Re: [Gimp-user] how to apply a stepping curve
Hi all, On Mon, Mar 21, 2011 at 7:09 PM, rich for...@gimpusers.com wrote: I think you will have to fake it. Draw the curve and keep it as a path. Assuming you want (say) the x-axis to have equal increments, set up the grid, enable snap-to-grid, and paint constraining the line with shift for point-to-point and ctrl for angles ... here's how to use the path as specification for a curves-alike color mapping: 0. Install Rob Antonishen's Sample Gradient along Path Script [1] 1. Create image 256x256 pixels 2. Draw gradient black to white from bottom to top 3. Create the desired curve as a path 4. Create a new gradient via sample gradient along path - with 256 steps and - sample radius = 1 5. Switch to target image 6. Apply Colors-Map-Gradient Map not for the faint of heart... regards, peter [1] http://ffaat.pointclark.net/blog/archives/155-GIMP-Script-Sample-a-Gradient-along-a-Path.html ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Layer masks: how do you memorize which color means opaque?
On 19.10.2010 11:48, Ofnuts wrote: On 10/19/2010 11:32 AM, yahvuu wrote: On 11.10.2010 18:29, Chris Mohler wrote: On Sun, Oct 10, 2010 at 2:18 PM, Patrick Horganphorg...@yahoo.com wrote: i'm curious how other people regard layer masks. In particular, which memory aids exist to remember when to use black and when to use white. I think of it like illumination. Cool. I think of it as a window or transparent overlay. Thank you very much, Patrick and Chris, for sharing your style of thinking. It's very interesting to learn how different the mental concepts/mnemonics are. If other variations are in use, please keep em coming! One can't look under the bride's dress :-) not bad! Those who wear black probably have a wet press background :-) ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Layer masks: how do you memorize which color means opaque?
On 11.10.2010 18:29, Chris Mohler wrote: On Sun, Oct 10, 2010 at 2:18 PM, Patrick Horganphorg...@yahoo.com wrote: i'm curious how other people regard layer masks. In particular, which memory aids exist to remember when to use black and when to use white. I think of it like illumination. Cool. I think of it as a window or transparent overlay. Thank you very much, Patrick and Chris, for sharing your style of thinking. It's very interesting to learn how different the mental concepts/mnemonics are. If other variations are in use, please keep em coming! regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
[Gimp-user] Layer masks: how do you memorize which color means opaque?
Hi, i'm curious how other people regard layer masks. In particular, which memory aids exist to remember when to use black and when to use white. Two contradicting examples which both seem to survive inside my head: - the (correct) math perspective: black equals zero, zero opacity means fully transparent - the (wrong) book example: black is where the letters are printed, that is where the layer is active, that is opaque. This one frequently lets me stumble for a split second, especially when working on a mostly opaque mask over a white background layer.. Obviously, the very question tells i'm using masks not that often.. How do you handle the situation? Do you use a memory aid to remember when to use black and when to use white? Or does it seem just natural to you, so you don't have to think (anymore)? How do you explain the white means opaque relationship when teaching masks to other people? regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] how to get middle path of text
On 07.10.2010 04:50, 黄毅 wrote: For example, I have text like this: Screenshot.png Text to path would give me this: Screenshot-1.png But what i want is this: Screenshot-2.png How can i do that automaticaly, google don't help me with that. Thanks. this might or might not help: morphological thinning springs to mind, as explained e.g. here: http://homepages.inf.ed.ac.uk/rbf/HIPR2/thin.htm regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] How do I delete to transparency?
On 02.10.2010 02:50, bobdobbs wrote: How can I figure out what the result of deletion operations on pixels will be? for the record, i just learned that a bold layer name indicates a missing alpha channel (as displayed in the layers dialog): http://docs.gimp.org/2.6/en/gimp-dialogs-structure.html#gimp-layer-dialog -peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] How do I delete to transparency?
