vgSeti(VG_RENDERING_QUALITY, VG_RENDERING_QUALITY_BETTER);
vgSeti(VG_IMAGE_QUALITY, VG_IMAGE_QUALITY_BETTER);

// create image and load external data
imgSrc = vgCreateImage(VG_sRGBA_8888, imgGirlAlphaWidth, imgGirlAlphaHeight, VG_IMAGE_QUALITY_NONANTIALIASED);
imgDst = vgCreateImage(VG_sRGBA_8888, imgGirlAlphaWidth, imgGirlAlphaHeight, VG_IMAGE_QUALITY_NONANTIALIASED);
vgImageSubData(imgSrc, (const void *)&imgGirlAlphaData[imgGirlAlphaWidth * (imgGirlAlphaHeight - 1)], -imgGirlAlphaDataStride, VG_sRGBA_8888, 0, 0, imgGirlAlphaWidth, imgGirlAlphaHeight);

vgSeti(VG_SCISSORING, VG_FALSE);
col[0] = 0.0f; col[1] = 0.0f; col[2] = 0.0f; col[3] = 0.0f;
vgSetfv(VG_CLEAR_COLOR, 4, col);
vgClear(0, 0, 256, 256);
vgSetPixels(0, 0, imgSrc, -128, -128, imgGirlAlphaWidth, imgGirlAlphaHeight);
vgSetPixels(0, 0, imgSrc, 128, 128, imgGirlAlphaWidth, imgGirlAlphaHeight);
vgSetPixels(-128, 128, imgSrc, 0, 0, imgGirlAlphaWidth, imgGirlAlphaHeight);
vgSetPixels(128, 0, imgSrc, 0, 128, imgGirlAlphaWidth, imgGirlAlphaHeight);
saveDrawingSurface(f, "drawing_surface_pixels00.png", "Test vgSetPixels, to write drawing surface pixels.", 0, 0, 256, 256);
eglSwapBuffers(display, surface);

// clear screen
col[0] = 1.0f; col[1] = 1.0f; col[2] = 1.0f; col[3] = 1.0f;
vgSetfv(VG_CLEAR_COLOR, 4, col);
vgClear(0, 0, 256, 256);

// set some scissor rectangle
scissorRects[0] =   0.0f;  scissorRects[1] = 128.0f;  scissorRects[2] = 128.0f;  scissorRects[3] = 128.0f;
scissorRects[4] = 128.0f;  scissorRects[5] =   0.0f;  scissorRects[6] = 128.0f;  scissorRects[7] = 128.0f;
vgSetfv(VG_SCISSOR_RECTS, 8, scissorRects);

// write two portions without scissoring
vgWritePixels((const void *)&imgGirlAlphaData[imgGirlAlphaWidth * (imgGirlAlphaHeight - 1)], -imgGirlAlphaDataStride, VG_sRGBA_8888, 128, 0, imgGirlAlphaWidth, imgGirlAlphaHeight);
vgWritePixels((const void *)&imgGirlAlphaData[imgGirlAlphaWidth * (imgGirlAlphaHeight - 1)], -imgGirlAlphaDataStride, VG_sRGBA_8888, -128, 0, imgGirlAlphaWidth, imgGirlAlphaHeight);
// enable scissoring
vgSeti(VG_SCISSORING, VG_TRUE);
vgWritePixels((const void *)&imgGirlAlphaData[imgGirlAlphaWidth * (imgGirlAlphaHeight - 1)], -imgGirlAlphaDataStride, VG_sRGBA_8888, 0, 128, imgGirlAlphaWidth, imgGirlAlphaHeight);
vgWritePixels((const void *)&imgGirlAlphaData[imgGirlAlphaWidth * (imgGirlAlphaHeight - 1)], -imgGirlAlphaDataStride, VG_sRGBA_8888, 0, -128, imgGirlAlphaWidth, imgGirlAlphaHeight);
saveDrawingSurface(f, "drawing_surface_pixels01.png", "Test vgWritePixels, to write drawing surface pixels.", 0, 0, 256, 256);
eglSwapBuffers(display, surface);

// reconstruct image using vgGetPixels
vgGetPixels(imgDst, -128, 0, -128, 128, imgGirlAlphaWidth, imgGirlAlphaHeight);
vgGetPixels(imgDst, -128, 128, 0, 128, imgGirlAlphaWidth, imgGirlAlphaHeight);
vgGetPixels(imgDst, 128, -128, 0, -128, imgGirlAlphaWidth, imgGirlAlphaHeight);
vgGetPixels(imgDst, 128, 0, 128, -128, imgGirlAlphaWidth, imgGirlAlphaHeight);
vgGetImageSubData(imgDst, (void *)&imgOutputDataRGBA[imgGirlAlphaWidth * (imgGirlAlphaHeight - 1)], -imgGirlAlphaDataStride, VG_sRGBA_8888, 0, 0, imgGirlAlphaWidth, imgGirlAlphaHeight);
saveImage32(f, "drawing_surface_pixels02.png", "Test vgGetPixels, to read drawing surface pixels.", imgGirlAlphaWidth, imgGirlAlphaHeight, imgOutputDataRGBA, 0);

// reconstruct image using vgReadPixels
memset(imgOutputDataRGBA, 0, imgGirlAlphaDataStride * imgGirlAlphaHeight);
vgReadPixels(&imgOutputDataRGBA[imgGirlAlphaWidth * (imgGirlAlphaHeight - 1)], -imgGirlAlphaDataStride, VG_sRGBA_8888, 0, 128, imgGirlAlphaWidth, imgGirlAlphaHeight);
vgReadPixels(&imgOutputDataRGBA[imgGirlAlphaWidth * 127], -imgGirlAlphaDataStride, VG_sRGBA_8888, 128, 128, imgGirlAlphaWidth, imgGirlAlphaHeight);
vgReadPixels(&imgOutputDataRGBA[imgGirlAlphaWidth * (imgGirlAlphaHeight - 1) + 128], -imgGirlAlphaDataStride, VG_sRGBA_8888, 0, 0, 128, 128);
vgReadPixels(&imgOutputDataRGBA[imgGirlAlphaWidth * 127 + 128], -imgGirlAlphaDataStride, VG_sRGBA_8888, 128, 0, 128, 128);
saveImage32(f, "drawing_surface_pixels03.png", "Test vgReadPixels, to read drawing surface pixels.", imgGirlAlphaWidth, imgGirlAlphaHeight, imgOutputDataRGBA, 0);
        
vgSeti(VG_SCISSORING, VG_FALSE);
vgCopyPixels(-64, -64, 64, 64, 128, 128);
vgCopyPixels(-64, 64, 64, 64, 128, 128);
vgCopyPixels(-64, 192, 64, 64, 128, 128);
vgCopyPixels(64, 192, 64, 64, 128, 128);
vgCopyPixels(192, 192, 64, 64, 128, 128);
vgCopyPixels(192, 64, 64, 64, 128, 128);
vgCopyPixels(192, -64, 64, 64, 128, 128);
vgCopyPixels(64, -64, 64, 64, 128, 128);
saveDrawingSurface(f, "drawing_surface_pixels04.png", "Test vgCopyPixels, to scramble drawing surface pixels.", 0, 0, 256, 256);
eglSwapBuffers(display, surface);

vgCopyPixels(0, 0, 64, 64, 192, 192);
saveDrawingSurface(f, "drawing_surface_pixels05.png", "Test vgCopyPixels, applied to overlapping regions.", 0, 0, 256, 256);
eglSwapBuffers(display, surface);

vgDestroyImage(imgSrc);
vgDestroyImage(imgDst);