I want to use a custom shaped window using gtk3. I found gtk_widget_shape_combine_mask_() in gtk2. The closest thing I can find in gtk3 is gdk_window_shape_combine_region_(), which only allows for rectangular shaped regions. Why was the support dropped? Or was it changed and implemented in a different way?
What do you mean with "why was the support dropped?".
gtk_widget_shape_combine_mask() only supports rectangular shapes, too. That's what a GdkBitmap is: An image with a bit depth of 1. This means that a pixel is either included or not.
This is basically the same as a cairo_region_t. The difference is only in how the data is stored: Instead of a bitmap, cairo_region_t uses a list of rectangles to describe the same result.
"Or was it changed and implemented in a different way?"
Yes and you already found the replacement yourself.
Related
I've already made a function to cut out the image, and the part I cut out has a black background. I'm trying to make the black part transparent, then I can generate an image sequence that I can create a video with. I've tried converting the image to a double and then replacing the 0 values with NaN:
J = imread('imgExample.jpg');
J2 = im2double(J);
J2(J2 == 0) = NaN;
imwrite(J2, 'newImg.jpg');
but when I convert it into a video, it doesn't seem to stay. Is there any way to get the black part of the image to be transparent?
From clarifications in comments, you are trying to create a video format that supports alpha transparency using matlab.
In general this seems impossible using matlab alone (at least in matlab 2013 which is the version I use). If you'd like to check if the newest matlab supports videos with alpha transparency, type doc videowriter and have a look at the available formats. If you see anything with transparency options there, take it from there. But the most I see on mine is 24bit RGB videos (i.e. three channels, no transparency).
So matlab does not have the ability to produce native .avi video with alpha transparency.
However, note that this is a very rare video format anyway, and even if you did manage to produce such a video, you would still have to find a suitable viewer which supports playing videos with transparency!
It's therefore important for you to tell us your particular use-case because it may be you're actually trying to do something much simpler (which may or may not be solvable via matlab) (i.e. a case of the XY Problem
E.g. you may be trying to create a video with transparency for the web instead, like here https://developers.google.com/web/updates/2013/07/Alpha-transparency-in-Chrome-video
If this is the case, then I would recommend you attempting the method outlined there; you can create individual .png "frames" with transparency in matlab using the imwrite function. have a look at its documentation, particularly the section about png images and the 'Alpha' property. But beyond that, you'd need an external tool to combine them into a .webm file, since matlab doesn't seem to have a tool like that (at least none that I can see at a glance; there might be a 3rd-party toolkit if you look on the web).
Hope this helps.
I have table of l,a,b values and want to visualise these colors in matlab (or any other suitable software). Is there any quick way like series of rectangles filled with color values from the table?
There are several versions of the Lab color space, but presumably you're referring to most common, CIELAB. You can use imwrite in Matlab to create a TIFF image with 'cielab' specified for the 'Colorspace' option. I wouldn't trust Matlab as a viewer for the resultant images though. Photoshop in lab mode (from the menu bar: Image > Mode > Lab Color) would be a good choice if you want work with and see the closest thing to the actual CIELAB space. Other viewers/editors may convert to RGB or CMYK before rendering to the screen (likely without warning you), but maybe you don't mind. If you just want to convert from CIELAB to RGB, you might find these functions useful.
After lots of research, I found out there is a plugin called 'color inspector' that can be used along with ImageJ (all opensource tools). Have excellent capacity to view and analyse different color space. Even it has some color tools that matlab yet to have. here is imageJ: http://rsbweb.nih.gov/ij/download.html
and the plugin
http://rsb.info.nih.gov/ij/plugins/color-inspector.html
Hope this is useful to someone
I am desiging a simple GUI application in Matlab using GUIDE.
I am displayed a number of axis - and I would like to add some simple design elements to make the interface clearer. I would like to draw a colored rectangle around an axis (seperate from the axis)... there are two such axes, each displaying details of some things shown in a third plot, and I would like this color clue to link the details to the overview.
So is it possible to add simple geometric shape objects to a Matlab GUI? I don't see anything but controls in GUIDE but perhaps its possible to add them manually with an explicit command?
It is generally difficult to draw any random shape. Except Square & rectangle, for which you can create panels and change the properties like BorderWidth and HighlightColor.
Since MATLAB GUI is based on Java, you can create any object in MATLAB GUI which can be created in Java. You can refer to this website [1] for further learning.
[1] http://undocumentedmatlab.com/matlab-java-book/
I would like to check whether an image has a lot of homogeneous areas. Therefore I would like to get some kind of value of an image that declares a ratio for images depending on the amount/size of homogeneous areas (e.g. that value could have a range from 0 to 5).
Instead of a value there could be some kind of classification as well.
[many homogeneous areas -> value/class 5 ; few homogeneous areas -> value/class 0]
I would like to do that in perl. Is there a package/function or something like that?
What you want seems to be an area of image processing research which I am not familiar with. However, GraphicsMagick's mogrify utility has a -segment option:
Use -segment to segment an image by analyzing the histograms of the color components and identifying units that are homogeneous with the fuzzy c-means technique. The scale-space filter analyzes the histograms of the three color components of the image and identifies a set of classes. The extents of each class is used to coarsely segment the image with thresholding. The color associated with each class is determined by the mean color of all pixels within the extents of a particular class. Finally, any unclassified pixels are assigned to the closest class with the fuzzy c-means technique.
I don't know if this is any use to you. You might have to hit the library on this one, and read some research. You do have access to this through PerlMagick as well. However, it does not look like it gives access to the internals, but just produces an image based on parameters.
In my tests (without really understanding what the parameters do), photos turned entirely black, whereas PNG images with large areas of similar colors were reduced to a sort of an average color. Whether you can use that fact to develop a measure is an open question I am not going to investigate ;-)
I'm trying to do top hat filtering in MATLAB. The imtophat function looks promising, but I have no idea how to use it. I don't have a lot of work with MATLAB before. I am trying to look find basically small spots several pixels wide that are local maxima in my 2 dimensional array.
I think you have more problem undertanding how to use STREL, than IMTOPHAT. The later can be described as simple threshold but per structural element, not the whole image.
Here is another good examples of using STREL and IMTOPHAT:
http://www.mathworks.com/matlabcentral/fx_files/2573/1/content/html/R14_MicroarrayImage_CaseStudy.html
This series of posts on Steve Eddins blog might be useful for you:
http://blogs.mathworks.com/steve/category/dilation-algorithms/
tophat is basically an "opening" procedure followed by a subtraction of the result from the original image. the best and most helpful explanation of opening I've found here:
http://homepages.inf.ed.ac.uk/rbf/HIPR2/morops.htm
"The effect of opening can be quite easily visualized. Imagine taking
the structuring element and sliding it around inside each foreground
region, without changing its orientation. All pixels which can be
covered by the structuring element with the structuring element being
entirely within the foreground region will be preserved. However, all
foreground pixels which cannot be reached by the structuring element
without parts of it moving out of the foreground region will be eroded
away."
The documentation on imtophat has an example .. did you try it? The following images are from the MATLAB documentation.
Code
I = imread('rice.png');
imshow(I)
se = strel('disk',12);
J = imtophat(I,se);
figure, imshow(J,[])
Original
(image source: mathworks.com)
Top Hat with a disk structuring element
(image source: mathworks.com)