On 30.09.2010 05:39, bobdobbs wrote: Hi all. I'd like to delete in such a way that transparency remains. I've found that this is the default when I'm working on images that I've created myself. But if I'm working on an image that I've downloaded or gotten from another source, I can't predict the behaviour of functions that remove pixels. In my immediate case, I've got a icon with a white background. I want to remove the background. However, when I try to remove the white pixels, the result is black pixels. How can I figure out what the result of deletion operations on pixels will be? How can I consistantly remove colour, leaving transparency? short answer: always add an alpha channel to the layer, either using the layers dialog or via Layers-Transparency-Add Alpha Channel [1]. The alpha channel determines the transparency for each pixel. The absence of an alpha channel means that all pixels are fully opaque and hence they get deleted to background color [2]. regards, peter [1] http://docs.gimp.org/2.6/en/gimp-layer-alpha-add.html [2] http://docs.gimp.org/2.6/en/gimp-image-combining.html#gimp-layer-properties ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Create From Clipboard -- Pasted Layer -- Problems Printing
On 01.09.2010 19:22, Jay Smith wrote: So, why do I have to save the image to a file... [..] - before the size is stated more reasonably Hi Jay, you'll be pleased to hear that the next release of GIMP will enable you to display the Megapixel count by configuring the status bar messsage. The corresponding change has just been pushed to git master. regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Create From Clipboard -- Pasted Layer -- Problems Printing
On 01.09.2010 19:22, Jay Smith wrote: So, I created a new image by doing the following. Select All in original image. Copy File, Create, From Clipboard Creates a new image that looks like the previous. I change the size (scale) to something more suitable for printing. AT THIS POINT I HAVE **NOT** SAVED THIS NEWLY CREATED IMAGE. THAT IS IMPORTANT. When I HOVER OVER AND look in the bottom status bar of the window containing the newly created image, it says Pasted Layer and gives a size in MB, about 20 MB. I say to myself Self, that does not look right. I do Flatten Image, I do Merge Layers, etc. The Pasted Layer text remains, but the size keeps increasing in roughly 20 MB jumps. Hi Jay, what gets displayed is the total amount of memory GIMP reserves for that image. For various (good) reasons, this is usually much more memory than required to hold a 'flattened down' version of that image. Have a look at Image-Image Properties: the first tab 'Properties' details a bit how the memory gets used. A good share is required for the undo/redo functionality. That is the reason why shrinking an image doesn't free much memory, if at all: the previous version is still kept in memory in case you want to undo the shrinking. When I look in the layer dialog, it only shows one layer. However, when I click the eyeball the picture disappears and I get a gray checkerboard, so there is something more present than just that one layer. No, that's a fallacy: the checkerboard isn't part of the image. It gets shown so you can identify transparent areas of your image. And if you hide all layers, your image becomes fully transparent. So, to get a SaveAs dialog, I start to Close the image (I know, that is a strange way to do it) and select Save, getting the SaveAs dialog. I save it to .jpg and accept the current defaults. Thus it is now closed and has an actual image name. I reopen the image. Now when I HOVER OVER AND look in the bottom status bar of the window containing the image, it now says Background and has a 3.9 MB size (completely reasonable). Everything is normal. It prints perfectly fine and quickly. So, why do I have to save the image to a file... - before I can print it? you shouldn't have to. Something is going wrong here... - before the Pasted Layer text goes away (and becomes Background)? The statusbar shows the name of the active layer and Pasted Layer is just the name of the newly pasted layer. When you store the file as JPEG, that name gets lost because JPEG does not support layers. On re-opening the default name 'Background' gets chosen. - before the size is stated more reasonably what is relevant for the amount of data that gets sent to the printer is the number of pixels, not how much memory GIMP consumes for your image. You already did rough estimes based on the pixel count and that is correct. Is this a problem with my (fairly elderly) printer vs Gimp's native while-in-editing file format? no Am I doing something wrong? possibly. Are you shure you used *Image*-Scale instead of Layer-Scale? That might explain the unexpected behaviour. It is no big deal to save and close the image to a file and then re-open it in order to print. It is not going to ruin my day. But, it seems very strange to have to do that (and has not been necessary in some other image editing programs I have used), thus my query. you are right, that should not be the normal mode of operation! A hint to possibly track down the problem: saving as JPEG and re-opening effectively flattens the image for you (and as a side-effect the memory required for undo/redo gets freed, as you have observed). regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Biggest Frustration
