I have a png file - black background with list of images and text near these images. Is it possible to write Autoit script to either detect specific icon or title?
This can do what you want: http://www.autoitscript.com/forum/topic/65748-image-search-library/
The download on the first page is broken I think. The real download link is somewhere in the other pages in the thread.
Related
i have tried using some photo editors online but to no avail. trying to extract and use a background image for a particular web page without the text from the image
If you're able to use Photoshop you can try to Content-Aware Fill.
I'd like to change the background color and text color programmatically in PDF documents so that they're nicer to read at night (kinda like in Adobe Reader: Edit -> Preferences -> Accessibility -> Replace Document Colors).
Is there any good command line tool or API for Windows that can do that?
So far I haven't found any. It's OK if it needs to save the newly colored PDF into a new file.
There is no way to do this directly, with no (Free Software or gratis) tool I'm aware of. (Because in the general case, you'll have to change all colors of the PDF pages, not just the background alone, so you can still have some contrast and color differences.)
What you describe for Adobe Reader does not change the PDF file itself, it changes the way the application renders the pages (by inverting colors, or similar). The PDF remains the same during and after viewing it.
However, you might be able to achieve a similar thing by applying a suitable ICC color profile to the input PDF and produce, with the help of (a very recent version of) Ghostscript, a new output PDF from this.
The question would remain: what IS a "suitable" ICC color profil for your purpose??
I've shortly considered to apply a gray-ish background to the PDF with the help of pdftk ... background ... command line. But this would probably make some or many PDFs unreadable. (A black background would surely make it unreadable, because most text is black and would remain so.)
To create a PDF page (A4 size) which could serve as the gray background, you could use Ghostscript: gs -o gray.pdf -sDEVICE=pdfwrite -g5950x8420 -c ".8 setgray 0 0 595 842 rectfill showpage".
Then apply it to your original PDF (A4): pdftk original.pdf background gray.pdf output orig-with-backgr.pdf.
Note, this will only change the background of these pages (or those areas of pages), where the original background is transparent, as most text-based PDFs are. It will not work for pages or areas where the background is opaque white or color.)
You can also achieve a permanent color change (inverse colors) quite easily with the help of ImageMagick. But this will at the same time munch and make mincemeat of your nice vector PDFs, converting them into complete-raster image pages: convert nice.pdf -alpha off -invert inverted-colors-ugly-raster.pdf.
Finally, here is a rather unreliable way to accomplish the inverting of colors with the help of Ghostscript. It sets up a colortransfer function for the output PDF file:
gs -o output.pdf \
-sDEVICE=pdfwrite \
-c "{1 exch sub}{1 exch sub}{1 exch sub}{1 exch sub} setcolortransfer" \
-f input.pdf
It is unreliable, because not every PDF viewer will honor that setting. I've tested it a few times in the past...
These viewers DO SHOW inverted colors:
Adobe Reader
Adobe Acrobat
gv
Ghostscript/gs
Chrome's native PDF renderer ('pdfium')
These ones DON'T SHOW inverted colors:
Chrome with PDF.js
Firefox with PDF.js
Zathura
MuPDF
Just in case the OP doesn't really need to change the PDF document colors permanently, but only wants a PDF viewer other than Acrobat that can do similarly change the displayed colors...
MuPDF: MuPDF is a lightweight PDF viewer (amongst other things). It can invert the displayed colors with the simple stroke of the i for any document while it is open. MuPDF is also available for Windows (and iOS, and Android, and OSX, and Linux). (It is made by the same company which brought us Ghostscript).
MuPDF screenshots here: "normal" view (left) and "inverted" view (right)
SumatraPDF: This is a very popular alternative PDF viewer for Windows. Its PDF rendering engine is based on MuPDF. Hitting . in presentation mode, it changes background to black. Hitting w in presentation mode, it changes background to white. (I don't think it can also invert all colors, but I do not have the latest release available right now to check.) For startup adding -invert-colors to the command line, it will invert the colors for the rendered document.
Zathura: A lightweight PDF viewer for Linux and OSX, which can be controlled by Vim-like keyboard shortcuts. ctrl+r will re-color the rendering of any opened document. Background will change to dark, texts will change to bright gray (however it will not invert a, say blue text to yellow, like MuPDF does). I'm not sure if it is available on Windows too.
Evince: The Gnome PDF viewer, available for Linux, OSX and Windows. It can invert the colors of the open document too; the keyboard shortcut is ctrl+i.
XPDF: XPDF is quite an ancient PDF viewer for Unix + Linux (not sure if there is a Windows version available -- maybe in Cygwin). It has a startup option in its command line: xpdf -rv -papercolor "#333333" file.pdf will invert the colors (-rv is for reverse video, -papercolor lets you change the background to something different from pure black [as any inverted white would become]).
As you asked for an API, I'll throw one additional possibility in the mix. It is actually possible to write a plug-in for Adobe Acrobat (should be possible for Adobe Reader too, but Reader plug-ins are more difficult) that interferes with display.
