// create image and load external data
imgSrc = vgCreateImage(VG_lRGBA_8888, imgGirlAlphaWidth, imgGirlAlphaHeight, VG_IMAGE_QUALITY_NONANTIALIASED);
vgImageSubData(imgSrc, (const void *)imgGirlAlphaData, imgGirlAlphaDataStride, imgGirlAlphaFormat, 0, 0, imgGirlAlphaWidth, imgGirlAlphaHeight);
imgDst = vgCreateImage(VG_lRGBA_8888, imgGirlAlphaWidth, imgGirlAlphaHeight, VG_IMAGE_QUALITY_NONANTIALIASED);

// create a 3x3 kernel matrix
kernelX[0] = 1;  kernelX[1] = 1;  kernelX[2] = -1;
kernelY[0] = -2;  kernelY[1] = 2;  kernelY[2] = 2;

// set channel masks and a border color
vgSeti(VG_FILTER_CHANNEL_MASK, VG_RED | VG_GREEN | VG_BLUE | VG_ALPHA);

col[0] = 0.12f;
col[1] = 0.35f;
col[2] = 0.75f;
col[3] = 1.0f;
vgSetfv(VG_TILE_FILL_COLOR, 4, col);
vgSeti(VG_FILTER_FORMAT_LINEAR, VG_TRUE);
vgSeti(VG_FILTER_FORMAT_PREMULTIPLIED, VG_FALSE);

// basic centered convolve filter
vgSeparableConvolve(imgDst, imgSrc, 3, 3, 1, 1, kernelX, kernelY, 1.0f / 2.0f, 0.2f, VG_TILE_FILL);
vgGetImageSubData(imgDst, imgOutputDataRGBA, imgGirlAlphaDataStride, imgGirlAlphaFormat, 0, 0, imgGirlAlphaWidth, imgGirlAlphaHeight);
strcpy(imgFileName, "filter_separable_convolve.png");
saveImage32(f, imgFileName, "Basic centered separable convolve filter.", imgGirlAlphaWidth, imgGirlAlphaHeight, imgOutputDataRGBA, 0);

// decentered convolve filter, with tile fill
vgSeparableConvolve(imgDst, imgSrc, 3, 3, 128, -128, kernelX, kernelY, 1.0f / 2.0f, 0.2f, VG_TILE_FILL);
vgGetImageSubData(imgDst, imgOutputDataRGBA, imgGirlAlphaDataStride, imgGirlAlphaFormat, 0, 0, imgGirlAlphaWidth, imgGirlAlphaHeight);
strcpy(imgFileName, "filter_separable_convolve_fill.png");
saveImage32(f, imgFileName, "Decentered separable convolve filter, with tile fill.", imgGirlAlphaWidth, imgGirlAlphaHeight, imgOutputDataRGBA, 0);

// decentered convolve filter, with tile pad
vgSeparableConvolve(imgDst, imgSrc, 3, 3, 128, -128, kernelX, kernelY, 1.0f / 2.0f, 0.2f, VG_TILE_PAD);
vgGetImageSubData(imgDst, imgOutputDataRGBA, imgGirlAlphaDataStride, imgGirlAlphaFormat, 0, 0, imgGirlAlphaWidth, imgGirlAlphaHeight);
strcpy(imgFileName, "filter_separable_convolve_pad.png");
saveImage32(f, imgFileName, "Decentered separable convolve filter, with tile pad.", imgGirlAlphaWidth, imgGirlAlphaHeight, imgOutputDataRGBA, 0);

// decentered convolve filter, with tile repeat
vgSeparableConvolve(imgDst, imgSrc, 3, 3, 128, -128, kernelX, kernelY, 1.0f / 2.0f, 0.2f, VG_TILE_REPEAT);
vgGetImageSubData(imgDst, imgOutputDataRGBA, imgGirlAlphaDataStride, imgGirlAlphaFormat, 0, 0, imgGirlAlphaWidth, imgGirlAlphaHeight);
strcpy(imgFileName, "filter_separable_convolve_repeat.png");
saveImage32(f, imgFileName, "Decentered separable convolve filter, with tile repeat.", imgGirlAlphaWidth, imgGirlAlphaHeight, imgOutputDataRGBA, 0);

// decentered convolve filter, with tile reflect
vgSeparableConvolve(imgDst, imgSrc, 3, 3, 128, -128, kernelX, kernelY, 1.0f / 2.0f, 0.2f, VG_TILE_REFLECT);
vgGetImageSubData(imgDst, imgOutputDataRGBA, imgGirlAlphaDataStride, imgGirlAlphaFormat, 0, 0, imgGirlAlphaWidth, imgGirlAlphaHeight);
strcpy(imgFileName, "filter_separable_convolve_reflect.png");
saveImage32(f, imgFileName, "Decentered separable convolve filter, with tile reflect.", imgGirlAlphaWidth, imgGirlAlphaHeight, imgOutputDataRGBA, 0);

vgDestroyImage(imgSrc);
vgDestroyImage(imgDst);