I am writing some scripts using BGI and I am facing an interesting problem I do not know how to solve. Let us say I want to create a log pannel, where I want to write on window(using outtextxy() function) some events that happened in sofware (like delete, create etc). But I do not know how.
So far, I thought of floodfill the entire area where the text has been written, but it seems that is not working.
floodfill(3.7*width_rectangle+1, height_rectangle*14.3+1, WHITE);
setcolor(BLACK)
outtextxy(x,y, char*);
I tried some other things, like having a stack that stores all logs and when a new event happens, I take last element, I write it in BLACK again (to overwrite the existing one) and then a push the event to the stack. But it seems that this is not working too.
Can anybody suggest me a way to write text over another text in BGI?
Related
Basically i have these two lines of code written right after each other.:
console.log(typeof (noAdsCallback));
document.write('<sc' + 'ript type="text/javascript">console.log(typeof(noAdsCallback));</scr' + 'ipt>');
The first one logs function, the second logs undefined.
Of course it's a bit trickier than that. So here is the set-up in a nutshell:
I have a so called waterfall of ad-providers. That means, I try to load some Ads, by writing (using document.write) some special tags (given to me by my ad-provider).
If the provider doesn't find an ad for me, they send back a javascript-snippet which looks like this:
if (typeof(window.noAdsCallback) === "function") noAdsCallback();
This function essentially writes the tags of the next provider, which does the same as the first one until I reach the end of the list.
This system actually works fine, doing exactly what I want it to do. Both lines given in the beginning log function.
Except if I use Google as an ad-provider. There is one thing Google does differently, which seems to mess everything up.
In Google, I cannot define a fallback-JavaScript-snippet. All I can do is provide a fallback-url. So this fallback-url (since it's loaded inside an iframe inside an iframe inside...) sends a postMessage to the top, which then calls the same noAdsCallback() method. And this too, works just fine. The message is received and the right method executed. However, already the two lines already give different results, i.e. function and undefined respectively
The next provider then fails to find the noAdsCallback() Method, when it returns, because it uses document.write to try to execute it. Somehow, the context was lost.
First hint: It works fine (i.e. both lines log function) in Chrome, but it doesn't work in FF or IE.
Second hint: It works fine, as long as context never switches, but if communication runs at any point through messaging, it get's confused.
Third hint: Using the fantastic postscribe library as mentioned below, actually solves the problem, but introduces new ones somewhere else.
Fourth hint: Debugging the window.name, before using document.write, gives the correct name, so I'm not in a random iFrame.
Finishing thoughts. I know, i know: DON'T USE DOCUMENT WRITE!! I know that. But since Adproviders use it all the time, I am forced to use it to, otherwise I get this:
Failed to execute 'write' on 'Document': It isn't possible to write into a document from an asynchronously-loaded external script unless it is explicitly opened.
In Fact, right now I'm using postscribe (https://github.com/krux/postscribe) and it works like a charm, except for one lousey provider. And the workauround solution would be, to use document.write only for this lousy provider and postscribe for all the others. But i would really like to find out what the root of the problem is.
Any Ideas, much appreciated.
I think I understood it now. Long story short: DON'T USE DOCUMENT.WRITE :)
Try postscribe, if you have to.
So in hindsight it is quite obvious, because really, anywhere you read about document.write() it says, that write() clears the whole document. And I just didn't get it, because I never saw it happening and every ad is using it, like the whole time. Plus, it seemed to work fine on Chrome. So what's going on??
Well here is what happens. As long as the document is open, which basically means while it is being written, document.write() just appends to the stream, and doesn't clear the document. And as long as I used document.write(), to append foreign ad-scripts (which may and will contain document.write()), the page does not close, hence the document stays open.
This is the reason, why adding Google to my waterfall, posed a problem: Google puts everything in iframes. So the page containing the waterfall model just sees the iframe and says: "well as far as I'm concerned, I'm done" and closes the document, while in fact, Google is still at it.
Afterwards, Google didn't find an ad, sends a postMessage to the main page, causing the next provider to be used. Who then uses document.write() and clears everything.
Everything? Not everything. Remember, it still used to work when I used Chrome? The reason for that is, Chrome just clears the HTML but leaves the Javascript intact. So on Chrome, my Javascript-waterfall worked fine, because all the JS-objects where still in place. All other browsers cleared it.
So that's it. Probably noone's gonna read it, but if you do, USE POSTSCRIBE! Now that I finally really understood document.write() and document.open() and document.close() I'm a big fan.
I have worked a great deal with the text system in Objective-C for macOS/iOS (e.g. NSTextView, NSTextStorage, etc.) I am now experimenting with GTK3 to see how well I can translate my project for use on Linux, etc.
I am brand new to using GTK, but after a few days of Google time and experimenting, I have a working text editor prototype with my custom code plugged in.
