stb
stb_image下载
https://github.com/nothings/stb
stb_image.h用于解析图片格式:
JPG, PNG, TGA, BMP, PSD, GIF, HDR, PIC
stb_image_write.h用于保存图片格式:
PNG, TGA, BMP, HDR
示例
具体流程为：
加载图片->算法处理->保存图片->打开保存图片(仅windows)
并对 加载，处理，保存 这三个环节都进行了耗时计算并输出。
#include <iOStream>
#include <algorithm>
#include <cstdint>
#include <numeric>
#include <math.h>
#include <io.h>
//使用stbImage http://nothings.org/
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#define STB_IMAGE_WRITE_IMPLEMENTATION
#include "stb_image_write.h"
//如果是Windows的话，调用系统API ShellExecuteA打开图片
#if defined(_MSC_VER)
#include <windows.h>
#define USE_SHELL_OPEN
#endif
//是否使用OMP方式计时
#define USE_OMP 0
#if USE_OMP
#include <omp.h>
auto const epoch = omp_get_wtime();
double now() {
return omp_get_wtime() - epoch;
};
#else
#include <chrono>
auto const epoch = std::chrono::steady_clock::now();
double now() {
return std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::steady_clock::now() - epoch).count() / 1000.0;
};
#endif
//计时函数
template<typename FN>
double bench(const FN &fn) {
auto took = -now();
return (fn(), took + now());
}
//存储当前传入文件位置的变量
std::string m_curFilePath;
//加载图片
void loadImage(const char* filename, unsigned char*& Output, int &Width, int &Height, int &Channels)
{
Output = stbi_load(filename, &Width, &Height, &Channels, 0);
}
//保存图片
void saveImage(const char* filename, int Width, int Height, int Channels, unsigned char* Output, bool open = true)
{
std::string saveFile = m_curFilePath;
saveFile += filename;
//保存为png,也可以调用stbi_write_bmp 保存为bmp
stbi_write_png(saveFile.c_str(), Width, Height, Channels, Output, 0);
#ifdef USE_SHELL_OPEN
if (open)
ShellExecuteA(NULL, "open", saveFile.c_str(), NULL, NULL, SW_SHOW);
#else
//其他平台暂不实现
#endif
}
//取当前传入的文件位置
void getCurrentFilePath(const char* filePath, std::string& curFilePath)
{
char drive[_MAX_DRIVE];
char dir[_MAX_DIR];
char fname[_MAX_FNAME];
char ext[_MAX_EXT];
curFilePath.clear();
_splitpath_s(filePath, drive, dir, fname, ext);
curFilePath += drive;
curFilePath += dir;
curFilePath += fname;
curFilePath += "_";
}
//算法处理,这里以一个反色作为例子
void processImage(unsigned char* Input, unsigned char* Output, unsigned int Width, unsigned int Height, unsigned int Channels)
{
int widthstep = Width*Channels;
if (Channels == 1)
{
for (unsigned int Y = 0; Y < Height; Y++)
{
unsigned char* pOutput = Output + (Y * WidthStep);
unsigned char* pInput = Input + (Y * WidthStep);
for (unsigned int X = 0; X < Width; X++)
{
pOutput[0] = 255 - pInput[0];
//下一个像素点
pInput += Channels;
pOutput += Channels;
}
}
}
else if (Channels == 3 || Channels == 4)
{
for (unsigned int Y = 0; Y < Height; Y++)
{
unsigned char* pOutput = Output + (Y * WidthStep);
unsigned char* pInput = Input + (Y * WidthStep);
for (unsigned int X = 0; X < Width; X++)
{
pOutput[0] = 255 - pInput[0];
pOutput[1] = 255 - pInput[1];
pOutput[2] = 255 - pInput[2];
//通道数为4时，不处理A通道反色(pOutput[3] = 255 - pInput[3];)
//下一个像素点
pInput += Channels;
pOutput += Channels;
}
}
}
}
//本人博客:http://tntmonks.cnblogs.com/转载请注明出处.
