/**
Extract the luminance channel L from a RGBF image.
Luminance is calculated from the sRGB model (RGB2XYZ matrix)
using a D65 white point :
L = ( 0.2126 * r ) + ( 0.7152 * g ) + ( 0.0722 * b )
Reference :
A Standard Default Color Space for the Internet - sRGB.
[online] http://www.w3.org/Graphics/Color/sRGB
*/
FIBITMAP*
ConvertRGBFToY(FIBITMAP *src) {
if(FreeImage_GetImageType(src) != FIT_RGBF)
return FALSE;
const unsigned width = FreeImage_GetWidth(src);
const unsigned height = FreeImage_GetHeight(src);
FIBITMAP *dst = FreeImage_AllocateT(FIT_FLOAT, width, height);
if(!dst) return NULL;
const unsigned src_pitch = FreeImage_GetPitch(src);
const unsigned dst_pitch = FreeImage_GetPitch(dst);
BYTE *src_bits = (BYTE*)FreeImage_GetBits(src);
BYTE *dst_bits = (BYTE*)FreeImage_GetBits(dst);
for(unsigned y = 0; y < height; y++) {
const FIRGBF *src_pixel = (FIRGBF*)src_bits;
float *dst_pixel = (float*)dst_bits;
for(unsigned x = 0; x < width; x++) {
const float L = LUMA_REC709(src_pixel[x].red, src_pixel[x].green, src_pixel[x].blue);
dst_pixel[x] = (L > 0) ? L : 0;
}
// next line
src_bits += src_pitch;
dst_bits += dst_pitch;
}
return dst;
}
FIBITMAP * DLL_CALLCONV
FreeImage_ConvertToFloat(FIBITMAP *dib) {
FIBITMAP *src = NULL;
FIBITMAP *dst = NULL;
if(!FreeImage_HasPixels(dib)) return NULL;
FREE_IMAGE_TYPE src_type = FreeImage_GetImageType(dib);
// check for allowed conversions
switch(src_type) {
case FIT_BITMAP:
{
// allow conversion from 8-bit
if((FreeImage_GetBPP(dib) == 8) && (FreeImage_GetColorType(dib) == FIC_MINISBLACK)) {
src = dib;
} else {
src = FreeImage_ConvertToGreyscale(dib);
if(!src) return NULL;
}
break;
}
case FIT_UINT16:
case FIT_RGB16:
case FIT_RGBA16:
case FIT_RGBF:
case FIT_RGBAF:
src = dib;
break;
case FIT_FLOAT:
// float type : clone the src
return FreeImage_Clone(dib);
default:
return NULL;
}
// allocate dst image
const unsigned width = FreeImage_GetWidth(src);
const unsigned height = FreeImage_GetHeight(src);
dst = FreeImage_AllocateT(FIT_FLOAT, width, height);
if(!dst) {
if(src != dib) {
FreeImage_Unload(src);
}
return NULL;
}
// copy metadata from src to dst
FreeImage_CloneMetadata(dst, src);
// convert from src type to float
const unsigned src_pitch = FreeImage_GetPitch(src);
const unsigned dst_pitch = FreeImage_GetPitch(dst);
const BYTE *src_bits = (BYTE*)FreeImage_GetBits(src);
BYTE *dst_bits = (BYTE*)FreeImage_GetBits(dst);
switch(src_type) {
case FIT_BITMAP:
{
for(unsigned y = 0; y < height; y++) {
const BYTE *src_pixel = (BYTE*)src_bits;
float *dst_pixel = (float*)dst_bits;
for(unsigned x = 0; x < width; x++) {
// convert and scale to the range [0..1]
dst_pixel[x] = (float)(src_pixel[x]) / 255;
}
src_bits += src_pitch;
dst_bits += dst_pitch;
}
}
break;
case FIT_UINT16:
{
for(unsigned y = 0; y < height; y++) {
const WORD *src_pixel = (WORD*)src_bits;
float *dst_pixel = (float*)dst_bits;
for(unsigned x = 0; x < width; x++) {
// convert and scale to the range [0..1]
dst_pixel[x] = (float)(src_pixel[x]) / 65535;
}
src_bits += src_pitch;
dst_bits += dst_pitch;
}
}
break;
case FIT_RGB16:
{
for(unsigned y = 0; y < height; y++) {
const FIRGB16 *src_pixel = (FIRGB16*)src_bits;
float *dst_pixel = (float*)dst_bits;
for(unsigned x = 0; x < width; x++) {
// convert and scale to the range [0..1]
dst_pixel[x] = LUMA_REC709(src_pixel[x].red, src_pixel[x].green, src_pixel[x].blue) / 65535.0F;
