[Ctrl] to intersect the new selection with the previous one (intersecting means to keep only the part that is shared by both selections).

You can use this in inventive ways. For instance, you could select a box then remove a color with [Ctrl] and the color select tool to keep the inside of the box that's not of that color.

I actually needed to do this for a project I did.

I wanted to make a scan of the copy protection codewheel for the C64 game Demon Stalkers, but I didn't want to rip my original codewheel apart to do it. So I drew two pencil lines on the back at the 12 & 9 O'clock positions and placed two pieces of tape on the edges of my scanner. I then aligned the wheel to the first selection and made a scan. Then I turned it to the next one and made another scan. I did this 24 times, which gave me scans of all the words on the back wheel, nine at a time, visible through the windows in the front wheel. I marked the exact center of each scan, then created a blank copy of the back wheel by erasing one of the scans and filling it with the same color. I then loaded each scan and used the multi-select option to outline each of the nine windows and the center mark simultaneously. Once copied, I could switch to my copy of the back wheel, line up the center mark and paste in all nine words at once, which would automatically be in the right positions. I repeated this 24 times and ended up with a filled in copy of the back wheel.
It works. Personally I would have layered all the images in GIMP and then erased the plain part of each one except the last to see underneath. Then I would have aligned them if needed and "merged them down" for export. The advantage of working this way is if something goes wrong, you can go back and adjust the problematic layer independently.



About drawing with an image part.
Also, is there any way to select part of an image, copy it and then just draw with it, at the original size? Using Paste requires you to position the frame and then click outside to make it permanent. Using the copy in the brush panel shrinks the size to a thumbnail, seems to rotate the brush as it moves and blends the edges.

Can I just copy, say a 100x100 area of the image and then draw with it, with no change to the size, no blending and no rotation? Basically I'm looking for something similar to copy & paste, but where the copy becomes your brush, follows the pointer around and you just use the left button to stamp it down, or hold the button and move the mouse to draw with it.
Yes, you can. However, you won't see it follow your cursor like in Ultimate Paint (you'll only see the outline). If you need to precisely see what you are going to stamp, use copy and paste. For drawing, you were in the right direction with the brush panel "clipboard brush". To prevent size change, you must click the small icon next to "size" (in the tool options) called "Reset size to brush's native size".

Use the pencil tool instead of the paintbrush tool to get rid of the blending.

About the rotation, I don't understand. Make sure "Angle" is set to 0 and if you are drawing with a tablet, check the "dynamics" options.