On 22.06.2010 00:30, Alexandre Prokoudine wrote: Well, it looks like slightly improved existing Move tool to me :) Actually, i was thinking of a pure object selection tool without any manipulation functionality. Just to choose the current paint context without obscuring it, and without having to resort to the layers dialog. Somewhat paradoxically, this would be my favourite tool for color adjustments. regards, yahvuu ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Biggest Frustration
On 22.06.2010 18:42, Alexandre Prokoudine wrote: On 6/22/10, yahvuu wrote: Actually, i was thinking of a pure object selection tool without any manipulation functionality. Just to choose the current paint context without obscuring it, and without having to resort to the layers dialog. In the times of transformation tools to be merged and some selection tools to be merged as well a tool for just selection sounds a bit limiting, don't you think? :) not limiting, but liberating ;) An object picker nicely complements the unified transformation tool. Using the latter to select objects is like taking the sledgehammer to crack a nut: it takes quite some attention to select without accidentally moving things and additionally, the transform tool's handle will obscure parts of the target. Somewhat paradoxically, this would be my favourite tool for color adjustments. For what color adjustments precisely? anything from the 'Color' menu as well as filters. An object picker might also be regarded as a 'Menu target selection tool'. You are right though, that peter is striving hard to cut down the tool count... - yahvuu ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Biggest Frustration
On 22.06.2010 20:28, Sven Neumann wrote: On Tue, 2010-06-22 at 17:55 +0200, yahvuu wrote: On 22.06.2010 00:30, Alexandre Prokoudine wrote: Well, it looks like slightly improved existing Move tool to me :) Actually, i was thinking of a pure object selection tool without any manipulation functionality. Just to choose the current paint context without obscuring it, and without having to resort to the layers dialog. Somewhat paradoxically, this would be my favourite tool for color adjustments. And why does the Move tool not work for you then? It allows you to select a layer simply by clicking into the image. Perhaps you missed the Set layer or path as active option in the Preferences dialog? No, the problem with the move tool is that it requires attention to select a layer without accidentally moving it. You really have to stop the mouse and keep it fixed while clicking. Or did i miss some other option? regards, yahvuu ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Biggest Frustration
On 22.06.2010 21:12, Branko Vukelic wrote: On Tue, Jun 22, 2010 at 9:08 PM, yahvuuyah...@gmail.com wrote: No, the problem with the move tool is that it requires attention to select a layer without accidentally moving it. You really have to stop the mouse and keep it fixed while clicking. Or did i miss some other option? I use Gimp with a tablet. And you know how tablets are. There's no way you can stop the cursor in place. But the move tool still doesn't accidentally move stuff around for me. And I don't think I've got some serious mouse-fu... well, possibly it's just me (and i'm not too fond of mice, anyway). I actually trained myself to activate the rectangle selection tool while doing color adjustments -- after struggling with a serious of images which contained miraculously slightly off-moved layers... regards, yahvuu ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Biggest Frustration
On 22.06.2010 21:26, Branko Vukelic wrote: On Tue, Jun 22, 2010 at 9:23 PM, yahvuuyah...@gmail.com wrote: well, possibly it's just me (and i'm not too fond of mice, anyway). I actually trained myself to activate the rectangle selection tool while doing color adjustments -- after struggling with a serious of images which contained miraculously slightly off-moved layers... Wasn't it easier to just use the layers palette? thanks, but i refuse to select layers by their thumbnails in the layers dialog, when i can just click them right there in image! .-) With one hand on the keyboard, tools can be switched quite fast.. thanks anyway, yahvuu ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Biggest Frustration
On 22.06.2010 21:47, Alexandre Prokoudine wrote: On 6/22/10, yahvuu wrote: And why does the Move tool not work for you then? It allows you to select a layer simply by clicking into the image. Perhaps you missed the Set layer or path as active option in the Preferences dialog? No, the problem with the move tool is that it requires attention to select a layer without accidentally moving it. There is no such problem. Look at the tool's options palette. The default mode is to select, not move. that gives hope, it's just that i can't reproduce... The active options reads Pick a layer or guide, but when i start dragging, the freshly picked layer gets moved. The Preferences option given by Sven determines wether a picked and or moved layer will be activated after the operation but doesn't change anything else. At least that's the behaviour i'm used too (and just checked). now i'm really astonished, yahvuu (running git master from last week on kubuntu, in case that matters...) ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Biggest Frustration
