test_gray.cpp

// Description: Testing for lightness
// Documentation: color.txt

#include "test/test_init.h"

#include "pastel/sys/view.h"

#include "pastel/gfx/image_file.h"
#include "pastel/gfx/color.h"

namespace
{

    Color lumaColor(const Color& rgb)
    {
        return Color(luma(rgb));
    }

    Color lightness(const Color& rgb)
    {
        Color lab(xyzToLab(srgbToXyz(rgb)));
        lab[1] = 0;
        lab[2] = 0;
        return xyzToSrgb(labToXyz(lab));
    }

}

TEST_CASE("Gray (Gray)")
{
    Array<Color, 2> image;
    loadPcx("lena.pcx", image);

    Array<Color, 2> transformed(image.extent());

    transform(constArrayView(image),
        arrayView(transformed), lumaColor);

    savePcx(transformed, "gray_luma.pcx");

    transform(constArrayView(image),
        arrayView(transformed), lightness);

    savePcx(transformed, "gray_lightness.pcx");
}

TEST_CASE("LinearLuminance (LinearLuminance)")
{
    real Width = 400;
    real Height = 100;
    Array<Color, 2> image(Vector2i(Width, Height));

    real32 Step = 1 / Width;

    for (integer x = 0;x < Width;++x)
    {
        Color color(
            linearSrgbToSrgb(
            Color(Step * x)));
        for (integer y = 0;y < Height;++y)
        {
            image(x, y) = color;
        }
    }

    savePcx(image, "gray_linear_luminance.pcx");
}

TEST_CASE("LinearLuma (LinearLuma)")
{
    real Width = 400;
    real Height = 100;
    Array<Color, 2> image(Vector2i(Width, Height));

    real32 Step = 1 / Width;

    for (integer x = 0;x < Width;++x)
    {
        Color color(
            Color(Step * x));
        for (integer y = 0;y < Height;++y)
        {
            image(x, y) = color;
        }
    }

    savePcx(image, "gray_linear_luma.pcx");
}

TEST_CASE("LinearLightness (LinearLightness)")
{
    real Width = 400;
    real Height = 100;
    Array<Color, 2> image(Vector2i(Width, Height));

    real32 Step = 100 / Width;

    for (integer x = 0;x < Width;++x)
    {
        Color color(
            xyzToSrgb(labToXyz(Color(Step * x, 0, 0))));
        for (integer y = 0;y < Height;++y)
        {
            image(x, y) = color;
        }
    }

    savePcx(image, "gray_linear_lightness.pcx");
}