}
src_bits += src_pitch;
dst_bits += dst_pitch;
}
}
break;
case FIT_RGBA16:
{
for(unsigned y = 0; y < height; y++) {
const FIRGBA16 *src_pixel = (FIRGBA16*)src_bits;
float *dst_pixel = (float*)dst_bits;
for(unsigned x = 0; x < width; x++) {
// convert and scale to the range [0..1]
dst_pixel[x] = LUMA_REC709(src_pixel[x].red, src_pixel[x].green, src_pixel[x].blue) / 65535.0F;
}
src_bits += src_pitch;
dst_bits += dst_pitch;
}
}
break;
case FIT_RGBF:
{
for(unsigned y = 0; y < height; y++) {
const FIRGBF *src_pixel = (FIRGBF*)src_bits;
float *dst_pixel = (float*)dst_bits;
for(unsigned x = 0; x < width; x++) {
// convert (assume pixel values are in the range [0..1])
dst_pixel[x] = LUMA_REC709(src_pixel[x].red, src_pixel[x].green, src_pixel[x].blue);
}
src_bits += src_pitch;
dst_bits += dst_pitch;
}
}
break;
case FIT_RGBAF:
{
for(unsigned y = 0; y < height; y++) {
const FIRGBAF *src_pixel = (FIRGBAF*)src_bits;
float *dst_pixel = (float*)dst_bits;
for(unsigned x = 0; x < width; x++) {
// convert (assume pixel values are in the range [0..1])
dst_pixel[x] = LUMA_REC709(src_pixel[x].red, src_pixel[x].green, src_pixel[x].blue);
}
src_bits += src_pitch;
dst_bits += dst_pitch;
}
}
break;
}
if(src != dib) {
FreeImage_Unload(src);
}
return dst;
}
FIBITMAP * DLL_CALLCONV
FreeImage_ConvertToUINT16(FIBITMAP *dib) {
FIBITMAP *src = NULL;
FIBITMAP *dst = NULL;
if(!FreeImage_HasPixels(dib)) return NULL;
const FREE_IMAGE_TYPE src_type = FreeImage_GetImageType(dib);
// check for allowed conversions
switch(src_type) {
case FIT_BITMAP:
{
// convert to greyscale if needed
if((FreeImage_GetBPP(dib) == 8) && (FreeImage_GetColorType(dib) == FIC_MINISBLACK)) {
src = dib;
} else {
src = FreeImage_ConvertToGreyscale(dib);
if(!src) return NULL;
}
break;
}
case FIT_UINT16:
// UINT16 type : clone the src
return FreeImage_Clone(dib);
break;
case FIT_RGB16:
// allow conversion from 48-bit RGB
src = dib;
break;
case FIT_RGBA16:
// allow conversion from 64-bit RGBA (ignore the alpha channel)
src = dib;
break;
default:
return NULL;
}
// allocate dst image
const unsigned width = FreeImage_GetWidth(src);
const unsigned height = FreeImage_GetHeight(src);
dst = FreeImage_AllocateT(FIT_UINT16, width, height);
if(!dst) return NULL;
// copy metadata from src to dst
FreeImage_CloneMetadata(dst, src);
// convert from src type to UINT16
switch(src_type) {
case FIT_BITMAP:
{
for(unsigned y = 0; y < height; y++) {
const BYTE *src_bits = (BYTE*)FreeImage_GetScanLine(src, y);
WORD *dst_bits = (WORD*)FreeImage_GetScanLine(dst, y);
for(unsigned x = 0; x < width; x++) {
dst_bits[x] = src_bits[x] << 8;
}
}
}
break;
case FIT_RGB16:
{
for(unsigned y = 0; y < height; y++) {
const FIRGB16 *src_bits = (FIRGB16*)FreeImage_GetScanLine(src, y);
WORD *dst_bits = (WORD*)FreeImage_GetScanLine(dst, y);
for(unsigned x = 0; x < width; x++) {
// convert to grey
dst_bits[x] = (WORD)LUMA_REC709(src_bits[x].red, src_bits[x].green, src_bits[x].blue);
}
}
}
break;
case FIT_RGBA16:
{
for(unsigned y = 0; y < height; y++) {
const FIRGBA16 *src_bits = (FIRGBA16*)FreeImage_GetScanLine(src, y);
WORD *dst_bits = (WORD*)FreeImage_GetScanLine(dst, y);
for(unsigned x = 0; x < width; x++) {
// convert to grey
dst_bits[x] = (WORD)LUMA_REC709(src_bits[x].red, src_bits[x].green, src_bits[x].blue);
}
}
}
break;
default:
break;
}
if(src != dib) {
FreeImage_Unload(src);
}
return dst;
}
