I'm trying to figure out how to convert an image from a stream with ImageResizer (http://imageresizing.net/).
I have tried something like this.
Stream s = WebRequest.Create("http://example.com/resources/gfx/unnamed.webp").GetResponse().GetResponseStream();
ImageBuilder.Current.Build(s, "~/resources/gfx/photo3.png", new ResizeSettings("format=png"));
But i just get the error
"File may be corrupted, empty, or may contain a PNG image with a single dimension greater than 65,535 pixels."
When i do
using (Stream output = File.OpenWrite(Server.MapPath("~/resources/gfx/test.webp")))
using (Stream input = WebRequest.Create("http:///example.com/resources/gfx/unnamed.webp").GetResponse().GetResponseStream()) {
input.CopyTo(output);
}
ImageBuilder.Current.Build("~/resources/gfx/test.webp", "~/resources/gfx/photo3.png",
new ResizeSettings("format=png"));
It works fine, am i'm missing something here?
It's possible that 'output' has not been flushed to disk. .NET 4+ doesn't guarantee the file's actually written to disk just because you disposed the stream.
I assume you have the ImageResizer.Plugins.WebP plugin installed?
Related
As part of my project I wanted to send stream of images using websockets from embedded machine to client application and display them in img tag to achieve streaming.
Firstly I tried to send raw RGB data (752*480*3 - something about 1MB) but in the end I got some problems with encoding image to png in javascript based on my RGB image so I wanted to try to encode my data to PNG firstly and then sent it using websockets.
The thing is, I am having some problems with encoding my data to PNG using OpenCV library that is already used in the project.
Firstly, some code:
websocketBrokerStructure.matrix = cvEncodeImage(0, websocketBrokerStructure.bgrImageToSend, 0);
websocketBrokerStructure.imageDataLeft = websocketBrokerStructure.matrix->rows * websocketBrokerStructure.matrix->cols * websocketBrokerStructure.matrix->step;
websocketBrokerStructure.imageDataSent = 0;
but I am getting strange error during execution of the second line:
terminate called after throwing an instance of 'std::logic_error'
what(): basic_string::_S_construct NULL not valid
and I am a bit confused why I am getting this error from my code.
Also I am wondering if I understand it right: after invoking cvEncodeImage (where bgrImage is IplImage* with 3 channels - BGR) I just need to iterate through data member of my CvMatto get all of the png encoded data?
The cvEncodeImage function takes as its first parameter the extension of the image you want to encode. You are passing 0, which is the same thing as NULL. That's why you are getting the message NULL not valid.
You should probably use this:
websocketBrokerStructure.matrix = cvEncodeImage(".png", websocketBrokerStructure.bgrImageToSend, 0);
You can check out the documentation of cvEncodeImage here.
You can check out some examples of cvEncodeImage, or its C++ brother imencode here: encode_decode_test.cpp. They also show some parameters you can pass to cvEncodeImage in case you want to adjust them.
I'm using C++ Builder XE3 to develop a graph editor. All of the editing and drawing capabilities are made in a DLL that is loaded by the end user applications.
To store information about the available graph objects I use a SQLite database. That database contains BMP icons that are loaded into a TImageList at run-time.
Everything works fine with Win-7, Win-8 and Win-vista but with Win-XP a "Floating point division by 0" occurs when loading the bitmap. I use a temporary memory stream to load the blob from the database and then load it into a temporary TBitmap which is used to add the new icon into the final TImageList.
Here is the function used to do so...
void TIcons::AddMaskedBitmap( TImageList *ptImgList, unsigned char *pucIcon, unsigned int uiSize )
{
TMemoryStream *ptMemStream;
// Use a memory stream
ptMemStream = new TMemoryStream();
ptMemStream->Write( pucIcon, uiSize );
ptMemStream->Position = 0;//Seek( ( int )0, ( unsigned short )soBeginning );
// Load using the cached bmp object
m_ptBmp->Transparent = true;
#warning "floatting point division by 0 error with WinXP"
m_ptBmp->LoadFromStream( ptMemStream ); // floatting point division by 0 error with WinXP
// m_ptBmp->LoadFromFile( ".\\d.bmp" ); // works
// Create a mask
m_ptBmpMask->Assign( m_ptBmp );
m_ptBmpMask->Canvas->Brush->Color = m_ptBmp->TransparentColor;
m_ptBmpMask->Monochrome = true;
// Add it to the list
ptImgList->Add( m_ptBmp, m_ptBmpMask );
// Free mem
m_ptBmp->FreeImage();
m_ptBmpMask->FreeImage();
delete ptMemStream;
}
I've traced the TBitmap::LoadFromStream function and the exception occurs in the CreateDIBSection function.
To make sure the loaded bitmap files are saved using the right encoding I've tried to load them using the TBitmap::LoadFromFile function and it works fine, so I think there's something wrong with the TBitmap::LoadFromStream function but I can't figure out what !
If anyone has an idea...
Thanks.
LoadFromFile is implemented by creating a file stream, and passing that to LoadFromStream. This, if the contents of your memory stream are the same as the contents of the file, then the call to LoadFromStream will succeed.