On 22.06.2010 21:50, Alexandre Prokoudine wrote: On 6/22/10, yahvuu wrote: thanks, but i refuse to select layers by their thumbnails in the layers dialog, when i can just click them right there in image! .-) That is, you refuse to work on images with layers completely overlapping other layers? :) quoting myself: when i *can* just click them right there in image! as a sidenode, it's indeed an interesting question why completely overlapping layers get stacked. Probably quite some cases of 'layer abuse' can be found in such images. But let's get this thread closed gracefully :_) regards, yahvuu ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Biggest Frustration
Hey Alexandre, hopefully this doesn't compromise your health, but an object picker has already been proposed (which is my fault) [1], and for good reason: If you take non-destructive editing serious, you inevitably end up with a finer granularity of adjustability than with the current scheme -- hence objects [2]. This is not my fault, but GEGL's. Should also produce a little relief for those poor little abused layers ;-) Nobody is allowed to die until GIMP is finished! - yahvuu [1] http://gimp-brainstorm.blogspot.com/2009/06/object-picker.html [2] http://gimp-brainstorm.blogspot.com/2009/06/objects-within-layers.html ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Enlarge Canvas: Is there a way to do it by dragging? Could/Should there be?
Jay Smith wrote: It just occurred to me that it would be really handy to be able to enlarge the _canvas_ by dragging. Hi Jay, that's a cool idea! Be shure to post it to the brainstorm so it doesn't get lost -- the UI team is listening there [1]. - Layers: The Resize Layers (when changing canvas size) issue that we have been discussing the last couple of days rears its ugly head here. In order for this suggested drag feature to work, the user must have control of the Resize Layers setting. no need to worry, for a brainstorm posting it is fully valid to assume that layer sizes get managed automatically. - Floating Selection: This drag feature must be possible while a floating selection is currently active and floating. That is part of the point; that the canvas was not big enough to put the floating selection where I want to put it, thus I am increasing the canvas size. Same goes here: to develop your idea, you can just pretend there were no floating selections getting in your way. It often helps to make some idealizing assumptions so an idea can be worked out as clear as possible. To subsequently determine if and how a new concept fits into GIMP is a delicate task and best carried out by the UI team anyway. regards, peter PS: If you're seeking further discussion of your idea, feel free to post on the developer's list. [1] http://gimp-brainstorm.blogspot.com/ ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] ?? Status of remembering Layers setting for Canvas Resizing -- in most recent version
Jay Smith wrote: On 03/10/2010 03:27 PM, yahvuu wrote: Martin Nordholts wrote: 2010/3/10 yahvuu yah...@gmail.com: Each of these dialog options points at a potential interaction problem. If the dialog remembers an option, the user also has to remember that option. In general, this amounts to additional cognitive burden to keep the mental model in sync with the application state. Hmm I don't understand, how would there be additional cognitive burden on users if a dialog remembers a setting across invocations? You are right, that was an invalid generalisation. I was thinking of the 'New Layer' dialog where the 'fill' option tends to get in the way. (If i leave that option to a fixed value -- like a prefs item -- there's no problem, i can just hit enter to create the new layer. If i, however, do change this value, i'd better remember this the next time i create a new layer.) [..] I am not convinced that the 'New Layer' example given presents a better situation as described. well, it additionally depends on the task at hand -- which tells that it was bad idea to hold the dialog state responsible for getting in the way. This cannot be generalized. Allow me to rephrase my original point: Each of said dialog options can potentially get in the way of smooth workflows and is worth being questioned. Now for my example where it's indeed the dialog state that is counter-productive: For the New Layer dialog, the crucial question is wether the next layer will be created with the same fill as the last one. If that assumption holds true most of the time, then a stateful option is useful, as you described here: In the 'New Layer' example given, if I am doing a certain repetitive task, it is *highly* likely that I will want the new layer to have the same fill every time I do that