the heading says it all actually:
i want to convert a pdf file into several jpg images. This is to be a part of a software coded in c++ (I'm using Qt for my interface if that matters... :)
Preferably i want the images output to be 72 dpi.
Is there a easy way to do this?
Please comment if you need any more information form me, I'm grateful for any help, tips or answer!
Take pdf2image utility, and run it from you program, collecting its output files.
If you really need single executable (why?) — take a look at its source, and rip everything from it.
You should try to use poppler (or xpdf). You'll have full control of the rendering resolution and can take advantage of image output devices (ImageOutputDev) which will render pages to a framebuffer.Saving this framebuffer to jpeg with libjpeg is ,then , pretty straightforward.
Related
I am currently coding a winrate statistics menu for League of Legends (which got approved) using ImGui and I wonder if it is possible to display a GIF or MP4 on the Menu as a Preview or Usage Tutorial not from File/Memory but from an URL as I want to keep the File as small as possible for now.
You probably would have to use a filestream, downloading the file to tmp and then displaying it as a Texture?
I found a similar question, and I wonder if something since then has changed:
https://github.com/ocornut/imgui/issues/2680
Is it still required to use an additional GIF loader?
Are there any easy ways now to achieve that?
I am a bit (new) to ImGui and would be very happy about any reference source code (not to copy paste, just to learn it).
Thanks for any help :).
I am creating a pdf using libharu in C++ (compiled as a .cgi) that features .png images.
The code is fine, but my pdf's are ridiculously oversized.
Each page features one image of around 30kb and around 4 text characters in libharu's system font. If I open a 20 page output file of 25mb and "print" it to a file in my operating system it becomes 256kb or so with no visible change to the images.
I think the issue is related to libharu because this guy see's it too, here. He is using php so, libharu as a compiled .cgi. (my C++ code is also compiled .cgi, linked to libharu).
Another guy here on stack overflow has also seen size issues with libharu, but his problem does not mention anything to do with .png so it may be unrelated.
Code for reference:
WorkingGraphic = HPDF_LoadPngImageFromMem ( *gPdfPtr,
PngAssets[AssetIndex], //Image data ptr
PngSizes[AssetIndex]); //data length
//Render Appropriate
HPDF_Page_DrawImage (*BlitParams->page,
WorkingGraphic,
BlitParams->OutputRect->X,
BlitParams->OutputRect->Y,
BlitParams->OutputRect->Width,
BlitParams->OutputRect->Height);
Does anyone know how to drive libharu so it creates sensible sized pdf's when you use .png images?
Right I don't know how to remove a question but maybe this info will be useful to others anyway.
I may have had the same issue as this fellow here where I have duplicated this answer.
What I needed to do was enable compression of the .pdf, which I had not done.
Documentation link
C Code:
HPDF_SetCompressionMode (pdf, HPDF_COMP_ALL);
It's because I didn't do enough research to know that .pdf format does not natively support .png, or if it has been updated to do so, libharu still doesn't. So, this option tells libharu to use zlib to zip compress everything it can, including your images.
The implementation is not perfect (you will still see a size difference if you zip your output .pdf) but it is acceptable for my use case.
If you don't need the full-size image in the PDF, you can reduce the image to a thumbnail using GDI+ APIs, equal in size to however big you want the image to appear in the PDF.
Save the scaled PNG to a temporary file, and pass the thumbnail PNG to Haru PDF. This will reduce the size of the PDF file.
The image will be pixellated when the viewer zooms in.
I want to make a screen capture utility, so far i am able to capture the screen in regular interval to get a numbered sequence of images and now i want to encode them to a video format preferably flv(because of good compression and web support)
....I tried the ffmpeg.exe for that reason but for some strange reason it did'nt work
on my vista ultimate...only the first picture is encoded while the rest -I dont know what happened to them.
Also I would prefer doing the encoding stuf programatically (using c/c++ library api if any for that purpose) rather than using tools as ffmpeg.exe and i am interested in encoding picture sequence to video not capturing contineouse video directly.
I searched through internet....there are lots of libraries and tutorial for converting between video formats but I did'nt find something usefull for my problem.
