Image.cpp

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#include "Image.h"
#include "PNGHelper.h"

bool Image::ReadPNG(const char* fileName)
{

    // store here image data
    int channels, bit_depth;
    int color_type = PNG_COLOR_TYPE_RGB;
    unsigned char* buffer = NULL;

    // read png file 
    read_png(fileName, buffer, resX, resY, channels, bit_depth, color_type, true);

    // check supported color types
    if (!(color_type == PNG_COLOR_TYPE_GRAY
        || color_type == PNG_COLOR_TYPE_RGB
        || color_type == PNG_COLOR_TYPE_RGBA))
    {
        std::cout << "Image::ReadPNG(" << fileName << "): not supported color type!" << endl;
        if (buffer) free(buffer);
        return false;
    }

    // currently only support 8 bit 
    if (bit_depth != 8)
    {
        std::cout << "Image::ReadPNG(" << fileName << "): not supported bit depth!" << endl;
        if (buffer) free(buffer);
        return false;
    }

    std::cout << "Read PNG File : " << fileName << std::endl;

    // check whenever we have gray scale png file 
    bool grey = color_type == PNG_COLOR_TYPE_GRAY;
    bool rgba = color_type == PNG_COLOR_TYPE_RGBA;

    // create pixel to store the data
    if (pixel) delete [] pixel;
    pixel = new ColorRGBA[resX * resY];

    // copy and convert pixel data
    for (int y=0; y < resY; y++)
        for (int x=0; x < resX; x++)
        {
            // convert values
            ColorRGBA v = ColorRGBA(float(buffer[(y * resX + x) * channels + (grey ? 0 : 0)]) / 255.0,
                            float(buffer[(y * resX + x) * channels + (grey ? 0 : 1)]) / 255.0,
                            float(buffer[(y * resX + x) * channels + (grey ? 0 : 2)]) / 255.0,
                            rgba ? float(buffer[(y * resX + x) * channels + (grey ? 0 : 3)]) / 255.0 : 1);
            // set pixel 
            setPixel(v, x, y);
        }

    // free up the used data 
    if (buffer) free (buffer);

    return true;        
}


void Image::WritePNG(const char* fileName)
{
    // store here image data
    int channels = 3;
    int bit_depth = 8;
    int color_type = PNG_COLOR_TYPE_RGB;

    // create pixel to store the data
    unsigned char* buffer = (unsigned char*)malloc(resX * resY * sizeof(unsigned char) * channels);

    // copy and convert pixel data
    for (int y=0; y < resY; y++)
        for (int x=0; x < resX; x++)
        {
            // get pixel 
            const ColorRGBA& p = getPixel(x,y);

            // convert values
            buffer[(y * resX + x) * channels + 0] = (unsigned char)(255.0 * p.red());
            buffer[(y * resX + x) * channels + 1] = (unsigned char)(255.0 * p.green());
            buffer[(y * resX + x) * channels + 2] = (unsigned char)(255.0 * p.blue());
        }

    // write file 
    write_png(fileName, buffer, resX, resY, channels, bit_depth, color_type, true);

    // free up the used data 
    if (buffer) free (buffer);
}

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