QtImageCompressionTest Uses http://code.google.com/p/libsquish/

mail.cpp

#include <QCoreApplication>

#include <QByteArray>
#include <QBuffer>
#include <QFile>
#include <QImage>
#include <QDebug>

#include <squish.h>


#include <iostream>

#if !defined(_WIN64) && !defined(_WIN32)
#  include <sys/time.h>
typedef timeval sys_time_t;
inline void system_time(sys_time_t* t) {
    gettimeofday(t, NULL);
}
inline long long time_to_msec(const sys_time_t& t) {
    return t.tv_sec * 1000LL + t.tv_usec / 1000;
}
#else
#  include <sys/timeb.h>
typedef _timeb sys_time_t;
inline void system_time(sys_time_t* t) { _ftime(t); }
inline long long time_to_msec(const sys_time_t& t) {
    return t.time * 1000LL + t.millitm;
}
#endif

#define PERF_INIT() sys_time_t t; long long startTimeMs; long long endTimeMs;

#define PERF_(x,file,line) system_time(&t); \
                startTimeMs = time_to_msec(t); \
                x; \
                system_time(&t); \
                endTimeMs = time_to_msec(t); \
                std::cout << "file:\t"<<file << "\tline:\t"<<line<< "\ttime:\t"<<(endTimeMs - startTimeMs)<<"\tms"<<std::endl;

#define PERF(x) PERF_(x,__FILE__,__LINE__);


QByteArray load_binary_resource(const std::string &qtResource){
    QFile file( qtResource.c_str());
    if (!file.open(QIODevice::ReadOnly)){
        qWarning() << "Cannot open file " << qtResource.c_str();
        exit( EXIT_FAILURE );
    }
    return file.readAll();
}


int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    static QImage img;
    QByteArray blockBuffer = load_binary_resource(":/ThrowBlurLarge.jpg");
    qDebug() << "length "<<blockBuffer.length();
    img.loadFromData((uchar *)blockBuffer.data(), blockBuffer.length(), "JPG");

    // modify the image
    img.setPixel(0,0,0x123);
    QByteArray ba;
    QBuffer buffer(&ba);
    buffer.open(QIODevice::WriteOnly);
    qDebug() << "Raw length "<<img.byteCount();
    PERF_INIT();
    PERF(img.save(&buffer, "jpg"));
    qDebug() << "JPEG Size "<<ba.length();
    ba.clear();

    PERF(img.save(&buffer, "png"));
    qDebug() << "PNG Size "<<ba.length();
    ba.clear();

    squish::u8 *pixels = (squish::u8*)img.bits();
    int storage = squish::GetStorageRequirements(img.width(),img.height(),squish::kDxt1 );
    squish::u8* blocks = new squish::u8[storage];
    PERF(squish::CompressImage( pixels,img.width(), img.height(), blocks, squish::kDxt1 | squish::kColourRangeFit));
    qDebug() << "DXT1 Size "<<(storage);
    ba.clear();

    // verify result
    squish::DecompressImage(pixels,img.width(), img.height(), blocks, squish::kDxt1 | squish::kColourRangeFit);
    img.save("tmp.png");

    return a.exec();
}

QtImageCompressionTest.pro

#-------------------------------------------------
#
# Project created by QtCreator 2013-07-08T13:26:39
#
#-------------------------------------------------

QT += core gui widgets opengl network

TARGET = QtImageCompressionTest
CONFIG   += console
CONFIG   -= app_bundle

LIBS += /Users/morten/Downloads/squish-1.11/libsquish.a

INCLUDEPATH += /Users/morten/Downloads/squish-1.11/

TEMPLATE = app

SOURCES += main.cpp

HEADERS += PerformanceTool.h

RESOURCES += \
    res.qrc