I'm working on a website design in gimp. I really love the figures and math equations at University of Iowa's stats website (http://www.stat.uiowa.edu/). I would like to create something like this, perhaps do handrawn equations and figures and scan it in.
Once I have the appropriate image, how could I turn it into a transparent image that I can overlay onto a header (in gimp)?
Thanks
I would scan some diagrams and handwritten math equations . Then I would open it from gimp. After you done it you can go to --> colours and use Desaturate. You can use any method from there. There are only 3. See which one looks the best on your photo. After you got black and white photo go to colours and choose --> Posterise and use it with level set to 2. After this you go to --> Layers --> Transparency and choose Colours to Alpha. Choose white to remove the background. After this save you image as . png file. You should scan possible black and white image. You can write some diagrams on white paper without lines of print some diagrams and math equation. If you got scanner you can also set the settings to scann only in two colours and then you do not have to use Desaturation. I hope this will help you.
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Let's say I have an image with a few colors.
I would like to replace programmatically a specific existing color by a new one.
(something simple, no need to support gradients, like I saw elsewhere).
E.g. I have an image showing a green circle and I want to display it as a red circle (every pixel initially defined with a given (R,G,B) is now displayed with a new (R,G,B).
Any idea of how to do that with the Apple ios SDK ? (or open source ...)
And btw what would be the best image file format to make this easier (png, jpg ....) ?
Thanks !
You should be able to do this using Core Image filters. the Color Cube CI filter lets you map a source color range to destination colors. You should be able to define a source color range and map it to different colors.
That's one CI Filter I didn't figure out how to use however. If you do a search on "Color Cube" in the Xcode help system there is sample code that does a "chromakey" effect that knocks out green shades to transparent. You should be able to adapt that to your needs.
I have a project on Github called CIFilterTest that shows how to use Core Image filters to process images. It's written as a general-purpose system that lets you try a wide variety of filters that use a standard set of parameters (points, colors, 1 or 2 source images, and floating-point values.) I never did take the time to generate the 3D color mapping "cube" that the color cube filter needs as input, so it doesn't allow you to use that particular filter. You'll have to look at the color Cube sample code in the Xcode docs to generate inputs for the Color Cube filter, but my sample app should help a great deal with the basic setup for doing CI based image processing.
answered similar question here:
Replace particular color of image in iOS
in short: I would suggest using CoreImage filter.
Using GIMP, I am attempting to generate a large number of the same image but with different colors. In order to preserve the "shadowing", I am using the below steps. These steps get me exactly what I want in the end. The problem is, it's very tedious repeating them by hand over and over. There has to be a better way.
GIMP's batch scripting seems a little daunting, so I'm hoping to get some suggestions on how to automate this. Basically, what would be nice, is I'd like to essentially specify an array or list of colors...and then "automagically" perform the steps below to generate the output with the desired color.
Steps I'm doing by hand...
1.) Load a base PNG file that has an alpha channel.
2.) Add a new transparent layer.
3.) Activate the layer.
4.) Change mode to "multiply".
Then, for a range of different colors, I do the following...
5.) Select a foreground color.
6.) Apply bucket fill (fill similar colors, fill transparent areas, default threshold, fill by composite).
7.) Save the new PNG.
8.) Go to Step #5.
Here's kind of a cheesy representation of the effect I'm trying to achieve...
I'm also open to other non-GIMP suggestions as well.
Thanks for any and all help and suggestions.
I can offer you a nice Javascript example that do this.
try:
https://stackoverflow.com/a/9304367/1726419
there is a link there that actually do what you wand in JS - you can translate it to many other languages...
I'm making a GUI for selecting regions to crop from images. I have been using Seesaw and cans select rectangular regions, but cannot find a way to set an image to the background of seesaw.canvas. This suggests using icons on labels. Can I make a label paintable and then use it as a canvas? Is there a way to overlap a label and a canvas or somehow use a panel that gives a background to its contents?
I think Quil has this functionality, but I'm not sure how to build a GUI around its draw, setup, sketch form if I want add widgets.
Existing solutions would appreciated as well, as long as I can decompose them. Using GIMP or Photoshop isn't an option for the workflow I want: multiple crops per photo, of different kinds on each page and different metadata added depending on the type of image outlined. Any suggestions for libraries for working with metadata for photos? I was planning on using a shell interface to exiftool, but a more portable option may be better.
You can draw a java.awt.Image (or sub-class) to a canvas with seesaw.graphics/image-shape:
(require '[seesaw.graphics :as g])
(defn paint-canvas [c g2d]
(g/draw g2d (g/image-shape my-image 0 0) (g/style)))
It seems like that should do it.
Also note that labels (and all Seesaw widgets) are paintable. Just set the :paint option like on a canvas and paint away.
I want to replace the particular color of an image with other user selected color. While replacing color of image, I want to maintain the gradient effect of that original color. for example see the attached images.
I have tried to do so with CoreGraphics & I got success to replace color. But the replacing color do not maintain the gradient effect of the original color in the image.
Can someone help me on this? Is the CoreGraphics is right way to do this?
Thanks in advance.
After some struggling almost with the same problem (but with NSImage), made a category for replacing colors in NSImage which uses ColorCube CIFilter.
https://github.com/braginets/NSImage-replace-color
inspired by this code for UIImage (also uses CIColorCube):
https://github.com/vhbit/ColorCubeSample
I do a lot of color transfer/blend/replacement/swapping between images in my projects and have found the following publications very useful, both by Erik Reinhard:
Color Transfer Between Images
Real-Time Color Blending of Rendered and Captured Video
Unfortunately I can't post any source code (or images) right now because the results are being submitted to an upcoming conference, but I have implemented variations of the above algorithms with very pleasing results. I'm sure with some tweaks (and a bit of patience) you might be able to get what you're after!
EDIT:
Furthermore, the real challenge will lie in separating the different picture elements (e.g. isolating the wall). This is not unlike Photoshop's magic wand tool which obviously requires a lot of processing power and complex algorithms (and is still not perfect).
I'm trying to convert hundreds of images that
Have an unknown subject centered in the image
Have a white background
I've used ImageMagick's convert utility in the following way
convert ORIGINAL.jpg -fuzz 2% -matte -transparent "#FFFFFF" TRANSPARENT.png
The problem is, some of my subjects are within the "white" scale, so, just like the weatherman wearing a green tie, some of my subjects seem to be disitegrating.
Is there any way to solve this via ImageMagick? Are there any alternative solutions? Scripting GIMP?
As you said, GIMP has a magic wand tool that can be used to select continuous areas of the same color, and so it can avoid the "green tie syndrome". The problem is that it may introduce a problem if there is something like a human hair crossing the image (that will seperate some of the white areas). Another common problem, especially with pictures of people, is when they put their hand next to the body and between the hand and the body there is a small hole.
Basically, it is not too hard to create a GIMP script that opens in batch many images, uses the magic wand to select the pixel at some corner (or if desired, in several known fixed places, not just one) and then removes the selection.
If it's hard to find a white area at a fixed spot, it is possible to do a search inside - meaning that the script searches for a white pixel on the borders, and it goes inside gradually in a spiral untill it finds some white pixel. But this is very very unefficient in the basic scripting engine, so I hope you don't need this.
If any of the suggested options above is OK, tell me and I'll create a gimp script for it. It will be even better if you can post some samples images, but I'll try to help even without these.