I am using CGPDFScanner to scan the pdf. Should I use Td operator to find positions of text? Can I have an example that how to use this operator to get positions of the text? Current I have used Tj and TJ operator to find the text. Now I would like to know position of each word in a single page of pdf. How can I do that?
Thanks
Look this library:
https://github.com/KurtCode/PDFKitten/
search and highlight text
To get the coordinates of the text you need to keep track of the text transformation matrix. See section 5.3.1, "Text Positioning Operators" of the PDF 1.4 Reference. (I'm not sure if later versions of the reference number things the same or not.) While the Td operator will set the current translation in the text matrix, there are other operators that affect the text matrix and other text state, as well. You need to keep track of the text matrix as the file is processed. The Tm operator will directly set the text matrix. The TD operator moves to the next line and offsets by the x and y parameters. T* just moves to the next line.
Related
So, I have to build an IDE inside Unity 3D. So far I made a canvas, panel, input field, image and a text on the image. So... my question is how to dynamically show the line numbers on the left side?
Make sure your input field's line type is set as 'Multiline New Line'. Get the text from OnValueChanged event of your input field. Split the string by '\n'. You will get the array of lines. The length of that array is number of lines in your input field. Add 1 to that length value & use it as your last line number.
I am developing an image processing software that extracts/crops and enhances this cropped single page form from an image taken from a cellphone camera.The form has no rectangular boundaries to simplify the process of extraction.Yes it is a white background black text format but nothing apart from that is fixed.Now some Text will be present which will verify that the image is of the form required.So my questions are these.
1) Can i search for a specific regular expression using leptonica library itself or do i have to shift focus to other libraries like the tessarect API to do this.So far i have not found anything of this sort
2) Now suppose i know the text at the top left corner and the bottom right corner and i search it succesfully.Can i get the co-ordinates of the particular text that i am searching and then crop the image accordingly?
Leptonica doesn't do anything with text, it's an image processing library.
To enable acquiring position of the text, add tessedit_create_hocr 1 to you Tesseract config file (or set this option whichever way you configure Tesseract if you're using it as a library).
The result is no longer a text file, but a UTF-8-encoded HTML file (note: it's not valid XML). Its format is self-explanatory. It will contain positions and dimensions of all words on all pages in pixels, as found on the input image. You need to parse that HTML, find the words you're looking for, and then get bounding boxed of those words.
I am drawing text in a PDF page using iTextSharp, and I have two requirements:
1) the text needs to be searchable by Adobe Reader and such
2) I need character-level control over where the text is drawn.
I can draw the text word-by-word using PdfContentByte.ShowText(), but I don't have control over where each character is drawn.
I can draw the text character-by-character using PdfContentByte.ShowText() but then it isn't searchable.
I'm now trying to create a PdfTextArray, which would seem to satisfy both of my requirements, but I'm having trouble calculating the correct offsets.
So my first question is: do you agree that PdfTextArray is what I need to do, in order to satisfy both of my original requirements?
If so, I have the PdfTextArray working correctly (in that it's outputting text) but I can't figure out how to accurately calculate the positioning offset that needs to get put between each pair of characters (right now I'm just using the fixed value -200 just to prove that the function works).
I believe the positioning offset is the distance from the right edge of the previous character to the left edge of the new character, expressed in "thousandths of a unit of text space". That leaves me two problems:
1) How wide is the previous character (in points), as drawn in the specified font & height? (I know where its left edge is, since I drew it there)
2) How do I convert from points to "units of text space"?
I'm not doing any fancy scaling or rotating, so my transformation matrices should all be identity matrices, which should simplify the calculations ...
Thanks,
Chris
Using GetHOCRText(0) method in tesseract I'm able to retrieve the text in html and on presenting the html in webview i'm able get the text but the postion of text in image is different from the output. Any idea is highly helpful.
tesseract->SetInputName("word");
tesseract->SetOutputName("xyz");
tesseract->Recognize(NULL);
char *utf8Text=tesseract->GetHOCRText(0);
and output image
If you have the hocr output, you should have a tag for each word. These tags should have class="ocrx_word" and name="bbox x1 y1 x2 y2" where the x and y are the top left and bottom right corner of the bounding box around the word. I don't think it's possible to automatically use this information to format a text document - would require translating pixel differences to number of tabs/spaces. But, you should be able to render text in the given location.
GetBoxText() method will return exact position of each characters in an array.
char *boxtext = _tesseract->GetBoxText(0);
NSString* aBoxText = [NSString stringWithUTF8String:boxtext];
Below is the user interface I have created to simulate LDPC coding and decoding
The code sequence is decoded iteratively by passing values between the left and right nodes through the connections.
The first thing it would be good to add in order to improve visualization is to add arrows to the connections in the direction of passing values. The alternative is to draw a bigger arrow at the top of the connection showing the direction.
Another thing I would like to do is displaying the current mathematical operation below the connection (in this example c * H'). What I don't know how to do is displaying special characters and mathematical symbols and other kinds of text such as subscript and superscript in the figure (for example sum sign and subscript "T" instead of sign ="'" to indicate transposed matrix).
I would be very thankful if anyone could point to any useful resources for the questions above or show the solution.
Thank you.
To add arrows, you can either use the built-in QUIVER, or, for more options, ARROW from the file exchange. Both of these have to be plotted into axes, so if you want a big arrow on the top, you have to create an additional set of axes above the main axes.
As far as I know, you cannot use TeX or LaTeX symbols in text uicontrols. However, you can use them in axes labels. Thus, I suggest that you add an XLabel to the axes, for example
xlabel('\sigma c*H_T')
or (note the $-signs required for LaTeX)
xlabel('$\sum c*H_T$','interpreter','latex')
EDIT
I hadn't mentioned the use of text (as suggested by #gnovice and #YYC) because I thought it wasn't possible to place text outside of the axes. It turns out that I was wrong. text(0.5,-0.2,'\Sigma etc.') should work fine as well. I guess the only advantage of using 'xlabel' would be that you can easily add and position the axes label during GUI creation.
In regards to the 1st question, annotation (http://www.mathworks.com/access/helpdesk/help/techdoc/ref/annotation.html) might be an alternative solution.
In regards to the 2nd question, try text property in Matlab Help.
Search "Character Sequence" for the special characters; search "Specifying Subscript and Superscript Characters" for the subscript and superscript.
For drawing the arrow, I would go Jonas' suggestion arrow.m by Erik Johnson on the MathWorks File Exchange. It's the easiest way I've found to create arrows in figures.
For creating text with symbols, you can use the function TEXT. It lets you place text at a given point in an axes, and you can use the 'tex' (default) or 'latex' options for the 'Interpreter' property to get access to different symbols. For example, this places the text you want at the point (0,0) using 'latex' as the interpreter:
hText = text(0,0,'$\sum c*H_T$','Interpreter','latex');
The variable hText is a handle to the text object created, which you can then use with the SET command to change the properties of the object (string, position, etc.).