function. There is a significant burden in having to change this setting _every_ time. (And to make it worse, some of these settings are not so easily accessible via keyboard, thus wrecking my shoulder from mousing too much.) If however, say, a mixed stack of 10 transparent layers and 5 colored layers is to be created, then using the stateful option becomes a burden: The user is forced to read and potentially adjust its value for each new layer. In this case, it is more efficient to leave to the fill option to 'transparent' and manually fill the layer later on, if required. Why? Because it can be done blindly, at least when using the keyboard (see below). So, which is better: a) Knowing that the program will always force a default value and having to change it much of the time (in my case for Canvas Resizing, ALL the time). b) Knowing that the user is responsible to paying attention to what the value says when they get to the dialog and if it is correct for the task (which it will then be, once the user has set it, until later changed by the user). Sorry, i cannot give a useful general answer here. Consider e.g. the Gaussian Blur filter, whose radius setting matches both a) and b). For the New Layer dialog, i'd prefer: c) Always create a transparent layer, without showing a dialog. Then let the user fill the new layer if desired (not considering layer size here). This works nicely for a keyboard workflow: CTRL-SHIFT-N, CTRL-. Fast, no confirmation required and no application state has to be remembered. An open question is how to make this fast for a mouse only / tablet user. For your original case of Canvas Resizing, i fully agree that the dialog should remember the 'resize layers' option (until we get auto-sizing layers, of course). regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] ?? Status of remembering Layers setting for Canvas Resizing -- in most recent version
Hi, Jay Smith wrote: Image Canvas Size in the Set Image Canvas Size dialog in the Layers section at the bottom there are five different possible settings, including None, All Layers, etc. etc. In Gimp 2.6.6 (Ubuntu Linux 8.04) this defaults to None and ALWAYS remains none EVERY time I go to the dialog, even if I had it changed to something else on this image or a previous image. I believe that this setting should be remembered a) during the session of editing an image; b) during all sessions editing all images; and c) between sessions of shutting down and restarting Gimp. [..] It seems to me that there are quite a few of these situations in Gimp. I know it is a big PITA, but eventually, I think they should all get remembered as the last-used state *where appropriate*. I fully realize that it is *not appropriate* to remember last used state in all situations. Is there an organized checklist of all this stuff that we could work through? Another point of view: Each of these dialog options points at a potential interaction problem. If the dialog remembers an option, the user also has to remember that option. In general, this amounts to additional cognitive burden to keep the mental model in sync with the application state. In consequence, each of these settings is worth beeing questioned and every potential solution to get rid of such an option is worth a posting on the brainstorm. For example, the Image-Canvas Size |resize layers| option, with which you started this thread, can be obliterated by automatic layer size management. regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] ?? Status of remembering Layers setting for Canvas Resizing -- in most recent version
Martin Nordholts wrote: 2010/3/10 yahvuu yah...@gmail.com: Each of these dialog options points at a potential interaction problem. If the dialog remembers an option, the user also has to remember that option. In general, this amounts to additional cognitive burden to keep the mental model in sync with the application state. Hmm I don't understand, how would there be additional cognitive burden on users if a dialog remembers a setting across invocations? You are right, that was an invalid generalisation. I was thinking of the 'New Layer' dialog where the 'fill' option tends to get in the way. (If i leave that option to a fixed value -- like a prefs item -- there's no problem, i can just hit enter to create the new layer. If i, however, do change this value, i'd better remember this the next time i create a new layer.) The more options we can get rid of, the better. yep, that's what i was after regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] How to make a set of curves
Hi Tőkés, Tőkés Ábel wrote: Solved. [..] Sorry for bothering. Not at all: thank you for posting the solution! Somebody with a similar problem will find it in the archives. regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] collages in gimp?
hi, Gracia M. Littauer wrote: any way to easiely make a collage...I know I can add pix to a new image. But I would love something that picasa photoshop seem to have. then why not use picasa? At least it is free as in 'free beer'. regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] how to invert greyscale values only...