Thus the only sane conclusion is that the contents of the memory stream are invalid in some way.
The bitmap stored into the database is encoded using the BITMAPV4HEADER structure which is supposed to be supported since Win95/NT4 but there's something wrong.
It works fine if I encode the bitmap using the BITMAPINFOHEADER structure which is an older version of bitmap encoding which does not contain color space information.
Just found out a solution that works for me.
My problem was that software that was developed on Win7, when running on XP was throwing the division by 0 error when loading one of my BMPs.
It turns out that the problematic BMP was saved using Win7 Paint (other BMPs that were ok were saved from Gimp).
All I needed to do to fix it was to open this BMP on XP Paint and save it from there.
I have written a program that relies on Magick++ simply for importing and exporting of a wide variety of image formats. It uses Image.getPixels() to get a PixelPacket, does a lot of matrix transformations, then calls Image.syncPixels() before writing a new image. The general approach is the same as the example shown in Magick++'s documentation. More or less, the relevant code is:
Magick::Image image("image01.bmp");
image.modifyImage();
Magick::PixelPacket *imagePixels = image.getPixels(0, 0, 10, 10);
// Matrix manipulation occurs here.
// All actual changes to the PixelPacket direct changes to pixels like so:
imagePixels[i].red = 4; // or any other integer
// finally, after matrix manipulation is done
image.syncPixels();
image.write("image01_transformed.bmp");
When I run the above code, the new image file ("image01_transformed.bmp" in this example) ends up being the same as the original. However, if I write it to a different format, such as "image01_transformed.ppm", I get the correct result: a modified image. I assume this is due to a cached version of the format-encoded image, and that Magick++ is for some reason not aware that the image is actually changed and therefore the cache is out of date. I tested this idea by adding image.blur(1.0, 0.1); immediately before image.syncPixels();, and forcing this inconsequential change did indeed result in the correct result for same-format images.
Is there a way to force Magick++ to realize that the cache is out-of-date? Am I using getPixels() and syncPixels() incorrectly in the first place? Thanks!
I am using tika to extract text from a pdf file that has lot of tables.
java -jar tika-app-0.9.jar -t https://s3.amazonaws.com/centraldoc/alg1.pdf
It is returning some invalid text and sometimes it is trimming white space between 2 words; for example it returns
"qu inakli fmyathematical ideas to the real world" instead of "Link mathematical ideas to the real world".
Is there a way to minimize this kind of error? or is there another library that I can use? Does it make sense to use OCR to process these kind of pdf.
Try to control order when using PDFBox parser: PDFTextStripper has a flag that controls the order of lines in the document. By default (in PDFBox) it's set to false for performance reasons (no order preserved), but Tika changed its behavior between releases switching this flag on and off.
More details exactly on this problem in my blog Extracting text from PDF files with Apache Tika 0.9 (and PDFBox under the hood).
To get text from PDF to display in the right order, I had to set the SortByPosition flag to true... (tika-app-1.19.jar)
BodyContentHandler handler = new BodyContentHandler();
Metadata metadata = new Metadata();
ParseContext context = new ParseContext();
PDFParser pdfParser = new PDFParser();
PDFParserConfig config = pdfParser.getPDFParserConfig();
config.setSortByPosition(true); // needed for text in correct order
pdfParser.setPDFParserConfig(config);
pdfParser.parse(is, handler, metadata, context);
I don't really understand how Content importer/processor works in XNA.
I need to read a text file (Content/levels/level1.txt) of the form:
x x
x x
x x
where x's are just integers, into an int[,] array.
Any tips on writting a SIMPLE .txt importer??? By searching google/msdn I only found .x/.fbx file importer examples. And they seem too complicated.
Do you actually need to process the text file? If not, then you can probably skip most of the content pipeline.
Something like:
string filename = "Content/TextFiles/sometext.txt";
string path = Path.Combine(StorageContainer.TitleLocation, filename);
string lineOfText;
StreamReader sr = new StreamReader(path);
while ((lineOfText = sr.ReadLine()) != null)
{
// do something
}
Also, be sure to set the "Build Action" to "None" and the "Copy to Output Directory" to "Copy if newer" on the text files you've added. This tells the content pipeline not to compile the text file but rather copy it to the output directory for use as is.
I got this (more or less) from the RacingGame sample provided by Microsoft. It foregoes much of the content pipeline and simply loads and processes text files (XML) for much of its level data.
XNA 4.0 uses
System.IO.Stream stream = TitleContainer.OpenStream("tilename.txt");
See http://msdn.microsoft.com/en-us/library/bb199094.aspx and also http://blogs.msdn.com/b/shawnhar/archive/2010/12/09/reading-files-in-xna-game-studio-4-0.aspx
There doesn't seem to be a lot of info out there, but this blog post does indicate how you can load .txt files through code using XNA.
Hopefully this can help you get the file into memory, from there it should be straightforward to parse it in any way you like.
XNA 3.0 - Reading Text Files on the Xbox
http://www.ziggyware.com/readarticle.php?article_id=69 is probably a good place to start. It covers creating a basic content processor.