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  • How do I do high quality scaling of a image?

    - by pbhogan
    I'm writing some code to scale a 32 bit RGBA image in C/C++. I have written a few attempts that have been somewhat successful, but they're slow and most importantly the quality of the sized image is not acceptable. I compared the same image scaled by OpenGL (i.e. my video card) and my routine and it's miles apart in quality. I've Google Code Searched, scoured source trees of anything I thought would shed some light (SDL, Allegro, wxWidgets, CxImage, GD, ImageMagick, etc.) but usually their code is either convoluted and scattered all over the place or riddled with assembler and little or no comments. I've also read multiple articles on Wikipedia and elsewhere, and I'm just not finding a clear explanation of what I need. I understand the basic concepts of interpolation and sampling, but I'm struggling to get the algorithm right. I do NOT want to rely on an external library for one routine and have to convert to their image format and back. Besides, I'd like to know how to do it myself anyway. :) I have seen a similar question asked on stack overflow before, but it wasn't really answered in this way, but I'm hoping there's someone out there who can help nudge me in the right direction. Maybe point me to some articles or pseudo code... anything to help me learn and do. Here's what I'm looking for: 1. No assembler (I'm writing very portable code for multiple processor types). 2. No dependencies on external libraries. 3. I am primarily concerned with scaling DOWN, but will also need to write a scale up routine later. 4. Quality of the result and clarity of the algorithm is most important (I can optimize it later). My routine essentially takes the following form: DrawScaled( uint32 *src, uint32 *dst, src_x, src_y, src_w, src_h, dst_x, dst_y, dst_w, dst_h ); Thanks! UPDATE: To clarify, I need something more advanced than a box resample for downscaling which blurs the image too much. I suspect what I want is some kind of bicubic (or other) filter that is somewhat the reverse to a bicubic upscaling algorithm (i.e. each destination pixel is computed from all contributing source pixels combined with a weighting algorithm that keeps things sharp. EXAMPLE: Here's an example of what I'm getting from the wxWidgets BoxResample algorithm vs. what I want on a 256x256 bitmap scaled to 55x55. And finally: the original 256x256 image

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  • Resized image degrades in quality.

    - by Venkats
    I resized an image using Java2D Graphics class. But it doesn't look right. BufferedImage resizedImage = new BufferedImage(IMG_WIDTH, IMG_HEIGHT, type); Graphics2D g = resizedImage.createGraphics(); g.drawImage(originalImage, 0, 0, IMG_WIDTH, IMG_HEIGHT, null); g.dispose(); Is it possible to scale an image without introducing artifacts?

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  • Removing text within parentheses (parentheses within parentheses prob)

    - by TenJack
    Hi, I am trying to remove text that is within parentheses (along with the parentheses themselves) but am having trouble with the scenario where there are parentheses within parentheses. This is the method I am using (in Ruby): sentence.gsub(/\(.*?\)/, "") and that works fine until I have a sentence such as: "This is (a test (string))" Then the above chokes. Anyone have any idea how to do this? I am completely stumped.

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  • How to find about structure of bitmap and JPEG files?

    - by Sorush Rabiee
    I'm trying to write a very simple image processing program for fun and practice. I was using System.Drawing. ... .Bitmap class to handle images and edit their data. but now I want to write my own class of Bitmap object implementation and want to know how bmp files (and other common bitmap formats) and their meta-data (indexing, color system & etc) are stored in files, and how to read and write them directly?

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  • How to detect an 'image area' percentage inside an image?

    - by DaNieL
    Mhh, kinda hard to explain with my poor english ;) So, lets say I have an image, doesnt matter what kind of (gif, jpg, png) with 200x200 pixel size (total area 40000 pixels) This image have a background, that can be trasparent, or every color (but i know the background-color in advance). Lets say that in the middle of this image, there is a picture (for keep the example simple lets suppose is a square drawn), of 100x100 pixels (total area 10000 pixels). I need to know the area percentage that the small square fill inside the image. So, in i know the full image size and the background-color, there is a way in php/python to scan the image and retrieve that (in short, counting the pixel that are different from the given background)? In the above example, the result should be 25%

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  • Extracting URLs (to array) in Ruby

    - by FearMediocrity
    Good afternoon, I'm learning about using RegEx's in Ruby, and have hit a point where I need some assistance. I am trying to extract 0 to many URLs from a string. This is the code I'm using: sStrings = ["hello world: http://www.google.com", "There is only one url in this string http://yahoo.com . Did you get that?", "The first URL in this string is http://www.bing.com and the second is http://digg.com","This one is more complicated http://is.gd/12345 http://is.gd/4567?q=1", "This string contains no urls"] sStrings.each do |s| x = s.scan(/((http|https):\/\/[a-z0-9]+([\-\.]{1}[a-z0-9]+)*\.[a-z]{2,5}(([0-9]{1,5})?\/.[\w-]*)?)/ix) x.each do |url| puts url end end This is what is returned: http://www.google.com http .google nil nil http://yahoo.com http nil nil nil http://www.bing.com http .bing nil nil http://digg.com http nil nil nil http://is.gd/12345 http nil /12345 nil http://is.gd/4567 http nil /4567 nil What is the best way to extract only the full URLs and not the parts of the RegEx? Thanks Jim

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  • Filter string in C

    - by Paul Tarjan
    How can I filter a string in c? I want to remove anything that isn't [a-z0-9_]. int main(int argc, char ** argv) { char* name = argv[1]; // remove anything that isn't [a-z0-9_] printf("%s", name); }

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  • How might I escape Unicode characters in a JSON string using JavaScript?

