I need to develop a desktop application which will
1.) have a list of the Different Application logos (Background Transparent) e.g. IE, FIREFOX, CHROME, PHOTOSHOP ETC.
2.) User will take a screenshot of desktop and save the image.
3.) Now my application need to search all the logos in the screenshot image and tell which all logos are present and where.
4.) I used OPENCV, it's working, but when user changes the desktop background & captures screenshot, it's not working as the transparent area of logo is getting the desktop background content.
Can somebody provide a solution or libraries open source, commercial to do this job.
This is easy to do using cross-correlation.
See my answer to this question.
Basically:
Start with desktop image and one template image for each icon
Apply edge detection (e.g. Sobel) to the desktop image and template images.
Throw away the original desktop image and templates, you won't need them anymore cause we'll be using the edge-detected images
For each template
Do template matching as you normally would
Threshold the maximum of the result. If it's above the threshold, you have a match at that position. Otherwise, no match.
If your icons are aligned in a grid on the desktop, you may be able to speed up your processing by only checking those specific grid positions.
EDIT
You can also save a lot of time by knowing which icons to search for. If you have access to the file system, then just look for *.lnk files (or any other extensions you may be interested in) in the directory that corresponds to the desktop (can't remember exactly what it is, but for Windows7 it's something like c:\users\misha\desktop). That will tell you what icons are there on the desktop. This will allow you to shorten your template candidate list before you go and do the template matching.
I like misha's answer and I think it should work for you. But it that doesn't work you could try replacing the transparant pixels in your reference logo with uniformly distributed random noise before trying the match. This will make the transparant pixels irrelevant for any matching computation because they will match just as bad no matter what there is on the desktop in those pixels.
I'm not familiar with the tools you're using, but I'm guessing you have to either:
a) Tell your program to ignore transparent pixels in the icon images during the comparison operation.
OR
b) Tell your program to treat transparent pixels in the icon images as "wildcards" which can be any color.
Related
We are running cobalt with openGL enabled, and the graphics appear to display correctly under 1920x1080 resolution.
But once in a while, some icons in the "Settings" menu may have unexpected vertical lines on top (as shown in the picture).
We are guessing the icons are created from TTF font file, but we are not sure how it is rendering onto the screen.
We want to dump the icons to file at the following points to check what went wrong.
When the icon is actually converted to image.
When the icon experience further modification. (eg, color change, bolding, etc)
When the icons are rendered onto screen canvas.
Would really appreciate if someone can help to point out where in source code these events may be happening.
I guess the first question is: are you running the stable branch or the experimental branch of Cobalt?
Beyond that, yes, the icons are created from a TTF font file that is downloaded remotely. The icon itself is simply a character that is converted into a glyph, like the text above it, albeit at a much larger size.
I believe that the logic that you're looking for is within RenderText() in cobalt/renderer/rasterizer/skia/render_tree_node_visitor.cc. SkCanvas::drawTextBlob() is passed the glyph and color information that it uses to render the icon.
The specific glyph that is being used looks correct, but the location where the render_tree::GlyphBuffer representing it is created is TextShaper::CreateGlyphBuffer() in cobalt/renderer/rasterizer/skia/text_shaper.cc.
I am working on a Xamarin App compatible with all devices. I have a general question related to images. I am using Location Mark Image Icons to provide locations available on the Map. My issue is, Image has a white background which is also showing along with its background. I want to show only the Image.
Is this related to the designer to provide the image without background? Or as a developer, I can do something on it.
Xamarin.Forms doesn't delete your white background. What you need to do is following a small tutorial on how to use Adobe Photoshop for example and export your images as png, you might even consider which png type you need, there's 3 types of png:
png8
png24
png32
I won't be going deep in explaining each one of them, but you need to know that they all support transparency and could have a transparent background, however, you might notice some differences between them on the edges.
For example, png8 will give a small white border while png24 will not show that.
You can check this for example: https://helpx.adobe.com/photoshop-elements/using/optimizing-images-png-24-format.html
No, you can't do anything about it using Xamarin.Forms. You need to modify the image and remove the background (using Adobe Photoshop, etc.) and make sure to save it as .png.
If its simple white background you want to remove, You can utilise simple [MakeTransparent][1] method ofBitMap.
But this will remove all white coloured pixel. So IF your logo also contains white color, better you contact your designer.
I don't remember how it started, although I believe it began after using 3D tools at one point. I was looking for TWO answers, if possible:
For some reason, I find this hard to describe in words, so following the description is a link to a screenshot.