A long time ago I wrote code for Enfocus PitStop to implement a wireframe rendering mode for PDF files inside of Adobe Acrobat. Click a button and the display changes to wireframe, click again and you have your normal view. This works because you can (as a plug-in) modify the display list (the list of objects) drawn by Acrobat.
This means that to draw your special display mode you could create a new display list (or modify the existing one) so that it has a rectangle at the very back in the color that you want and then modify the color of all objects in the display list to suit your needs.
This is relatively complex as it is, what makes it more complex is that - if you don't want your changes to affect the PDF file on disk, you have to intercept a myriad of Acrobat notifications and undo your changes. For example, if the user attempts to save the PDF document while viewing in your display mode, you have to make sure you are warned about that and undo the changes during the save. Adobe Acrobat makes this possible because it sends you notifications before and after the save process but it's still a serious job to make sure nothing gets screwed up.
But it's a absolutely cool and very flexible way to implement what you were after. Just make sure you have more than a couple of weeks to implement it :)
Install nodejs.
npm i -g serve
In directory with pdfs run: serve
Open http://localhost:5000 in Chrome and click on some file.
Install Chrome extension Dark Reader
Dark Reader > Toggle localhost:5000
Basically, I'd like to resize or resample a .png image (in order to reduce its file size) and yet retain it's transparency.
Anybody got an idea how best to go about this?
Thanks.
You can use paint.net, it is a free tool. Although it is pretty basic, it does the job.
Go to Image > Resize
Stumbled upon this thread and found the following site that does exactly what is requested: https://onlinepngtools.com/resize-png
What graphics program are you using?
Photoshop does this by simply going thru IMAGE > IMAGE SIZE and resizing. Transparency is not affected.
I'm sure Paint Shop Pro does the same
I know this is an old question, but the answer that worked for me was to use Inkscape.
Start Inkscape (free on Inkscape.org).
File -> Import... (Ctrl+I) the PNG file you want to resize (defaults on import dialog are ok).
With the image you just imported selected, select File -> Export PNG image... (Shift+Ctrl+E)
In the Export PNG Image tool pane, click the Export As... button to set the output filename and location.
In this same tool pane, set the image size using width/height or pixels.
In this same tool pane, click the Export button to create the output file.
This worked for me, hope it helps someone else.
Providing the image you have created / have been working on is transparent in the first place, using the "Resize" or "Resample" tools in any major image editing package (e.g. PhotoShop, PaintShop Pro and so on) should not affect (or lose) the transparency at all.
I use PaintShop Pro (X6, 64 Bit) myself and typically find that the "PNG Optimizer" option offers more options along these lines (than the default "Save As > .png" route).
Hope that this helps (specific to PaintShop Pro Users) in relation to the source question.
While I was waiting for the downloads of other image editing softwares, I tried Microsoft Power Point and succeeded in preserving the transparency.
Drag the image inside any slide, crop or resize, then save as a new picture as .png.
You can drag the image back in ppt to confirm the transparency is maintained
The complete Autodesk Sketchbook is now out for free including all the previous premium features such as resizing an image.
You do it as you would in paint by clicking on Image > Image Size... and then you can save as a .png without losing transparency.
Image size can be reduced by reducing number of colors and there are online tools to do this .
Try these..Hope they solve your problem
https://tinypng.com/
http://pngcrush.com/ and
http://tools.dynamicdrive.com/imageoptimizer/ --It provides more output images with different number of colors. However, smoothness will be effected, take care.
I added image to canvas element, but visitor than can save that image to local comp.
Is there any way to disable that option? I don't know, putting some transparent image over?
Thx
So i thought this can help you just disable rightclicks:
$('#canvas').bind("contextmenu",function(e){
return false;
});
None of this (not even image slicing) stops a user from simply copying the screen on to the clipboard and pasting it into MSpaint or any other image utility, and saving the result. Its trivial to do; And a transparency image is no impediment to this.
The only effective options that I know of are (as was said), watermarking or low quality.
*Avoid 1 pixel wide lines or dot watermarks that can be removed easily with a Photoshop filter.
~If its commercial... You could have a pay-wall, and steganographically embed the purchaser's name and or information into the image (or preview), such that if it does get used without permission, at least you know who did it.
Basicly: if your image is loaded by the Browser you can never protect the user to download it, because if the browser knows where to find the image, the user can find this out as well. So all this download protection only works for users not familiar with computers and the internet and nowadays i think most people are able to download such an image if they really want to.
If you want to prevent users to use your images for their work, you can use images with watermarks or in a lower resolution otherwise can you tell what reason do you have to prevent users from downloading?
I found this question in review of an HTML5 captcha alternative I'm developing. My goal is not to "prevent" users from downloading the image as much as blocking OCR on the image capture. To prevent it, I added a onclick event to the canvas object that resets the canvas element on click. The user can "download" it, but it no longer is the original code presented.
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.