(Only understandable if you're using Chrome)
Whenever I try to press Ctrl+U on an image page, nothing happens. So, I manually typed in the search bar "view-source:http://assets.silverdroid.ga/assets/discord/stop2.gif" and there, I found some very strange unicode characters, none of them readable.
Can someone explain to me what this is?
Linked screenshot of "image code".
That's the image data of the GIF. You can see that it starts with "GIF89a", which is a GIF format
Basically what you are seeing is the binary data of the image displayed as characters, that's why most of them are "weird" or non-readable.
Related
I am working with an old system of palletes. When I export an image, it also creates an pallete with 15/16 colors. But when I try to replicate the same result, the program does not recognize the image which I just created. To analyse what happened, I opened some images with notepad and compared them with my "creation" and I noticed quite some differences.
But the most interesting thing was that at the beginning of my images' code was the type "BM6", while they should be "png" or "bmp". I think that is some thing of codification, but I cannot find anything about it.
If the image file is properly formed, then you can take your .bm6 file and simple change / rename the extension to .bmp. And it should suddenly be an image.
.bm6 can result from creating an image file using a text editor, as seen here.
While in class I like to take handwritten notes, afterwards I scan them and then type them up (helps me remember them and also makes them easily searchable). The main issue is I have is I use A LOT of drawings and complex math and converting the math formulas into latex (or word) is very time consuming and the drawings require that I keep the PDF and the text document. What I would like to do is take the basic text that I have typed myself (no OCR) and add a text layer to the PDF's that way the PDF's will be searchable and I can save a lot of time by not converting the math or drawings.
I've looked into Preview, PDFpenPro, acrobat, a couple of linux programs but so far I haven't really found anything that will do this.
Any idea of how I could do this or a program to use?
I also scan my notes. Sometimes I go back and add some text to them using this technique:
Open up the scanned pdf in Preview, then click on the "Edit" button in the top right corner, then the "Text tools" button on the left side (its a little box with Aa in it). From there you can drag open a text box and type into it.
Now the secret trick is that if you save it here as it is and try to open it in your ipad using PDFExpert or some other program then the text might not be there. So here's how to go through that slight hiccup: After you've annotated your notes how you want instead of just saving it as a pdf, use the Print option: File->Print or Command+P. Now click the PDF button on the left to "Save it as a pdf". Now that its printed you can open it and search it in any program that reads pdfs. Attached is an example.
One other thing, it seems like maybe you want to write over your existing handwritten text with typed text? I'm not sure if this is the best way. But if that's what I was trying to do I would:
Scan my notes
Read through them, typing them up as you said
Open the scanned notes in Photoshop or some other program
Draw a giant White Fill White Stroke rectangle over the handwritten text
Save it as a pdf
Do the technique above and copy and paste the typed text from step 2.
I hope this helps. And I wish you luck, I'm still working out the kinks myself for scanned notes but the possibilities have me pretty excited!
EDIT: I just checked out PDFpenPro, which I highly recommend because you don't have to go through that printing trick, you can just save the pdf document after annotating and other programs will recognize the annotations.
I'm creating PDF files using PDFClown java library.
Sometimes, when openning these files with Adobe Acrobat Reader I get the famous error message:
"An error exists on this page. Acrobat may not display the page correctly. Please contact the person who created the PDF document to correct the problem."
The error shows while reading (with Adobe) the attached file only when scrolling down to the 8'th page, then scrolling back up to 3'td page. Alternatively, Zooming out to 33.3% will also produce the message.
Just for the record, Foxit reader reads the file flawlessly, as well as other PDF readers like browsers.
My questions are:
What's wrong with my file?? (file is attached)
How can I find what's wrong with it? is there a tool which tells you where does the error lie?
Thanks!
Ok, this wasn't easy -
Due to a bug in PDFClown the my main stream of information in the PDF page has been corrupted.
After it's end it had a copy of a past instance of it.
This caused a partial text section without the starting command "BT" - which left a single "ET" without a "BT" in the end of the stream.
once I corrected this, it ran great.
Thank you all for your help.
I would have much more difficult time debugging it without the tool RUPS which #Bruno suggested.
edit:
The bug was in the Buffer.java:clone() (line 217)
instead of line:
clone.append(data);
needs to be:
clone.append(data, 0, this.length);
Without this correction it clones the whole data buffer, and set the cloned Buffer's length to the data[].length. This is very problematic if the Buffer.length is smaller than the data[].length.
The result in my case was that in the end of the stream there was garbage.
The error shows while reading (with Adobe) the attached file only when scrolling down to the 8'th page, then scrolling back up to 3'td page. Alternatively, Zooming out to 33.3% will also produce the message.
Well, I get it easier, I merely open the PDF and scroll down using the cursor keys. As soon as the top 2 cm of page 3 appear, the message appears.
What's wrong with my file??
The content of pages 1 and 2 look ok, so let's look at the content of page 3.
My initial attributing the issue to the use of text specific operations (especially Tf and Tw) outside of a text object was wrong as Stefano Chizzolini pointed out: Some text related operations indeed are allowed outside text objects, namely the text state operations, cf. figure 9 from the PDF specification:
So while being less common, text state operations at page description level are completely ok.
After my incorrect attempt to explain the issue, the OP's own answer indicated that the
main stream of information in the PDF page has been corrupted. After it's end it had a copy of a past instance of it. This caused a partial text section without the starting command "BT" - which left a single "ET" without a "BT" in the end of the stream.
An ET without a prior BT indeed would be an error, and quite likely it would be accompanied by operations at the wrong level... Inspecting the stream content of that third page (the focused page of this issue), though, I could not find any unmatched ET. In the course of that inspection, though, I discovered that the content stream contains more than 2000 trailing 0 bytes! Adobe Reader seems not to be able to cope with these 0 bytes.
The bug the OP found, can explain the issue:
in the Buffer.java:clone() (line 217)
instead of line:
clone.append(data);
needs to be:
clone.append(data, 0, this.length);
Without this correction it clones the whole data buffer, and set the cloned Buffer's length to the data[].length. This is very problematic if the Buffer.length`` is smaller than the data[].length.
Trailing 0 bytes can be an effect of such a buffer copying bug.
Furthermore symptoms as found by the OP (After it's end it had a copy of a past instance of it) can also be the effect of such a bug. So I assume the OP found those symptoms on a different page, not page 3, but fixing the bug healed all symptoms.
How can I find what's wrong with it? is there a tool which tells you where does the error lie?
There are PDF syntax checkers, e.g. the Preflight tool included in Adobe Acrobat. but even that fails on your file.
So essentially you have to extract the page content (using a PDF browser, e.g. RUPS) and check manually with the PDF specification on the other screen.
the general post about debugging pdf might have been also helpful as rups / pdfstreamdump etc is mentioned there How do you debug PDF files?
http://moztw.org/images/product-front-thunderbird.png
I am sure that this is a PNG image in RGB colors and a alpha channel (look at the shadow below the icon), but this file mysteriously works with IE6 w/o any special CSS hack (though it seems the alpha channel is being replaced by 2-bit mask in IE6).
Can anyone tell me exactly what information is in the file? It would be even better if someone could give a guidance on how to create such file. Thanks.
Edit: Friends at moztw.org added script hack to the website, so the above statement is no longer verifiable. But your are still welcome to investigate the image format.
That's PNG8+alpha. Explanation and examples in "PNG that works" article.
You can generate such files with pngquant (on a Mac, ImageAlpha is a GUI for it).
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.