I am not verry proficient with video formats and sdk library, I just need a quick way to encode some pictures to video with some basic control (as time interval between two consecutive frames).
So can you help me with some pointers as to which library i should use and how(code fragment and little descriptive answer would greatly help) and please dont recomend any .NET solution I need to learn something out of this and dont want to apply some bruteforce approach to solve the problem.
Sorry for my english....and thanks in advance.
It appears that an .avi file can more or less directly be made of .jpg's:
An AVI file may carry audio/visual data inside the chunks in virtually any compression scheme, including Full Frame (Uncompressed), ..., Motion JPEG.
Also, something very similar has been discussed here before.
I need an animation in my program. My designer draws animation in Flash and provides me with *.fla file. All I need is to grab 30-40 PNGs from this file and store them within my internal storage.
Is it possible grab resources from *.fla with C++ ? Probably, some Adobe OLE objects can help?
Please, advice.
Thanks in advance.
If I asked an artist to make me an icon I wouldn't expect to need to write code to convert a .3DS model into a usable icon format.
You can save yourself a lot of time and hassle by having your designer use File->Export and give you PNGs of the layers and frames instead of a .FLA file if that's the format you require for your implementation.
If that's not possible for some reason then you can probably find a flash decompiler that has a command line option which you could launch from your program to extract assets as part of your loading sequence but that is generally frowned upon because this is not the intended use of the proprietary format for .swf/.fla anymore than you should design applications to extract source code from a binary executable.
Assuming
You are using CS5
The assets used internally in the FLA are already PNG's as you want them to be.
Then simply get the FLA saved as a XFL file, and you will be able to grab them from the library folder ( but then why not just get them to mail you the pngs ? )
So if for some reason you can only get access to the fla and not the designer, then you can do it programatically by renaming the fla to .zip, extracting.. and you have the XFL format.
I want to decode JPEG files and obtain uncompressed decoded output in BMP/RGB format.I am using GNU/Linux, and C/C++.
I had a look at libjpeg, but there seemed not to be any good documentation available.
So my questions are:
Where is documentation on libjpeg?
Can you suggest other C-based jpeg-decompression libraries?
The documentation for libjpeg comes with the source-code. Since you haven't found it yet:
Download the source-code archive and open the file libjpeg.doc. It's a plain ASCII file, not a word document, so better open it in notepad or another ASCII editor.
There are some other .doc files as well. Most of them aren't that interesting though.
Unfortunately I cannot recommend any other library besides libjpeg. I tried a couple of alternatives, but Libjpeg always won. Is pretty easy to work with once you have the basics done. Also it's the most complete and most stable jpeg library out there.
MagickWand is the C API for ImageMagick:
http://imagemagick.org/script/magick-wand.php
I have not used it, but the documentation looks quite extensive.
You should check out Qt's QImage. It has a pretty easy interface that makes this task really easy. Setup is pretty simple for every platform.
If Qt is overkill, you can try Magick++ http://www.imagemagick.org/Magick++/. It supports similar operations and is also well suited for that sort of task. The last time I used it, I struggled a bit with dependencies for it on Windows, but don't recall much trouble on Linux.
For Magick++'s Image class, the function you probably want is getConstPixels.
I have code that you can copy ( or just use as a reference ) for loading a jpeg image using the libjpeg library.
You can browse the code here: http://code.google.com/p/kgui/source/browse/trunk/kguiimage.cpp
Just look for the function LoadJPGImage.
The code is setup to handle c++ binding of my DataHandle class to it for loading the image, that way the image can be a file or data already in memory or whatever.
A slightly out of the box solution is to acquire a copy of the netpbm tools, which transform images from pretty much any format to any other format via one of several very simple intermediate formats. They work well from the shell, and are most often used in pipes to read some arbitrary image, perform an operation on it, and write it out to some other format.
The pbm formats can be as simple as a plain ASCII header followed by the RGB data in ASCII or binary. They are intended to be simple enough to use without required a library to implement.
JPEG is supported in netpbm by read and write filters that are implemented on top of libjpeg.