    - by user293006
    JSON String: { "id":31896, "name":"Zickey attitude - McKinley, La Rosi\u00e8re, 21 ao\u00fbt 2006", ... } this causes an unterminated string in JavaScript. My attempt at a solution is: data.replace(/(\S)\1(\1)+/g, ''); or data.replace(/\\u([0-9A-Z])/, ''); any ideas/solution? Example: http://api.jamendo.com/get2/id+name+url+stream+album_name+album_url+album_id+artist_id+artist_name/track/jsonpretty/track_album+album_artist/?n=13&order=ratingmonth_desc&tag_idstr=jazz last node is the problem, fyi. (/\\u([0-9A-Z])/, '\1');

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  • How can I make nested string splits?

    - by Statement
    I have what seemed at first to be a trivial problem but turned out to become something I can't figure out how to easily solve. I need to be able to store lists of items in a string. Then those items in turn can be a list, or some other value that may contain my separator character. I have two different methods that unpack the two different cases but I realized I need to encode the contained value from any separator characters used with string.Split. To illustrate the problem: string[] nested = { "mary;john;carl", "dog;cat;fish", "plainValue" } string list = string.Join(";", nested); string[] unnested = list.Split(';'); // EEK! returns 7 items, expected 3! This would produce a list "mary;john;carl;dog;cat;fish;plainValue", a value I can't split to get the three original nested strings from. Indeed, instead of the three original strings, I'd get 7 strings on split and this approach thus doesn't work at all. What I want is to allow the values in my string to be encoded so I can unpack/split the contents just the way before I packed/join them. I assume I might need to go away from string.Split and string.Join and that is perfectly fine. I might just have overlooked some useful class or method. How can I allow any string values to be packed / unpacked into lists? I prefer neat, simple solutions over bulky if possible. For the curious mind, I am making extensions for PlayerPrefs in Unity3D, and I can only work with ints, floats and strings. Thus I chose strings to be my data carrier. This is why I am making this nested list of strings.

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  • get city, state or zip from a string in python

    - by Joe
    I'd like to be able to parse out the city, state or zip from a string in python. So, if I entered Boulder, Co 80303 Boulder, Colorado Boulder, Co 80303 ... any variation of these it would return the city, state or zip. This is all going to be user inputted data and inputted in one text field.

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  • How can we extract substring of the string by position and separator.

    - by Harikrishna
    How can we divide the substring from the string Like I have string String mainString="///Trade Time///Trade Number///Amount Rs.///"; Now I have other string String subString="Amount" Then I want to extract the substring Amount Rs. with the help of second string named subString not by any other method But it should be extracted through two parameters like first is I have index no of Amount string and second is until the next string ///.

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  • Coldfusion: insert new line into string

    - by dmr
    I would like to insert a line break into the first space between words in a string variable. Here is my code so far: <cfset myPosition = find(" ", #myVar#)> <cfset lineBreak = Chr(13)&Chr(10)> <cfset myVar = insert(#lineBreak#, #myVar#, #myPosition#)> What am I doing wrong?

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  • I'm writing a spellchecking program, how do I replace ch in a string?

    - by Ajay Hopkins
    What am I doing wrong/what can I do? import sys import string def remove(file): punctuation = string.punctuation for ch in file: if len(ch) > 1: print('error - ch is larger than 1 --| {0} |--'.format(ch)) if ch in punctuation: ch = ' ' return ch else: return ch ref = (open("ref.txt","r")) test_file = (open("test.txt", "r")) dictionary = ref.read().split() file = test_file.read().lower() file = remove(file) print(file) This is in Python 3.1.2

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  • Efficient way in Python to add an element to a comma-separated string

    - by ensnare
    I'm looking for the most efficient way to add an element to a comma-separated string while maintaining alphabetical order for the words: For example: string = 'Apples, Bananas, Grapes, Oranges' addition = 'Cherries' result = 'Apples, Bananas, Cherries, Grapes, Oranges' Also, a way to do this but while maintaining IDs: string = '1:Apples, 4:Bananas, 6:Grapes, 23:Oranges' addition = '62:Cherries' result = '1:Apples, 4:Bananas, 62:Cherries, 6:Grapes, 23:Oranges' Sample code is greatly appreciated. Thank you so much.