Rich Evans wrote: That's it! Perfect. glad to hear it works as expected. Just want to add that the programmer's route, aka doing it by the math, is quite viable, too. Some selected options: - the MathMap plugin probably enables the most concise solution: http://www.complang.tuwien.ac.at/schani/mathmap/ - with knowledge in C, it's not a big step to prototype using either Lua (the gluas plugin) or the built-in python-fu. - a plain C plugin gives the best processing speed at the price of the slowest development cycle. In lieu of being able to buy everyone who helped a round of beer, is there a way for me to show my gratitude to the GIMP community? Would a donation to GIMP help you guys? New contributors are always welcome! There are plenty of opportunities to help the project, by far it's not just about coding [1]. And posing useful problems here is already helpful, too. Of course, donations are always welcome [2]. regards, peter [1] http://www.gimp.org/develop [2] http://www.gimp.org/donating ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] how to invert greyscale values only...
hi, Rich Evans wrote: [..] Is there a technique or tool to invert any part of the image that is only a shade of grey? i.e. invert pixeils with a saturation of ~0 (if that is how you say it). The on-board tools are just fine for this. Do something to some pixels (here: invert) and leave the rest unchanged translates to: duplicate the layer, do that something and apply a suitable layer mask. Where the layer mask is white, the modified pixels from the top layer are visible, otherwise the unchanged pixels from the bottom layer show through. So a layer mask is needed which equates the image's saturation, such that it is white (= show inverted pixels) where the saturation is zero (or close to zero). The saturation gets calculated during conversion to the HSV color model: Color-Components-Decompose delivers a saturation layer. The lighter this layers is, the more saturation the corresponding image pixel has. In consequence, it must be inverted. To further mask out image pixels, which are not close to a saturation of 0, a threshold of 254 can be applied. (More on that later). Using this layer as a layer mask for the inverted layer will reveal wether this train of thought is correct... The steps: 1. Create inverse copy of picture Duplicate the picture layer Invert that new layer 2. Create HSV color separation Select picture layer and do Colors-Components-Decompose (color model HSV), which creates a new image. Copy the saturation layer to your original image. (simply drag the layer from the layers dialog to the image window.) Invert that new layer (for better finetuning, we'll do the thresholding later) 3. Turn saturation layer into a layer mask for the inverted picture crude hack somebody please help out and insert a sane way to copy a layer to another layer's mask With saturation layer: Add Layer Mask (Grayscale copy of layer) Mask to Selection Delete the saturation layer (all required information is in the selection mask) With the inverted picture layer: Add Layer Mask (Selection) Select-None /crude hack now we're basicly done 4. Fine-tuning of layer mask Select newly created layer mask According to the question, now a Colors-Threshold of 254 should be applied, but Color-Levels and dragging the middle slider to the right gives better control. Don't expect the saturation mask to be perfect, some rounding errors due to 8bit resolution might show up. have fun, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] whan means tube button ?
