libpng

实验需要，加上好奇，使用libpng库将png文件的背景，由黑色，替换成无背景颜色。效果如下图： 替换前： 替换后： 黑色背景都没了，只剩下白色了，看不出来。。。。。。 步骤： 1. 下载png相关库，libpng，以及zlib压缩解压缩文件 　　libpng官网下载，Ubuntu下zlib下载安装: sudo apt-get install zlib1-dev 2. 代码： 　　 来源： https://www.cnblogs.com/hanrp/p/11419147.html

I'm currently using the following to write a PNG to a file: #include <png.h> #include <stdio.h> #include <stdlib.h> #include <stdint.h> /* Pixels in this bitmap structure are stored as BGR. */ typedef struct _RGBPixel { uint8_t blue; uint8_t green; uint8_t red; } RGBPixel; /* Structure for containing decompressed bitmaps. */ typedef struct _RGBBitmap { RGBPixel *pixels; size_t width; size_t height; size_t bytewidth; uint8_t bytes_per_pixel; } RGBBitmap; /* Returns pixel of bitmap at given point. */ #define RGBPixelAtPoint(image, x, y) \ *(((image)->pixels) + (((image)->bytewidth * (y)) \ + ((x

转载: Android原生(Native)C开发之一 环境搭建篇 转载: Android原生(Native)C开发之二 framebuffer篇 转载: Android原生(Native)C开发之三 鼠标事件篇(捕鼠记) 转载: Android原生(Native)C开发之四 SDL移植笔记 转载: Android原生(Native)C开发之五 zlib移植笔记 转载: Android原生(Native)C开发之六 libpng移植笔记 转载: Android原生(Native)C开发之一 环境搭建篇 2009年02月25日，星期三 Android是基于Linux的操作系统，处理器是ARM的，所以要在Linux或Windows等x86系统上编译Android能运行的程序，你需要一个交叉编译器。 在Linux下面，你可以自已编译一个交叉编译环境，但Windows下面，就比较复杂（也可以在cygwin中编译一个），但你可以选择下载一个现成的交叉编译环境： http://www.codesourcery.com/gnu_toolchains/arm/download.html Windows: http://www.codesourcery.com/gnu_toolchains/arm/portal/package3400/public/arm-none-linux-gnueabi/arm

How to know if palette png is with alpha or not? I get information about the image png_get_IHDR After that i look at color_type - PNG_COLOR_TYPE_PALETTE But i can't find how to know if this png image has alpha channel or not. PNG supports transparency in two (or three) quite different ways: Truecolor or grayscale images with a separated alpha channel (RGBA or GA) Transparency extra info in the (optional) tRNS chunk . Which has two different flavors: 2a. For indexed images: the tRNS chunk specifies a transparency value ("alpha") for one, several or all the palette indexes . 2b. For truecolor or

I got an email from Google play store regarding - "Google Play warning: You are using a vulnerable version of libpng". Email contains the below information - https://support.google.com/faqs/answer/7011127 I didn't use libpng library in my application anywhere. But, In my android application, I am using the OpenCV2.4.5 library. After searching in the internet, I came to know that the OpenCV library uses the libpng. My question - The upgrading of OpenCV2.4.5 to OpenCV3.1.0 will resolve "vulnerable version of libpng" warning? Yes, now confirmed with Google: Updating to 3.1.0 will fix the issue -

I'm trying to load a PNG image using SDL but the program doesn't work and this error appears in the console libpng warning: iCCP: known incorrect sRGB profile Why does this warning appear? What should I do to solve this problem? Glenn Randers-Pehrson Libpng-1.6 is more stringent about checking ICC profiles than previous versions. You can ignore the warning. To get rid of it, remove the iCCP chunk from the PNG image. Some applications treat warnings as errors; if you are using such an application you do have to remove the chunk. You can do that with any of a variety of PNG editors such as

一、准备工作（把安装环境需要使用到的包都下载好） 　　 mysql （官网）： http://dev.mysql.com/downloads/ 　　 php （官网）： http://php.net/downloads.php 　　 nginx （官网）：http://nginx.org/；选择稳定版本(Nginx 有很多种版本 , 比如 mainline( 主线版 ),stable( 稳定版 )) 　　 下载mysql、php、nginx的教程：http://www.cnblogs.com/zengguowang/p/5812999.html 　　 还要其他的一些依赖包需要童鞋们去一个一个寻找并下载，下面是写一些依赖包的解释： 　　　　 libxml ：是一个用来解析 XML 文档的函数库（用C语言写的） 　　　　 libmcrypt ：加密算法扩展库，支持DES, 3DES, RIJNDAEL, Twofish, IDEA, GOST, CAST-256, ARCFOUR, SERPENT, SAFER+等算法 　　　　 mhash ：hash是基于 离散数学 原理的不可逆向的php加密方式扩展库，其在默认情况下不开启。mhash的可以用于创建校验数值，消息摘要，消息认证码，以及无需原文的关键信息保存（如密码）等 　　　　 mcrypt ：mcrypt 是 php