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  • Help with manipulating child/parent elements with jQuery

    - by Mohammad
    Currently I have this JQuery script var img = $(this); img.wrap('<div class="photo"></div>'); img.parent().append("<p>" + img.attr("alt") + "</p>"); which successfully turns the following: <img src="photo.jpg" alt="caption"> into this <div class="photo"> <img src="photos.jpg" alt="caption"/> <p>caption</p> </div> All is well unless the image has a link as a parent; <a href="#"><img since I want it to be correct html (I'm fussy) improving the resulting outcome bellow would be satisfactory <a href="#"> <div class="photo"> <img src="photos.jpg" alt="caption"/> <p>caption</p> </div> </a> to this: <div class="photo"> <a href="#"> <img src="photos.jpg" alt="caption"/> </a> <p><a href="#">caption</a></p> </div> </a> This is my jQuery script so far (which doesn't work bc I'm a noob) aha if(img.parent('a')){ var targetLink = img.parent('a').attr('href').val(); img.parent('a').wrap('<div class="photo"></div>'); img.parent('div').append('<p><a href="'+targetLink+'">' + img.attr("alt") + '</p></a>'); }else{ img.wrap('<div class="photo"></div>'); img.parent().append("<p>" + img.attr("alt") + "</p>"); }; Any advice, or help will be greatly appreciated : ) Thank You! Update *Answer* (works but looks sloppy) I'm editing it atm; if(img.parent('a').length){ var targetLink = img.parent().attr('href'); img.parent().wrap('<div class="photo"></div>'); var divTarget = img.parent('a').parent('div'); divTarget.append('<p><a href="'+targetLink+'">' + img.attr("alt") + '</p></a>'); }else{ img.wrap('<div class="photo"></div>'); img.parent().append("<p>" + img.attr("alt") + "</p>"); };

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  • Finding the Column Index for a Specific Value

    - by Btibert3
    Hi All, I am having a brain cramp. Below is a toy dataset: df <- data.frame( id = 1:6, v1 = c("a", "a", "c", NA, "g", "h"), v2 = c("z", "y", "a", NA, "a", "g"), stringsAsFactors=F) I have a specific value that I want to find across a set of defined columns and I want to identify the position it is located in. The fields I am searching are characters and the trick is that the value I am looking for might not exist. In addition, null strings are also present in the dataset. Assuming I knew how to do this, the variable position indicates the values I would like returned. > df id v1 v2 position 1 1 a z 1 2 2 a y 1 3 3 c a 2 4 4 <NA> <NA> 99 5 5 g a 2 6 6 h g 99 The general rule is that I want to find the position of value "a", and if it is not located or if v1 is missing, then I want 99 returned. In this instance, I am searching across v1 and v2, but in reality, I have 10 different variables. It is also worth noting that the value I am searching for can only exist once across the 10 variables. What is the best way to generate this recode? Many thanks in advance.

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  • jQuery + Validation plugin: add/remove class to/from element's parent

    - by FreekOne
    Hi guys, I'm working with the jQuery Validation plugin and I wrote the following code which adds a class to the element's parent if not valid (as well as inserting the actual error message at a particular location within the parent): errorPlacement: function(error, element) { element.parent().addClass('error'); error.insertBefore(element.parent().children("br")); } This works, however, if a field's content is corrected and becomes valid, the class obviously doesn't get removed from its parent (actually, neither does the error element, instead it just gets a display: none; CSS property). How can I check if an element becomes valid and remove its parent class if so ? Any help would be much appreciated, thank you !

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  • Using Apache Velocity with StringBuilders/CharSequences

    - by mindas
    We are using Apache Velocity for dynamic templates. At the moment Velocity has following methods for evaluation/replacing: public static boolean evaluate(Context context, Writer writer, String logTag, Reader reader) public static boolean evaluate(Context context, Writer out, String logTag, String instring) We use these methods by providing StringWriter to write evaluation results. Our incoming data is coming in StringBuilder format so we use StringBuilder.toString and feed it as instring. The problem is that our templates are fairly large (can be megabytes, tens of Ms on rare cases), replacements occur very frequently and each replacement operation triples the amount of required memory (incoming data + StringBuilder.toString() which creates a new copy + outgoing data). I was wondering if there is a way to improve this. E.g. if I could find a way to provide a Reader and Writer on top of same StringBuilder instance that only uses extra memory for in/out differences, would that be a good approach? Has anybody done anything similar and could share any source for such a class? Or maybe there any better solutions to given problem?

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  • Better name for CHAR_BIT?

    - by Potatoswatter
    I was just checking an answer and realized that CHAR_BIT isn't defined by headers as I'd expect, not even by #include <bitset>, on newer GCC. Do I really have to #include <climits> just to get the "functionality" of CHAR_BIT?

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