hi, Cristian Secară wrote: On Wed, 3 Feb 2010 12:44:33 +0100, Simon Budig wrote: Ok, I go to http://gimp.org. Where are the tubes ? In the past. The tube on our homepage is long history... :-) If so, then it would be better to remove the particular reference to gimp.org from that tooltips ? the old homepage survived on http://classic.gimp.org I think it's best to just change the reference to that address. (unless someone dares to remove these scripts from core GIMP) regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Hue GUI
Hi Cédric, Cédric Gémy wrote: i find this rainbow UI really nice because it lets you quite easily (gimp curve-like) modify any hue of the document. looks fine, thank you. Be sure to compile a posting for the UI brainstorm, so the idea doesn't get lost: http://gimp-brainstorm.blogspot.com/ regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Sampling Toned Images
hi, Bryan wrote: Peter, thanks for reponding. I have the same version as you do. What I did was save a sample file from the site I was on to use in my learning. All I did was save it in the same directory as my own image but maybe I need to store that sample image in a specific location in order to access it for this purpose? No, location is irrelevant. You need to open both images in GIMP, both the sample image as well as the the image you want to colorize. The drop down boxes in question show a list of all opened images and the layers contained therein. regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Sampling Toned Images
Bryan wrote: [..] If I open up the drop down selector above the sample image, the only choices I have are My own image file name, or From Gradient, or From Reverse Gradient. ahh, possibly your sample image is a GIF? Please check the Image-Mode menu and make shure it is set to RGB. That's an ugly pitfall, because many operations only work on RGB images and GIF images are loaded as indexed color images (=256 color only). Same goes for grayscale images. regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] gimp wiki offline, where is a mirror
photocomix wrote: Nobody know ? Gimp wiki is still offline but i remember well that somebody advice that was always possible get the same page from a mirror somewhere The problem is that i can't find the mirror, searching didn't helped me. (and usual tricks, as search in the internet archive failed too= http://web.archive.org/web/20080225114447/wiki.gimp.org/gimp/ have fun, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] JPG file size increases with saving
Frank Gore wrote: But a much better and simpler idea is to just use a number range from 1..13, similar to photoshop. I'll take that over to the developer's list. I disagree, I think Photoshop's way of displaying the JPG compression slider is ridiculous. You can move the slider back and forth within a very wide range before the corresponding number changes. And since the slider doesn't spring back to a pre-determined spot on the line, that means one could select a different grade of level 8 depending on where the slider is positioned. You can actually see this by looking at the file size. If I select the lower range of level 8, the file is smaller than if I pick the higher range of level 8. I fully agree that this is bad design. If there are interstages of say, 8.0 8.25 8.5 and 8.75, those clearly have to be displayed. regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Create a clickable hotspot?
hi BGP, BGP wrote: How do I create a clickable hotspot in GIMP? Filters-Web-Image Map will do the job. Documentation is here: http://docs.gimp.org/2.6/en/plug-in-imagemap.html have fun, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] JPG file size increases with saving
Norman Silverstone wrote: Here is a table that provides an approximate mapping between Photoshop quality levels and GIMP (actually IJG JPEG library) quality levels: Adobe Photoshop quality 12 = GIMP quality 98, subsampling 1x1 [..] wow, i grossly underestimated the influence of the advanced parameters: Subsampling 1x1 ist even more important than the quality slider for images with sharp edges.. In the meantime, i stumbled across a blog entry which also compares Photoshop's 'save to web' results: http://blogs.gnome.org/raphael/2007/10/23/mapping-jpeg-compression-levels-between-adobe-photoshop-and-gimp-24/ regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] JPG file size increases with saving
Philip Rhoades wrote: It still seems counter intuitive that opening a JPG (even if it is a photo rather than a computer generated image) and immediately saving it with 100% quality increases the size by 2.5 . . so you mean the scale should be different? Like 1 .. 10 ... 100 ... 10 ^ ^ | \ extravagant luxury quality for the filthy rich current 90 default i'm not shure if that would not create even more confusion... regards, peter PS: as Michael Schumacher previously noted, the quality value is indeed just a number, not a percentage. ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] JPG file size increases with saving