int main(int argc, char **argv) {
std::cout << "Image Processing " << std::endl;
std::cout << "Demo By Gaozhihan (build 2016-03-22)" << std::endl;
std::cout << "支持解析如下图片格式:" << std::endl;
std::cout << "JPG, PNG, TGA, BMP, PSD, GIF, HDR, PIC" << std::endl;
//检查参数是否正确
if (argc < 2)
{
std::cout << "参数错误。" << std::endl;
std::cout << "请拖放文件到可执行文件上，或使用命令行：imageProc.exe 图片" << std::endl;
std::cout << "例如: imageProc.exe d:image.jpg" << std::endl;
return 0;
}
std::string szfile = argv[1];
//检查输入的文件是否存在
if (_access(szfile.c_str(), 0) == -1)
{
std::cout << "输入的文件不存在，参数错误！" << std::endl;
}
getCurrentFilePath(szfile.c_str(), m_curFilePath);
int Width = 0; //图片宽度
int Height = 0; //图片高度
int Channels = 0; //图片通道数
unsigned char* inputImage = NULL; //输入图片指针
double nLoadTime = bench([&]{
//加载图片
loadImage(szfile.c_str(), inputImage, Width, Height, Channels);
});
std::cout << " 加载耗时: " << int(nLoadTime * 1000) << " 毫秒" << std::endl;
if ((Channels != 0) && (Width != 0) && (Height != 0))
{
//分配与载入同等内存用于处理后输出结果
unsigned char* outputImg = (unsigned char*)STBI_malloc(Width*Channels*Height*sizeof(unsigned char));
if (inputImage) {
//如果图片加载成功，则将内容复制给输出内存，方便处理
memcpy(outputImg, inputImage, Width*Channels*Height);
}
else {
std::cout << " 加载文件:
" << szfile.c_str() << " 失败!" << std::endl;
}
double nProcessTime = bench([&]{
//处理算法
processImage(inputImage, outputImg, Width, Height, Channels);
});
std::cout << " 处理耗时: " << int(nProcessTime * 1000) << " 毫秒" << std::endl;
//保存处理后的图片
double nSaveTime = bench([&]{
saveImage("_done.png", Width, Height, Channels, outputImg);
});
std::cout << " 保存耗时: " << int(nSaveTime * 1000) << " 毫秒" << std::endl;
//释放占用的内存
if (outputImg)
{
STBI_FREE(outputImg);
outputImg = NULL;
}
if (inputImage)
{
STBI_FREE(inputImage);
inputImage = NULL;
}
}
else
{
std::cout << " 加载文件:
" << szfile.c_str() << " 失败!" << std::endl;
}
getchar();
std::cout << "按任意键退出程序
" << std::endl;
return 0;
}实例2
#include <stdio.h>
#define STB_IMAGE_WRITE_IMPLEMENTATION
#include "stb_image_write.h"
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
int main(int argc, char** argv)
{
int w, h, n;
//rgba
//load image
unsigned char *data = stbi_load("rgba.png", &w, &h, &n, 0);
printf("%d, %d, %d\n", w, h, n);
//change pixel
//rgba,write 10 red pixel at line 11
for (int dx = 0; dx < 10; ++dx)
{
data[n * w * 10 + dx * n + 0] = 255;
data[n * w * 10 + dx * n + 1] = 0;
data[n * w * 10 + dx * n + 2] = 0;
data[n * w * 10 + dx * n + 3] = 255;
}
//write image
stbi_write_png("write.png", w, h, n, data, w * 4);
stbi_image_free(data);
return 0;
}ref
https://blog.csdn.net/lg1259156776/article/details/73385373
https://www.cnblogs.com/kileyi/p/8000199.html
文章最后发布于: 2018-07-01 22:56:36
相关阅读
作者：我有黑桃A来源：卢松松博客，欢迎分享。某种意义上，SEO 就是一场围绕关键词的竞技游戏。用户通过关键词寻找答案，搜索引擎根据关键
场景 使用Docker Registry提供的Insecure Registry方式，可以避开设定证书等一系列较为繁琐的操作，一般只需要在dockerd启动的op
A5创业网（公众号：iadmin5）6月7日报道，近日，有多家媒体报道称美国司法部正联合联邦贸易委员会等监管机构，正对包括苹果、谷歌、Facebook
生成密码库可以查询密码使用最多的字符串：思路：从文本文件中提取密码字符串，保存在链表中，链表有密码字段和密码出现次数的字段，当有新
SVN客户端使用——如何访问库文件本地选择一个空间足够大的存储盘，新建一个名为SVN_WORK 文件夹专门用来存放SVN文件，在SVN_WORK文