libpng

libpng “png_set_longjmp_fn” not found

由 耗尽温柔 提交于 2019-12-01 16:04:28
问题 I'm using libpng from ubuntu and when I try to compile a c++ file I get undefined reference to `png_set_longjmp_fn' I'm using libpng version 1.6.8 If you are interested in reading the code please let me know, but I do not this has to do with my bad code. Thank you in advance. 回答1: Perhaps you have built with libpng-1.6.8 but are linking to an earlier version of libpng. The "png_set_longjmp_fn()" API was introduced in libpng-1.4.x. Ubuntu 13:10 currently comes with libpng-1.2.49 (see /usr

libpng size of png

由 為{幸葍}努か 提交于 2019-12-01 09:38:05
My program reads from a data stream of indeterminate length. When it reads a PNG file it needs to store it for later and not decode it. Does libpng provide any function for providing the size of the PNG so it knows how many bytes to store? If it does not, do I have to write my own PNG chunk parser to skip through the chunks until the ending chunk? I figured that I might as well include CRC verification, but it seems very complicated, which is why I was hoping libpng would provide a way to do this transparently. The short answer is NO. Libpng doesn't even return the length of the individual

libpng size of png

由 限于喜欢 提交于 2019-12-01 07:24:20
问题 My program reads from a data stream of indeterminate length. When it reads a PNG file it needs to store it for later and not decode it. Does libpng provide any function for providing the size of the PNG so it knows how many bytes to store? If it does not, do I have to write my own PNG chunk parser to skip through the chunks until the ending chunk? I figured that I might as well include CRC verification, but it seems very complicated, which is why I was hoping libpng would provide a way to do

import matplotlib.pyplot gives ImportError: dlopen(…) Library not loaded libpng15.15.dylib

由 时间秒杀一切 提交于 2019-12-01 07:04:56
Importing pyplot gives an error: In [1]: import matplotlib In [2]: import matplotlib.pyplot as plt ImportError Traceback (most recent call last) <ipython-input-2-eff513f636fd> in <module>() ----> 1 import matplotlib.pyplot as plt /Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/pyplot.py in <module>() 25 26 import matplotlib ---> 27 import matplotlib.colorbar 28 from matplotlib import style 29 from matplotlib import _pylab_helpers, interactive /Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/colorbar.py in <module>() 32 import matplotlib.artist as martist 33 import

libpng 1.5.10 error: dereferencing pointer to incomplete type

由 时间秒杀一切 提交于 2019-12-01 05:13:29
png_read_info (png_ptr, info_ptr); { png_byte color_type = info_ptr->color_type; png_byte bit_depth = info_ptr->bit_depth; ... For last 2 lines I get error: dereferencing pointer to incomplete type What's wrong? In libpng 1.4 this was always ok. The png_info struct was removed from the png.h in 1.5.0 and now you should use this pointer with the png_get_* and png_set_* functions. As specified in libpng manual : The png_info structure is designed to provide information about the PNG file. At one time, the fields of png_info were intended to be directly accessible to the user. However, this

libpng error: PNG unsigned integer out of range

由 喜欢而已 提交于 2019-12-01 04:38:11
When trying to read a PNG from memory I came across this funky error: libpng error:: PNG unsigned integer out of range This error is caused by png_read_info(png_ptr,info_ptr); Which uses following handler: static void ReadDataFromBuffer(png_structp png_ptr, png_bytep outBytes, png_size_t byteCountToRead){ PNGDataPtr dataptr=(PNGDataPtr)png_get_io_ptr(png_ptr); png_uint_32 i; cout<<byteCountToRead<<endl; cout<<&outBytes<<endl; cout<<dataptr->len<<endl; cout<<dataptr->p<<endl; if(byteCountToRead>dataptr->len){ png_error(png_ptr,"EOF"); return; } for(i=0;i<byteCountToRead;i++){ outBytes[i]

Loading PNGs with CImg

由 吃可爱长大的小学妹 提交于 2019-12-01 03:08:02
问题 I am unable to load PNGs with CImg. I've heard you need to get libpng / zlib to get to work first but I am unsure how to set this up. I am on Ubuntu. My source: #include <cmath> #include <cstdio> #include <string> #include <assert.h> #include <stdarg.h> #define cimg_using_png #include "CImg.h" using namespace cimg_library; #include "png.h" int main(int argc, char** argv) { CImg<unsigned char> img2("test.png"); img2.display(); return 0; } 回答1: Close, but you need #define cimg_use_png and add

libpng 1.5.10 error: dereferencing pointer to incomplete type

由 孤街浪徒 提交于 2019-12-01 03:06:40
问题 png_read_info (png_ptr, info_ptr); { png_byte color_type = info_ptr->color_type; png_byte bit_depth = info_ptr->bit_depth; ... For last 2 lines I get error: dereferencing pointer to incomplete type What's wrong? In libpng 1.4 this was always ok. 回答1: The png_info struct was removed from the png.h in 1.5.0 and now you should use this pointer with the png_get_* and png_set_* functions. As specified in libpng manual: The png_info structure is designed to provide information about the PNG file.

libpng error: PNG unsigned integer out of range

由 自闭症网瘾萝莉.ら 提交于 2019-12-01 01:57:29
问题 When trying to read a PNG from memory I came across this funky error: libpng error:: PNG unsigned integer out of range This error is caused by png_read_info(png_ptr,info_ptr); Which uses following handler: static void ReadDataFromBuffer(png_structp png_ptr, png_bytep outBytes, png_size_t byteCountToRead){ PNGDataPtr dataptr=(PNGDataPtr)png_get_io_ptr(png_ptr); png_uint_32 i; cout<<byteCountToRead<<endl; cout<<&outBytes<<endl; cout<<dataptr->len<<endl; cout<<dataptr->p<<endl; if

Iphone - device - linker error

由 扶醉桌前 提交于 2019-11-30 14:08:45
问题 I have added libpng to my application. If I build for simulator, everything is OK. When I build application for device, I got linker error: Undefined symbols for architecture armv7: "_png_init_filter_functions_neon", referenced from: _png_read_filter_row in libpng-arm7-release.a(pngrutil.o) I have build libpng manually from source, same way for simulator and device (only with changed target of compilation). I have tried to find this problem, but noone seems to post anything about this problem
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