The problem is this -- I need to be able to detect when a user highlights a section of text, and then replaces it with other text (e.g. a keystroke). This is distinct from highlighting a section of text, hitting the delete key, and then typing the new text. A specific use example would be highlighting a word, then typing a double quote character in order to wrap the word in quotes (e.g. foo becomes "foo").
In Cocoa, one would receive replaceCharactersInRange: that indicates the range originally selected, as well as the new string to replace it with. I can then detect the presumed intent of the user based on the information received.
In GTK, it seems that we receive a delete-range signal, followed by a separate insert-text signal. Because of this separation, the code in the "insert" section has no way of knowing that the user intended to replace text, not insert new text.
I used the following to receive the signals above:
g_signal_connect(buffer, "insert-text", G_CALLBACK(insert_text_cb), NULL);
g_signal_connect(buffer, "delete-range", G_CALLBACK(delete_range_cb), NULL);
Is there something else I can do in order to tell that there is a delete, followed by an insert as part of the same user action?
Thanks for any pointers offered!
Instead of trying to correlate the delete and insert events, I would suggest creating a GAction for your desired action (e.g. toggle quotes around the selected text) and setting its shortcut key to " using gtk_application_set_accels_for_action().
For more information, check out this HowDoI wiki page.
No answers over the last month, so I kept brainstorming and digging around. I finally came up with this, which works, but is not quite as elegant as I had hoped.
Handle delete-range signal as before, but keep track of the the deleted text for later (e.g. in char * deletedText).
Handle the insert-text signal as before, but if we have a string in deletedText then change the behavior to perform a replacement instead of an insertion. In my case, this actually meant inserting the deleted text back in, and then performing the replacement.
Add a callback for the end-user-action signal, which indicates that all delete/inserts associated with a particular action are complete. In this callback, free deletedText from above and set to NULL (to indicate that everything has been handled).
Again -- this works, but feels a bit inelegant. And depending on how complex your delete/insert routines are, it may slow the performance slightly since some steps have to be duplicated. A better solution would be to detect during the delete-range callback that there is a pending insert-text callback and handle both steps at once. I have thus far not been able to do that.
I'm trying to record how a file changes over time down to the smallest details, which means that reading any changes per file save wouldn't give sufficient data for my use-case, it needs to be per-keystroke.
I just tried out inotify, but it can only notify me on file-save, not file-modification.
I then realized (I'm quite inexperienced with file-system stuff) that this is because text-editors use buffers to store yet-to-happen changes, committing the contents of the buffer on file save (I think, at least).
So, it seems to me that I could
read the buffer of a text-editor (which seems like it would have to be code specific to each particular editor; not viable)
force a save to the file on every keypress (which again seems like it would require editor-specific code)
monitor the keypresses of the user, store my own buffer of them, and then once the file is saved, correlate the keypresses with the diff (this seems way too hard and prone to error)
read the contents of the file on an interval faster than a person is likely the press any keys (this is hacky, and ridiculous)
I can't think of any other ways. It seems that to properly get the behavior I want I'd need to have editing occur within the terminal, or within a web form. I'd love to hear other ideas though, or a potential editor-agnostic solution to this problem. Thank you for your time.
My goal is to write a program that would capture the screen in an efficient way.
Little twist, the screen will not be saved. My program will do various check on it (pixel's colors in some area.. etc).
The program will run in windows, and will need to take(and analyze) as many screenshot as possible per second, and will not be used in games. (That imply that I need the whole screen, like pressing prntscreen. It's not a problem if that fail in fullscreen game.)
All propositions are welcome, and I'd be glad to share any missing details.
Edit
As I wrote in the comment, capturing the screen for storing purpose is really common and easy to find.
I asked to be sure to not miss any method of capturing the screen without storing it at all.
The program will look the screen, take some decision then will quickly go to the next frame.
Perhaps look into SDL
A guick google returned this screenshot code for SDL: http://lists.libsdl.org/pipermail/sdl-libsdl.org/2000-August/011387.html
I'm trying to look through and find a way to annotate a video in C with polygons bounding boxes, however I'm stuck at a very elementary step.
Assuming I know how to break a .MPEG movie up into multiple JPEG images, how do I manipulate that file in C? The things I'll eventually need to draw on are text, points, and lines, but I am having a hard time figuring out how to get started with this.
If I declare:
FILE* img = fopen('foo.jpeg', 'r');
then what could I do with img? Is there a way to access certain pixels in the drawing?
What you did in your code sample is just opening a file. You didn't even read any data from it yet.
The simplest way to load an image file is to use dedicated library, such as SOIL.
If you weren't able to do it by yourself, however, I really don't think you will be able to accomplish your project goals - it is really advanced stuff you want to create, and you failed, as you already noticed, on the most basic of steps.