When I open, or create a new image followed by pasting an image from the Clipboard, in Photoshop, there is this zone at the top-left of the image window containing a smaller image, which is surrounded by an area that appears to be transparent - but when clicked on, or the window itself is moved, this "picture-in-picture" feature disappears - then comes back after the dragging is finished.
SCREENSHOT: http://i.imgur.com/MJq8I1W.jpg
1) What is this "feature" named?
2) How do I turn it off?
Thank you!
I don't think I can tell what you hit, or where this is located from the image you shared... can you upload a more comprehensive interface snapshot? It feels like you simply have a duplicate layer on top of your main layer...
Perhaps take a look at your workspace settings and try going to essential and see if that preview panel goes away.
I would like to write a program that can mirror a portion of the main display into a new window. Ideally this new window could then be displayed on an external monitor. I have seen this uiltity for a flightsim that does this on a pc (a multifunction display extractor).
CLick here for a screenshot of the program (MFD Extractor)
This would be a live window ie. constantaly updated video display not just a static graphic.
I have looked at screen magnifiers or vnc clients for ideas but I think I need to write something from scratch. I have tried to do some reading on osx programing but where do I start in terms of gaining access to the display? I somehow need to extract the graphics from a particular program. Is it best to go near the final output stage (the individual pixels sent to the display) or somewhere nearer the window management stage.
Any ideas or pointers would be much appreciated. I just need somewhere to start from.
Regards,
There are a few ways to do this:
Quartz Display Services will let you get access to the video memory for a screen.
Quartz Window Services (a.k.a. CGWindow) will let you create an image of everything that lies below a window. If you create a borderless, transparent, empty, high-level window whose frame occupies an entire screen, everything below it will be everything on that screen. (Of course, you could create a smaller window in order to copy a section of the screen.)
There's also a way to do it using OpenGL that I never fully understood. That technique is demonstrated by a couple of code samples, OpenGLScreenSnapshot and OpenGLCaptureToMovie. It's more or less obsoleted by CGWindow, though.
Each of those will get you an image that you can then show or write to a file or something.
To show an image, use NSImageView or IKImageView. If you want to magnify it, IKImageView has a zoomFactor property, but if you want nearest-neighbor scaling (like Pixie, DigitalColor Meter, or xScope), I think you'll need to write a custom view for that (but even that isn't all that hard).
I'm working with Course Management System Moodle and in the admin the folder tree (which uses folder icons) displays for about a second the alt attribute given (In this case "Open Folder") then it hides and shows the image when the image is ready.
The system is kind of slow so I assume Firefox thinks at first that the images don't exist.
This is a problem because during that split second the layout stretches to fit the wider words making it look unprofessional in my opinion.
Is there a way I can hide this tag without having to remove the alt tags? (which would be labor intensive) maybe using JQUERY or CSS.
displays for about a second the alt attribute given (In this case "Open Folder") then it hides and shows the image when the image is ready.
Yes, that's what alt text is for: it provides a textual alternative for when the image isn't available — whether that's because there's an error, or images are turned off in the browser settings, or, in this case, the file just hasn't arrived yet.
Is alt text really what you want? Unless the image in question actually contains the words “Open Folder”, the above is inappropriate alt text. If we're talking about one of those little plus/minus icons that opens a tree, a better alt text would be ‘+’. “Open folder”, as a description of what the image does (as opposed to what it contains), would be better applied to the ‘title’ attribute used for tooltips.
Note that if you're using Quirks Mode and the image has a fixed size specified, Firefox will use a ‘broken image’ icon with the alt text overlaid and cropped inside, instead of the plain alt text on its own. This is to match IE's old behaviour. But you don't really want to use Quirks Mode, and in the common case where the fixed size is small, the cropping makes the alt text unreadable and useless.
This is a problem because during that split second the layout stretches to fit the wider words making it look unprofessional in my opinion.
I'd recommend: getting over it. That's how the web rolls, any page can move about a bit as it renders progressively. For images you should only ever see it happen once, then the image will be cached and will appear straight away. If it doesn't, there's something wrong with the cacheing setup.
Depending on what kind of layout you are talking about, you can perhaps fix that to not respond to the changing image size, too. For example if using a table, setting “table-layout: fixed” on the table and “width: (some number of)px” on the top row's image cell will make it stick to that width even if the text inside is smaller. Possibly causing the alt text to run over into the next cell though, mind.
If the images are part of the layout, I'd recommend moving them to CSS. You should also optimize your images wherever possible whether they are CSS or otherwise. You could also move your JavaScript files to the bottom of the page where possible as they block parallel downloads. In general, applying a lot of the techniques here would probably help.
If the images have to be a certain width, give them an explicit width.