Philip Rhoades wrote: Peter, On 2010-01-18 20:40, yahvuu wrote: Philip Rhoades wrote: It still seems counter intuitive that opening a JPG (even if it is a photo rather than a computer generated image) and immediately saving it with 100% quality increases the size by 2.5 . . so you mean the scale should be different? Like 1 .. 10 ... 100 ... 10 ^ ^ | \ extravagant luxury quality for the filthy rich current 90 default ?? - that's an odd comment . . oh yeah, i should have been more clear. Now that you and me and probably a few others have learned something new about JPG peculiarities, i was brainstorming how the user interface could be tweaked to avoid misleading associations. Above diagram was intended to depict a logarithmic scale for the quality value, where the numbers relate to the typical growth in file size [1]. But a much better and simpler idea is to just use a number range from 1..13, similar to photoshop. I'll take that over to the developer's list. regards, peter [1] http://en.wikipedia.org/wiki/File:Quality_comparison_jpg_vs_saveforweb.jpg ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] JPG file size increases with saving
Hi Philip, Philip Rhoades wrote: - When saving as JPG with 85% quality am I losing information? JPG utilizes lossy compression, which means you'll loose information every time you save as JPG, even at 100% quality setting. That value does not specify the percentage of information stored in the JPG. It is just a number which allows to choose a trade-off between subjective image quality and file size. In consequence, the workflow recommendation is to routinely save as XCF and only create a JPG when the (finished) work leaves your system. - How can saving as JPG with 100% quality increase information (file size)? As said above, it is wrong to assume you were saving 100% of the 85% of the original image's information here. In practice, one has to look at the compression artifacts to be able to adjust for minimum file size at acceptable quality. There's no way to just rely on the numbers. What happens in detail: when opening the JPG it gets decompressed to 2048x1536 RGB pixels of 3 bytes each, a whopping total of 9437184 bytes of RAM. (This holds true for any color JPG of 2048x1536 size, regardless of file size). Now when saving this image as JPG, it's these 9437184 byte of image that get compressed, regardless from where this data originated. Compressing an image of 9437184 bytes at 100% gives a larger file size than compressing the same image at 85%. There's no memory of previously used compression rates. And regardless of file size, each new JPG compression step adds new artifacts to the image, degrading quality. - Why is PNG so inefficient? PNG offers lossless compression and isn't designed for use with photos. It excels at graphic data which e.g. has uniform color areas. regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] JPG file size increases with saving
Philip Rhoades wrote: What still doesn't make sense is that if the original file is JPG and one simply opens it and then saves it as another JPG file with 100% quality - you are saying that introduced artifacts are adding about 150% to the file size? (681 KB to 1.618 MB) How could the compression algorithms be so different as to cause this sort of result? - At worst I would have expected maybe a 10% increase in size . . well firstly, 1.6MB are not that bad in comparison to 9MB of raw RGB data, right? (just try saving to uncompressed BMP as Greg suggested). Btw, 100% quality for JPG gives very little visible advantage over the default 90% setting. The relationship between quality value, file size and perceived image quality is very delicate. Any assertion has to be made with a lot of weasel words. So yes, compression artifacts have a tendency to hinder compression, resulting in larger file sizes after re-compression to comparable quality. A similar effect is caused by noise. So to get optimal JPG files, it's best to use a RAW-XCF-JPG workflow where the JPG is created only once. Just have a look at the advanced settings in the JPG save dialog to get a first impression of what machinery is at work here. There also was a very long thread on gimp.developer on that very quality setting... How does image quality compare if you adjust the quality slider such that the resulting file size is about 680KB? regards, peter ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Luminosity blend mode
hi, Yang Zhang wrote: Is there anything in GIMP that's equivalent to Photoshop's luminosity blend mode? what comes closest is 'value' mode. regards, yahvuu ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] sky question
Joel Glanfield schrieb: Just curious about how to change sky-colors like you see in a lot of professional photographs. Hi Joel, just shoot your photos around sunrise/sunset (at the right day). Ken Rockwell explains: Most people never see colors like this because they live indoors, work in an office, drive to and from work, and live in a house. These colors happen outdoors in nature. The peak color, which are the shots I show, only exists for 60 seconds at most, if it happens at all, any given day http://www.kenrockwell.com/tech/color.htm For changing colors using gimp, you can play with the various commands in the color section, e.g. Hue-Saturation greetings, peter related: http://www.kenrockwell.com/tech/timing.htm ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
